1 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V3.1//EN" [
2 <!entity % dummy "IGNORE">
3 <!entity supported SYSTEM "supported.sgml">
4 <!entity newfeatures SYSTEM "newfeatures.sgml">
5 <!entity p-intro SYSTEM "privoxy.sgml">
6 <!entity seealso SYSTEM "seealso.sgml">
7 <!entity buildsource SYSTEM "buildsource.sgml">
8 <!entity contacting SYSTEM "contacting.sgml">
9 <!entity history SYSTEM "history.sgml">
10 <!entity copyright SYSTEM "copyright.sgml">
11 <!entity license SYSTEM "license.sgml">
12 <!entity p-authors SYSTEM "p-authors.sgml">
13 <!entity config SYSTEM "p-config.sgml">
14 <!entity p-version "3.0.20">
15 <!entity p-status "beta">
16 <!entity % p-authors-formal "INCLUDE"> <!-- include additional text, etc -->
17 <!entity % p-not-stable "INCLUDE">
18 <!entity % p-stable "IGNORE">
19 <!entity % p-text "IGNORE"> <!-- define we are not a text only doc -->
20 <!entity % p-doc "INCLUDE"> <!-- and we are a formal doc -->
21 <!entity % p-readme "IGNORE">
22 <!entity % user-man "IGNORE">
23 <!entity % config-file "IGNORE">
24 <!entity % p-supp-userman "IGNORE"> <!-- Omit some from supported.sgml -->
25 <!entity my-copy "©"> <!-- kludge for docbook2man -->
26 <!entity % draft "IGNORE"> <!-- WIP stuff -->
27 <!entity % seealso-extra "INCLUDE"> <!-- extra stuff from seealso.sgml -->
28 <!entity my-app "<application>Privoxy</application>">
31 File : $Source: /cvsroot/ijbswa/current/doc/source/user-manual.sgml,v $
34 This file belongs into
35 ijbswa.sourceforge.net:/home/groups/i/ij/ijbswa/htdocs/
37 $Id: user-manual.sgml,v 2.159 2013/01/09 15:03:06 fabiankeil Exp $
39 Copyright (C) 2001-2013 Privoxy Developers http://www.privoxy.org/
42 ========================================================================
43 NOTE: Please read developer-manual/documentation.html before touching
44 anything in this, or other Privoxy documentation.
45 ========================================================================
52 <title>Privoxy &p-version; User Manual</title>
56 <!-- Completely the wrong markup, but very little is allowed -->
57 <!-- in this part of an article. FIXME -->
58 <link linkend="copyright">Copyright</link> &my-copy; 2001-2013 by
59 <ulink url="http://www.privoxy.org/">Privoxy Developers</ulink>
63 <pubdate>$Id: user-manual.sgml,v 2.159 2013/01/09 15:03:06 fabiankeil Exp $</pubdate>
67 Note: the following should generate a separate page, and a live link to it,
68 all nicely done. But it doesn't for some mysterious reason. Please leave
69 commented unless it can be fixed proper. For the time being, the
70 copyright/license declarations will be in their own sgml.
83 This is here to keep vim syntax file from breaking :/
84 If I knew enough to fix it, I would.
85 PLEASE DO NOT REMOVE! HB: hal@foobox.net
91 The <citetitle>Privoxy User Manual</citetitle> gives users information on how to
92 install, configure and use <ulink
93 url="http://www.privoxy.org/">Privoxy</ulink>.
96 <!-- Include privoxy.sgml boilerplate: -->
98 <!-- end privoxy.sgml -->
101 You can find the latest version of the <citetitle>Privoxy User Manual</citetitle> at <ulink
102 url="http://www.privoxy.org/user-manual/">http://www.privoxy.org/user-manual/</ulink>.
103 Please see the <link linkend="contact">Contact section</link> on how to
104 contact the developers.
108 <!-- Feel free to send a note to the developers at <email>ijbswa-developers@lists.sourceforge.net</email>. -->
114 <!-- ~~~~~ New section ~~~~~ -->
115 <sect1 label="1" id="introduction"><title>Introduction</title>
117 This documentation is included with the current &p-status; version of
118 <application>Privoxy</application>, v.&p-version;<![%p-not-stable;[,
119 and is mostly complete at this point. The most up to date reference for the
120 time being is still the comments in the source files and in the individual
121 configuration files. Development of a new version is currently nearing
122 completion, and includes significant changes and enhancements over
126 <!-- include only in non-stable versions -->
129 Since this is a &p-status; version, not all new features are well tested. This
130 documentation may be slightly out of sync as a result (especially with
131 CVS sources). And there <emphasis>may be</emphasis> bugs, though hopefully
136 <!-- ~~~~~ New section ~~~~~ -->
137 <sect2 id="features"><title>Features</title>
139 In addition to the core
140 features of ad blocking and
141 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookie</ulink> management,
142 <application>Privoxy</application> provides many supplemental
143 features<![%p-not-stable;[, some of them currently under development]]>,
144 that give the end-user more control, more privacy and more freedom:
146 <!-- Include newfeatures.sgml boilerplate here: -->
148 <!-- end boilerplate -->
153 <!-- ~ End section ~ -->
156 <!-- ~~~~~ New section ~~~~~ -->
157 <sect1 id="installation"><title>Installation</title>
160 <application>Privoxy</application> is available both in convenient pre-compiled
161 packages for a wide range of operating systems, and as raw source code.
162 For most users, we recommend using the packages, which can be downloaded from our
163 <ulink url="http://sourceforge.net/projects/ijbswa/">Privoxy Project
169 On some platforms, the installer may remove previously installed versions, if
170 found. (See below for your platform). In any case <emphasis>be sure to backup
171 your old configuration if it is valuable to you.</emphasis> See the <link
172 linkend="upgradersnote">note to upgraders</link> section below.
175 <!-- ~~~~~ New section ~~~~~ -->
176 <sect2 id="installation-packages"><title>Binary Packages</title>
178 How to install the binary packages depends on your operating system:
181 <!-- XXX: The installation sections should be sorted -->
183 <!-- ~~~~~ New section ~~~~~ -->
184 <sect3 id="installation-pack-rpm"><title>Red Hat and Fedora RPMs</title>
187 RPMs can be installed with <literal>rpm -Uvh privoxy-&p-version;-1.rpm</literal>,
188 and will use <filename>/etc/privoxy</filename> for the location
189 of configuration files.
193 Note that on Red Hat, <application>Privoxy</application> will
194 <emphasis>not</emphasis> be automatically started on system boot. You will
195 need to enable that using <command>chkconfig</command>,
196 <command>ntsysv</command>, or similar methods.
200 If you have problems with failed dependencies, try rebuilding the SRC RPM:
201 <literal>rpm --rebuild privoxy-&p-version;-1.src.rpm</literal>. This
202 will use your locally installed libraries and RPM version.
206 Also note that if you have a <application>Junkbuster</application> RPM installed
207 on your system, you need to remove it first, because the packages conflict.
208 Otherwise, RPM will try to remove <application>Junkbuster</application>
209 automatically if found, before installing <application>Privoxy</application>.
213 <!-- ~~~~~ New section ~~~~~ -->
214 <sect3 id="installation-deb"><title>Debian and Ubuntu</title>
216 DEBs can be installed with <literal>apt-get install privoxy</literal>,
217 and will use <filename>/etc/privoxy</filename> for the location of
222 <!-- ~~~~~ New section ~~~~~ -->
223 <sect3 id="installation-pack-win"><title>Windows</title>
226 Just double-click the installer, which will guide you through
227 the installation process. You will find the configuration files
228 in the same directory as you installed <application>Privoxy</application> in.
231 Version 3.0.5 beta introduced full <application>Windows</application> service
232 functionality. On Windows only, the <application>Privoxy</application>
233 program has two new command line arguments to install and uninstall
234 <application>Privoxy</application> as a <emphasis>service</emphasis>.
238 <term>Arguments:</term>
241 <replaceable class="parameter">--install</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
244 <replaceable class="parameter">--uninstall</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
250 After invoking <application>Privoxy</application> with
251 <command>--install</command>, you will need to bring up the
252 <application>Windows</application> service console to assign the user you
253 want <application>Privoxy</application> to run under, and whether or not you
254 want it to run whenever the system starts. You can start the
255 <application>Windows</application> services console with the following
256 command: <command>services.msc</command>. If you do not take the manual step
257 of modifying <application>Privoxy's</application> service settings, it will
258 not start. Note too that you will need to give Privoxy a user account that
259 actually exists, or it will not be permitted to
260 write to its log and configuration files.
265 <!-- ~~~~~ New section ~~~~~ -->
266 <sect3 id="installation-pack-bintgz"><title>Solaris <!--, NetBSD, HP-UX--></title>
269 Create a new directory, <literal>cd</literal> to it, then unzip and
270 untar the archive. For the most part, you'll have to figure out where
271 things go. <!-- FIXME, more info needed? -->
275 <!-- ~~~~~ New section ~~~~~ -->
276 <sect3 id="installation-os2"><title>OS/2</title>
279 First, make sure that no previous installations of
280 <application>Junkbuster</application> and / or
281 <application>Privoxy</application> are left on your
282 system. Check that no <application>Junkbuster</application>
283 or <application>Privoxy</application> objects are in
289 Then, just double-click the WarpIN self-installing archive, which will
290 guide you through the installation process. A shadow of the
291 <application>Privoxy</application> executable will be placed in your
292 startup folder so it will start automatically whenever OS/2 starts.
296 The directory you choose to install <application>Privoxy</application>
297 into will contain all of the configuration files.
301 <!-- ~~~~~ New section ~~~~~ -->
302 <sect3 id="installation-mac"><title>Mac OS X</title>
304 Installation instructions for the OS X platform depend upon whether
305 you downloaded a ready-built installation package (.pkg or .mpkg) or have
306 downloaded the source code.
309 <sect3 renderas="sect4" id="OS-X-install-from-package">
310 <title>Installation from ready-built package</title>
312 The downloaded file will either be a .pkg (for OS X 10.5 upwards) or a bzipped
313 .mpkg file (for OS X 10.4). The former can be double-clicked as is and the
314 installation will start; double-clicking the latter will unzip the .mpkg file
315 which can then be double-clicked to commence the installation.
318 The privoxy service will automatically start after a successful installation
319 (and thereafter every time your computer starts up) however you will need to
320 configure your web browser(s) to use it. To do so, configure them to use a
321 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
324 To prevent the privoxy service from automatically starting when your computer
325 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
326 (on OS X 10.5 and higher) or the folder named
327 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
330 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
331 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
332 administrator account, using sudo.
335 To uninstall, run /Applications/Privoxy/uninstall.command as sudo from an
336 administrator account.
339 <sect3 renderas="sect4" id="OS-X-install-from-source">
340 <title>Installation from source</title>
342 To build and install the Privoxy source code on OS X you will need to obtain
343 the macsetup module from the Privoxy Sourceforge CVS repository (refer to
344 Sourceforge help for details of how to set up a CVS client to have read-only
345 access to the repository). This module contains scripts that leverage the usual
346 open-source tools (available as part of Apple's free of charge Xcode
347 distribution or via the usual open-source software package managers for OS X
348 (MacPorts, Homebrew, Fink etc.) to build and then install the privoxy binary
349 and associated files. The macsetup module's README file contains complete
350 instructions for its use.
353 The privoxy service will automatically start after a successful installation
354 (and thereafter every time your computer starts up) however you will need to
355 configure your web browser(s) to use it. To do so, configure them to use a
356 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
359 To prevent the privoxy service from automatically starting when your computer
360 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
361 (on OS X 10.5 and higher) or the folder named
362 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
365 To manually start or stop the privoxy service, use the Privoxy Utility
366 for Mac OS X (also part of the macsetup module). This application can start
367 and stop the privoxy service and display its log and configuration files.
370 To uninstall, run the macsetup module's uninstall.sh as sudo from an
371 administrator account.
375 <!-- ~~~~~ New section ~~~~~ -->
376 <sect3 id="installation-amiga"><title>AmigaOS</title>
378 Copy and then unpack the <filename>lha</filename> archive to a suitable location.
379 All necessary files will be installed into <application>Privoxy</application>
380 directory, including all configuration and log files. To uninstall, just
381 remove this directory.
385 <!-- ~~~~~ New section ~~~~~ -->
386 <sect3 id="installation-tbz"><title>FreeBSD</title>
389 Privoxy is part of FreeBSD's Ports Collection, you can build and install
390 it with <literal>cd /usr/ports/www/privoxy; make install clean</literal>.
393 If you don't use the ports, you can fetch and install
394 the package with <literal>pkg_add -r privoxy</literal>.
397 The port skeleton and the package can also be downloaded from the
398 <ulink url="https://sourceforge.net/project/showfiles.php?group_id=11118">File Release
399 Page</ulink>, but there's no reason to use them unless you're interested in the
400 beta releases which are only available there.
404 <!-- ~~~~~ New section ~~~~~ -->
405 <sect3 id="installattion-gentoo"><title>Gentoo</title>
407 Gentoo source packages (Ebuilds) for <application>Privoxy</application> are
408 contained in the Gentoo Portage Tree (they are not on the download page,
409 but there is a Gentoo section, where you can see when a new
410 <application>Privoxy</application> Version is added to the Portage Tree).
413 Before installing <application>Privoxy</application> under Gentoo just do
414 first <literal>emerge --sync</literal> to get the latest changes from the
415 Portage tree. With <literal>emerge privoxy</literal> you install the latest
419 Configuration files are in <filename>/etc/privoxy</filename>, the
420 documentation is in <filename>/usr/share/doc/privoxy-&p-version;</filename>
421 and the Log directory is in <filename>/var/log/privoxy</filename>.
427 <!-- ~~~~~ New section ~~~~~ -->
428 <sect2 id="installation-source"><title>Building from Source</title>
431 The most convenient way to obtain the <application>Privoxy</application> sources
432 is to download the source tarball from our
433 <ulink url="http://sourceforge.net/project/showfiles.php?group_id=11118&package_id=10571">project download
438 If you like to live on the bleeding edge and are not afraid of using
439 possibly unstable development versions, you can check out the up-to-the-minute
440 version directly from <ulink url="http://sourceforge.net/cvs/?group_id=11118">the
441 CVS repository</ulink>.
443 deprecated...out of business.
444 or simply download <ulink
445 url="http://cvs.sourceforge.net/cvstarballs/ijbswa-cvsroot.tar.bz2">the nightly CVS
450 <!-- include buildsource.sgml boilerplate: -->
452 <!-- end boilerplate -->
455 <!-- ~~~~~ New section ~~~~~ -->
456 <sect2 id="installation-keepupdated"><title>Keeping your Installation Up-to-Date</title>
459 If you wish to receive an email notification whenever we release updates of
460 <application>Privoxy</application> or the actions file, <ulink
461 url="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce/">subscribe
462 to our announce mailing list</ulink>, ijbswa-announce@lists.sourceforge.net.
466 In order not to lose your personal changes and adjustments when updating
467 to the latest <literal>default.action</literal> file we <emphasis>strongly
468 recommend</emphasis> that you use <literal>user.action</literal> and
469 <literal>user.filter</literal> for your local
470 customizations of <application>Privoxy</application>. See the <link
471 linkend="actions-file">Chapter on actions files</link> for details.
479 <!-- ~ End section ~ -->
481 <!-- ~~~~~ New section ~~~~~ -->
482 <sect1 id="whatsnew">
483 <title>What's New in this Release</title>
485 <application>Privoxy 3.0.19</application> is a stable release.
486 The changes since 3.0.18 stable are:
497 Prevent a segmentation fault when de-chunking buffered content.
498 It could be triggered by malicious web servers if Privoxy was
499 configured to filter the content and running on a platform
500 where SIZE_T_MAX isn't larger than UINT_MAX, which probably
501 includes most 32-bit systems. On those platforms, all Privoxy
502 versions before 3.0.19 appear to be affected.
503 To be on the safe side, this bug should be presumed to allow
504 code execution as proving that it doesn't seems unrealistic.
509 Do not expect a response from the SOCKS4/4A server until it
510 got something to respond to. This regression was introduced
511 in 3.0.18 and prevented the SOCKS4/4A negotiation from working.
512 Reported by qqqqqw in #3459781.
520 General improvements:
524 Fix an off-by-one in an error message about connect failures.
529 Use a GNUMakefile variable for the webserver root directory and
530 update the path. Sourceforge changed it which broke various
536 Update the CODE_STATUS description.
546 The following changes were made between 3.0.17 and 3.0.18:
557 If a generated redirect URL contains characters RFC 3986 doesn't
558 permit, they are (re)encoded. Not doing this makes Privoxy versions
559 from 3.0.5 to 3.0.17 susceptible to HTTP response splitting (CWE-113)
560 attacks if the +fast-redirects{check-decoded-url} action is used.
565 Fix a logic bug that could cause Privoxy to reuse a server
566 socket after it got tainted by a server-header-tagger-induced
567 block that was triggered before the whole server response had
568 been read. If keep-alive was enabled and the request following
569 the blocked one was to the same host and using the same forwarding
570 settings, Privoxy would send it on the tainted server socket.
571 While the server would simply treat it as a pipelined request,
572 Privoxy would later on fail to properly parse the server's
573 response as it would try to parse the unread data from the
574 first response as server headers for the second one.
575 Regression introduced in 3.0.17.
580 When implying keep-alive in client_connection(), remember that
581 the client didn't. Fixes a regression introduced in 3.0.13 that
582 would cause Privoxy to wait for additional client requests after
583 receiving a HTTP/1.1 request with "Connection: close" set
584 and connection sharing enabled.
585 With clients which terminates the client connection after detecting
586 that the whole body has been received it doesn't really matter,
587 but with clients that don't the connection would be kept open until
593 Fix a subtle race condition between prepare_csp_for_next_request()
594 and sweep(). A thread preparing itself for the next client request
595 could briefly appear to be inactive.
596 If all other threads were already using more recent files,
597 the thread could get its files swept away under its feet.
598 So far this has only been reproduced while stress testing in
599 valgrind while touching action files in a loop. It's unlikely
600 to have caused any actual problems in the real world.
605 Disable filters if SDCH compression is used unless filtering is forced.
606 If SDCH was combined with a supported compression algorithm, Privoxy
607 previously could try to decompress it and ditch the Content-Encoding
608 header even though the SDCH compression wasn't dealt with.
609 Reported by zebul666 in #3225863.
614 Make a copy of the --user value and only mess with that when splitting
615 user and group. On some operating systems modifying the value directly
616 is reflected in the output of ps and friends and can be misleading.
617 Reported by zepard in #3292710.
622 If forwarded-connect-retries is set, only retry if Privoxy is actually
623 forwarding the request. Previously direct connections would be retried
629 Fixed a small memory leak when retrying connections with IPv6
635 Remove an incorrect assertion in compile_dynamic_pcrs_job_list()
636 It could be triggered by a pcrs job with an invalid pcre
637 pattern (for example one that contains a lone quantifier).
642 If the --user argument user[.group] contains a dot, always bail out
643 if no group has been specified. Previously the intended, but undocumented
644 (and apparently untested), behaviour was to try interpreting the whole
645 argument as user name, but the detection was flawed and checked for '0'
646 instead of '\0', thus merely preventing group names beginning with a zero.
651 In html_code_map[], use a numeric character reference instead of '
652 which wasn't standardized before XHTML 1.0.
657 Fix an invalid free when compiled with FEATURE_GRACEFUL_TERMINATION
658 and shut down through http://config.privoxy.org/die
663 In get_actions(), fix the "temporary" backwards compatibility hack
664 to accept block actions without reason.
665 It also covered other actions that should be rejected as invalid.
666 Reported by Billy Crook.
674 General improvements:
678 Privoxy can (re)compress buffered content before delivering
679 it to the client. Disabled by default as most users wouldn't
685 The +fast-redirects{check-decoded-url} action checks URL
686 segments separately. If there are other parameters behind
687 the redirect URL, this makes it unnecessary to cut them off
688 by additionally using a +redirect{} pcrs command.
689 Initial patch submitted by Jamie Zawinski in #3429848.
694 When loading action sections, verify that the referenced filters
695 exist. Currently missing filters only result in an error message,
696 but eventually the severity will be upgraded to fatal.
701 Allow to bind to multiple separate addresses.
702 Patch set submitted by Petr Pisar in #3354485.
707 Set socket_error to errno if connecting fails in rfc2553_connect_to().
708 Previously rejected direct connections could be incorrectly reported
709 as DNS issues if Privoxy was compiled with IPv6 support.
714 Adjust url_code_map[] so spaces are replaced with %20 instead of '+'
715 While '+' can be used by client's submitting form data, this is not
716 actually what Privoxy is using the lookups for. This is more of a
717 cosmetic issue and doesn't fix any known problems.
722 When compiled without FEATURE_FAST_REDIRECTS, do not silently
723 ignore +fast-redirect{} directives
728 Added a workaround for GNU libc's strptime() reporting negative
729 year values when the parsed year is only specified with two digits.
730 On affected systems cookies with such a date would not be turned
731 into session cookies by the +session-cookies-only action.
732 Reported by Vaeinoe in #3403560
737 Fixed bind failures with certain GNU libc versions if no non-loopback
738 IP address has been configured on the system. This is mainly an issue
739 if the system is using DHCP and Privoxy is started before the network
740 is completely configured.
741 Reported by Raphael Marichez in #3349356.
742 Additional insight from Petr Pisar.
747 Privoxy log messages now use the ISO 8601 date format %Y-%m-%d.
748 It's only slightly longer than the old format, but contains
749 the full date including the year and allows sorting by date
750 (when grepping in multiple log files) without hassle.
755 In get_last_url(), do not bother trying to decode URLs that do
756 not contain at least one '%' sign. It reduces the log noise and
757 a number of unnecessary memory allocations.
762 In case of SOCKS5 failures, dump the socks response in the log message.
767 Simplify the signal setup in main().
772 Streamline socks5_connect() slightly.
777 In socks5_connect(), require a complete socks response from the server.
778 Previously Privoxy didn't care how much data the server response
779 contained as long as the first two bytes contained the expected
780 values. While at it, shrink the buffer size so Privoxy can't read
781 more than a whole socks response.
786 In chat(), do not bother to generate a client request in case of
787 direct CONNECT requests. It will not be used anyway.
792 Reduce server_last_modified()'s stack size.
797 Shorten get_http_time() by using strftime().
802 Constify the known_http_methods pointers in unknown_method().
807 Constify the time_formats pointers in parse_header_time().
812 Constify the formerly_valid_actions pointers in action_used_to_be_valid().
817 Introduce a GNUMakefile MAN_PAGE variable that defaults to privoxy.1.
818 The Debian package uses section 8 for the man page and this
819 should simplify the patch.
824 Deduplicate the INADDR_NONE definition for Solaris by moving it to jbsockets.h
829 In block_url(), ditch the obsolete workaround for ancient Netscape versions
830 that supposedly couldn't properly deal with status code 403.
835 Remove a useless NULL pointer check in load_trustfile().
840 Remove two useless NULL pointer checks in load_one_re_filterfile().
845 Change url_code_map[] from an array of pointers to an array of arrays
846 It removes an unnecessary layer of indirection and on 64bit system reduces
847 the size of the binary a bit.
852 Fix various typos. Fixes taken from Debian's 29_typos.dpatch by Roland Rosenfeld.
857 Add a dok-tidy GNUMakefile target to clean up the messy HTML
858 generated by the other dok targets.
863 GNUisms in the GNUMakefile have been removed.
868 Change the HTTP version in static responses to 1.1
873 Synced config.sub and config.guess with upstream
874 2011-11-11/386c7218162c145f5f9e1ff7f558a3fbb66c37c5.
879 Add a dedicated function to parse the values of toggles. Reduces duplicated
880 code in load_config() and provides better error handling. Invalid or missing
881 toggle values are now a fatal error instead of being silently ignored.
886 Terminate HTML lines in static error messages with \n instead of \r\n.
891 Simplify cgi_error_unknown() a bit.
896 In LogPutString(), don't bother looking at pszText when not
897 actually logging anything.
902 Change ssplit()'s fourth parameter from int to size_t.
903 Fixes a clang complaint.
908 Add a warning that the statistics currently can't be trusted.
909 Mention Privoxy-Log-Parser's --statistics option as
910 an alternative for the time being.
915 In rfc2553_connect_to(), start setting cgi->error_message on error.
920 Change the expected status code returned for http://p.p/die depending
921 on whether or not FEATURE_GRACEFUL_TERMINATION is available.
926 In cgi_die(), mark the client connection for closing.
927 If the client will fetch the style sheet through another connection
928 it gets the main thread out of the accept() state and should thus
929 trigger the actual shutdown.
934 Add a proper CGI message for cgi_die().
939 Don't enforce a logical line length limit in read_config_line().
944 Slightly refactor server_last_modified() to remove useless gmtime*() calls.
949 In get_content_type(), also recognize '.jpeg' as JPEG extension.
954 Add '.png' to the list of recognized file extensions in get_content_type().
959 In block_url(), consistently use the block reason "Request blocked by Privoxy"
960 In two places the reason was "Request for blocked URL" which hides the
961 fact that the request got blocked by Privoxy and isn't necessarily
962 correct as the block may be due to tags.
967 In listen_loop(), reload the configuration files after accepting
968 a new connection instead of before.
969 Previously the first connection that arrived after a configuration
970 change would still be handled with the old configuration.
975 In chat()'s receive-data loop, skip a client socket check if
976 the socket will be written to right away anyway. This can
977 increase the transfer speed for unfiltered content on fast
983 The socket timeout is used for SOCKS negotiations as well which
984 previously couldn't timeout.
989 Don't keep the client connection alive if any configuration file
990 changed since the time the connection came in. This is closer to
991 Privoxy's behaviour before keep-alive support for client connection
992 has been added and also less confusing in general.
997 Treat all Content-Type header values containing the pattern
998 'script' as a sign of text. Reported by pribog in #3134970.
1006 Action file improvements:
1010 Moved the site-specific block pattern section below the one for the
1011 generic patterns so for requests that are matched in both, the block
1012 reason for the domain is shown which is usually more useful than showing
1013 the one for the generic pattern.
1018 Remove -prevent-compression from the fragile alias. It's no longer
1019 used anywhere by default and isn't known to break stuff anyway.
1024 Add a (disabled) section to block various Facebook tracking URLs.
1025 Reported by Dan Stahlke in #3421764.
1030 Add a (disabled) section to rewrite and redirect click-tracking
1031 URLs used on news.google.com.
1032 Reported by Dan Stahlke in #3421755.
1037 Unblock linuxcounter.net/.
1038 Reported by Dan Stahlke in #3422612.
1043 Block 'www91.intel.com/' which is used by Omniture.
1044 Reported by Adam Piggott in #3167370.
1049 Disable the handle-as-empty-doc-returns-ok option and mark it as deprecated.
1050 Reminded by tceverling in #2790091.
1055 Add ".ivwbox.de/" to the "Cross-site user tracking" section.
1056 Reported by Nettozahler in #3172525.
1061 Unblock and fast-redirect ".awin1.com/.*=http://".
1062 Reported by Adam Piggott in #3170921.
1067 Block "b.collective-media.net/".
1072 Widen the Debian popcon exception to "qa.debian.org/popcon".
1073 Seen in Debian's 05_default_action.dpatch by Roland Rosenfeld.
1078 Block ".gemius.pl/" which only seems to be used for user tracking.
1079 Reported by johnd16 in #3002731. Additional input from Lee and movax.
1084 Disable banners-by-size filters for '.thinkgeek.com/'.
1085 The filter only seems to catch pictures of the inventory.
1090 Block requests for 'go.idmnet.bbelements.com/please/showit/'.
1091 Reported by kacperdominik in #3372959.
1096 Unblock adainitiative.org/.
1101 Add a fast-redirects exception for '.googleusercontent.com/.*=cache'.
1106 Add a fast-redirects exception for webcache.googleusercontent.com/.
1111 Unblock http://adassier.wordpress.com/ and http://adassier.files.wordpress.com/.
1119 Filter file improvements:
1123 Let the yahoo filter hide '.ads'.
1128 Let the msn filter hide overlay ads for Facebook 'likes' in search
1129 results and elements with the id 's_notf_div'. They only seem to be
1130 used to advertise site 'enhancements'.
1135 Let the js-events filter additionally disarm setInterval().
1136 Suggested by dg1727 in #3423775.
1144 Documentation improvements:
1148 Clarify the effect of compiling Privoxy with zlib support.
1149 Suggested by dg1727 in #3423782.
1154 Point out that the SourceForge messaging system works like a black
1155 hole and should thus not be used to contact individual developers.
1160 Mention some of the problems one can experience when not explicitly
1161 configuring an IP addresses as listen address.
1166 Explicitly mention that hostnames can be used instead of IP addresses
1167 for the listen-address, that only the first address returned will be
1168 used and what happens if the address is invalid.
1169 Requested by Calestyo in #3302213.
1177 Log message improvements:
1181 If only the server connection is kept alive, do not pretend to
1182 wait for a new client request.
1187 Remove a superfluous log message in forget_connection().
1192 In chat(), properly report missing server responses as such
1193 instead of calling them empty.
1198 In forwarded_connect(), fix a log message nobody should ever see.
1203 Fix a log message in socks5_connect(), a failed write operation
1204 was logged as failed read operation.
1209 Let load_one_actions_file() properly complain about a missing
1210 '{' at the beginning of the file.
1211 Simply stating that a line is invalid isn't particularly helpful.
1216 Do not claim to listen on a socket until Privoxy actually does.
1217 Patch submitted by Petr Pisar #3354485
1222 Prevent a duplicated LOG_LEVEL_CLF message when sending out
1223 the "no-server-data" response.
1228 Also log the client socket when dropping a connection.
1233 Include the destination host in the 'Request ... marked for
1234 blocking. limit-connect{...} doesn't allow CONNECT ...' message
1235 Patch submitted by Saperski in #3296250.
1240 Prevent a duplicated log message if none of the resolved IP
1241 addresses were reachable.
1246 In connect_to(), do not pretend to retry if forwarded-connect-retries
1252 When a specified user or group can't be found, put the name in
1253 single-quotes when logging it.
1258 In rfc2553_connect_to(), explain getnameinfo() errors better.
1263 Remove a useless log message in chat().
1268 When retrying to connect, also log the maximum number of connection
1274 Rephrase a log message in compile_dynamic_pcrs_job_list().
1275 Divide the error code and its meaning with a colon. Call the pcrs
1276 job dynamic and not the filter. Filters may contain dynamic and
1277 non-dynamic pcrs jobs at the same time. Only mention the name of
1278 the filter or tagger, but don't claim it's a filter when it could
1284 In a fatal error message in load_one_actions_file(), cover both
1285 URL and TAG patterns.
1290 In pcrs_strerror(), properly report unknown positive error code
1291 values as such. Previously they were handled like 0 (no error).
1296 In compile_dynamic_pcrs_job_list(), also log the actual error code as
1297 pcrs_strerror() doesn't handle all errors reported by pcre.
1302 Don't bother trying to continue chatting if the client didn't ask for it.
1303 Reduces log noise a bit.
1308 Make two fatal error message in load_one_actions_file() more descriptive.
1313 In cgi_send_user_manual(), log when rejecting a file name due to '/' or '..'.
1318 In load_file(), log a message if opening a file failed.
1319 The CGI error message alone isn't too helpful.
1324 In connection_destination_matches(), improve two log messages
1325 to help understand why the destinations don't match.
1330 Rephrase a log message in serve(). Client request arrival
1331 should be differentiated from closed client connections now.
1336 In serve(), log if a client connection isn't reused due to a
1337 configuration file change.
1342 Let mark_server_socket_tainted() always mark the server socket tainted,
1343 just don't talk about it in cases where it has no effect. It doesn't change
1344 Privoxy's behaviour, but makes understanding the log file easier.
1356 Added a --disable-ipv6-support switch for platforms where support
1357 is detected but doesn't actually work.
1362 Do not check for the existence of strerror() and memmove() twice
1367 Remove a useless test for setpgrp(2). Privoxy doesn't need it and
1368 it can cause problems when cross-compiling.
1373 Rename the --disable-acl-files switch to --disable-acl-support.
1374 Since about 2001, ACL directives are specified in the standard
1380 Update the URL of the 'Removing outdated PCRE version after the
1381 next stable release' posting. The old URL stopped working after
1382 one of SF's recent site "optimizations". Reported by Han Liu.
1390 Privoxy-Regression-Test:
1394 Added --shuffle-tests option to increase the chances of detection race conditions.
1399 Added a --local-test-file option that allows to use Privoxy-Regression-Test without Privoxy.
1404 Added tests for missing socks4 and socks4a forwarders.
1409 The --privoxy-address option now works with IPv6 addresses containing brackets, too.
1414 Perform limited sanity checks for parameters that are supposed to have numerical values.
1419 Added a --sleep-time option to specify a number of seconds to
1420 sleep between tests, defaults to 0.
1425 Disable the range-requests tagger for tests that break if it's enabled.
1430 Log messages use the ISO 8601 date format %Y-%m-%d.
1435 Fix spelling in two error messages.
1440 In the --help output, include a list of supported tests and their default levels.
1445 Adjust the tests to properly deal with FEATURE_TOGGLE being disabled.
1457 Perform limited sanity checks for command line parameters that
1458 are supposed to have numerical values.
1463 Implement a --unbreak-lines-only option to try to revert MUA breakage.
1468 Accept and highlight: Added header: Content-Encoding: deflate
1473 Accept and highlight: Compressed content from 29258 to 8630 bytes.
1478 Accept and highlight: Client request arrived in time on socket 21.
1483 Highlight: Didn't receive data in time: a.fsdn.com:443
1488 Accept log messages with ISO 8601 time stamps, too.
1500 Bump generated Firefox version to 8.0.
1505 Only randomize the release date if the new --randomize-release-date
1506 option is enabled. Firefox versions after 4 use a fixed date string
1517 <!-- ~~~~~ New section ~~~~~ -->
1519 <sect2 id="upgradersnote">
1520 <title>Note to Upgraders</title>
1523 A quick list of things to be aware of before upgrading from earlier
1524 versions of <application>Privoxy</application>:
1532 The recommended way to upgrade &my-app; is to backup your old
1533 configuration files, install the new ones, verify that &my-app;
1534 is working correctly and finally merge back your changes using
1535 <application>diff</application> and maybe <application>patch</application>.
1538 There are a number of new features in each &my-app; release and
1539 most of them have to be explicitly enabled in the configuration
1540 files. Old configuration files obviously don't do that and due
1541 to syntax changes using old configuration files with a new
1542 &my-app; isn't always possible anyway.
1547 Note that some installers remove earlier versions completely,
1548 including configuration files, therefore you should really save
1549 any important configuration files!
1554 On the other hand, other installers don't overwrite existing configuration
1555 files, thinking you will want to do that yourself.
1560 <filename>standard.action</filename> has been merged into
1561 the <filename>default.action</filename> file.
1566 In the default configuration only fatal errors are logged now.
1567 You can change that in the <link linkend="DEBUG">debug section</link>
1568 of the configuration file. You may also want to enable more verbose
1569 logging until you verified that the new &my-app; version is working
1576 Three other config file settings are now off by default:
1577 <link linkend="enable-remote-toggle">enable-remote-toggle</link>,
1578 <link linkend="enable-remote-http-toggle">enable-remote-http-toggle</link>,
1579 and <link linkend="enable-edit-actions">enable-edit-actions</link>.
1580 If you use or want these, you will need to explicitly enable them, and
1581 be aware of the security issues involved.
1588 What constitutes a <quote>default</quote> configuration has changed,
1589 and you may want to review which actions are <quote>on</quote> by
1590 default. This is primarily a matter of emphasis, but some features
1591 you may have been used to, may now be <quote>off</quote> by default.
1592 There are also a number of new actions and filters you may want to
1593 consider, most of which are not fully incorporated into the default
1594 settings as yet (see above).
1601 The default actions setting is now <literal>Cautious</literal>. Previous
1602 releases had a default setting of <literal>Medium</literal>. Experienced
1603 users may want to adjust this, as it is fairly conservative by &my-app;
1604 standards and past practices. See <ulink
1605 url="http://config.privoxy.org/edit-actions-list?f=default">
1606 http://config.privoxy.org/edit-actions-list?f=default</ulink>. New users
1607 should try the default settings for a while before turning up the volume.
1613 The default setting has filtering turned <emphasis>off</emphasis>, which
1614 subsequently means that compression is <emphasis>on</emphasis>. Remember
1615 that filtering does not work on compressed pages, so if you use, or want to
1616 use, filtering, you will need to force compression off. Example:
1620 { +<link linkend="filter">filter</link>{google} +<link linkend="prevent-compression">prevent-compression</link> }
1624 Or if you use a number of filters, or filter many sites, you may just want
1625 to turn off compression for all sites in
1626 <filename>default.action</filename> (or
1627 <filename>user.action</filename>).
1634 Also, <link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> is
1635 off by default now. If you've liked this feature in the past, you may want
1636 to turn it back on in <filename>user.action</filename> now.
1643 Some installers may not automatically start
1644 <application>Privoxy</application> after installation.
1655 <!-- ~~~~~ New section ~~~~~ -->
1656 <sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
1662 Install <application>Privoxy</application>. See the <link
1663 linkend="installation">Installation Section</link> below for platform specific
1670 Advanced users and those who want to offer <application>Privoxy</application>
1671 service to more than just their local machine should check the <link
1672 linkend="config">main config file</link>, especially the <link
1673 linkend="access-control">security-relevant</link> options. These are
1680 Start <application>Privoxy</application>, if the installation program has
1681 not done this already (may vary according to platform). See the section
1682 <link linkend="startup">Starting <application>Privoxy</application></link>.
1688 Set your browser to use <application>Privoxy</application> as HTTP and
1689 HTTPS (SSL) <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
1690 by setting the proxy configuration for address of
1691 <literal>127.0.0.1</literal> and port <literal>8118</literal>.
1692 <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
1693 any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
1694 browser from using these protocols.
1700 Flush your browser's disk and memory caches, to remove any cached ad images.
1701 If using <application>Privoxy</application> to manage
1702 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1703 you should remove any currently stored cookies too.
1709 A default installation should provide a reasonable starting point for
1710 most. There will undoubtedly be occasions where you will want to adjust the
1711 configuration, but that can be dealt with as the need arises. Little
1712 to no initial configuration is required in most cases, you may want
1714 <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
1715 Be sure to read the warnings first.
1718 See the <link linkend="configuration">Configuration section</link> for more
1719 configuration options, and how to customize your installation.
1720 You might also want to look at the <link
1721 linkend="quickstart-ad-blocking">next section</link> for a quick
1722 introduction to how <application>Privoxy</application> blocks ads and
1729 If you experience ads that slip through, innocent images that are
1730 blocked, or otherwise feel the need to fine-tune
1731 <application>Privoxy's</application> behavior, take a look at the <link
1732 linkend="actions-file">actions files</link>. As a quick start, you might
1733 find the <link linkend="act-examples">richly commented examples</link>
1734 helpful. You can also view and edit the actions files through the <ulink
1735 url="http://config.privoxy.org">web-based user interface</ulink>. The
1736 Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
1737 Action</link></quote> has hints on how to understand and debug actions that
1738 <quote>misbehave</quote>.
1743 Did anyone test these lately?
1747 For easy access to &my-app;'s most important controls, drag the provided
1748 <link linkend="bookmarklets">Bookmarklets</link> into your browser's
1756 Please see the section <link linkend="contact">Contacting the
1757 Developers</link> on how to report bugs, problems with websites or to get
1764 Now enjoy surfing with enhanced control, comfort and privacy!
1772 <!-- ~~~~~ New section ~~~~~ -->
1774 <sect2 id="quickstart-ad-blocking">
1775 <title>Quickstart to Ad Blocking</title>
1777 NOTE: This section is deliberately redundant for those that don't
1778 want to read the whole thing (which is getting lengthy).
1781 Ad blocking is but one of <application>Privoxy's</application>
1782 array of features. Many of these features are for the technically minded advanced
1783 user. But, ad and banner blocking is surely common ground for everybody.
1786 This section will provide a quick summary of ad blocking so
1787 you can get up to speed quickly without having to read the more extensive
1788 information provided below, though this is highly recommended.
1791 First a bit of a warning ... blocking ads is much like blocking SPAM: the
1792 more aggressive you are about it, the more likely you are to block
1793 things that were not intended. And the more likely that some things
1794 may not work as intended. So there is a trade off here. If you want
1795 extreme ad free browsing, be prepared to deal with more
1796 <quote>problem</quote> sites, and to spend more time adjusting the
1797 configuration to solve these unintended consequences. In short, there is
1798 not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
1799 the easy way and settle for <emphasis>most</emphasis> ads blocked with the
1800 default configuration, or jump in and tweak it for your personal surfing
1801 habits and preferences.
1804 Secondly, a brief explanation of <application>Privoxy's </application>
1805 <quote>actions</quote>. <quote>Actions</quote> in this context, are
1806 the directives we use to tell <application>Privoxy</application> to perform
1807 some task relating to HTTP transactions (i.e. web browsing). We tell
1808 <application>Privoxy</application> to take some <quote>action</quote>. Each
1809 action has a unique name and function. While there are many potential
1810 <application>actions</application> in <application>Privoxy's</application>
1811 arsenal, only a few are used for ad blocking. <link
1812 linkend="actions">Actions</link>, and <link linkend="actions-file">action
1813 configuration files</link>, are explained in depth below.
1816 Actions are specified in <application>Privoxy's</application> configuration,
1817 followed by one or more URLs to which the action should apply. URLs
1818 can actually be URL type <link linkend="af-patterns">patterns</link> that use
1819 wildcards so they can apply potentially to a range of similar URLs. The
1820 actions, together with the URL patterns are called a section.
1823 When you connect to a website, the full URL will either match one or more
1824 of the sections as defined in <application>Privoxy's</application> configuration,
1825 or not. If so, then <application>Privoxy</application> will perform the
1826 respective actions. If not, then nothing special happens. Furthermore, web
1827 pages may contain embedded, secondary URLs that your web browser will
1828 use to load additional components of the page, as it parses the
1829 original page's HTML content. An ad image for instance, is just an URL
1830 embedded in the page somewhere. The image itself may be on the same server,
1831 or a server somewhere else on the Internet. Complex web pages will have many
1832 such embedded URLs. &my-app; can deal with each URL individually, so, for
1833 instance, the main page text is not touched, but images from such-and-such
1838 The most important actions for basic ad blocking are: <literal><link
1839 linkend="block">block</link></literal>, <literal><link
1840 linkend="handle-as-image">handle-as-image</link></literal>,
1842 linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
1843 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
1851 <literal><link linkend="block">block</link></literal> - this is perhaps
1852 the single most used action, and is particularly important for ad blocking.
1853 This action stops any contact between your browser and any URL patterns
1854 that match this action's configuration. It can be used for blocking ads,
1855 but also anything that is determined to be unwanted. By itself, it simply
1856 stops any communication with the remote server and sends
1857 <application>Privoxy</application>'s own built-in BLOCKED page instead to
1858 let you now what has happened (with some exceptions, see below).
1864 <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
1865 tells <application>Privoxy</application> to treat this URL as an image.
1866 <application>Privoxy</application>'s default configuration already does this
1867 for all common image types (e.g. GIF), but there are many situations where this
1868 is not so easy to determine. So we'll force it in these cases. This is particularly
1869 important for ad blocking, since only if we know that it's an image of
1870 some kind, can we replace it with an image of our choosing, instead of the
1871 <application>Privoxy</application> BLOCKED page (which would only result in
1872 a <quote>broken image</quote> icon). There are some limitations to this
1873 though. For instance, you can't just brute-force an image substitution for
1874 an entire HTML page in most situations.
1880 <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
1881 sends an empty document instead of <application>Privoxy's</application>
1882 normal BLOCKED HTML page. This is useful for file types that are neither
1883 HTML nor images, such as blocking JavaScript files.
1890 linkend="set-image-blocker">set-image-blocker</link></literal> - tells
1891 <application>Privoxy</application> what to display in place of an ad image that
1892 has hit a block rule. For this to come into play, the URL must match a
1893 <literal><link linkend="block">block</link></literal> action somewhere in the
1894 configuration, <emphasis>and</emphasis>, it must also match an
1895 <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
1898 The configuration options on what to display instead of the ad are:
1902 <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
1903 replacement is obvious. This is the default.
1908 <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
1909 This is the so-called <quote>invisible</quote> configuration option.
1914 <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
1915 of the user's choosing (advanced usage).
1924 Advanced users will eventually want to explore &my-app;
1925 <literal><link linkend="filter">filters</link></literal> as well. Filters
1926 are very different from <literal><link
1927 linkend="block">blocks</link></literal>.
1928 A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
1929 are a way of filtering or modifying what is actually on the page. An example
1930 filter usage: a text replacement of <quote>no-no</quote> for
1931 <quote>nasty-word</quote>. That is a very simple example. This process can be
1932 used for ad blocking, but it is more in the realm of advanced usage and has
1933 some pitfalls to be wary off.
1937 The quickest way to adjust any of these settings is with your browser through
1938 the special <application>Privoxy</application> editor at <ulink
1939 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1940 (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
1941 is an internal page, and does not require Internet access.
1945 Note that as of <application>Privoxy</application> 3.0.7 beta the
1946 action editor is disabled by default. Check the
1947 <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
1948 section in the configuration file</ulink> to learn why and in which
1949 cases it's safe to enable again.
1953 If you decided to enable the action editor, select the appropriate
1954 <quote>actions</quote> file, and click
1955 <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
1956 local preferences in <filename>user.action</filename> since this is not
1957 meant to be overwritten during upgrades, and will over-ride the settings in
1958 other files. Here you can insert new <quote>actions</quote>, and URLs for ad
1959 blocking or other purposes, and make other adjustments to the configuration.
1960 <application>Privoxy</application> will detect these changes automatically.
1964 A quick and simple step by step example:
1972 Right click on the ad image to be blocked, then select
1973 <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
1981 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1986 Find <filename>user.action</filename> in the top section, and click
1987 on <quote><guibutton>Edit</guibutton></quote>:
1990 <!-- image of editor and actions files selections -->
1992 <figure pgwide="0" float="0"><title>Actions Files in Use</title>
1995 <imagedata fileref="files-in-use.jpg" format="jpg">
1998 <phrase>[ Screenshot of Actions Files in Use ]</phrase>
2007 You should have a section with only
2008 <literal><link linkend="block">block</link></literal> listed under
2009 <quote>Actions:</quote>.
2010 If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
2011 button, and in the new section that just appeared, click the
2012 <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
2013 This will bring up a list of all actions. Find
2014 <literal><link linkend="block">block</link></literal> near the top, and click
2015 in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
2016 just below the list.
2021 Now, in the <literal><link linkend="block">block</link></literal> actions section,
2022 click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
2023 browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
2024 Remove the <literal>http://</literal> at the beginning of the URL. Then, click
2025 <quote><guibutton>Submit</guibutton></quote> (or
2026 <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
2031 Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
2032 (or flush all browser caches). The image should be gone now.
2040 This is a very crude and simple example. There might be good reasons to use a
2041 wildcard pattern match to include potentially similar images from the same
2042 site. For a more extensive explanation of <quote>patterns</quote>, and
2043 the entire actions concept, see <link linkend="actions-file">the Actions
2048 For advanced users who want to hand edit their config files, you might want
2049 to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
2050 The ideas explained therein also apply to the web-based editor.
2053 There are also various
2054 <link linkend="filter">filters</link> that can be used for ad blocking
2055 (filters are a special subset of actions). These
2056 fall into the <quote>advanced</quote> usage category, and are explained in
2057 depth in later sections.
2064 <!-- ~ End section ~ -->
2067 <!-- ~~~~~ New section ~~~~~ -->
2068 <sect1 id="startup">
2069 <title>Starting Privoxy</title>
2071 Before launching <application>Privoxy</application> for the first time, you
2072 will want to configure your browser(s) to use
2073 <application>Privoxy</application> as a HTTP and HTTPS (SSL)
2074 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
2075 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
2076 used port 8000). This is the one configuration step <emphasis>that must be done
2080 Please note that <application>Privoxy</application> can only proxy HTTP and
2081 HTTPS traffic. It will not work with FTP or other protocols.
2084 <!-- image of Mozilla Proxy configuration -->
2086 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
2087 Mozilla/Netscape HTTP and HTTPS (SSL) Settings</title>
2090 <imagedata fileref="proxy_setup.jpg" format="jpg">
2093 <phrase>[ Screenshot of Mozilla Proxy Configuration ]</phrase>
2101 With <application>Firefox</application>, this is typically set under:
2105 <guibutton>Tools</guibutton> -> <guibutton>Options</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Network</guibutton> -><guibutton>Connection</guibutton> -> <guibutton>Settings</guibutton>
2110 Or optionally on some platforms:
2114 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
2120 With <application>Netscape</application> (and
2121 <application>Mozilla</application>), this can be set under:
2126 <!-- Mix ascii and gui art, something for everybody -->
2127 <!-- spacing on this is tricky -->
2128 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
2133 For <application>Internet Explorer v.5-7</application>:
2137 <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
2141 Then, check <quote>Use Proxy</quote> and fill in the appropriate info
2142 (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
2143 proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
2144 checkboxes like <quote>Use the same proxy server for all protocols</quote> is
2145 <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
2148 <!-- image of IE Proxy configuration -->
2150 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
2151 Internet Explorer HTTP and HTTPS (Secure) Settings</title>
2154 <imagedata fileref="proxy2.jpg" format="jpg">
2157 <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
2165 After doing this, flush your browser's disk and memory caches to force a
2166 re-reading of all pages and to get rid of any ads that may be cached. Remove
2167 any <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
2168 if you want <application>Privoxy</application> to manage that. You are now
2169 ready to start enjoying the benefits of using
2170 <application>Privoxy</application>!
2174 <application>Privoxy</application> itself is typically started by specifying the
2175 main configuration file to be used on the command line. If no configuration
2176 file is specified on the command line, <application>Privoxy</application>
2177 will look for a file named <filename>config</filename> in the current
2178 directory. Except on Win32 where it will try <filename>config.txt</filename>.
2181 <sect2 id="start-redhat">
2182 <title>Red Hat and Fedora</title>
2184 A default Red Hat installation may not start &my-app; upon boot. It will use
2185 the file <filename>/etc/privoxy/config</filename> as its main configuration
2190 # /etc/rc.d/init.d/privoxy start
2198 # service privoxy start
2203 <sect2 id="start-debian">
2204 <title>Debian</title>
2206 We use a script. Note that Debian typically starts &my-app; upon booting per
2207 default. It will use the file
2208 <filename>/etc/privoxy/config</filename> as its main configuration
2213 # /etc/init.d/privoxy start
2218 <sect2 id="start-windows">
2219 <title>Windows</title>
2221 Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
2222 specified on the command line, <application>Privoxy</application> will look
2223 for a file named <filename>config.txt</filename>. Note that Windows will
2224 automatically start &my-app; when the system starts if you chose that option
2228 <application>Privoxy</application> can run with full Windows service functionality.
2229 On Windows only, the &my-app; program has two new command line arguments
2230 to install and uninstall &my-app; as a service. See the
2231 <link linkend="installation-pack-win">Windows Installation
2232 instructions</link> for details.
2236 <sect2 id="start-unices">
2237 <title>Solaris, NetBSD, FreeBSD, HP-UX and others</title>
2239 Example Unix startup command:
2243 # /usr/sbin/privoxy /etc/privoxy/config
2248 <sect2 id="start-os2">
2251 During installation, <application>Privoxy</application> is configured to
2252 start automatically when the system restarts. You can start it manually by
2253 double-clicking on the <application>Privoxy</application> icon in the
2254 <application>Privoxy</application> folder.
2258 <sect2 id="start-macosx">
2259 <title>Mac OS X</title>
2261 After downloading the privoxy software, unzip the downloaded file by
2262 double-clicking on the zip file icon. Then, double-click on the
2263 installer package icon and follow the installation process.
2266 The privoxy service will automatically start after a successful
2267 installation. In addition, the privoxy service will automatically
2268 start every time your computer starts up.
2271 To prevent the privoxy service from automatically starting when your
2272 computer starts up, remove or rename the folder named
2273 /Library/StartupItems/Privoxy.
2276 A simple application named Privoxy Utility has been created which
2277 enables administrators to easily start and stop the privoxy service.
2280 In addition, the Privoxy Utility presents a simple way for
2281 administrators to edit the various privoxy config files. A method
2282 to uninstall the software is also available.
2285 An administrator username and password must be supplied in order for
2286 the Privoxy Utility to perform any of the tasks.
2291 <sect2 id="start-amigaos">
2292 <title>AmigaOS</title>
2294 Start <application>Privoxy</application> (with RUN <>NIL:) in your
2295 <filename>startnet</filename> script (AmiTCP), in
2296 <filename>s:user-startup</filename> (RoadShow), as startup program in your
2297 startup script (Genesis), or as startup action (Miami and MiamiDx).
2298 <application>Privoxy</application> will automatically quit when you quit your
2299 TCP/IP stack (just ignore the harmless warning your TCP/IP stack may display that
2300 <application>Privoxy</application> is still running).
2304 <sect2 id="start-gentoo">
2305 <title>Gentoo</title>
2307 A script is again used. It will use the file <filename>/etc/privoxy/config
2308 </filename> as its main configuration file.
2312 /etc/init.d/privoxy start
2316 Note that <application>Privoxy</application> is not automatically started at
2317 boot time by default. You can change this with the <literal>rc-update</literal>
2322 rc-update add privoxy default
2330 See the section <link linkend="cmdoptions">Command line options</link> for
2334 must find a better place for this paragraph
2337 The included default configuration files should give a reasonable starting
2338 point. Most of the per site configuration is done in the
2339 <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
2340 where various cookie actions are defined, ad and banner blocking, and other
2341 aspects of <application>Privoxy</application> configuration. There are several
2342 such files included, with varying levels of aggressiveness.
2346 You will probably want to keep an eye out for sites for which you may prefer
2347 persistent cookies, and add these to your actions configuration as needed. By
2348 default, most of these will be accepted only during the current browser
2349 session (aka <quote>session cookies</quote>), unless you add them to the
2350 configuration. If you want the browser to handle this instead, you will need
2351 to edit <filename>user.action</filename> (or through the web based interface)
2352 and disable this feature. If you use more than one browser, it would make
2353 more sense to let <application>Privoxy</application> handle this. In which
2354 case, the browser(s) should be set to accept all cookies.
2358 Another feature where you will probably want to define exceptions for trusted
2359 sites is the popup-killing (through <ulink
2360 url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
2361 because your favorite shopping, banking, or leisure site may need
2362 popups (explained below).
2366 <application>Privoxy</application> does not support all of the optional HTTP/1.1
2367 features yet. In the unlikely event that you experience inexplicable problems
2368 with browsers that use HTTP/1.1 per default
2369 (like <application>Mozilla</application> or recent versions of I.E.), you might
2370 try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
2371 Preferences -> Debug -> Networking</literal>.
2372 Alternatively, set the <quote>+downgrade-http-version</quote> config option in
2373 <filename>default.action</filename> which will downgrade your browser's HTTP
2374 requests from HTTP/1.1 to HTTP/1.0 before processing them.
2378 After running <application>Privoxy</application> for a while, you can
2379 start to fine tune the configuration to suit your personal, or site,
2380 preferences and requirements. There are many, many aspects that can
2381 be customized. <quote>Actions</quote>
2382 can be adjusted by pointing your browser to
2383 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
2384 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
2385 and then follow the link to <quote>View & Change the Current Configuration</quote>.
2386 (This is an internal page and does not require Internet access.)
2390 In fact, various aspects of <application>Privoxy</application>
2391 configuration can be viewed from this page, including
2392 current configuration parameters, source code version numbers,
2393 the browser's request headers, and <quote>actions</quote> that apply
2394 to a given URL. In addition to the actions file
2395 editor mentioned above, <application>Privoxy</application> can also
2396 be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
2400 If you encounter problems, try loading the page without
2401 <application>Privoxy</application>. If that helps, enter the URL where
2402 you have the problems into <ulink url="http://p.p/show-url-info">the browser
2403 based rule tracing utility</ulink>. See which rules apply and why, and
2404 then try turning them off for that site one after the other, until the problem
2405 is gone. When you have found the culprit, you might want to turn the rest on
2410 If the above paragraph sounds gibberish to you, you might want to <link
2411 linkend="actions-file">read more about the actions concept</link>
2412 or even dive deep into the <link linkend="actionsanat">Appendix
2417 If you can't get rid of the problem at all, think you've found a bug in
2418 Privoxy, want to propose a new feature or smarter rules, please see the
2419 section <link linkend="contact"><quote>Contacting the
2420 Developers</quote></link> below.
2425 <!-- ~~~~~ New section ~~~~~ -->
2426 <sect2 id="cmdoptions">
2427 <title>Command Line Options</title>
2429 <application>Privoxy</application> may be invoked with the following
2430 command-line options:
2438 <emphasis>--config-test</emphasis>
2441 Exit after loading the configuration files before binding to
2442 the listen address. The exit code signals whether or not the
2443 configuration files have been successfully loaded.
2446 If the exit code is 1, at least one of the configuration files
2447 is invalid, if it is 0, all the configuration files have been
2448 successfully loaded (but may still contain errors that can
2449 currently only be detected at run time).
2452 This option doesn't affect the log setting, combination with
2453 <emphasis>--no-daemon</emphasis> is recommended if a configured
2454 log file shouldn't be used.
2459 <emphasis>--version</emphasis>
2462 Print version info and exit. Unix only.
2467 <emphasis>--help</emphasis>
2470 Print short usage info and exit. Unix only.
2475 <emphasis>--no-daemon</emphasis>
2478 Don't become a daemon, i.e. don't fork and become process group
2479 leader, and don't detach from controlling tty. Unix only.
2484 <emphasis>--pidfile FILE</emphasis>
2487 On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
2488 <emphasis>FILE</emphasis> on exit. Failure to create or delete the
2489 <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
2490 option is given, no PID file will be used. Unix only.
2495 <emphasis>--user USER[.GROUP]</emphasis>
2498 After (optionally) writing the PID file, assume the user ID of
2499 <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
2500 privileges are not sufficient to do so. Unix only.
2505 <emphasis>--chroot</emphasis>
2508 Before changing to the user ID given in the <emphasis>--user</emphasis> option,
2509 chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
2510 process that the directory tree starts there. If set up carefully, this can limit
2511 the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
2517 <emphasis>--pre-chroot-nslookup hostname</emphasis>
2520 Specifies a hostname to look up before doing a chroot. On some systems, initializing the
2521 resolver library involves reading config files from /etc and/or loading additional shared
2522 libraries from /lib. On these systems, doing a hostname lookup before the chroot reduces
2523 the number of files that must be copied into the chroot tree.
2526 For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
2527 your local name server (listed in /etc/resolv.conf) can resolve without recursion
2528 (that is, without having to ask any other name servers). The hostname need not exist,
2529 but if it doesn't, an error message (which can be ignored) will be output.
2535 <emphasis>configfile</emphasis>
2538 If no <emphasis>configfile</emphasis> is included on the command line,
2539 <application>Privoxy</application> will look for a file named
2540 <quote>config</quote> in the current directory (except on Win32
2541 where it will look for <quote>config.txt</quote> instead). Specify
2542 full path to avoid confusion. If no config file is found,
2543 <application>Privoxy</application> will fail to start.
2551 On <application>MS Windows</application> only there are two additional
2552 command-line options to allow <application>Privoxy</application> to install and
2553 run as a <emphasis>service</emphasis>. See the
2554 <link linkend="installation-pack-win">Window Installation section</link>
2562 <!-- ~ End section ~ -->
2565 <!-- ~~~~~ New section ~~~~~ -->
2566 <sect1 id="configuration"><title>Privoxy Configuration</title>
2568 All <application>Privoxy</application> configuration is stored
2569 in text files. These files can be edited with a text editor.
2570 Many important aspects of <application>Privoxy</application> can
2571 also be controlled easily with a web browser.
2575 <!-- ~~~~~ New section ~~~~~ -->
2578 <title>Controlling Privoxy with Your Web Browser</title>
2580 <application>Privoxy</application>'s user interface can be reached through the special
2581 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
2582 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
2583 which is a built-in page and works without Internet access.
2584 You will see the following section:
2588 <!-- Needs to be put in a table and colorized -->
2591 <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
2595 ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
2598 ▪ <ulink url="http://config.privoxy.org/show-version">View the source code version numbers</ulink>
2601 ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
2604 ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
2607 ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
2610 ▪ <ulink
2611 url="http://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
2619 This should be self-explanatory. Note the first item leads to an editor for the
2620 <link linkend="actions-file">actions files</link>, which is where the ad, banner,
2621 cookie, and URL blocking magic is configured as well as other advanced features of
2622 <application>Privoxy</application>. This is an easy way to adjust various
2623 aspects of <application>Privoxy</application> configuration. The actions
2624 file, and other configuration files, are explained in detail below.
2628 <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
2629 have problems with your current actions and filters. You can in fact use
2630 it as a test to see whether it is <application>Privoxy</application>
2631 causing the problem or not. <application>Privoxy</application> continues
2632 to run as a proxy in this case, but all manipulation is disabled, i.e.
2633 <application>Privoxy</application> acts like a normal forwarding proxy. There
2634 is even a toggle <link linkend="bookmarklets">Bookmarklet</link> offered, so
2635 that you can toggle <application>Privoxy</application> with one click from
2640 Note that several of the features described above are disabled by default
2641 in <application>Privoxy</application> 3.0.7 beta and later.
2643 <ulink url="config.html">configuration file</ulink> to learn why
2644 and in which cases it's safe to enable them again.
2649 <!-- ~ End section ~ -->
2654 <!-- ~~~~~ New section ~~~~~ -->
2656 <sect2 id="confoverview">
2657 <title>Configuration Files Overview</title>
2659 For Unix, *BSD and Linux, all configuration files are located in
2660 <filename>/etc/privoxy/</filename> by default. For MS Windows, OS/2, and
2661 AmigaOS these are all in the same directory as the
2662 <application>Privoxy</application> executable. <![%p-not-stable;[ The name
2663 and number of configuration files has changed from previous versions, and is
2664 subject to change as development progresses.]]>
2668 The installed defaults provide a reasonable starting point, though
2669 some settings may be aggressive by some standards. For the time being, the
2670 principle configuration files are:
2678 The <link linkend="config">main configuration file</link> is named <filename>config</filename>
2679 on Linux, Unix, BSD, OS/2, and AmigaOS and <filename>config.txt</filename>
2680 on Windows. This is a required file.
2686 <filename>match-all.action</filename> is used to define which <quote>actions</quote>
2687 relating to banner-blocking, images, pop-ups, content modification, cookie handling
2688 etc should be applied by default. It should be the first actions file loaded.
2691 <filename>default.action</filename> defines many exceptions (both positive and negative)
2692 from the default set of actions that's configured in <filename>match-all.action</filename>.
2693 It should be the second actions file loaded and shouldn't be edited by the user.
2696 Multiple actions files may be defined in <filename>config</filename>. These
2697 are processed in the order they are defined. Local customizations and locally
2698 preferred exceptions to the default policies as defined in
2699 <filename>match-all.action</filename> (which you will most probably want
2700 to define sooner or later) are best applied in <filename>user.action</filename>,
2701 where you can preserve them across upgrades. The file isn't installed by all
2702 installers, but you can easily create it yourself with a text editor.
2705 There is also a web based editor that can be accessed from
2707 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2709 url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
2710 various actions files.
2716 <quote>Filter files</quote> (the <link linkend="filter-file">filter
2717 file</link>) can be used to re-write the raw page content, including
2718 viewable text as well as embedded HTML and JavaScript, and whatever else
2719 lurks on any given web page. The filtering jobs are only pre-defined here;
2720 whether to apply them or not is up to the actions files.
2721 <filename>default.filter</filename> includes various filters made
2722 available for use by the developers. Some are much more intrusive than
2723 others, and all should be used with caution. You may define additional
2724 filter files in <filename>config</filename> as you can with
2725 actions files. We suggest <filename>user.filter</filename> for any
2726 locally defined filters or customizations.
2734 The syntax of the configuration and filter files may change between different
2735 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
2736 <!-- Add link to documentation-->
2740 All files use the <quote><literal>#</literal></quote> character to denote a
2741 comment (the rest of the line will be ignored) and understand line continuation
2742 through placing a backslash ("<literal>\</literal>") as the very last character
2743 in a line. If the <literal>#</literal> is preceded by a backslash, it looses
2744 its special function. Placing a <literal>#</literal> in front of an otherwise
2745 valid configuration line to prevent it from being interpreted is called "commenting
2746 out" that line. Blank lines are ignored.
2750 The actions files and filter files
2751 can use Perl style <link linkend="regex">regular expressions</link> for
2752 maximum flexibility.
2756 After making any changes, there is no need to restart
2757 <application>Privoxy</application> in order for the changes to take
2758 effect. <application>Privoxy</application> detects such changes
2759 automatically. Note, however, that it may take one or two additional
2760 requests for the change to take effect. When changing the listening address
2761 of <application>Privoxy</application>, these <quote>wake up</quote> requests
2762 must obviously be sent to the <emphasis>old</emphasis> listening address.
2767 While under development, the configuration content is subject to change.
2768 The below documentation may not be accurate by the time you read this.
2769 Also, what constitutes a <quote>default</quote> setting, may change, so
2770 please check all your configuration files on important issues.
2776 <!-- ~ End section ~ -->
2779 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
2781 <!-- **************************************************** -->
2782 <!-- Include config.sgml here -->
2783 <!-- This is where the entire config file is detailed. -->
2785 <!-- end include -->
2788 <!-- ~ End section ~ -->
2792 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
2794 <sect1 id="actions-file"><title>Actions Files</title>
2798 XXX: similar descriptions are in the Configuration Files sections.
2799 We should only describe them at one place.
2802 The actions files are used to define what <emphasis>actions</emphasis>
2803 <application>Privoxy</application> takes for which URLs, and thus determines
2804 how ad images, cookies and various other aspects of HTTP content and
2805 transactions are handled, and on which sites (or even parts thereof).
2806 There are a number of such actions, with a wide range of functionality.
2807 Each action does something a little different.
2808 These actions give us a veritable arsenal of tools with which to exert
2809 our control, preferences and independence. Actions can be combined so that
2810 their effects are aggregated when applied against a given set of URLs.
2814 are three action files included with <application>Privoxy</application> with
2821 <filename>match-all.action</filename> - is used to define which
2822 <quote>actions</quote> relating to banner-blocking, images, pop-ups,
2823 content modification, cookie handling etc should be applied by default.
2824 It should be the first actions file loaded
2829 <filename>default.action</filename> - defines many exceptions (both
2830 positive and negative) from the default set of actions that's configured
2831 in <filename>match-all.action</filename>. It is a set of rules that should
2832 work reasonably well as-is for most users. This file is only supposed to
2833 be edited by the developers. It should be the second actions file loaded.
2838 <filename>user.action</filename> - is intended to be for local site
2839 preferences and exceptions. As an example, if your ISP or your bank
2840 has specific requirements, and need special handling, this kind of
2841 thing should go here. This file will not be upgraded.
2846 <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
2849 These have increasing levels of aggressiveness <emphasis>and have no
2850 influence on your browsing unless you select them explicitly in the
2851 editor</emphasis>. A default installation should be pre-set to
2852 <literal>Cautious</literal>. New users should try this for a while before
2853 adjusting the settings to more aggressive levels. The more aggressive
2854 the settings, then the more likelihood there is of problems such as sites
2855 not working as they should.
2858 The <guibutton>Edit</guibutton> button allows you to turn each
2859 action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
2860 button changes the actions list to low/safe settings which will activate
2861 ad blocking and a minimal set of &my-app;'s features, and subsequently
2862 there will be less of a chance for accidental problems. The
2863 <guibutton>Medium</guibutton> button sets the list to a medium level of
2864 other features and a low level set of privacy features. The
2865 <guibutton>Advanced</guibutton> button sets the list to a high level of
2866 ad blocking and medium level of privacy. See the chart below. The latter
2867 three buttons over-ride any changes via with the
2868 <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
2869 lower sections of this internal page.
2872 While the actions file editor allows to enable these settings in all
2873 actions files, they are only supposed to be enabled in the first one
2874 to make sure you don't unintentionally overrule earlier rules.
2877 The default profiles, and their associated actions, as pre-defined in
2878 <filename>default.action</filename> are:
2881 <table frame=all><title>Default Configurations</title>
2882 <tgroup cols=4 align=left colsep=1 rowsep=1>
2883 <colspec colname=c1>
2884 <colspec colname=c2>
2885 <colspec colname=c3>
2886 <colspec colname=c4>
2889 <entry>Feature</entry>
2890 <entry>Cautious</entry>
2891 <entry>Medium</entry>
2892 <entry>Advanced</entry>
2897 <!-- <entry>f1</entry> -->
2898 <!-- <entry>f2</entry> -->
2899 <!-- <entry>f3</entry> -->
2900 <!-- <entry>f4</entry> -->
2906 <entry>Ad-blocking Aggressiveness</entry>
2907 <entry>medium</entry>
2913 <entry>Ad-filtering by size</entry>
2920 <entry>Ad-filtering by link</entry>
2926 <entry>Pop-up killing</entry>
2927 <entry>blocks only</entry>
2928 <entry>blocks only</entry>
2929 <entry>blocks only</entry>
2933 <entry>Privacy Features</entry>
2935 <entry>medium</entry>
2936 <entry>medium/high</entry>
2940 <entry>Cookie handling</entry>
2942 <entry>session-only</entry>
2947 <entry>Referer forging</entry>
2954 <entry>GIF de-animation</entry>
2961 <entry>Fast redirects</entry>
2968 <entry>HTML taming</entry>
2975 <entry>JavaScript taming</entry>
2982 <entry>Web-bug killing</entry>
2989 <entry>Image tag reordering</entry>
3005 The list of actions files to be used are defined in the main configuration
3006 file, and are processed in the order they are defined (e.g.
3007 <filename>default.action</filename> is typically processed before
3008 <filename>user.action</filename>). The content of these can all be viewed and
3010 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
3011 The over-riding principle when applying actions, is that the last action that
3012 matches a given URL wins. The broadest, most general rules go first
3013 (defined in <filename>default.action</filename>),
3014 followed by any exceptions (typically also in
3015 <filename>default.action</filename>), which are then followed lastly by any
3016 local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
3017 Generally, <filename>user.action</filename> has the last word.
3021 An actions file typically has multiple sections. If you want to use
3022 <quote>aliases</quote> in an actions file, you have to place the (optional)
3023 <link linkend="aliases">alias section</link> at the top of that file.
3024 Then comes the default set of rules which will apply universally to all
3025 sites and pages (be <emphasis>very careful</emphasis> with using such a
3026 universal set in <filename>user.action</filename> or any other actions file after
3027 <filename>default.action</filename>, because it will override the result
3028 from consulting any previous file). And then below that,
3029 exceptions to the defined universal policies. You can regard
3030 <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
3031 with the advantage that it is a separate file, which makes preserving your
3032 personal settings across <application>Privoxy</application> upgrades easier.
3036 Actions can be used to block anything you want, including ads, banners, or
3037 just some obnoxious URL whose content you would rather not see. Cookies can be accepted
3038 or rejected, or accepted only during the current browser session (i.e. not
3039 written to disk), content can be modified, some JavaScripts tamed, user-tracking
3040 fooled, and much more. See below for a <link linkend="actions">complete list
3044 <!-- ~~~~~ New section ~~~~~ -->
3046 <title>Finding the Right Mix</title>
3048 Note that some <link linkend="actions">actions</link>, like cookie suppression
3049 or script disabling, may render some sites unusable that rely on these
3050 techniques to work properly. Finding the right mix of actions is not always easy and
3051 certainly a matter of personal taste. And, things can always change, requiring
3052 refinements in the configuration. In general, it can be said that the more
3053 <quote>aggressive</quote> your default settings (in the top section of the
3054 actions file) are, the more exceptions for <quote>trusted</quote> sites you
3055 will have to make later. If, for example, you want to crunch all cookies per
3056 default, you'll have to make exceptions from that rule for sites that you
3057 regularly use and that require cookies for actually useful purposes, like maybe
3058 your bank, favorite shop, or newspaper.
3062 We have tried to provide you with reasonable rules to start from in the
3063 distribution actions files. But there is no general rule of thumb on these
3064 things. There just are too many variables, and sites are constantly changing.
3065 Sooner or later you will want to change the rules (and read this chapter again :).
3069 <!-- ~~~~~ New section ~~~~~ -->
3071 <title>How to Edit</title>
3073 The easiest way to edit the actions files is with a browser by
3074 using our browser-based editor, which can be reached from <ulink
3075 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
3076 Note: the config file option <link
3077 linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
3078 this to work. The editor allows both fine-grained control over every single
3079 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
3080 like <quote>Cautious</quote>, <quote>Medium</quote> or
3081 <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
3082 aggressive, and will be more likely to cause problems for some sites.
3083 Experienced users only!
3087 If you prefer plain text editing to GUIs, you can of course also directly edit the
3088 the actions files with your favorite text editor. Look at
3089 <filename>default.action</filename> which is richly commented with many
3095 <sect2 id="actions-apply">
3096 <title>How Actions are Applied to Requests</title>
3098 Actions files are divided into sections. There are special sections,
3099 like the <quote><link linkend="aliases">alias</link></quote> sections which will
3100 be discussed later. For now let's concentrate on regular sections: They have a
3101 heading line (often split up to multiple lines for readability) which consist
3102 of a list of actions, separated by whitespace and enclosed in curly braces.
3103 Below that, there is a list of URL and tag patterns, each on a separate line.
3107 To determine which actions apply to a request, the URL of the request is
3108 compared to all URL patterns in each <quote>action file</quote>.
3109 Every time it matches, the list of applicable actions for the request is
3110 incrementally updated, using the heading of the section in which the
3111 pattern is located. The same is done again for tags and tag patterns later on.
3115 If multiple applying sections set the same action differently,
3116 the last match wins. If not, the effects are aggregated.
3117 E.g. a URL might match a regular section with a heading line of <literal>{
3118 +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
3119 then later another one with just <literal>{
3120 +<link linkend="block">block</link> }</literal>, resulting
3121 in <emphasis>both</emphasis> actions to apply. And there may well be
3122 cases where you will want to combine actions together. Such a section then
3128 { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
3129 # Block these as if they were images. Send no block page.
3131 media.example.com/.*banners
3132 .example.com/images/ads/</screen>
3136 You can trace this process for URL patterns and any given URL by visiting <ulink
3137 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
3141 Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
3142 Troubleshooting: Anatomy of an Action</link> section.
3146 <!-- ~~~~~ New section ~~~~~ -->
3147 <sect2 id="af-patterns">
3148 <title>Patterns</title>
3150 As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
3151 to determine what <emphasis>actions</emphasis> might apply to which sites and
3152 pages your browser attempts to access. These <quote>patterns</quote> use wild
3153 card type <emphasis>pattern</emphasis> matching to achieve a high degree of
3154 flexibility. This allows one expression to be expanded and potentially match
3155 against many similar patterns.
3159 Generally, an URL pattern has the form
3160 <literal><domain><port>/<path></literal>, where the
3161 <literal><domain></literal>, the <literal><port></literal>
3162 and the <literal><path></literal> are optional. (This is why the special
3163 <literal>/</literal> pattern matches all URLs). Note that the protocol
3164 portion of the URL pattern (e.g. <literal>http://</literal>) should
3165 <emphasis>not</emphasis> be included in the pattern. This is assumed already!
3168 The pattern matching syntax is different for the domain and path parts of
3169 the URL. The domain part uses a simple globbing type matching technique,
3170 while the path part uses more flexible
3171 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3172 Expressions</quote></ulink> (POSIX 1003.2).
3175 The port part of a pattern is a decimal port number preceded by a colon
3176 (<literal>:</literal>). If the domain part contains a numerical IPv6 address,
3177 it has to be put into angle brackets
3178 (<literal><</literal>, <literal>></literal>).
3183 <term><literal>www.example.com/</literal></term>
3186 is a domain-only pattern and will match any request to <literal>www.example.com</literal>,
3187 regardless of which document on that server is requested. So ALL pages in
3188 this domain would be covered by the scope of this action. Note that a
3189 simple <literal>example.com</literal> is different and would NOT match.
3194 <term><literal>www.example.com</literal></term>
3197 means exactly the same. For domain-only patterns, the trailing <literal>/</literal> may
3203 <term><literal>www.example.com/index.html</literal></term>
3206 matches all the documents on <literal>www.example.com</literal>
3207 whose name starts with <literal>/index.html</literal>.
3212 <term><literal>www.example.com/index.html$</literal></term>
3215 matches only the single document <literal>/index.html</literal>
3216 on <literal>www.example.com</literal>.
3221 <term><literal>/index.html$</literal></term>
3224 matches the document <literal>/index.html</literal>, regardless of the domain,
3225 i.e. on <emphasis>any</emphasis> web server anywhere.
3230 <term><literal>/</literal></term>
3233 Matches any URL because there's no requirement for either the
3234 domain or the path to match anything.
3239 <term><literal>:8000/</literal></term>
3242 Matches any URL pointing to TCP port 8000.
3247 <term><literal><2001:db8::1>/</literal></term>
3250 Matches any URL with the host address <literal>2001:db8::1</literal>.
3251 (Note that the real URL uses plain brackets, not angle brackets.)
3256 <term><literal>index.html</literal></term>
3259 matches nothing, since it would be interpreted as a domain name and
3260 there is no top-level domain called <literal>.html</literal>. So its
3268 <!-- ~~~~~ New section ~~~~~ -->
3269 <sect3><title>The Domain Pattern</title>
3272 The matching of the domain part offers some flexible options: if the
3273 domain starts or ends with a dot, it becomes unanchored at that end.
3279 <term><literal>.example.com</literal></term>
3282 matches any domain with first-level domain <literal>com</literal>
3283 and second-level domain <literal>example</literal>.
3284 For example <literal>www.example.com</literal>,
3285 <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
3286 Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
3291 <term><literal>www.</literal></term>
3294 matches any domain that <emphasis>STARTS</emphasis> with
3295 <literal>www.</literal> (It also matches the domain
3296 <literal>www</literal> but most of the time that doesn't matter.)
3301 <term><literal>.example.</literal></term>
3304 matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
3305 And, by the way, also included would be any files or documents that exist
3306 within that domain since no path limitations are specified. (Correctly
3307 speaking: It matches any FQDN that contains <literal>example</literal> as
3308 a domain.) This might be <literal>www.example.com</literal>,
3309 <literal>news.example.de</literal>, or
3310 <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
3318 Additionally, there are wild-cards that you can use in the domain names
3319 themselves. These work similarly to shell globbing type wild-cards:
3320 <quote>*</quote> represents zero or more arbitrary characters (this is
3322 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3323 Expression</quote></ulink> based syntax of <quote>.*</quote>),
3324 <quote>?</quote> represents any single character (this is equivalent to the
3325 regular expression syntax of a simple <quote>.</quote>), and you can define
3326 <quote>character classes</quote> in square brackets which is similar to
3327 the same regular expression technique. All of this can be freely mixed:
3332 <term><literal>ad*.example.com</literal></term>
3335 matches <quote>adserver.example.com</quote>,
3336 <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
3341 <term><literal>*ad*.example.com</literal></term>
3344 matches all of the above, and then some.
3349 <term><literal>.?pix.com</literal></term>
3352 matches <literal>www.ipix.com</literal>,
3353 <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
3358 <term><literal>www[1-9a-ez].example.c*</literal></term>
3361 matches <literal>www1.example.com</literal>,
3362 <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
3363 <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
3364 <literal>wwww.example.com</literal>.
3371 While flexible, this is not the sophistication of full regular expression based syntax.
3376 <!-- ~ End section ~ -->
3379 <!-- ~~~~~ New section ~~~~~ -->
3380 <sect3><title>The Path Pattern</title>
3383 <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
3384 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3385 Expressions</quote></ulink> for matching the path portion (after the slash),
3386 and is thus more flexible.
3390 There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
3391 expressions, you also might want to have a look at your operating system's documentation
3392 on regular expressions (try <literal>man re_format</literal>).
3396 Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
3397 i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
3398 for the beginning of a line).
3402 Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
3403 by default, but you can switch to case sensitive at any point in the pattern by using the
3404 <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
3405 only documents whose path starts with <literal>PaTtErN</literal> in
3406 <emphasis>exactly</emphasis> this capitalization.
3411 <term><literal>.example.com/.*</literal></term>
3414 Is equivalent to just <quote>.example.com</quote>, since any documents
3415 within that domain are matched with or without the <quote>.*</quote>
3416 regular expression. This is redundant
3421 <term><literal>.example.com/.*/index.html$</literal></term>
3424 Will match any page in the domain of <quote>example.com</quote> that is
3425 named <quote>index.html</quote>, and that is part of some path. For
3426 example, it matches <quote>www.example.com/testing/index.html</quote> but
3427 NOT <quote>www.example.com/index.html</quote> because the regular
3428 expression called for at least two <quote>/'s</quote>, thus the path
3429 requirement. It also would match
3430 <quote>www.example.com/testing/index_html</quote>, because of the
3431 special meta-character <quote>.</quote>.
3436 <term><literal>.example.com/(.*/)?index\.html$</literal></term>
3439 This regular expression is conditional so it will match any page
3440 named <quote>index.html</quote> regardless of path which in this case can
3441 have one or more <quote>/'s</quote>. And this one must contain exactly
3442 <quote>.html</quote> (but does not have to end with that!).
3447 <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
3450 This regular expression will match any path of <quote>example.com</quote>
3451 that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
3452 <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
3453 The path does not have to end in these words, just contain them.
3458 <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
3461 This is very much the same as above, except now it must end in either
3462 <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
3463 one is limited to common image formats.
3470 There are many, many good examples to be found in <filename>default.action</filename>,
3471 and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
3476 <!-- ~ End section ~ -->
3479 <!-- ~~~~~ New section ~~~~~ -->
3480 <sect3 id="tag-pattern"><title>The Tag Pattern</title>
3483 Tag patterns are used to change the applying actions based on the
3484 request's tags. Tags can be created with either the
3485 <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
3486 or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
3490 Tag patterns have to start with <quote>TAG:</quote>, so &my-app;
3491 can tell them apart from URL patterns. Everything after the colon
3492 including white space, is interpreted as a regular expression with
3493 path pattern syntax, except that tag patterns aren't left-anchored
3494 automatically (&my-app; doesn't silently add a <quote>^</quote>,
3495 you have to do it yourself if you need it).
3499 To match all requests that are tagged with <quote>foo</quote>
3500 your pattern line should be <quote>TAG:^foo$</quote>,
3501 <quote>TAG:foo</quote> would work as well, but it would also
3502 match requests whose tags contain <quote>foo</quote> somewhere.
3503 <quote>TAG: foo</quote> wouldn't work as it requires white space.
3507 Sections can contain URL and tag patterns at the same time,
3508 but tag patterns are checked after the URL patterns and thus
3509 always overrule them, even if they are located before the URL patterns.
3513 Once a new tag is added, Privoxy checks right away if it's matched by one
3514 of the tag patterns and updates the action settings accordingly. As a result
3515 tags can be used to activate other tagger actions, as long as these other
3516 taggers look for headers that haven't already be parsed.
3520 For example you could tag client requests which use the
3521 <literal>POST</literal> method,
3522 then use this tag to activate another tagger that adds a tag if cookies
3523 are sent, and then use a block action based on the cookie tag. This allows
3524 the outcome of one action, to be input into a subsequent action. However if
3525 you'd reverse the position of the described taggers, and activated the
3526 method tagger based on the cookie tagger, no method tags would be created.
3527 The method tagger would look for the request line, but at the time
3528 the cookie tag is created, the request line has already been parsed.
3532 While this is a limitation you should be aware of, this kind of
3533 indirection is seldom needed anyway and even the example doesn't
3534 make too much sense.
3541 <!-- ~ End section ~ -->
3544 <!-- ~~~~~ New section ~~~~~ -->
3546 <sect2 id="actions">
3547 <title>Actions</title>
3549 All actions are disabled by default, until they are explicitly enabled
3550 somewhere in an actions file. Actions are turned on if preceded with a
3551 <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
3552 <literal>+action</literal> means <quote>do that action</quote>, e.g.
3553 <literal>+block</literal> means <quote>please block URLs that match the
3554 following patterns</quote>, and <literal>-block</literal> means <quote>don't
3555 block URLs that match the following patterns, even if <literal>+block</literal>
3556 previously applied.</quote>
3561 Again, actions are invoked by placing them on a line, enclosed in curly braces and
3562 separated by whitespace, like in
3563 <literal>{+some-action -some-other-action{some-parameter}}</literal>,
3564 followed by a list of URL patterns, one per line, to which they apply.
3565 Together, the actions line and the following pattern lines make up a section
3566 of the actions file.
3570 Actions fall into three categories:
3577 Boolean, i.e the action can only be <quote>enabled</quote> or
3578 <quote>disabled</quote>. Syntax:
3582 +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
3583 -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable></screen>
3586 Example: <literal>+handle-as-image</literal>
3593 Parameterized, where some value is required in order to enable this type of action.
3598 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
3599 # overwriting parameter from previous match if necessary
3600 -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted</screen>
3603 Note that if the URL matches multiple positive forms of a parameterized action,
3604 the last match wins, i.e. the params from earlier matches are simply ignored.
3607 Example: <literal>+hide-user-agent{Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.8.1.4) Gecko/20070602 Firefox/2.0.0.4}</literal>
3613 Multi-value. These look exactly like parameterized actions,
3614 but they behave differently: If the action applies multiple times to the
3615 same URL, but with different parameters, <emphasis>all</emphasis> the parameters
3616 from <emphasis>all</emphasis> matches are remembered. This is used for actions
3617 that can be executed for the same request repeatedly, like adding multiple
3618 headers, or filtering through multiple filters. Syntax:
3622 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
3623 -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
3624 # If it was the last one left, disable the action.
3625 <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list</screen>
3628 Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
3629 <literal>+filter{html-annoyances}</literal>
3637 If nothing is specified in any actions file, no <quote>actions</quote> are
3638 taken. So in this case <application>Privoxy</application> would just be a
3639 normal, non-blocking, non-filtering proxy. You must specifically enable the
3640 privacy and blocking features you need (although the provided default actions
3641 files will give a good starting point).
3645 Later defined action sections always over-ride earlier ones of the same type.
3646 So exceptions to any rules you make, should come in the latter part of the file (or
3647 in a file that is processed later when using multiple actions files such
3648 as <filename>user.action</filename>). For multi-valued actions, the actions
3649 are applied in the order they are specified. Actions files are processed in
3650 the order they are defined in <filename>config</filename> (the default
3651 installation has three actions files). It also quite possible for any given
3652 URL to match more than one <quote>pattern</quote> (because of wildcards and
3653 regular expressions), and thus to trigger more than one set of actions! Last
3657 <!-- start actions listing -->
3659 The list of valid <application>Privoxy</application> actions are:
3663 <!-- ********************************************************** -->
3664 <!-- Please note the below defined actions use id's that are -->
3665 <!-- probably linked from other places, so please don't change. -->
3667 <!-- ********************************************************** -->
3670 <!-- ~~~~~ New section ~~~~~ -->
3672 <sect3 renderas="sect4" id="add-header">
3673 <title>add-header</title>
3677 <term>Typical use:</term>
3679 <para>Confuse log analysis, custom applications</para>
3684 <term>Effect:</term>
3687 Sends a user defined HTTP header to the web server.
3694 <!-- boolean, parameterized, Multi-value -->
3696 <para>Multi-value.</para>
3701 <term>Parameter:</term>
3704 Any string value is possible. Validity of the defined HTTP headers is not checked.
3705 It is recommended that you use the <quote><literal>X-</literal></quote> prefix
3715 This action may be specified multiple times, in order to define multiple
3716 headers. This is rarely needed for the typical user. If you don't know what
3717 <quote>HTTP headers</quote> are, you definitely don't need to worry about this
3721 Headers added by this action are not modified by other actions.
3727 <term>Example usage:</term>
3730 <screen>+add-header{X-User-Tracking: sucks}</screen>
3738 <!-- ~~~~~ New section ~~~~~ -->
3739 <sect3 renderas="sect4" id="block">
3740 <title>block</title>
3744 <term>Typical use:</term>
3746 <para>Block ads or other unwanted content</para>
3751 <term>Effect:</term>
3754 Requests for URLs to which this action applies are blocked, i.e. the
3755 requests are trapped by &my-app; and the requested URL is never retrieved,
3756 but is answered locally with a substitute page or image, as determined by
3758 linkend="handle-as-image">handle-as-image</link></literal>,
3760 linkend="set-image-blocker">set-image-blocker</link></literal>, and
3762 linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
3770 <!-- boolean, parameterized, Multi-value -->
3772 <para>Parameterized.</para>
3777 <term>Parameter:</term>
3779 <para>A block reason that should be given to the user.</para>
3787 <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
3788 for requests to blocked pages. This page contains the block reason given as
3789 parameter, a link to find out why the block action applies, and a click-through
3790 to the blocked content (the latter only if the force feature is available and
3794 A very important exception occurs if <emphasis>both</emphasis>
3795 <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
3796 apply to the same request: it will then be replaced by an image. If
3797 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
3798 (see below) also applies, the type of image will be determined by its parameter,
3799 if not, the standard checkerboard pattern is sent.
3802 It is important to understand this process, in order
3803 to understand how <application>Privoxy</application> deals with
3804 ads and other unwanted content. Blocking is a core feature, and one
3805 upon which various other features depend.
3808 The <literal><link linkend="filter">filter</link></literal>
3809 action can perform a very similar task, by <quote>blocking</quote>
3810 banner images and other content through rewriting the relevant URLs in the
3811 document's HTML source, so they don't get requested in the first place.
3812 Note that this is a totally different technique, and it's easy to confuse the two.
3818 <term>Example usage (section):</term>
3821 <screen>{+block{No nasty stuff for you.}}
3822 # Block and replace with "blocked" page
3823 .nasty-stuff.example.com
3825 {+block{Doubleclick banners.} +handle-as-image}
3826 # Block and replace with image
3830 {+block{Layered ads.} +handle-as-empty-document}
3831 # Block and then ignore
3832 adserver.example.net/.*\.js$</screen>
3842 <!-- ~~~~~ New section ~~~~~ -->
3843 <sect3 renderas="sect4" id="change-x-forwarded-for">
3844 <title>change-x-forwarded-for</title>
3848 <term>Typical use:</term>
3850 <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
3855 <term>Effect:</term>
3858 Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
3866 <!-- Boolean, Parameterized, Multi-value -->
3868 <para>Parameterized.</para>
3873 <term>Parameter:</term>
3877 <para><quote>block</quote> to delete the header.</para>
3881 <quote>add</quote> to create the header (or append
3882 the client's IP address to an already existing one).
3893 It is safe and recommended to use <literal>block</literal>.
3896 Forwarding the source address of the request may make
3897 sense in some multi-user setups but is also a privacy risk.
3902 <term>Example usage:</term>
3905 <screen>+change-x-forwarded-for{block}</screen>
3912 <!-- ~~~~~ New section ~~~~~ -->
3913 <sect3 renderas="sect4" id="client-header-filter">
3914 <title>client-header-filter</title>
3918 <term>Typical use:</term>
3921 Rewrite or remove single client headers.
3927 <term>Effect:</term>
3930 All client headers to which this action applies are filtered on-the-fly through
3931 the specified regular expression based substitutions.
3938 <!-- boolean, parameterized, Multi-value -->
3940 <para>Parameterized.</para>
3945 <term>Parameter:</term>
3948 The name of a client-header filter, as defined in one of the
3949 <link linkend="filter-file">filter files</link>.
3958 Client-header filters are applied to each header on its own, not to
3959 all at once. This makes it easier to diagnose problems, but on the downside
3960 you can't write filters that only change header x if header y's value is z.
3961 You can do that by using tags though.
3964 Client-header filters are executed after the other header actions have finished
3965 and use their output as input.
3968 If the request URI gets changed, &my-app; will detect that and use the new
3969 one. This can be used to rewrite the request destination behind the client's
3970 back, for example to specify a Tor exit relay for certain requests.
3973 Please refer to the <link linkend="filter-file">filter file chapter</link>
3974 to learn which client-header filters are available by default, and how to
3982 <term>Example usage (section):</term>
3986 # Hide Tor exit notation in Host and Referer Headers
3987 {+client-header-filter{hide-tor-exit-notation}}
3998 <!-- ~~~~~ New section ~~~~~ -->
3999 <sect3 renderas="sect4" id="client-header-tagger">
4000 <title>client-header-tagger</title>
4004 <term>Typical use:</term>
4007 Block requests based on their headers.
4013 <term>Effect:</term>
4016 Client headers to which this action applies are filtered on-the-fly through
4017 the specified regular expression based substitutions, the result is used as
4025 <!-- boolean, parameterized, Multi-value -->
4027 <para>Parameterized.</para>
4032 <term>Parameter:</term>
4035 The name of a client-header tagger, as defined in one of the
4036 <link linkend="filter-file">filter files</link>.
4045 Client-header taggers are applied to each header on its own,
4046 and as the header isn't modified, each tagger <quote>sees</quote>
4050 Client-header taggers are the first actions that are executed
4051 and their tags can be used to control every other action.
4057 <term>Example usage (section):</term>
4061 # Tag every request with the User-Agent header
4062 {+client-header-tagger{user-agent}}
4065 # Tagging itself doesn't change the action
4066 # settings, sections with TAG patterns do:
4068 # If it's a download agent, use a different forwarding proxy,
4069 # show the real User-Agent and make sure resume works.
4070 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
4071 -hide-if-modified-since \
4072 -overwrite-last-modified \
4077 TAG:^User-Agent: NetBSD-ftp/
4078 TAG:^User-Agent: Novell ZYPP Installer
4079 TAG:^User-Agent: RPM APT-HTTP/
4080 TAG:^User-Agent: fetch libfetch/
4081 TAG:^User-Agent: Ubuntu APT-HTTP/
4082 TAG:^User-Agent: MPlayer/
4087 # Tag all requests with the Range header set
4088 {+client-header-tagger{range-requests}}
4091 # Disable filtering for the tagged requests.
4093 # With filtering enabled Privoxy would remove the Range headers
4094 # to be able to filter the whole response. The downside is that
4095 # it prevents clients from resuming downloads or skipping over
4096 # parts of multimedia files.
4097 {-filter -deanimate-gifs}
4108 <!-- ~~~~~ New section ~~~~~ -->
4109 <sect3 renderas="sect4" id="content-type-overwrite">
4110 <title>content-type-overwrite</title>
4114 <term>Typical use:</term>
4116 <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
4121 <term>Effect:</term>
4124 Replaces the <quote>Content-Type:</quote> HTTP server header.
4131 <!-- Boolean, Parameterized, Multi-value -->
4133 <para>Parameterized.</para>
4138 <term>Parameter:</term>
4150 The <quote>Content-Type:</quote> HTTP server header is used by the
4151 browser to decide what to do with the document. The value of this
4152 header can cause the browser to open a download menu instead of
4153 displaying the document by itself, even if the document's format is
4154 supported by the browser.
4157 The declared content type can also affect which rendering mode
4158 the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
4159 many browsers treat it as yet another broken HTML document.
4160 If it is send as <quote>application/xml</quote>, browsers with
4161 XHTML support will only display it, if the syntax is correct.
4164 If you see a web site that proudly uses XHTML buttons, but sets
4165 <quote>Content-Type: text/html</quote>, you can use &my-app;
4166 to overwrite it with <quote>application/xml</quote> and validate
4167 the web master's claim inside your XHTML-supporting browser.
4168 If the syntax is incorrect, the browser will complain loudly.
4171 You can also go the opposite direction: if your browser prints
4172 error messages instead of rendering a document falsely declared
4173 as XHTML, you can overwrite the content type with
4174 <quote>text/html</quote> and have it rendered as broken HTML document.
4177 By default <literal>content-type-overwrite</literal> only replaces
4178 <quote>Content-Type:</quote> headers that look like some kind of text.
4179 If you want to overwrite it unconditionally, you have to combine it with
4180 <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
4181 This limitation exists for a reason, think twice before circumventing it.
4184 Most of the time it's easier to replace this action with a custom
4185 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
4186 It allows you to activate it for every document of a certain site and it will still
4187 only replace the content types you aimed at.
4190 Of course you can apply <literal>content-type-overwrite</literal>
4191 to a whole site and then make URL based exceptions, but it's a lot
4192 more work to get the same precision.
4198 <term>Example usage (sections):</term>
4201 <screen># Check if www.example.net/ really uses valid XHTML
4202 { +content-type-overwrite{application/xml} }
4205 # but leave the content type unmodified if the URL looks like a style sheet
4206 {-content-type-overwrite}
4207 www.example.net/.*\.css$
4208 www.example.net/.*style
4217 <!-- ~~~~~ New section ~~~~~ -->
4218 <sect3 renderas="sect4" id="crunch-client-header">
4222 <title>crunch-client-header</title>
4226 <term>Typical use:</term>
4228 <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
4233 <term>Effect:</term>
4236 Deletes every header sent by the client that contains the string the user supplied as parameter.
4243 <!-- Boolean, Parameterized, Multi-value -->
4245 <para>Parameterized.</para>
4250 <term>Parameter:</term>
4262 This action allows you to block client headers for which no dedicated
4263 <application>Privoxy</application> action exists.
4264 <application>Privoxy</application> will remove every client header that
4265 contains the string you supplied as parameter.
4268 Regular expressions are <emphasis>not supported</emphasis> and you can't
4269 use this action to block different headers in the same request, unless
4270 they contain the same string.
4273 <literal>crunch-client-header</literal> is only meant for quick tests.
4274 If you have to block several different headers, or only want to modify
4275 parts of them, you should use a
4276 <literal><link linkend="client-header-filter">client-header filter</link></literal>.
4280 Don't block any header without understanding the consequences.
4287 <term>Example usage (section):</term>
4290 <screen># Block the non-existent "Privacy-Violation:" client header
4291 { +crunch-client-header{Privacy-Violation:} }
4301 <!-- ~~~~~ New section ~~~~~ -->
4302 <sect3 renderas="sect4" id="crunch-if-none-match">
4303 <title>crunch-if-none-match</title>
4309 <term>Typical use:</term>
4311 <para>Prevent yet another way to track the user's steps between sessions.</para>
4316 <term>Effect:</term>
4319 Deletes the <quote>If-None-Match:</quote> HTTP client header.
4326 <!-- Boolean, Parameterized, Multi-value -->
4328 <para>Boolean.</para>
4333 <term>Parameter:</term>
4345 Removing the <quote>If-None-Match:</quote> HTTP client header
4346 is useful for filter testing, where you want to force a real
4347 reload instead of getting status code <quote>304</quote> which
4348 would cause the browser to use a cached copy of the page.
4351 It is also useful to make sure the header isn't used as a cookie
4352 replacement (unlikely but possible).
4355 Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
4356 caching problems, as long as the <quote>If-Modified-Since:</quote> header
4357 isn't blocked or missing as well.
4360 It is recommended to use this action together with
4361 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
4363 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
4369 <term>Example usage (section):</term>
4372 <screen># Let the browser revalidate cached documents but don't
4373 # allow the server to use the revalidation headers for user tracking.
4374 {+hide-if-modified-since{-60} \
4375 +overwrite-last-modified{randomize} \
4376 +crunch-if-none-match}
4385 <!-- ~~~~~ New section ~~~~~ -->
4386 <sect3 renderas="sect4" id="crunch-incoming-cookies">
4387 <title>crunch-incoming-cookies</title>
4391 <term>Typical use:</term>
4394 Prevent the web server from setting HTTP cookies on your system
4400 <term>Effect:</term>
4403 Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
4410 <!-- Boolean, Parameterized, Multi-value -->
4412 <para>Boolean.</para>
4417 <term>Parameter:</term>
4429 This action is only concerned with <emphasis>incoming</emphasis> HTTP cookies. For
4430 <emphasis>outgoing</emphasis> HTTP cookies, use
4431 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
4432 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
4435 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
4436 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
4437 since it would prevent the session cookies from being set. See also
4438 <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
4444 <term>Example usage:</term>
4447 <screen>+crunch-incoming-cookies</screen>
4455 <!-- ~~~~~ New section ~~~~~ -->
4456 <sect3 renderas="sect4" id="crunch-server-header">
4457 <title>crunch-server-header</title>
4463 <term>Typical use:</term>
4465 <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
4470 <term>Effect:</term>
4473 Deletes every header sent by the server that contains the string the user supplied as parameter.
4480 <!-- Boolean, Parameterized, Multi-value -->
4482 <para>Parameterized.</para>
4487 <term>Parameter:</term>
4499 This action allows you to block server headers for which no dedicated
4500 <application>Privoxy</application> action exists. <application>Privoxy</application>
4501 will remove every server header that contains the string you supplied as parameter.
4504 Regular expressions are <emphasis>not supported</emphasis> and you can't
4505 use this action to block different headers in the same request, unless
4506 they contain the same string.
4509 <literal>crunch-server-header</literal> is only meant for quick tests.
4510 If you have to block several different headers, or only want to modify
4511 parts of them, you should use a custom
4512 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
4516 Don't block any header without understanding the consequences.
4523 <term>Example usage (section):</term>
4526 <screen># Crunch server headers that try to prevent caching
4527 { +crunch-server-header{no-cache} }
4536 <!-- ~~~~~ New section ~~~~~ -->
4537 <sect3 renderas="sect4" id="crunch-outgoing-cookies">
4538 <title>crunch-outgoing-cookies</title>
4542 <term>Typical use:</term>
4545 Prevent the web server from reading any HTTP cookies from your system
4551 <term>Effect:</term>
4554 Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
4561 <!-- Boolean, Parameterized, Multi-value -->
4563 <para>Boolean.</para>
4568 <term>Parameter:</term>
4580 This action is only concerned with <emphasis>outgoing</emphasis> HTTP cookies. For
4581 <emphasis>incoming</emphasis> HTTP cookies, use
4582 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
4583 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
4586 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
4587 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
4588 since it would prevent the session cookies from being read.
4594 <term>Example usage:</term>
4597 <screen>+crunch-outgoing-cookies</screen>
4606 <!-- ~~~~~ New section ~~~~~ -->
4607 <sect3 renderas="sect4" id="deanimate-gifs">
4608 <title>deanimate-gifs</title>
4612 <term>Typical use:</term>
4614 <para>Stop those annoying, distracting animated GIF images.</para>
4619 <term>Effect:</term>
4622 De-animate GIF animations, i.e. reduce them to their first or last image.
4629 <!-- boolean, parameterized, Multi-value -->
4631 <para>Parameterized.</para>
4636 <term>Parameter:</term>
4639 <quote>last</quote> or <quote>first</quote>
4648 This will also shrink the images considerably (in bytes, not pixels!). If
4649 the option <quote>first</quote> is given, the first frame of the animation
4650 is used as the replacement. If <quote>last</quote> is given, the last
4651 frame of the animation is used instead, which probably makes more sense for
4652 most banner animations, but also has the risk of not showing the entire
4653 last frame (if it is only a delta to an earlier frame).
4656 You can safely use this action with patterns that will also match non-GIF
4657 objects, because no attempt will be made at anything that doesn't look like
4664 <term>Example usage:</term>
4667 <screen>+deanimate-gifs{last}</screen>
4674 <!-- ~~~~~ New section ~~~~~ -->
4675 <sect3 renderas="sect4" id="downgrade-http-version">
4676 <title>downgrade-http-version</title>
4680 <term>Typical use:</term>
4682 <para>Work around (very rare) problems with HTTP/1.1</para>
4687 <term>Effect:</term>
4690 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
4697 <!-- boolean, parameterized, Multi-value -->
4699 <para>Boolean.</para>
4704 <term>Parameter:</term>
4716 This is a left-over from the time when <application>Privoxy</application>
4717 didn't support important HTTP/1.1 features well. It is left here for the
4718 unlikely case that you experience HTTP/1.1-related problems with some server
4722 Note that enabling this action is only a workaround. It should not
4723 be enabled for sites that work without it. While it shouldn't break
4724 any pages, it has an (usually negative) performance impact.
4727 If you come across a site where enabling this action helps, please report it,
4728 so the cause of the problem can be analyzed. If the problem turns out to be
4729 caused by a bug in <application>Privoxy</application> it should be
4730 fixed so the following release works without the work around.
4736 <term>Example usage (section):</term>
4739 <screen>{+downgrade-http-version}
4740 problem-host.example.com</screen>
4748 <!-- ~~~~~ New section ~~~~~ -->
4749 <sect3 renderas="sect4" id="fast-redirects">
4750 <title>fast-redirects</title>
4754 <term>Typical use:</term>
4756 <para>Fool some click-tracking scripts and speed up indirect links.</para>
4761 <term>Effect:</term>
4764 Detects redirection URLs and redirects the browser without contacting
4765 the redirection server first.
4772 <!-- boolean, parameterized, Multi-value -->
4774 <para>Parameterized.</para>
4779 <term>Parameter:</term>
4784 <quote>simple-check</quote> to just search for the string <quote>http://</quote>
4785 to detect redirection URLs.
4790 <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
4791 for redirection URLs.
4802 Many sites, like yahoo.com, don't just link to other sites. Instead, they
4803 will link to some script on their own servers, giving the destination as a
4804 parameter, which will then redirect you to the final target. URLs
4805 resulting from this scheme typically look like:
4806 <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
4809 Sometimes, there are even multiple consecutive redirects encoded in the
4810 URL. These redirections via scripts make your web browsing more traceable,
4811 since the server from which you follow such a link can see where you go
4812 to. Apart from that, valuable bandwidth and time is wasted, while your
4813 browser asks the server for one redirect after the other. Plus, it feeds
4817 This feature is currently not very smart and is scheduled for improvement.
4818 If it is enabled by default, you will have to create some exceptions to
4819 this action. It can lead to failures in several ways:
4822 Not every URLs with other URLs as parameters is evil.
4823 Some sites offer a real service that requires this information to work.
4824 For example a validation service needs to know, which document to validate.
4825 <literal>fast-redirects</literal> assumes that every URL parameter that
4826 looks like another URL is a redirection target, and will always redirect to
4827 the last one. Most of the time the assumption is correct, but if it isn't,
4828 the user gets redirected anyway.
4831 Another failure occurs if the URL contains other parameters after the URL parameter.
4833 <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
4834 contains the redirection URL <quote>http://www.example.net/</quote>,
4835 followed by another parameter. <literal>fast-redirects</literal> doesn't know that
4836 and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
4837 Depending on the target server configuration, the parameter will be silently ignored
4838 or lead to a <quote>page not found</quote> error. You can prevent this problem by
4839 first using the <literal><link linkend="redirect">redirect</link></literal> action
4840 to remove the last part of the URL, but it requires a little effort.
4843 To detect a redirection URL, <literal>fast-redirects</literal> only
4844 looks for the string <quote>http://</quote>, either in plain text
4845 (invalid but often used) or encoded as <quote>http%3a//</quote>.
4846 Some sites use their own URL encoding scheme, encrypt the address
4847 of the target server or replace it with a database id. In theses cases
4848 <literal>fast-redirects</literal> is fooled and the request reaches the
4849 redirection server where it probably gets logged.
4855 <term>Example usage:</term>
4859 { +fast-redirects{simple-check} }
4862 { +fast-redirects{check-decoded-url} }
4863 another.example.com/testing</screen>
4872 <!-- ~~~~~ New section ~~~~~ -->
4873 <sect3 renderas="sect4" id="filter">
4874 <title>filter</title>
4878 <term>Typical use:</term>
4880 <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
4881 do fun text replacements, add personalized effects, etc.</para>
4886 <term>Effect:</term>
4889 All instances of text-based type, most notably HTML and JavaScript, to which
4890 this action applies, can be filtered on-the-fly through the specified regular
4891 expression based substitutions. (Note: as of version 3.0.3 plain text documents
4892 are exempted from filtering, because web servers often use the
4893 <literal>text/plain</literal> MIME type for all files whose type they don't know.)
4900 <!-- boolean, parameterized, Multi-value -->
4902 <para>Parameterized.</para>
4907 <term>Parameter:</term>
4910 The name of a content filter, as defined in the <link linkend="filter-file">filter file</link>.
4911 Filters can be defined in one or more files as defined by the
4912 <literal><link linkend="filterfile">filterfile</link></literal>
4913 option in the <link linkend="config">config file</link>.
4914 <filename>default.filter</filename> is the collection of filters
4915 supplied by the developers. Locally defined filters should go
4916 in their own file, such as <filename>user.filter</filename>.
4919 When used in its negative form,
4920 and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
4929 For your convenience, there are a number of pre-defined filters available
4930 in the distribution filter file that you can use. See the examples below for
4934 Filtering requires buffering the page content, which may appear to
4935 slow down page rendering since nothing is displayed until all content has
4936 passed the filters. (The total time until the page is completely rendered
4937 doesn't change much, but it may be perceived as slower since the page is
4938 not incrementally displayed.)
4939 This effect will be more noticeable on slower connections.
4942 <quote>Rolling your own</quote>
4943 filters requires a knowledge of
4944 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
4945 Expressions</quote></ulink> and
4946 <ulink url="http://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
4947 This is very powerful feature, and potentially very intrusive.
4948 Filters should be used with caution, and where an equivalent
4949 <quote>action</quote> is not available.
4952 The amount of data that can be filtered is limited to the
4953 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
4954 option in the main <link linkend="config">config file</link>. The
4955 default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
4956 data, and all pending data, is passed through unfiltered.
4959 Inappropriate MIME types, such as zipped files, are not filtered at all.
4960 (Again, only text-based types except plain text). Encrypted SSL data
4961 (from HTTPS servers) cannot be filtered either, since this would violate
4962 the integrity of the secure transaction. In some situations it might
4963 be necessary to protect certain text, like source code, from filtering
4964 by defining appropriate <literal>-filter</literal> exceptions.
4967 Compressed content can't be filtered either, but if &my-app;
4968 is compiled with zlib support and a supported compression algorithm
4969 is used (gzip or deflate), &my-app; can first decompress the content
4973 If you use a &my-app; version without zlib support, but want filtering to work on
4974 as much documents as possible, even those that would normally be sent compressed,
4975 you must use the <literal><link linkend="prevent-compression">prevent-compression</link></literal>
4976 action in conjunction with <literal>filter</literal>.
4979 Content filtering can achieve some of the same effects as the
4980 <literal><link linkend="block">block</link></literal>
4981 action, i.e. it can be used to block ads and banners. But the mechanism
4982 works quite differently. One effective use, is to block ad banners
4983 based on their size (see below), since many of these seem to be somewhat
4987 <link linkend="contact">Feedback</link> with suggestions for new or
4988 improved filters is particularly welcome!
4991 The below list has only the names and a one-line description of each
4992 predefined filter. There are <link linkend="predefined-filters">more
4993 verbose explanations</link> of what these filters do in the <link
4994 linkend="filter-file">filter file chapter</link>.
5000 <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
5001 See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
5002 more explanation on each:</term>
5005 <anchor id="filter-js-annoyances">
5006 <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse.</screen>
5009 <anchor id="filter-js-events">
5010 <screen>+filter{js-events} # Kill all JS event bindings and timers (Radically destructive! Only for extra nasty sites).</screen>
5013 <anchor id="filter-html-annoyances">
5014 <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse.</screen>
5017 <anchor id="filter-content-cookies">
5018 <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content.</screen>
5021 <anchor id="filter-refresh-tags">
5022 <screen>+filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups).</screen>
5025 <anchor id="filter-unsolicited-popups">
5026 <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability.</screen>
5029 <anchor id="filter-all-popups">
5030 <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability.</screen>
5033 <anchor id="filter-img-reorder">
5034 <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective.</screen>
5037 <anchor id="filter-banners-by-size">
5038 <screen>+filter{banners-by-size} # Kill banners by size.</screen>
5041 <anchor id="filter-banners-by-link">
5042 <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers.</screen>
5045 <anchor id="filter-webbugs">
5046 <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking).</screen>
5049 <anchor id="filter-tiny-textforms">
5050 <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap.</screen>
5053 <anchor id="filter-jumping-windows">
5054 <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves.</screen>
5057 <anchor id="filter-frameset-borders">
5058 <screen>+filter{frameset-borders} # Give frames a border and make them resizable.</screen>
5061 <anchor id="filter-demoronizer">
5062 <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets.</screen>
5065 <anchor id="filter-shockwave-flash">
5066 <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects.</screen>
5069 <anchor id="filter-quicktime-kioskmode">
5070 <screen>+filter{quicktime-kioskmode} # Make Quicktime movies saveable.</screen>
5073 <anchor id="filter-fun">
5074 <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
5077 <anchor id="filter-crude-parental">
5078 <screen>+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably.</screen>
5081 <anchor id="filter-ie-exploits">
5082 <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits.</screen>
5085 <anchor id="filter-site-specifics">
5086 <screen>+filter{site-specifics} # Cure for site-specific problems. Don't apply generally!</screen>
5089 <anchor id="filter-no-ping">
5090 <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
5093 <anchor id="filter-google">
5094 <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
5097 <anchor id="filter-yahoo">
5098 <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
5101 <anchor id="filter-msn">
5102 <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
5105 <anchor id="filter-blogspot">
5106 <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</screen>
5114 <!-- ~~~~~ New section ~~~~~ -->
5115 <sect3 renderas="sect4" id="force-text-mode">
5116 <title>force-text-mode</title>
5122 <term>Typical use:</term>
5124 <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
5129 <term>Effect:</term>
5132 Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
5139 <!-- Boolean, Parameterized, Multi-value -->
5141 <para>Boolean.</para>
5146 <term>Parameter:</term>
5158 As explained <literal><link linkend="filter">above</link></literal>,
5159 <application>Privoxy</application> tries to only filter files that are
5160 in some kind of text format. The same restrictions apply to
5161 <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
5162 <literal>force-text-mode</literal> declares a document as text,
5163 without looking at the <quote>Content-Type:</quote> first.
5167 Think twice before activating this action. Filtering binary data
5168 with regular expressions can cause file damage.
5175 <term>Example usage:</term>
5188 <!-- ~~~~~ New section ~~~~~ -->
5189 <sect3 renderas="sect4" id="forward-override">
5190 <title>forward-override</title>
5196 <term>Typical use:</term>
5198 <para>Change the forwarding settings based on User-Agent or request origin</para>
5203 <term>Effect:</term>
5206 Overrules the forward directives in the configuration file.
5213 <!-- Boolean, Parameterized, Multi-value -->
5215 <para>Multi-value.</para>
5220 <term>Parameter:</term>
5224 <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
5228 <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
5233 <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
5234 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
5235 to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
5236 for socks5 connections (with remote DNS resolution).
5241 <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
5242 listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
5243 Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
5244 (with local DNS resolution) instead, use <quote>forward-socks5</quote>
5245 for socks5 connections (with remote DNS resolution).
5256 This action takes parameters similar to the
5257 <link linkend="forwarding">forward</link> directives in the configuration
5258 file, but without the URL pattern. It can be used as replacement, but normally it's only
5259 used in cases where matching based on the request URL isn't sufficient.
5263 Please read the description for the <link linkend="forwarding">forward</link> directives before
5264 using this action. Forwarding to the wrong people will reduce your privacy and increase the
5265 chances of man-in-the-middle attacks.
5268 If the ports are missing or invalid, default values will be used. This might change
5269 in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
5273 Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
5274 to verify that your forward settings do what you thought the do.
5281 <term>Example usage:</term>
5285 # Always use direct connections for requests previously tagged as
5286 # <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
5287 # resuming downloads continues to work.
5288 # This way you can continue to use Tor for your normal browsing,
5289 # without overloading the Tor network with your FreeBSD ports updates
5290 # or downloads of bigger files like ISOs.
5291 # Note that HTTP headers are easy to fake and therefore their
5292 # values are as (un)trustworthy as your clients and users.
5293 {+forward-override{forward .} \
5294 -hide-if-modified-since \
5295 -overwrite-last-modified \
5297 TAG:^User-Agent: fetch libfetch/2\.0$
5306 <!-- ~~~~~ New section ~~~~~ -->
5307 <sect3 renderas="sect4" id="handle-as-empty-document">
5308 <title>handle-as-empty-document</title>
5314 <term>Typical use:</term>
5316 <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
5321 <term>Effect:</term>
5324 This action alone doesn't do anything noticeable. It just marks URLs.
5325 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
5326 the presence or absence of this mark decides whether an HTML <quote>BLOCKED</quote>
5327 page, or an empty document will be sent to the client as a substitute for the blocked content.
5328 The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
5335 <!-- Boolean, Parameterized, Multi-value -->
5337 <para>Boolean.</para>
5342 <term>Parameter:</term>
5354 Some browsers complain about syntax errors if JavaScript documents
5355 are blocked with <application>Privoxy's</application>
5356 default HTML page; this option can be used to silence them.
5357 And of course this action can also be used to eliminate the &my-app;
5358 BLOCKED message in frames.
5361 The content type for the empty document can be specified with
5362 <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
5363 but usually this isn't necessary.
5369 <term>Example usage:</term>
5372 <screen># Block all documents on example.org that end with ".js",
5373 # but send an empty document instead of the usual HTML message.
5374 {+block{Blocked JavaScript} +handle-as-empty-document}
5384 <!-- ~~~~~ New section ~~~~~ -->
5385 <sect3 renderas="sect4" id="handle-as-image">
5386 <title>handle-as-image</title>
5390 <term>Typical use:</term>
5392 <para>Mark URLs as belonging to images (so they'll be replaced by images <emphasis>if they do get blocked</emphasis>, rather than HTML pages)</para>
5397 <term>Effect:</term>
5400 This action alone doesn't do anything noticeable. It just marks URLs as images.
5401 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
5402 the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
5403 page, or a replacement image (as determined by the <literal><link
5404 linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
5405 client as a substitute for the blocked content.
5412 <!-- Boolean, Parameterized, Multi-value -->
5414 <para>Boolean.</para>
5419 <term>Parameter:</term>
5431 The below generic example section is actually part of <filename>default.action</filename>.
5432 It marks all URLs with well-known image file name extensions as images and should
5436 Users will probably only want to use the handle-as-image action in conjunction with
5437 <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
5438 reflect the file type, like in the second example section.
5441 Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
5442 frames require an HTML page to be sent, or they won't display properly.
5443 Forcing <literal>handle-as-image</literal> in this situation will not replace the
5444 ad frame with an image, but lead to error messages.
5450 <term>Example usage (sections):</term>
5453 <screen># Generic image extensions:
5456 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
5458 # These don't look like images, but they're banners and should be
5459 # blocked as images:
5461 {+block{Nasty banners.} +handle-as-image}
5462 nasty-banner-server.example.com/junk.cgi\?output=trash
5471 <!-- ~~~~~ New section ~~~~~ -->
5472 <sect3 renderas="sect4" id="hide-accept-language">
5473 <title>hide-accept-language</title>
5479 <term>Typical use:</term>
5481 <para>Pretend to use different language settings.</para>
5486 <term>Effect:</term>
5489 Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
5496 <!-- Boolean, Parameterized, Multi-value -->
5498 <para>Parameterized.</para>
5503 <term>Parameter:</term>
5506 Keyword: <quote>block</quote>, or any user defined value.
5515 Faking the browser's language settings can be useful to make a
5516 foreign User-Agent set with
5517 <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
5521 However some sites with content in different languages check the
5522 <quote>Accept-Language:</quote> to decide which one to take by default.
5523 Sometimes it isn't possible to later switch to another language without
5524 changing the <quote>Accept-Language:</quote> header first.
5527 Therefore it's a good idea to either only change the
5528 <quote>Accept-Language:</quote> header to languages you understand,
5529 or to languages that aren't wide spread.
5532 Before setting the <quote>Accept-Language:</quote> header
5533 to a rare language, you should consider that it helps to
5534 make your requests unique and thus easier to trace.
5535 If you don't plan to change this header frequently,
5536 you should stick to a common language.
5542 <term>Example usage (section):</term>
5545 <screen># Pretend to use Canadian language settings.
5546 {+hide-accept-language{en-ca} \
5547 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
5557 <!-- ~~~~~ New section ~~~~~ -->
5558 <sect3 renderas="sect4" id="hide-content-disposition">
5559 <title>hide-content-disposition</title>
5565 <term>Typical use:</term>
5567 <para>Prevent download menus for content you prefer to view inside the browser.</para>
5572 <term>Effect:</term>
5575 Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
5582 <!-- Boolean, Parameterized, Multi-value -->
5584 <para>Parameterized.</para>
5589 <term>Parameter:</term>
5592 Keyword: <quote>block</quote>, or any user defined value.
5601 Some servers set the <quote>Content-Disposition:</quote> HTTP header for
5602 documents they assume you want to save locally before viewing them.
5603 The <quote>Content-Disposition:</quote> header contains the file name
5604 the browser is supposed to use by default.
5607 In most browsers that understand this header, it makes it impossible to
5608 <emphasis>just view</emphasis> the document, without downloading it first,
5609 even if it's just a simple text file or an image.
5612 Removing the <quote>Content-Disposition:</quote> header helps
5613 to prevent this annoyance, but some browsers additionally check the
5614 <quote>Content-Type:</quote> header, before they decide if they can
5615 display a document without saving it first. In these cases, you have
5616 to change this header as well, before the browser stops displaying
5620 It is also possible to change the server's file name suggestion
5621 to another one, but in most cases it isn't worth the time to set
5625 This action will probably be removed in the future,
5626 use server-header filters instead.
5632 <term>Example usage:</term>
5635 <screen># Disarm the download link in Sourceforge's patch tracker
5637 +content-type-overwrite{text/plain}\
5638 +hide-content-disposition{block} }
5639 .sourceforge.net/tracker/download\.php</screen>
5647 <!-- ~~~~~ New section ~~~~~ -->
5648 <sect3 renderas="sect4" id="hide-if-modified-since">
5649 <title>hide-if-modified-since</title>
5655 <term>Typical use:</term>
5657 <para>Prevent yet another way to track the user's steps between sessions.</para>
5662 <term>Effect:</term>
5665 Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
5672 <!-- Boolean, Parameterized, Multi-value -->
5674 <para>Parameterized.</para>
5679 <term>Parameter:</term>
5682 Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
5691 Removing this header is useful for filter testing, where you want to force a real
5692 reload instead of getting status code <quote>304</quote>, which would cause the
5693 browser to use a cached copy of the page.
5696 Instead of removing the header, <literal>hide-if-modified-since</literal> can
5697 also add or subtract a random amount of time to/from the header's value.
5698 You specify a range of minutes where the random factor should be chosen from and
5699 <application>Privoxy</application> does the rest. A negative value means
5700 subtracting, a positive value adding.
5703 Randomizing the value of the <quote>If-Modified-Since:</quote> makes
5704 it less likely that the server can use the time as a cookie replacement,
5705 but you will run into caching problems if the random range is too high.
5708 It is a good idea to only use a small negative value and let
5709 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
5710 handle the greater changes.
5713 It is also recommended to use this action together with
5714 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>,
5715 otherwise it's more or less pointless.
5721 <term>Example usage (section):</term>
5724 <screen># Let the browser revalidate but make tracking based on the time less likely.
5725 {+hide-if-modified-since{-60} \
5726 +overwrite-last-modified{randomize} \
5727 +crunch-if-none-match}
5736 <!-- ~~~~~ New section ~~~~~ -->
5737 <sect3 renderas="sect4" id="hide-from-header">
5738 <title>hide-from-header</title>
5742 <term>Typical use:</term>
5744 <para>Keep your (old and ill) browser from telling web servers your email address</para>
5749 <term>Effect:</term>
5752 Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
5760 <!-- Boolean, Parameterized, Multi-value -->
5762 <para>Parameterized.</para>
5767 <term>Parameter:</term>
5770 Keyword: <quote>block</quote>, or any user defined value.
5779 The keyword <quote>block</quote> will completely remove the header
5780 (not to be confused with the <literal><link linkend="block">block</link></literal>
5784 Alternately, you can specify any value you prefer to be sent to the web
5785 server. If you do, it is a matter of fairness not to use any address that
5786 is actually used by a real person.
5789 This action is rarely needed, as modern web browsers don't send
5790 <quote>From:</quote> headers anymore.
5796 <term>Example usage:</term>
5799 <screen>+hide-from-header{block}</screen> or
5800 <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
5808 <!-- ~~~~~ New section ~~~~~ -->
5809 <sect3 renderas="sect4" id="hide-referrer">
5810 <title>hide-referrer</title>
5811 <anchor id="hide-referer">
5814 <term>Typical use:</term>
5816 <para>Conceal which link you followed to get to a particular site</para>
5821 <term>Effect:</term>
5824 Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
5825 or replaces it with a forged one.
5832 <!-- Boolean, Parameterized, Multi-value -->
5834 <para>Parameterized.</para>
5839 <term>Parameter:</term>
5843 <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
5846 <para><quote>conditional-forge</quote> to forge the header if the host has changed.</para>
5849 <para><quote>block</quote> to delete the header unconditionally.</para>
5852 <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
5855 <para>Any other string to set a user defined referrer.</para>
5865 <literal>conditional-block</literal> is the only parameter,
5866 that isn't easily detected in the server's log file. If it blocks the
5867 referrer, the request will look like the visitor used a bookmark or
5868 typed in the address directly.
5871 Leaving the referrer unmodified for requests on the same host
5872 allows the server owner to see the visitor's <quote>click path</quote>,
5873 but in most cases she could also get that information by comparing
5874 other parts of the log file: for example the User-Agent if it isn't
5875 a very common one, or the user's IP address if it doesn't change between
5879 Always blocking the referrer, or using a custom one, can lead to
5880 failures on servers that check the referrer before they answer any
5881 requests, in an attempt to prevent their content from being
5882 embedded or linked to elsewhere.
5885 Both <literal>conditional-block</literal> and <literal>forge</literal>
5886 will work with referrer checks, as long as content and valid referring page
5887 are on the same host. Most of the time that's the case.
5890 <literal>hide-referer</literal> is an alternate spelling of
5891 <literal>hide-referrer</literal> and the two can be can be freely
5892 substituted with each other. (<quote>referrer</quote> is the
5893 correct English spelling, however the HTTP specification has a bug - it
5894 requires it to be spelled as <quote>referer</quote>.)
5900 <term>Example usage:</term>
5903 <screen>+hide-referrer{forge}</screen> or
5904 <screen>+hide-referrer{http://www.yahoo.com/}</screen>
5912 <!-- ~~~~~ New section ~~~~~ -->
5913 <sect3 renderas="sect4" id="hide-user-agent">
5914 <title>hide-user-agent</title>
5918 <term>Typical use:</term>
5920 <para>Try to conceal your type of browser and client operating system</para>
5925 <term>Effect:</term>
5928 Replaces the value of the <quote>User-Agent:</quote> HTTP header
5929 in client requests with the specified value.
5936 <!-- Boolean, Parameterized, Multi-value -->
5938 <para>Parameterized.</para>
5943 <term>Parameter:</term>
5946 Any user-defined string.
5956 This can lead to problems on web sites that depend on looking at this header in
5957 order to customize their content for different browsers (which, by the
5958 way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
5959 work browser-independently).
5963 Using this action in multi-user setups or wherever different types of
5964 browsers will access the same <application>Privoxy</application> is
5965 <emphasis>not recommended</emphasis>. In single-user, single-browser
5966 setups, you might use it to delete your OS version information from
5967 the headers, because it is an invitation to exploit known bugs for your
5968 OS. It is also occasionally useful to forge this in order to access
5969 sites that won't let you in otherwise (though there may be a good
5970 reason in some cases).
5973 More information on known user-agent strings can be found at
5974 <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
5976 <ulink url="http://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
5982 <term>Example usage:</term>
5985 <screen>+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}</screen>
5993 <!-- ~~~~~ New section ~~~~~ -->
5994 <sect3 renderas="sect4" id="limit-connect">
5995 <title>limit-connect</title>
5999 <term>Typical use:</term>
6001 <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
6006 <term>Effect:</term>
6009 Specifies to which ports HTTP CONNECT requests are allowable.
6016 <!-- Boolean, Parameterized, Multi-value -->
6018 <para>Parameterized.</para>
6023 <term>Parameter:</term>
6026 A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
6027 defaulting to 0 and the maximum to 65K).
6036 By default, i.e. if no <literal>limit-connect</literal> action applies,
6037 <application>Privoxy</application> allows HTTP CONNECT requests to all
6038 ports. Use <literal>limit-connect</literal> if fine-grained control
6039 is desired for some or all destinations.
6042 The CONNECT methods exists in HTTP to allow access to secure websites
6043 (<quote>https://</quote> URLs) through proxies. It works very simply:
6044 the proxy connects to the server on the specified port, and then
6045 short-circuits its connections to the client and to the remote server.
6046 This means CONNECT-enabled proxies can be used as TCP relays very easily.
6049 <application>Privoxy</application> relays HTTPS traffic without seeing
6050 the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
6051 filters. By specifying an invalid port range you can disable HTTPS entirely.
6057 <term>Example usages:</term>
6059 <!-- I had trouble getting the spacing to look right in my browser -->
6060 <!-- I probably have the wrong font setup, bollocks. -->
6061 <!-- Apparently the emphasis tag uses a proportional font no matter what -->
6063 <screen>+limit-connect{443} # Port 443 is OK.
6064 +limit-connect{80,443} # Ports 80 and 443 are OK.
6065 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
6066 +limit-connect{-} # All ports are OK
6067 +limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
6075 <!-- ~~~~~ New section ~~~~~ -->
6076 <sect3 renderas="sect4" id="limit-cookie-lifetime">
6077 <title>limit-cookie-lifetime</title>
6081 <term>Typical use:</term>
6083 <para>Limit the lifetime of HTTP cookies to a couple of minutes or hours.</para>
6088 <term>Effect:</term>
6091 Overwrites the expires field in Set-Cookie server headers if it's above the specified limit.
6098 <!-- Boolean, Parameterized, Multi-value -->
6100 <para>Parameterized.</para>
6105 <term>Parameter:</term>
6108 The lifetime limit in minutes, or 0.
6117 This action reduces the lifetime of HTTP cookies coming from the
6118 server to the specified number of minutes, starting from the time
6119 the cookie passes Privoxy.
6122 Cookies with a lifetime below the limit are not modified.
6123 The lifetime of session cookies is set to the specified limit.
6126 The effect of this action depends on the server.
6129 In case of servers which refresh their cookies with each response
6130 (or at least frequently), the lifetime limit set by this action
6132 Thus, a session associated with the cookie continues to work with
6133 this action enabled, as long as a new request is made before the
6134 last limit set is reached.
6137 However, some servers send their cookies once, with a lifetime of several
6138 years (the year 2037 is a popular choice), and do not refresh them
6139 until a certain event in the future, for example the user logging out.
6140 In this case this action may limit the absolute lifetime of the session,
6141 even if requests are made frequently.
6144 If the parameter is <quote>0</quote>, this action behaves like
6145 <literal><link linkend="session-cookies-only">session-cookies-only</link></literal>.
6151 <term>Example usages:</term>
6154 <screen>+limit-cookie-lifetime{60}
6162 <!-- ~~~~~ New section ~~~~~ -->
6163 <sect3 renderas="sect4" id="prevent-compression">
6164 <title>prevent-compression</title>
6168 <term>Typical use:</term>
6171 Ensure that servers send the content uncompressed, so it can be
6172 passed through <literal><link linkend="filter">filter</link></literal>s.
6178 <term>Effect:</term>
6181 Removes the Accept-Encoding header which can be used to ask for compressed transfer.
6188 <!-- Boolean, Parameterized, Multi-value -->
6190 <para>Boolean.</para>
6195 <term>Parameter:</term>
6207 More and more websites send their content compressed by default, which
6208 is generally a good idea and saves bandwidth. But the <literal><link
6209 linkend="filter">filter</link></literal> and
6210 <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
6211 actions need access to the uncompressed data.
6214 When compiled with zlib support (available since &my-app; 3.0.7), content that should be
6215 filtered is decompressed on-the-fly and you don't have to worry about this action.
6216 If you are using an older &my-app; version, or one that hasn't been compiled with zlib
6217 support, this action can be used to convince the server to send the content uncompressed.
6220 Most text-based instances compress very well, the size is seldom decreased by less than 50%,
6221 for markup-heavy instances like news feeds saving more than 90% of the original size isn't
6225 Not using compression will therefore slow down the transfer, and you should only
6226 enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
6227 predefined action settings.
6230 Note that some (rare) ill-configured sites don't handle requests for uncompressed
6231 documents correctly. Broken PHP applications tend to send an empty document body,
6232 some IIS versions only send the beginning of the content. If you enable
6233 <literal>prevent-compression</literal> per default, you might want to add
6234 exceptions for those sites. See the example for how to do that.
6240 <term>Example usage (sections):</term>
6244 # Selectively turn off compression, and enable a filter
6246 { +filter{tiny-textforms} +prevent-compression }
6247 # Match only these sites
6252 # Or instead, we could set a universal default:
6254 { +prevent-compression }
6257 # Then maybe make exceptions for broken sites:
6259 { -prevent-compression }
6260 .compusa.com/</screen>
6269 <!-- ~~~~~ New section ~~~~~ -->
6270 <sect3 renderas="sect4" id="overwrite-last-modified">
6271 <title>overwrite-last-modified</title>
6277 <term>Typical use:</term>
6279 <para>Prevent yet another way to track the user's steps between sessions.</para>
6284 <term>Effect:</term>
6287 Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
6294 <!-- Boolean, Parameterized, Multi-value -->
6296 <para>Parameterized.</para>
6301 <term>Parameter:</term>
6304 One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
6305 and <quote>randomize</quote>
6314 Removing the <quote>Last-Modified:</quote> header is useful for filter
6315 testing, where you want to force a real reload instead of getting status
6316 code <quote>304</quote>, which would cause the browser to reuse the old
6317 version of the page.
6320 The <quote>randomize</quote> option overwrites the value of the
6321 <quote>Last-Modified:</quote> header with a randomly chosen time
6322 between the original value and the current time. In theory the server
6323 could send each document with a different <quote>Last-Modified:</quote>
6324 header to track visits without using cookies. <quote>Randomize</quote>
6325 makes it impossible and the browser can still revalidate cached documents.
6328 <quote>reset-to-request-time</quote> overwrites the value of the
6329 <quote>Last-Modified:</quote> header with the current time. You could use
6330 this option together with
6331 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
6332 to further customize your random range.
6335 The preferred parameter here is <quote>randomize</quote>. It is safe
6336 to use, as long as the time settings are more or less correct.
6337 If the server sets the <quote>Last-Modified:</quote> header to the time
6338 of the request, the random range becomes zero and the value stays the same.
6339 Therefore you should later randomize it a second time with
6340 <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
6344 It is also recommended to use this action together with
6345 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
6351 <term>Example usage:</term>
6354 <screen># Let the browser revalidate without being tracked across sessions
6355 { +hide-if-modified-since{-60} \
6356 +overwrite-last-modified{randomize} \
6357 +crunch-if-none-match}
6366 <!-- ~~~~~ New section ~~~~~ -->
6367 <sect3 renderas="sect4" id="redirect">
6368 <title>redirect</title>
6374 <term>Typical use:</term>
6377 Redirect requests to other sites.
6383 <term>Effect:</term>
6386 Convinces the browser that the requested document has been moved
6387 to another location and the browser should get it from there.
6394 <!-- Boolean, Parameterized, Multi-value -->
6396 <para>Parameterized</para>
6401 <term>Parameter:</term>
6404 An absolute URL or a single pcrs command.
6413 Requests to which this action applies are answered with a
6414 HTTP redirect to URLs of your choosing. The new URL is
6415 either provided as parameter, or derived by applying a
6416 single pcrs command to the original URL.
6419 The syntax for pcrs commands is documented in the
6420 <link linkend="filter-file">filter file</link> section.
6423 This action will be ignored if you use it together with
6424 <literal><link linkend="block">block</link></literal>.
6425 It can be combined with
6426 <literal><link linkend="fast-redirects">fast-redirects{check-decoded-url}</link></literal>
6427 to redirect to a decoded version of a rewritten URL.
6430 Use this action carefully, make sure not to create redirection loops
6431 and be aware that using your own redirects might make it
6432 possible to fingerprint your requests.
6435 In case of problems with your redirects, or simply to watch
6436 them working, enable <link linkend="DEBUG">debug 128</link>.
6442 <term>Example usages:</term>
6445 <screen># Replace example.com's style sheet with another one
6446 { +redirect{http://localhost/css-replacements/example.com.css} }
6447 example.com/stylesheet\.css
6449 # Create a short, easy to remember nickname for a favorite site
6450 # (relies on the browser accept and forward invalid URLs to &my-app;)
6451 { +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
6454 # Always use the expanded view for Undeadly.org articles
6455 # (Note the $ at the end of the URL pattern to make sure
6456 # the request for the rewritten URL isn't redirected as well)
6457 {+redirect{s@$@&mode=expanded@}}
6458 undeadly.org/cgi\?action=article&sid=\d*$
6460 # Redirect Google search requests to MSN
6461 {+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}}
6464 # Redirect MSN search requests to Yahoo
6465 {+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}}
6466 search.msn.com//results\.aspx\?q=
6468 # Redirect remote requests for this manual
6469 # to the local version delivered by Privoxy
6470 {+redirect{s@^http://www@http://config@}}
6471 www.privoxy.org/user-manual/</screen>
6480 <!-- ~~~~~ New section ~~~~~ -->
6481 <sect3 renderas="sect4" id="server-header-filter">
6482 <title>server-header-filter</title>
6486 <term>Typical use:</term>
6489 Rewrite or remove single server headers.
6495 <term>Effect:</term>
6498 All server headers to which this action applies are filtered on-the-fly
6499 through the specified regular expression based substitutions.
6506 <!-- boolean, parameterized, Multi-value -->
6508 <para>Parameterized.</para>
6513 <term>Parameter:</term>
6516 The name of a server-header filter, as defined in one of the
6517 <link linkend="filter-file">filter files</link>.
6526 Server-header filters are applied to each header on its own, not to
6527 all at once. This makes it easier to diagnose problems, but on the downside
6528 you can't write filters that only change header x if header y's value is z.
6529 You can do that by using tags though.
6532 Server-header filters are executed after the other header actions have finished
6533 and use their output as input.
6536 Please refer to the <link linkend="filter-file">filter file chapter</link>
6537 to learn which server-header filters are available by default, and how to
6544 <term>Example usage (section):</term>
6548 {+server-header-filter{html-to-xml}}
6549 example.org/xml-instance-that-is-delivered-as-html
6551 {+server-header-filter{xml-to-html}}
6552 example.org/instance-that-is-delivered-as-xml-but-is-not
6562 <!-- ~~~~~ New section ~~~~~ -->
6563 <sect3 renderas="sect4" id="server-header-tagger">
6564 <title>server-header-tagger</title>
6568 <term>Typical use:</term>
6571 Enable or disable filters based on the Content-Type header.
6577 <term>Effect:</term>
6580 Server headers to which this action applies are filtered on-the-fly through
6581 the specified regular expression based substitutions, the result is used as
6589 <!-- boolean, parameterized, Multi-value -->
6591 <para>Parameterized.</para>
6596 <term>Parameter:</term>
6599 The name of a server-header tagger, as defined in one of the
6600 <link linkend="filter-file">filter files</link>.
6609 Server-header taggers are applied to each header on its own,
6610 and as the header isn't modified, each tagger <quote>sees</quote>
6614 Server-header taggers are executed before all other header actions
6615 that modify server headers. Their tags can be used to control
6616 all of the other server-header actions, the content filters
6617 and the crunch actions (<link linkend="redirect">redirect</link>
6618 and <link linkend="block">block</link>).
6621 Obviously crunching based on tags created by server-header taggers
6622 doesn't prevent the request from showing up in the server's log file.
6629 <term>Example usage (section):</term>
6633 # Tag every request with the content type declared by the server
6634 {+server-header-tagger{content-type}}
6645 <!-- ~~~~~ New section ~~~~~ -->
6646 <sect3 renderas="sect4" id="session-cookies-only">
6647 <title>session-cookies-only</title>
6651 <term>Typical use:</term>
6654 Allow only temporary <quote>session</quote> cookies (for the current
6655 browser session <emphasis>only</emphasis>).
6661 <term>Effect:</term>
6664 Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
6665 server headers. Most browsers will not store such cookies permanently and
6666 forget them in between sessions.
6673 <!-- Boolean, Parameterized, Multi-value -->
6675 <para>Boolean.</para>
6680 <term>Parameter:</term>
6692 This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
6693 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
6694 websites that insist or rely on setting cookies, without compromising your privacy too badly.
6697 Most browsers will not permanently store cookies that have been processed by
6698 <literal>session-cookies-only</literal> and will forget about them between sessions.
6699 This makes profiling cookies useless, but won't break sites which require cookies so
6700 that you can log in for transactions. This is generally turned on for all
6701 sites, and is the recommended setting.
6704 It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
6705 together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
6706 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
6707 will be plainly killed.
6710 Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
6711 field. If you use an exotic browser, you might want to try it out to be sure.
6714 This setting also has no effect on cookies that may have been stored
6715 previously by the browser before starting <application>Privoxy</application>.
6716 These would have to be removed manually.
6719 <application>Privoxy</application> also uses
6720 the <link linkend="filter-content-cookies">content-cookies filter</link>
6721 to block some types of cookies. Content cookies are not effected by
6722 <literal>session-cookies-only</literal>.
6728 <term>Example usage:</term>
6731 <screen>+session-cookies-only</screen>
6739 <!-- ~~~~~ New section ~~~~~ -->
6740 <sect3 renderas="sect4" id="set-image-blocker">
6741 <title>set-image-blocker</title>
6745 <term>Typical use:</term>
6747 <para>Choose the replacement for blocked images</para>
6752 <term>Effect:</term>
6755 This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
6756 <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
6757 linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
6758 apply, i.e. if the request is to be blocked as an image,
6759 <emphasis>then</emphasis> the parameter of this action decides what will be
6760 sent as a replacement.
6767 <!-- Boolean, Parameterized, Multi-value -->
6769 <para>Parameterized.</para>
6774 <term>Parameter:</term>
6779 <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
6780 decent, scales very well, and makes it obvious where banners were busted.
6785 <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
6786 completely, but makes it hard to detect where <application>Privoxy</application> has blocked
6787 images on a given page and complicates troubleshooting if <application>Privoxy</application>
6788 has blocked innocent images, like navigation icons.
6793 <quote><replaceable class="parameter">target-url</replaceable></quote> to
6794 send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
6795 to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
6796 (But note that not all browsers support redirecting to a local file system).
6799 A good application of redirects is to use special <application>Privoxy</application>-built-in
6800 URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
6801 This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
6802 the first place, but enables your browser to cache the replacement image, instead of requesting
6803 it over and over again.
6814 The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
6815 class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
6816 either <quote>blank</quote> or <quote>pattern</quote>.
6819 There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
6820 used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
6821 Auto will select the type of image that would have applied to the referring page, had it been an image.
6827 <term>Example usage:</term>
6833 <screen>+set-image-blocker{pattern}</screen>
6836 Redirect to the BSD daemon:
6839 <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
6842 Redirect to the built-in pattern for better caching:
6845 <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
6853 <!-- ~~~~~ New section ~~~~~ -->
6855 <title>Summary</title>
6857 Note that many of these actions have the potential to cause a page to
6858 misbehave, possibly even not to display at all. There are many ways
6859 a site designer may choose to design his site, and what HTTP header
6860 content, and other criteria, he may depend on. There is no way to have hard
6861 and fast rules for all sites. See the <link
6862 linkend="ACTIONSANAT">Appendix</link> for a brief example on troubleshooting
6868 <!-- ~~~~~ New section ~~~~~ -->
6869 <sect2 id="aliases">
6870 <title>Aliases</title>
6872 Custom <quote>actions</quote>, known to <application>Privoxy</application>
6873 as <quote>aliases</quote>, can be defined by combining other actions.
6874 These can in turn be invoked just like the built-in actions.
6875 Currently, an alias name can contain any character except space, tab,
6877 <quote>{</quote> and <quote>}</quote>, but we <emphasis>strongly
6878 recommend</emphasis> that you only use <quote>a</quote> to <quote>z</quote>,
6879 <quote>0</quote> to <quote>9</quote>, <quote>+</quote>, and <quote>-</quote>.
6880 Alias names are not case sensitive, and are not required to start with a
6881 <quote>+</quote> or <quote>-</quote> sign, since they are merely textually
6885 Aliases can be used throughout the actions file, but they <emphasis>must be
6886 defined in a special section at the top of the file!</emphasis>
6887 And there can only be one such section per actions file. Each actions file may
6888 have its own alias section, and the aliases defined in it are only visible
6892 There are two main reasons to use aliases: One is to save typing for frequently
6893 used combinations of actions, the other one is a gain in flexibility: If you
6894 decide once how you want to handle shops by defining an alias called
6895 <quote>shop</quote>, you can later change your policy on shops in
6896 <emphasis>one</emphasis> place, and your changes will take effect everywhere
6897 in the actions file where the <quote>shop</quote> alias is used. Calling aliases
6898 by their purpose also makes your actions files more readable.
6901 Currently, there is one big drawback to using aliases, though:
6902 <application>Privoxy</application>'s built-in web-based action file
6903 editor honors aliases when reading the actions files, but it expands
6904 them before writing. So the effects of your aliases are of course preserved,
6905 but the aliases themselves are lost when you edit sections that use aliases
6910 Now let's define some aliases...
6915 # Useful custom aliases we can use later.
6917 # Note the (required!) section header line and that this section
6918 # must be at the top of the actions file!
6922 # These aliases just save typing later:
6923 # (Note that some already use other aliases!)
6925 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6926 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6927 +block-as-image = +block{Blocked image.} +handle-as-image
6928 allow-all-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
6930 # These aliases define combinations of actions
6931 # that are useful for certain types of sites:
6933 fragile = -<link linkend="BLOCK">block</link> -<link linkend="FILTER">filter</link> -crunch-all-cookies -<link linkend="FAST-REDIRECTS">fast-redirects</link> -<link linkend="HIDE-REFERER">hide-referrer</link> -<link linkend="PREVENT-COMPRESSION">prevent-compression</link>
6935 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link>
6937 # Short names for other aliases, for really lazy people ;-)
6939 c0 = +crunch-all-cookies
6940 c1 = -crunch-all-cookies</screen>
6944 ...and put them to use. These sections would appear in the lower part of an
6945 actions file and define exceptions to the default actions (as specified further
6946 up for the <quote>/</quote> pattern):
6951 # These sites are either very complex or very keen on
6952 # user data and require minimal interference to work:
6955 .office.microsoft.com
6956 .windowsupdate.microsoft.com
6957 # Gmail is really mail.google.com, not gmail.com
6961 # Allow cookies (for setting and retrieving your customer data)
6965 .worldpay.com # for quietpc.com
6968 # These shops require pop-ups:
6970 {-filter{all-popups} -filter{unsolicited-popups}}
6972 .overclockers.co.uk</screen>
6976 Aliases like <quote>shop</quote> and <quote>fragile</quote> are typically used for
6977 <quote>problem</quote> sites that require more than one action to be disabled
6978 in order to function properly.
6984 <!-- ~~~~~ New section ~~~~~ -->
6985 <sect2 id="act-examples">
6986 <title>Actions Files Tutorial</title>
6988 The above chapters have shown <link linkend="actions-file">which actions files
6989 there are and how they are organized</link>, how actions are <link
6990 linkend="actions">specified</link> and <link linkend="actions-apply">applied
6991 to URLs</link>, how <link linkend="af-patterns">patterns</link> work, and how to
6992 define and use <link linkend="aliases">aliases</link>. Now, let's look at an
6993 example <filename>match-all.action</filename>, <filename>default.action</filename>
6994 and <filename>user.action</filename> file and see how all these pieces come together:
6998 <title>match-all.action</title>
7000 Remember <emphasis>all actions are disabled when matching starts</emphasis>,
7001 so we have to explicitly enable the ones we want.
7005 While the <filename>match-all.action</filename> file only contains a
7006 single section, it is probably the most important one. It has only one
7007 pattern, <quote><literal>/</literal></quote>, but this pattern
7008 <link linkend="af-patterns">matches all URLs</link>. Therefore, the set of
7009 actions used in this <quote>default</quote> section <emphasis>will
7010 be applied to all requests as a start</emphasis>. It can be partly or
7011 wholly overridden by other actions files like <filename>default.action</filename>
7012 and <filename>user.action</filename>, but it will still be largely responsible
7013 for your overall browsing experience.
7017 Again, at the start of matching, all actions are disabled, so there is
7018 no need to disable any actions here. (Remember: a <quote>+</quote>
7019 preceding the action name enables the action, a <quote>-</quote> disables!).
7020 Also note how this long line has been made more readable by splitting it into
7021 multiple lines with line continuation.
7027 +<link linkend="CHANGE-X-FORWARDED-FOR">change-x-forwarded-for{block}</link> \
7028 +<link linkend="HIDE-FROM-HEADER">hide-from-header{block}</link> \
7029 +<link linkend="SET-IMAGE-BLOCKER">set-image-blocker{pattern}</link> \
7036 The default behavior is now set.
7041 <title>default.action</title>
7044 If you aren't a developer, there's no need for you to edit the
7045 <filename>default.action</filename> file. It is maintained by
7046 the &my-app; developers and if you disagree with some of the
7047 sections, you should overrule them in your <filename>user.action</filename>.
7051 Understanding the <filename>default.action</filename> file can
7052 help you with your <filename>user.action</filename>, though.
7056 The first section in this file is a special section for internal use
7057 that prevents older &my-app; versions from reading the file:
7062 ##########################################################################
7063 # Settings -- Don't change! For internal Privoxy use ONLY.
7064 ##########################################################################
7066 for-privoxy-version=3.0.11</screen>
7070 After that comes the (optional) alias section. We'll use the example
7071 section from the above <link linkend="aliases">chapter on aliases</link>,
7072 that also explains why and how aliases are used:
7077 ##########################################################################
7079 ##########################################################################
7082 # These aliases just save typing later:
7083 # (Note that some already use other aliases!)
7085 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
7086 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
7087 +block-as-image = +block{Blocked image.} +handle-as-image
7088 mercy-for-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
7090 # These aliases define combinations of actions
7091 # that are useful for certain types of sites:
7093 fragile = -<link linkend="BLOCK">block</link> -<link linkend="FILTER">filter</link> -crunch-all-cookies -<link linkend="FAST-REDIRECTS">fast-redirects</link> -<link linkend="HIDE-REFERER">hide-referrer</link>
7094 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link></screen>
7098 The first of our specialized sections is concerned with <quote>fragile</quote>
7099 sites, i.e. sites that require minimum interference, because they are either
7100 very complex or very keen on tracking you (and have mechanisms in place that
7101 make them unusable for people who avoid being tracked). We will simply use
7102 our pre-defined <literal>fragile</literal> alias instead of stating the list
7103 of actions explicitly:
7108 ##########################################################################
7109 # Exceptions for sites that'll break under the default action set:
7110 ##########################################################################
7112 # "Fragile" Use a minimum set of actions for these sites (see alias above):
7115 .office.microsoft.com # surprise, surprise!
7116 .windowsupdate.microsoft.com
7117 mail.google.com</screen>
7121 Shopping sites are not as fragile, but they typically
7122 require cookies to log in, and pop-up windows for shopping
7123 carts or item details. Again, we'll use a pre-defined alias:
7132 .worldpay.com # for quietpc.com
7134 .scan.co.uk</screen>
7138 The <literal><link linkend="FAST-REDIRECTS">fast-redirects</link></literal>
7139 action, which may have been enabled in <filename>match-all.action</filename>,
7140 breaks some sites. So disable it for popular sites where we know it misbehaves:
7145 { -<link linkend="FAST-REDIRECTS">fast-redirects</link> }
7149 .altavista.com/.*(like|url|link):http
7150 .altavista.com/trans.*urltext=http
7151 .nytimes.com</screen>
7155 It is important that <application>Privoxy</application> knows which
7156 URLs belong to images, so that <emphasis>if</emphasis> they are to
7157 be blocked, a substitute image can be sent, rather than an HTML page.
7158 Contacting the remote site to find out is not an option, since it
7159 would destroy the loading time advantage of banner blocking, and it
7160 would feed the advertisers information about you. We can mark any
7161 URL as an image with the <literal><link
7162 linkend="handle-as-image">handle-as-image</link></literal> action,
7163 and marking all URLs that end in a known image file extension is a
7169 ##########################################################################
7171 ##########################################################################
7173 # Define which file types will be treated as images, in case they get
7174 # blocked further down this file:
7176 { +<link linkend="HANDLE-AS-IMAGE">handle-as-image</link> }
7177 /.*\.(gif|jpe?g|png|bmp|ico)$</screen>
7181 And then there are known banner sources. They often use scripts to
7182 generate the banners, so it won't be visible from the URL that the
7183 request is for an image. Hence we block them <emphasis>and</emphasis>
7184 mark them as images in one go, with the help of our
7185 <literal>+block-as-image</literal> alias defined above. (We could of
7186 course just as well use <literal>+<link linkend="block">block</link>
7187 +<link linkend="handle-as-image">handle-as-image</link></literal> here.)
7188 Remember that the type of the replacement image is chosen by the
7189 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
7190 action. Since all URLs have matched the default section with its
7191 <literal>+<link linkend="set-image-blocker">set-image-blocker</link>{pattern}</literal>
7192 action before, it still applies and needn't be repeated:
7197 # Known ad generators:
7202 .ad.*.doubleclick.net
7203 .a.yimg.com/(?:(?!/i/).)*$
7204 .a[0-9].yimg.com/(?:(?!/i/).)*$
7210 One of the most important jobs of <application>Privoxy</application>
7211 is to block banners. Many of these can be <quote>blocked</quote>
7212 by the <literal><link linkend="filter">filter</link>{banners-by-size}</literal>
7213 action, which we enabled above, and which deletes the references to banner
7214 images from the pages while they are loaded, so the browser doesn't request
7215 them anymore, and hence they don't need to be blocked here. But this naturally
7216 doesn't catch all banners, and some people choose not to use filters, so we
7217 need a comprehensive list of patterns for banner URLs here, and apply the
7218 <literal><link linkend="block">block</link></literal> action to them.
7221 First comes many generic patterns, which do most of the work, by
7222 matching typical domain and path name components of banners. Then comes
7223 a list of individual patterns for specific sites, which is omitted here
7224 to keep the example short:
7229 ##########################################################################
7230 # Block these fine banners:
7231 ##########################################################################
7232 { <link linkend="BLOCK">+block{Banner ads.}</link> }
7240 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
7241 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
7243 # Site-specific patterns (abbreviated):
7245 .hitbox.com</screen>
7249 It's quite remarkable how many advertisers actually call their banner
7250 servers ads.<replaceable>company</replaceable>.com, or call the directory
7251 in which the banners are stored simply <quote>banners</quote>. So the above
7252 generic patterns are surprisingly effective.
7255 But being very generic, they necessarily also catch URLs that we don't want
7256 to block. The pattern <literal>.*ads.</literal> e.g. catches
7257 <quote>nasty-<emphasis>ads</emphasis>.nasty-corp.com</quote> as intended,
7258 but also <quote>downlo<emphasis>ads</emphasis>.sourcefroge.net</quote> or
7259 <quote><emphasis>ads</emphasis>l.some-provider.net.</quote> So here come some
7260 well-known exceptions to the <literal>+<link linkend="BLOCK">block</link></literal>
7264 Note that these are exceptions to exceptions from the default! Consider the URL
7265 <quote>downloads.sourcefroge.net</quote>: Initially, all actions are deactivated,
7266 so it wouldn't get blocked. Then comes the defaults section, which matches the
7267 URL, but just deactivates the <literal><link linkend="BLOCK">block</link></literal>
7268 action once again. Then it matches <literal>.*ads.</literal>, an exception to the
7269 general non-blocking policy, and suddenly
7270 <literal><link linkend="BLOCK">+block</link></literal> applies. And now, it'll match
7271 <literal>.*loads.</literal>, where <literal><link linkend="BLOCK">-block</link></literal>
7272 applies, so (unless it matches <emphasis>again</emphasis> further down) it ends up
7273 with no <literal><link linkend="BLOCK">block</link></literal> action applying.
7278 ##########################################################################
7279 # Save some innocent victims of the above generic block patterns:
7280 ##########################################################################
7284 { -<link linkend="BLOCK">block</link> }
7285 adv[io]*. # (for advogato.org and advice.*)
7286 adsl. # (has nothing to do with ads)
7287 adobe. # (has nothing to do with ads either)
7288 ad[ud]*. # (adult.* and add.*)
7289 .edu # (universities don't host banners (yet!))
7290 .*loads. # (downloads, uploads etc)
7298 www.globalintersec.com/adv # (adv = advanced)
7299 www.ugu.com/sui/ugu/adv</screen>
7303 Filtering source code can have nasty side effects,
7304 so make an exception for our friends at sourceforge.net,
7305 and all paths with <quote>cvs</quote> in them. Note that
7306 <literal>-<link linkend="FILTER">filter</link></literal>
7307 disables <emphasis>all</emphasis> filters in one fell swoop!
7312 # Don't filter code!
7314 { -<link linkend="FILTER">filter</link> }
7319 .sourceforge.net</screen>
7323 The actual <filename>default.action</filename> is of course much more
7324 comprehensive, but we hope this example made clear how it works.
7329 <sect3><title>user.action</title>
7332 So far we are painting with a broad brush by setting general policies,
7333 which would be a reasonable starting point for many people. Now,
7334 you might want to be more specific and have customized rules that
7335 are more suitable to your personal habits and preferences. These would
7336 be for narrowly defined situations like your ISP or your bank, and should
7337 be placed in <filename>user.action</filename>, which is parsed after all other
7338 actions files and hence has the last word, over-riding any previously
7339 defined actions. <filename>user.action</filename> is also a
7340 <emphasis>safe</emphasis> place for your personal settings, since
7341 <filename>default.action</filename> is actively maintained by the
7342 <application>Privoxy</application> developers and you'll probably want
7343 to install updated versions from time to time.
7347 So let's look at a few examples of things that one might typically do in
7348 <filename>user.action</filename>:
7352 <!-- brief sample user.action here -->
7356 # My user.action file. <fred@example.com></screen>
7360 As <link linkend="aliases">aliases</link> are local to the actions
7361 file that they are defined in, you can't use the ones from
7362 <filename>default.action</filename>, unless you repeat them here:
7367 # Aliases are local to the file they are defined in.
7368 # (Re-)define aliases for this file:
7372 # These aliases just save typing later, and the alias names should
7373 # be self explanatory.
7375 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
7376 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
7377 allow-all-cookies = -crunch-all-cookies -session-cookies-only
7378 allow-popups = -filter{all-popups}
7379 +block-as-image = +block{Blocked as image.} +handle-as-image
7380 -block-as-image = -block
7382 # These aliases define combinations of actions that are useful for
7383 # certain types of sites:
7385 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer
7386 shop = -crunch-all-cookies allow-popups
7388 # Allow ads for selected useful free sites:
7390 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
7392 # Alias for specific file types that are text, but might have conflicting
7393 # MIME types. We want the browser to force these to be text documents.
7394 handle-as-text = -<link linkend="FILTER">filter</link> +-<link linkend="content-type-overwrite">content-type-overwrite{text/plain}</link> +-<link linkend="FORCE-TEXT-MODE">force-text-mode</link> -<link linkend="HIDE-CONTENT-DISPOSITION">hide-content-disposition</link></screen>
7399 Say you have accounts on some sites that you visit regularly, and
7400 you don't want to have to log in manually each time. So you'd like
7401 to allow persistent cookies for these sites. The
7402 <literal>allow-all-cookies</literal> alias defined above does exactly
7403 that, i.e. it disables crunching of cookies in any direction, and the
7404 processing of cookies to make them only temporary.
7409 { allow-all-cookies }
7413 .redhat.com</screen>
7417 Your bank is allergic to some filter, but you don't know which, so you disable them all:
7422 { -<link linkend="FILTER">filter</link> }
7423 .your-home-banking-site.com</screen>
7427 Some file types you may not want to filter for various reasons:
7432 # Technical documentation is likely to contain strings that might
7433 # erroneously get altered by the JavaScript-oriented filters:
7438 # And this stupid host sends streaming video with a wrong MIME type,
7439 # so that Privoxy thinks it is getting HTML and starts filtering:
7441 stupid-server.example.com/</screen>
7445 Example of a simple <link linkend="BLOCK">block</link> action. Say you've
7446 seen an ad on your favourite page on example.com that you want to get rid of.
7447 You have right-clicked the image, selected <quote>copy image location</quote>
7448 and pasted the URL below while removing the leading http://, into a
7449 <literal>{ +block{} }</literal> section. Note that <literal>{ +handle-as-image
7450 }</literal> need not be specified, since all URLs ending in
7451 <literal>.gif</literal> will be tagged as images by the general rules as set
7452 in default.action anyway:
7457 { +<link linkend="BLOCK">block</link>{Nasty ads.} }
7458 www.example.com/nasty-ads/sponsor\.gif
7459 another.example.net/more/junk/here/</screen>
7463 The URLs of dynamically generated banners, especially from large banner
7464 farms, often don't use the well-known image file name extensions, which
7465 makes it impossible for <application>Privoxy</application> to guess
7466 the file type just by looking at the URL.
7467 You can use the <literal>+block-as-image</literal> alias defined above for
7469 Note that objects which match this rule but then turn out NOT to be an
7470 image are typically rendered as a <quote>broken image</quote> icon by the
7471 browser. Use cautiously.
7480 ar.atwola.com/</screen>
7484 Now you noticed that the default configuration breaks Forbes Magazine,
7485 but you were too lazy to find out which action is the culprit, and you
7486 were again too lazy to give <link linkend="contact">feedback</link>, so
7487 you just used the <literal>fragile</literal> alias on the site, and
7488 -- <emphasis>whoa!</emphasis> -- it worked. The <literal>fragile</literal>
7489 aliases disables those actions that are most likely to break a site. Also,
7490 good for testing purposes to see if it is <application>Privoxy</application>
7491 that is causing the problem or not. We later find other regular sites
7492 that misbehave, and add those to our personalized list of troublemakers:
7500 .mybank.com</screen>
7504 You like the <quote>fun</quote> text replacements in <filename>default.filter</filename>,
7505 but it is disabled in the distributed actions file.
7506 So you'd like to turn it on in your private,
7507 update-safe config, once and for all:
7512 { +<link linkend="filter-fun">filter{fun}</link> }
7513 / # For ALL sites!</screen>
7517 Note that the above is not really a good idea: There are exceptions
7518 to the filters in <filename>default.action</filename> for things that
7519 really shouldn't be filtered, like code on CVS->Web interfaces. Since
7520 <filename>user.action</filename> has the last word, these exceptions
7521 won't be valid for the <quote>fun</quote> filtering specified here.
7525 You might also worry about how your favourite free websites are
7526 funded, and find that they rely on displaying banner advertisements
7527 to survive. So you might want to specifically allow banners for those
7528 sites that you feel provide value to you:
7540 Note that <literal>allow-ads</literal> has been aliased to
7541 <literal>-<link linkend="block">block</link></literal>,
7542 <literal>-<link linkend="filter-banners-by-size">filter{banners-by-size}</link></literal>, and
7543 <literal>-<link linkend="filter-banners-by-link">filter{banners-by-link}</link></literal> above.
7547 Invoke another alias here to force an over-ride of the MIME type <literal>
7548 application/x-sh</literal> which typically would open a download type
7549 dialog. In my case, I want to look at the shell script, and then I can save
7550 it should I choose to.
7560 <filename>user.action</filename> is generally the best place to define
7561 exceptions and additions to the default policies of
7562 <filename>default.action</filename>. Some actions are safe to have their
7563 default policies set here though. So let's set a default policy to have a
7564 <quote>blank</quote> image as opposed to the checkerboard pattern for
7565 <emphasis>ALL</emphasis> sites. <quote>/</quote> of course matches all URL
7571 { +<link linkend="set-image-blocker">set-image-blocker{blank}</link> }
7572 / # ALL sites</screen>
7578 <!-- ~ End section ~ -->
7582 <!-- ~ End section ~ -->
7584 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7586 <sect1 id="filter-file">
7587 <title>Filter Files</title>
7590 On-the-fly text substitutions need
7591 to be defined in a <quote>filter file</quote>. Once defined, they
7592 can then be invoked as an <quote>action</quote>.
7596 &my-app; supports three different filter actions:
7597 <literal><link linkend="filter">filter</link></literal> to
7598 rewrite the content that is send to the client,
7599 <literal><link linkend="client-header-filter">client-header-filter</link></literal>
7600 to rewrite headers that are send by the client, and
7601 <literal><link linkend="server-header-filter">server-header-filter</link></literal>
7602 to rewrite headers that are send by the server.
7606 &my-app; also supports two tagger actions:
7607 <literal><link linkend="client-header-tagger">client-header-tagger</link></literal>
7609 <literal><link linkend="server-header-tagger">server-header-tagger</link></literal>.
7610 Taggers and filters use the same syntax in the filter files, the difference
7611 is that taggers don't modify the text they are filtering, but use a rewritten
7612 version of the filtered text as tag. The tags can then be used to change the
7613 applying actions through sections with <link linkend="tag-pattern">tag-patterns</link>.
7618 Multiple filter files can be defined through the <literal> <link
7619 linkend="filterfile">filterfile</link></literal> config directive. The filters
7620 as supplied by the developers are located in
7621 <filename>default.filter</filename>. It is recommended that any locally
7622 defined or modified filters go in a separately defined file such as
7623 <filename>user.filter</filename>.
7627 Common tasks for content filters are to eliminate common annoyances in
7628 HTML and JavaScript, such as pop-up windows,
7629 exit consoles, crippled windows without navigation tools, the
7630 infamous <BLINK> tag etc, to suppress images with certain
7631 width and height attributes (standard banner sizes or web-bugs),
7632 or just to have fun.
7636 Enabled content filters are applied to any content whose
7637 <quote>Content Type</quote> header is recognised as a sign
7638 of text-based content, with the exception of <literal>text/plain</literal>.
7639 Use the <link linkend="FORCE-TEXT-MODE">force-text-mode</link> action
7640 to also filter other content.
7644 Substitutions are made at the source level, so if you want to <quote>roll
7645 your own</quote> filters, you should first be familiar with HTML syntax,
7646 and, of course, regular expressions.
7650 Just like the <link linkend="actions-file">actions files</link>, the
7651 filter file is organized in sections, which are called <emphasis>filters</emphasis>
7652 here. Each filter consists of a heading line, that starts with one of the
7653 <emphasis>keywords</emphasis> <literal>FILTER:</literal>,
7654 <literal>CLIENT-HEADER-FILTER:</literal> or <literal>SERVER-HEADER-FILTER:</literal>
7655 followed by the filter's <emphasis>name</emphasis>, and a short (one line)
7656 <emphasis>description</emphasis> of what it does. Below that line
7657 come the <emphasis>jobs</emphasis>, i.e. lines that define the actual
7658 text substitutions. By convention, the name of a filter
7659 should describe what the filter <emphasis>eliminates</emphasis>. The
7660 comment is used in the <ulink url="http://config.privoxy.org/">web-based
7661 user interface</ulink>.
7665 Once a filter called <replaceable>name</replaceable> has been defined
7666 in the filter file, it can be invoked by using an action of the form
7667 +<literal><link linkend="filter">filter</link>{<replaceable>name</replaceable>}</literal>
7668 in any <link linkend="actions-file">actions file</link>.
7672 Filter definitions start with a header line that contains the filter
7673 type, the filter name and the filter description.
7674 A content filter header line for a filter called <quote>foo</quote> could look
7679 <screen>FILTER: foo Replace all "foo" with "bar"</screen>
7683 Below that line, and up to the next header line, come the jobs that
7684 define what text replacements the filter executes. They are specified
7685 in a syntax that imitates <ulink url="http://www.perl.org/">Perl</ulink>'s
7686 <literal>s///</literal> operator. If you are familiar with Perl, you
7687 will find this to be quite intuitive, and may want to look at the
7688 PCRS documentation for the subtle differences to Perl behaviour. Most
7689 notably, the non-standard option letter <literal>U</literal> is supported,
7690 which turns the default to ungreedy matching.
7695 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
7696 Expressions</quote></ulink>, you might want to take a look at
7697 the <link linkend="regex">Appendix on regular expressions</link>, and
7698 see the <ulink url="http://perldoc.perl.org/perlre.html">Perl
7700 <ulink url="http://perldoc.perl.org/perlop.html">the
7701 <literal>s///</literal> operator's syntax</ulink> and <ulink
7702 url="http://perldoc.perl.org/perlre.html">Perl-style regular
7703 expressions</ulink> in general.
7704 The below examples might also help to get you started.
7708 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7710 <sect2><title>Filter File Tutorial</title>
7712 Now, let's complete our <quote>foo</quote> content filter. We have already defined
7713 the heading, but the jobs are still missing. Since all it does is to replace
7714 <quote>foo</quote> with <quote>bar</quote>, there is only one (trivial) job
7719 <screen>s/foo/bar/</screen>
7723 But wait! Didn't the comment say that <emphasis>all</emphasis> occurrences
7724 of <quote>foo</quote> should be replaced? Our current job will only take
7725 care of the first <quote>foo</quote> on each page. For global substitution,
7726 we'll need to add the <literal>g</literal> option:
7730 <screen>s/foo/bar/g</screen>
7734 Our complete filter now looks like this:
7737 <screen>FILTER: foo Replace all "foo" with "bar"
7738 s/foo/bar/g</screen>
7742 Let's look at some real filters for more interesting examples. Here you see
7743 a filter that protects against some common annoyances that arise from JavaScript
7744 abuse. Let's look at its jobs one after the other:
7750 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
7752 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
7754 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg</screen>
7758 Following the header line and a comment, you see the job. Note that it uses
7759 <literal>|</literal> as the delimiter instead of <literal>/</literal>, because
7760 the pattern contains a forward slash, which would otherwise have to be escaped
7761 by a backslash (<literal>\</literal>).
7765 Now, let's examine the pattern: it starts with the text <literal><script.*</literal>
7766 enclosed in parentheses. Since the dot matches any character, and <literal>*</literal>
7767 means: <quote>Match an arbitrary number of the element left of myself</quote>, this
7768 matches <quote><script</quote>, followed by <emphasis>any</emphasis> text, i.e.
7769 it matches the whole page, from the start of the first <script> tag.
7773 That's more than we want, but the pattern continues: <literal>document\.referrer</literal>
7774 matches only the exact string <quote>document.referrer</quote>. The dot needed to
7775 be <emphasis>escaped</emphasis>, i.e. preceded by a backslash, to take away its
7776 special meaning as a joker, and make it just a regular dot. So far, the meaning is:
7777 Match from the start of the first <script> tag in a the page, up to, and including,
7778 the text <quote>document.referrer</quote>, if <emphasis>both</emphasis> are present
7779 in the page (and appear in that order).
7783 But there's still more pattern to go. The next element, again enclosed in parentheses,
7784 is <literal>.*</script></literal>. You already know what <literal>.*</literal>
7785 means, so the whole pattern translates to: Match from the start of the first <script>
7786 tag in a page to the end of the last <script> tag, provided that the text
7787 <quote>document.referrer</quote> appears somewhere in between.
7791 This is still not the whole story, since we have ignored the options and the parentheses:
7792 The portions of the page matched by sub-patterns that are enclosed in parentheses, will be
7793 remembered and be available through the variables <literal>$1, $2, ...</literal> in
7794 the substitute. The <literal>U</literal> option switches to ungreedy matching, which means
7795 that the first <literal>.*</literal> in the pattern will only <quote>eat up</quote> all
7796 text in between <quote><script</quote> and the <emphasis>first</emphasis> occurrence
7797 of <quote>document.referrer</quote>, and that the second <literal>.*</literal> will
7798 only span the text up to the <emphasis>first</emphasis> <quote></script></quote>
7799 tag. Furthermore, the <literal>s</literal> option says that the match may span
7800 multiple lines in the page, and the <literal>g</literal> option again means that the
7801 substitution is global.
7805 So, to summarize, the pattern means: Match all scripts that contain the text
7806 <quote>document.referrer</quote>. Remember the parts of the script from
7807 (and including) the start tag up to (and excluding) the string
7808 <quote>document.referrer</quote> as <literal>$1</literal>, and the part following
7809 that string, up to and including the closing tag, as <literal>$2</literal>.
7813 Now the pattern is deciphered, but wasn't this about substituting things? So
7814 lets look at the substitute: <literal>$1"Not Your Business!"$2</literal> is
7815 easy to read: The text remembered as <literal>$1</literal>, followed by
7816 <literal>"Not Your Business!"</literal> (<emphasis>including</emphasis>
7817 the quotation marks!), followed by the text remembered as <literal>$2</literal>.
7818 This produces an exact copy of the original string, with the middle part
7819 (the <quote>document.referrer</quote>) replaced by <literal>"Not Your
7820 Business!"</literal>.
7824 The whole job now reads: Replace <quote>document.referrer</quote> by
7825 <literal>"Not Your Business!"</literal> wherever it appears inside a
7826 <script> tag. Note that this job won't break JavaScript syntax,
7827 since both the original and the replacement are syntactically valid
7828 string objects. The script just won't have access to the referrer
7829 information anymore.
7833 We'll show you two other jobs from the JavaScript taming department, but
7834 this time only point out the constructs of special interest:
7839 # The status bar is for displaying link targets, not pointless blahblah
7841 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig</screen>
7845 <literal>\s</literal> stands for whitespace characters (space, tab, newline,
7846 carriage return, form feed), so that <literal>\s*</literal> means: <quote>zero
7847 or more whitespace</quote>. The <literal>?</literal> in <literal>.*?</literal>
7848 makes this matching of arbitrary text ungreedy. (Note that the <literal>U</literal>
7849 option is not set). The <literal>['"]</literal> construct means: <quote>a single
7850 <emphasis>or</emphasis> a double quote</quote>. Finally, <literal>\1</literal> is
7851 a back-reference to the first parenthesis just like <literal>$1</literal> above,
7852 with the difference that in the <emphasis>pattern</emphasis>, a backslash indicates
7853 a back-reference, whereas in the <emphasis>substitute</emphasis>, it's the dollar.
7857 So what does this job do? It replaces assignments of single- or double-quoted
7858 strings to the <quote>window.status</quote> object with a dummy assignment
7859 (using a variable name that is hopefully odd enough not to conflict with
7860 real variables in scripts). Thus, it catches many cases where e.g. pointless
7861 descriptions are displayed in the status bar instead of the link target when
7862 you move your mouse over links.
7867 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
7869 s/(<body [^>]*)onunload(.*>)/$1never$2/iU</screen>
7874 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">OnUnload
7875 event binding</ulink> in the HTML DOM was a <emphasis>CRIME</emphasis>.
7876 When I close a browser window, I want it to close and die. Basta.
7877 This job replaces the <quote>onunload</quote> attribute in
7878 <quote><body></quote> tags with the dummy word <literal>never</literal>.
7879 Note that the <literal>i</literal> option makes the pattern matching
7880 case-insensitive. Also note that ungreedy matching alone doesn't always guarantee
7881 a minimal match: In the first parenthesis, we had to use <literal>[^>]*</literal>
7882 instead of <literal>.*</literal> to prevent the match from exceeding the
7883 <body> tag if it doesn't contain <quote>OnUnload</quote>, but the page's
7888 The last example is from the fun department:
7893 FILTER: fun Fun text replacements
7895 # Spice the daily news:
7897 s/microsoft(?!\.com)/MicroSuck/ig</screen>
7901 Note the <literal>(?!\.com)</literal> part (a so-called negative lookahead)
7902 in the job's pattern, which means: Don't match, if the string
7903 <quote>.com</quote> appears directly following <quote>microsoft</quote>
7904 in the page. This prevents links to microsoft.com from being trashed, while
7905 still replacing the word everywhere else.
7910 # Buzzword Bingo (example for extended regex syntax)
7912 s* industry[ -]leading \
7914 | customer[ -]focused \
7915 | market[ -]driven \
7916 | award[ -]winning # Comments are OK, too! \
7917 | high[ -]performance \
7918 | solutions[ -]based \
7922 *<font color="red"><b>BINGO!</b></font> \
7927 The <literal>x</literal> option in this job turns on extended syntax, and allows for
7928 e.g. the liberal use of (non-interpreted!) whitespace for nicer formatting.
7936 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7938 <sect2 id="predefined-filters"><title>The Pre-defined Filters</title>
7942 Note each filter is also listed in the +filter action section above. Please
7943 keep these listings in sync.
7948 The distribution <filename>default.filter</filename> file contains a selection of
7949 pre-defined filters for your convenience:
7954 <term><emphasis>js-annoyances</emphasis></term>
7957 The purpose of this filter is to get rid of particularly annoying JavaScript abuse.
7962 replaces JavaScript references to the browser's referrer information
7963 with the string "Not Your Business!". This compliments the <literal><link
7964 linkend="hide-referrer">hide-referrer</link></literal> action on the content level.
7969 removes the bindings to the DOM's
7970 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">unload
7971 event</ulink> which we feel has no right to exist and is responsible for most <quote>exit consoles</quote>, i.e.
7972 nasty windows that pop up when you close another one.
7977 removes code that causes new windows to be opened with undesired properties, such as being
7978 full-screen, non-resizeable, without location, status or menu bar etc.
7984 Use with caution. This is an aggressive filter, and can break sites that
7985 rely heavily on JavaScript.
7991 <term><emphasis>js-events</emphasis></term>
7994 This is a very radical measure. It removes virtually all JavaScript event bindings, which
7995 means that scripts can not react to user actions such as mouse movements or clicks, window
7996 resizing etc, anymore. Use with caution!
7999 We <emphasis>strongly discourage</emphasis> using this filter as a default since it breaks
8000 many legitimate scripts. It is meant for use only on extra-nasty sites (should you really
8007 <term><emphasis>html-annoyances</emphasis></term>
8010 This filter will undo many common instances of HTML based abuse.
8013 The <literal>BLINK</literal> and <literal>MARQUEE</literal> tags
8014 are neutralized (yeah baby!), and browser windows will be created as
8015 resizeable (as of course they should be!), and will have location,
8016 scroll and menu bars -- even if specified otherwise.
8022 <term><emphasis>content-cookies</emphasis></term>
8025 Most cookies are set in the HTTP dialog, where they can be intercepted
8027 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>
8028 and <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>
8029 actions. But web sites increasingly make use of HTML meta tags and JavaScript
8030 to sneak cookies to the browser on the content level.
8033 This filter disables most HTML and JavaScript code that reads or sets
8034 cookies. It cannot detect all clever uses of these types of code, so it
8035 should not be relied on as an absolute fix. Use it wherever you would also
8036 use the cookie crunch actions.
8042 <term><emphasis>refresh-tags</emphasis></term>
8045 Disable any refresh tags if the interval is greater than nine seconds (so
8046 that redirections done via refresh tags are not destroyed). This is useful
8047 for dial-on-demand setups, or for those who find this HTML feature
8054 <term><emphasis>unsolicited-popups</emphasis></term>
8057 This filter attempts to prevent only <quote>unsolicited</quote> pop-up
8058 windows from opening, yet still allow pop-up windows that the user
8059 has explicitly chosen to open. It was added in version 3.0.1,
8060 as an improvement over earlier such filters.
8063 Technical note: The filter works by redefining the window.open JavaScript
8064 function to a dummy function, <literal>PrivoxyWindowOpen()</literal>,
8065 during the loading and rendering phase of each HTML page access, and
8066 restoring the function afterward.
8069 This is recommended only for browsers that cannot perform this function
8070 reliably themselves. And be aware that some sites require such windows
8071 in order to function normally. Use with caution.
8077 <term><emphasis>all-popups</emphasis></term>
8080 Attempt to prevent <emphasis>all</emphasis> pop-up windows from opening.
8081 Note this should be used with even more discretion than the above, since
8082 it is more likely to break some sites that require pop-ups for normal
8083 usage. Use with caution.
8089 <term><emphasis>img-reorder</emphasis></term>
8092 This is a helper filter that has no value if used alone. It makes the
8093 <literal>banners-by-size</literal> and <literal>banners-by-link</literal>
8094 (see below) filters more effective and should be enabled together with them.
8100 <term><emphasis>banners-by-size</emphasis></term>
8103 This filter removes image tags purely based on what size they are. Fortunately
8104 for us, many ads and banner images tend to conform to certain standardized
8105 sizes, which makes this filter quite effective for ad stripping purposes.
8108 Occasionally this filter will cause false positives on images that are not ads,
8109 but just happen to be of one of the standard banner sizes.
8112 Recommended only for those who require extreme ad blocking. The default
8113 block rules should catch 95+% of all ads <emphasis>without</emphasis> this filter enabled.
8119 <term><emphasis>banners-by-link</emphasis></term>
8122 This is an experimental filter that attempts to kill any banners if
8123 their URLs seem to point to known or suspected click trackers. It is currently
8124 not of much value and is not recommended for use by default.
8130 <term><emphasis>webbugs</emphasis></term>
8133 Webbugs are small, invisible images (technically 1X1 GIF images), that
8134 are used to track users across websites, and collect information on them.
8135 As an HTML page is loaded by the browser, an embedded image tag causes the
8136 browser to contact a third-party site, disclosing the tracking information
8137 through the requested URL and/or cookies for that third-party domain, without
8138 the user ever becoming aware of the interaction with the third-party site.
8139 HTML-ized spam also uses a similar technique to verify email addresses.
8142 This filter removes the HTML code that loads such <quote>webbugs</quote>.
8148 <term><emphasis>tiny-textforms</emphasis></term>
8151 A rather special-purpose filter that can be used to enlarge textareas (those
8152 multi-line text boxes in web forms) and turn off hard word wrap in them.
8153 It was written for the sourceforge.net tracker system where such boxes are
8154 a nuisance, but it can be handy on other sites, too.
8157 It is not recommended to use this filter as a default.
8163 <term><emphasis>jumping-windows</emphasis></term>
8166 Many consider windows that move, or resize themselves to be abusive. This filter
8167 neutralizes the related JavaScript code. Note that some sites might not display
8168 or behave as intended when using this filter. Use with caution.
8174 <term><emphasis>frameset-borders</emphasis></term>
8177 Some web designers seem to assume that everyone in the world will view their
8178 web sites using the same browser brand and version, screen resolution etc,
8179 because only that assumption could explain why they'd use static frame sizes,
8180 yet prevent their frames from being resized by the user, should they be too
8181 small to show their whole content.
8184 This filter removes the related HTML code. It should only be applied to sites
8191 <term><emphasis>demoronizer</emphasis></term>
8194 Many Microsoft products that generate HTML use non-standard extensions (read:
8195 violations) of the ISO 8859-1 aka Latin-1 character set. This can cause those
8196 HTML documents to display with errors on standard-compliant platforms.
8199 This filter translates the MS-only characters into Latin-1 equivalents.
8200 It is not necessary when using MS products, and will cause corruption of
8201 all documents that use 8-bit character sets other than Latin-1. It's mostly
8202 worthwhile for Europeans on non-MS platforms, if weird garbage characters
8203 sometimes appear on some pages, or user agents that don't correct for this on
8206 My version of Mozilla (ancient) shows litte square boxes for quote
8207 characters, and apostrophes on moronized pages. So many pages have this, I
8208 can read them fine now. HB 08/27/06
8215 <term><emphasis>shockwave-flash</emphasis></term>
8218 A filter for shockwave haters. As the name suggests, this filter strips code
8219 out of web pages that is used to embed shockwave flash objects.
8227 <term><emphasis>quicktime-kioskmode</emphasis></term>
8230 Change HTML code that embeds Quicktime objects so that kioskmode, which
8231 prevents saving, is disabled.
8237 <term><emphasis>fun</emphasis></term>
8240 Text replacements for subversive browsing fun. Make fun of your favorite
8241 Monopolist or play buzzword bingo.
8247 <term><emphasis>crude-parental</emphasis></term>
8250 A demonstration-only filter that shows how <application>Privoxy</application>
8251 can be used to delete web content on a keyword basis.
8257 <term><emphasis>ie-exploits</emphasis></term>
8260 An experimental collection of text replacements to disable malicious HTML and JavaScript
8261 code that exploits known security holes in Internet Explorer.
8264 Presently, it only protects against Nimda and a cross-site scripting bug, and
8265 would need active maintenance to provide more substantial protection.
8271 <term><emphasis>site-specifics</emphasis></term>
8274 Some web sites have very specific problems, the cure for which doesn't apply
8275 anywhere else, or could even cause damage on other sites.
8278 This is a collection of such site-specific cures which should only be applied
8279 to the sites they were intended for, which is what the supplied
8280 <filename>default.action</filename> file does. Users shouldn't need to change
8281 anything regarding this filter.
8287 <term><emphasis>google</emphasis></term>
8290 A CSS based block for Google text ads. Also removes a width limitation
8291 and the toolbar advertisement.
8297 <term><emphasis>yahoo</emphasis></term>
8300 Another CSS based block, this time for Yahoo text ads. And removes
8301 a width limitation as well.
8307 <term><emphasis>msn</emphasis></term>
8310 Another CSS based block, this time for MSN text ads. And removes
8311 tracking URLs, as well as a width limitation.
8317 <term><emphasis>blogspot</emphasis></term>
8320 Cleans up some Blogspot blogs. Read the fine print before using this one!
8323 This filter also intentionally removes some navigation stuff and sets the
8324 page width to 100%. As a result, some rounded <quote>corners</quote> would
8325 appear to early or not at all and as fixing this would require a browser
8326 that understands background-size (CSS3), they are removed instead.
8332 <term><emphasis>xml-to-html</emphasis></term>
8335 Server-header filter to change the Content-Type from xml to html.
8341 <term><emphasis>html-to-xml</emphasis></term>
8344 Server-header filter to change the Content-Type from html to xml.
8350 <term><emphasis>no-ping</emphasis></term>
8353 Removes the non-standard <literal>ping</literal> attribute from
8354 anchor and area HTML tags.
8360 <term><emphasis>hide-tor-exit-notation</emphasis></term>
8363 Client-header filter to remove the <command>Tor</command> exit node notation
8364 found in Host and Referer headers.
8367 If &my-app; and <command>Tor</command> are chained and &my-app;
8368 is configured to use socks4a, one can use <quote>http://www.example.org.foobar.exit/</quote>
8369 to access the host <quote>www.example.org</quote> through the
8370 <command>Tor</command> exit node <quote>foobar</quote>.
8373 As the HTTP client isn't aware of this notation, it treats the
8374 whole string <quote>www.example.org.foobar.exit</quote> as host and uses it
8375 for the <quote>Host</quote> and <quote>Referer</quote> headers. From the
8376 server's point of view the resulting headers are invalid and can cause problems.
8379 An invalid <quote>Referer</quote> header can trigger <quote>hot-linking</quote>
8380 protections, an invalid <quote>Host</quote> header will make it impossible for
8381 the server to find the right vhost (several domains hosted on the same IP address).
8384 This client-header filter removes the <quote>foo.exit</quote> part in those headers
8385 to prevent the mentioned problems. Note that it only modifies
8386 the HTTP headers, it doesn't make it impossible for the server
8387 to detect your <command>Tor</command> exit node based on the IP address
8388 the request is coming from.
8395 <term><emphasis> </emphasis></term>
8409 <!-- ~ End section ~ -->
8413 <!-- ~~~~~ New section ~~~~~ -->
8415 <sect1 id="templates">
8416 <title>Privoxy's Template Files</title>
8418 All <application>Privoxy</application> built-in pages, i.e. error pages such as the
8419 <ulink url="http://show-the-404-error.page"><quote>404 - No Such Domain</quote>
8420 error page</ulink>, the <ulink
8421 url="http://ads.bannerserver.example.com/nasty-ads/sponsor.html"><quote>BLOCKED</quote>
8423 and all pages of its <ulink url="http://config.privoxy.org/">web-based
8424 user interface</ulink>, are generated from <emphasis>templates</emphasis>.
8425 (<application>Privoxy</application> must be running for the above links to work as
8430 These templates are stored in a subdirectory of the <link linkend="confdir">configuration
8431 directory</link> called <filename>templates</filename>. On Unixish platforms,
8433 <ulink url="file:///etc/privoxy/templates/"><filename>/etc/privoxy/templates/</filename></ulink>.
8437 The templates are basically normal HTML files, but with place-holders (called symbols
8438 or exports), which <application>Privoxy</application> fills at run time. It
8439 is possible to edit the templates with a normal text editor, should you want
8440 to customize them. (<emphasis>Not recommended for the casual
8441 user</emphasis>). Should you create your own custom templates, you should use
8442 the <filename>config</filename> setting <link linkend="templdir">templdir</link>
8443 to specify an alternate location, so your templates do not get overwritten
8447 Note that just like in configuration files, lines starting
8448 with <literal>#</literal> are ignored when the templates are filled in.
8452 The place-holders are of the form <literal>@name@</literal>, and you will
8453 find a list of available symbols, which vary from template to template,
8454 in the comments at the start of each file. Note that these comments are not
8455 always accurate, and that it's probably best to look at the existing HTML
8456 code to find out which symbols are supported and what they are filled in with.
8460 A special application of this substitution mechanism is to make whole
8461 blocks of HTML code disappear when a specific symbol is set. We use this
8462 for many purposes, one of them being to include the beta warning in all
8463 our user interface (CGI) pages when <application>Privoxy</application>
8464 is in an alpha or beta development stage:
8469 <!-- @if-unstable-start -->
8471 ... beta warning HTML code goes here ...
8473 <!-- if-unstable-end@ --></screen>
8477 If the "unstable" symbol is set, everything in between and including
8478 <literal>@if-unstable-start</literal> and <literal>if-unstable-end@</literal>
8479 will disappear, leaving nothing but an empty comment:
8483 <screen><!-- --></screen>
8487 There's also an if-then-else construct and an <literal>#include</literal>
8488 mechanism, but you'll sure find out if you are inclined to edit the
8493 All templates refer to a style located at
8494 <ulink url="http://config.privoxy.org/send-stylesheet"><literal>http://config.privoxy.org/send-stylesheet</literal></ulink>.
8495 This is, of course, locally served by <application>Privoxy</application>
8496 and the source for it can be found and edited in the
8497 <filename>cgi-style.css</filename> template.
8502 <!-- ~ End section ~ -->
8506 <!-- ~~~~~ New section ~~~~~ -->
8508 <sect1 id="contact"><title>Contacting the Developers, Bug Reporting and Feature
8511 <!-- Include contacting.sgml boilerplate: -->
8513 <!-- end boilerplate -->
8517 <!-- ~ End section ~ -->
8520 <!-- ~~~~~ New section ~~~~~ -->
8521 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
8523 <!-- Include copyright.sgml: -->
8525 <!-- end copyright -->
8527 <!-- ~~~~~ New section ~~~~~ -->
8528 <sect2><title>License</title>
8529 <!-- Include copyright.sgml: -->
8531 <!-- end copyright -->
8533 <!-- ~ End section ~ -->
8536 <!-- ~~~~~ New section ~~~~~ -->
8538 <sect2 id="history"><title>History</title>
8539 <!-- Include history.sgml: -->
8541 <!-- end history -->
8544 <sect2 id="authors"><title>Authors</title>
8545 <!-- Include p-authors.sgml: -->
8547 <!-- end authors -->
8552 <!-- ~ End section ~ -->
8555 <!-- ~~~~~ New section ~~~~~ -->
8556 <sect1 id="seealso"><title>See Also</title>
8557 <!-- Include seealso.sgml: -->
8559 <!-- end seealso -->
8564 <!-- ~~~~~ New section ~~~~~ -->
8565 <sect1 id="appendix"><title>Appendix</title>
8568 <!-- ~~~~~ New section ~~~~~ -->
8570 <title>Regular Expressions</title>
8572 <application>Privoxy</application> uses Perl-style <quote>regular
8573 expressions</quote> in its <link linkend="actions-file">actions
8574 files</link> and <link linkend="filter-file">filter file</link>,
8575 through the <ulink url="http://www.pcre.org/">PCRE</ulink> and
8578 <ulink url="http://www.oesterhelt.org/pcrs/">PCRS</ulink> libraries.
8580 <application>PCRS</application> libraries.
8584 If you are reading this, you probably don't understand what <quote>regular
8585 expressions</quote> are, or what they can do. So this will be a very brief
8586 introduction only. A full explanation would require a <ulink
8587 url="http://www.oreilly.com/catalog/regex/">book</ulink> ;-)
8591 Regular expressions provide a language to describe patterns that can be
8592 run against strings of characters (letter, numbers, etc), to see if they
8593 match the string or not. The patterns are themselves (sometimes complex)
8594 strings of literal characters, combined with wild-cards, and other special
8595 characters, called meta-characters. The <quote>meta-characters</quote> have
8596 special meanings and are used to build complex patterns to be matched against.
8597 Perl Compatible Regular Expressions are an especially convenient
8598 <quote>dialect</quote> of the regular expression language.
8602 To make a simple analogy, we do something similar when we use wild-card
8603 characters when listing files with the <command>dir</command> command in DOS.
8604 <literal>*.*</literal> matches all filenames. The <quote>special</quote>
8605 character here is the asterisk which matches any and all characters. We can be
8606 more specific and use <literal>?</literal> to match just individual
8607 characters. So <quote>dir file?.text</quote> would match
8608 <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
8609 matching, using a similar technique to <quote>regular expressions</quote>!
8613 Regular expressions do essentially the same thing, but are much, much more
8614 powerful. There are many more <quote>special characters</quote> and ways of
8615 building complex patterns however. Let's look at a few of the common ones,
8616 and then some examples:
8621 <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
8622 <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
8624 </simplelist></para>
8628 <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
8631 </simplelist></para>
8635 <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
8638 </simplelist></para>
8642 <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
8645 </simplelist></para>
8649 <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
8650 the following character should be taken literally. This is used where one of the
8651 special characters (e.g. <quote>.</quote>) needs to be taken literally and
8652 not as a special meta-character. Example: <quote>example\.com</quote>, makes
8653 sure the period is recognized only as a period (and not expanded to its
8654 meta-character meaning of any single character).
8656 </simplelist></para>
8660 <emphasis>[ ]</emphasis> - Characters enclosed in brackets will be matched if
8661 any of the enclosed characters are encountered. For instance, <quote>[0-9]</quote>
8662 matches any numeric digit (zero through nine). As an example, we can combine
8663 this with <quote>+</quote> to match any digit one of more times: <quote>[0-9]+</quote>.
8665 </simplelist></para>
8669 <emphasis>( )</emphasis> - parentheses are used to group a sub-expression,
8670 or multiple sub-expressions.
8672 </simplelist></para>
8676 <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
8677 <quote>or</quote> conditional statement. A match is successful if the
8678 sub-expression on either side of <quote>|</quote> matches. As an example:
8679 <quote>/(this|that) example/</quote> uses grouping and the bar character
8680 and would match either <quote>this example</quote> or <quote>that
8681 example</quote>, and nothing else.
8683 </simplelist></para>
8686 These are just some of the ones you are likely to use when matching URLs with
8687 <application>Privoxy</application>, and is a long way from a definitive
8688 list. This is enough to get us started with a few simple examples which may
8689 be more illuminating:
8693 <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
8694 that uses the common combination of <quote>.</quote> and <quote>*</quote> to
8695 denote any character, zero or more times. In other words, any string at all.
8696 So we start with a literal forward slash, then our regular expression pattern
8697 (<quote>.*</quote>) another literal forward slash, the string
8698 <quote>banners</quote>, another forward slash, and lastly another
8699 <quote>.*</quote>. We are building
8700 a directory path here. This will match any file with the path that has a
8701 directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
8702 any characters, and this could conceivably be more forward slashes, so it
8703 might expand into a much longer looking path. For example, this could match:
8704 <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
8705 <quote>/banners/annoying.html</quote>, or almost an infinite number of other
8706 possible combinations, just so it has <quote>banners</quote> in the path
8711 And now something a little more complex:
8715 <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
8716 We have several literal forward slashes again (<quote>/</quote>), so we are
8717 building another expression that is a file path statement. We have another
8718 <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
8719 it matches our expression. The only true literal that <emphasis>must
8720 match</emphasis> our pattern is <application>adv</application>, together with
8721 the forward slashes. What comes after the <quote>adv</quote> string is the
8726 Remember the <quote>?</quote> means the preceding expression (either a
8727 literal character or anything grouped with <quote>(...)</quote> in this case)
8728 can exist or not, since this means either zero or one match. So
8729 <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
8730 individual sub-expressions: <quote>(er)</quote>,
8731 <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
8732 means <quote>or</quote>. We have two of those. For instance,
8733 <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
8734 <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
8735 attempt at matching as many variations of <quote>advertisement</quote>, and
8736 similar, as possible. So this would expand to match just <quote>adv</quote>,
8737 or <quote>advert</quote>, or <quote>adverts</quote>, or
8738 <quote>advertising</quote>, or <quote>advertisement</quote>, or
8739 <quote>advertisements</quote>. You get the idea. But it would not match
8740 <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
8741 changing our regular expression to:
8742 <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
8747 <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
8748 another path statement with forward slashes. Anything in the square brackets
8749 <quote>[ ]</quote> can be matched. This is using <quote>0-9</quote> as a
8750 shorthand expression to mean any digit one through nine. It is the same as
8751 saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
8752 means one or more of the preceding expression must be included. The preceding
8753 expression here is what is in the square brackets -- in this case, any digit
8754 one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
8755 This includes a <quote>|</quote>, so this needs to match the expression on
8756 either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
8757 side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
8758 since the <quote>?</quote> means the letter <quote>e</quote> is optional and
8759 can be matched once or not at all. So we are building an expression here to
8760 match image GIF or JPEG type image file. It must include the literal
8761 string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
8762 (which is now a literal, and not a special character, since it is escaped
8763 with <quote>\</quote>), and lastly either <quote>gif</quote>, or
8764 <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
8765 include: <quote>//advert1.jpg</quote>,
8766 <quote>/nasty/ads/advert1234.gif</quote>,
8767 <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
8768 <quote>advert1.gif</quote> (no leading slash), or
8769 <quote>/adverts232.jpg</quote> (the expression does not include an
8770 <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
8771 in the expression anywhere).
8775 We are barely scratching the surface of regular expressions here so that you
8776 can understand the default <application>Privoxy</application>
8777 configuration files, and maybe use this knowledge to customize your own
8778 installation. There is much, much more that can be done with regular
8779 expressions. Now that you know enough to get started, you can learn more on
8784 More reading on Perl Compatible Regular expressions:
8785 <ulink url="http://perldoc.perl.org/perlre.html">http://perldoc.perl.org/perlre.html</ulink>
8789 For information on regular expression based substitutions and their applications
8790 in filters, please see the <link linkend="filter-file">filter file tutorial</link>
8795 <!-- ~ End section ~ -->
8798 <!-- ~~~~~ New section ~~~~~ -->
8800 <title>Privoxy's Internal Pages</title>
8803 Since <application>Privoxy</application> proxies each requested
8804 web page, it is easy for <application>Privoxy</application> to
8805 trap certain special URLs. In this way, we can talk directly to
8806 <application>Privoxy</application>, and see how it is
8807 configured, see how our rules are being applied, change these
8808 rules and other configuration options, and even turn
8809 <application>Privoxy's</application> filtering off, all with
8815 The URLs listed below are the special ones that allow direct access
8816 to <application>Privoxy</application>. Of course,
8817 <application>Privoxy</application> must be running to access these. If
8818 not, you will get a friendly error message. Internet access is not
8831 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
8835 There is a shortcut: <ulink url="http://p.p/">http://p.p/</ulink> (But it
8836 doesn't provide a fall-back to a real page, in case the request is not
8837 sent through <application>Privoxy</application>)
8843 Show information about the current configuration, including viewing and
8844 editing of actions files:
8848 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
8855 Show the source code version numbers:
8859 <ulink url="http://config.privoxy.org/show-version">http://config.privoxy.org/show-version</ulink>
8866 Show the browser's request headers:
8870 <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
8877 Show which actions apply to a URL and why:
8881 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8888 Toggle Privoxy on or off. This feature can be turned off/on in the main
8889 <filename>config</filename> file. When toggled <quote>off</quote>, <quote>Privoxy</quote>
8890 continues to run, but only as a pass-through proxy, with no actions taking
8895 <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
8899 Short cuts. Turn off, then on:
8903 <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
8908 <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
8917 These may be bookmarked for quick reference. See next.
8921 <sect3 id="bookmarklets">
8922 <title>Bookmarklets</title>
8924 Below are some <quote>bookmarklets</quote> to allow you to easily access a
8925 <quote>mini</quote> version of some of <application>Privoxy's</application>
8926 special pages. They are designed for MS Internet Explorer, but should work
8927 equally well in Netscape, Mozilla, and other browsers which support
8928 JavaScript. They are designed to run directly from your bookmarks - not by
8929 clicking the links below (although that should work for testing).
8932 To save them, right-click the link and choose <quote>Add to Favorites</quote>
8933 (IE) or <quote>Add Bookmark</quote> (Netscape). You will get a warning that
8934 the bookmark <quote>may not be safe</quote> - just click OK. Then you can run the
8935 Bookmarklet directly from your favorites/bookmarks. For even faster access,
8936 you can put them on the <quote>Links</quote> bar (IE) or the <quote>Personal
8937 Toolbar</quote> (Netscape), and run them with a single click.
8946 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=enabled','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Enable</ulink>
8953 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=disabled','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Disable</ulink>
8960 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=toggle','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Toggle Privoxy</ulink> (Toggles between enabled and disabled)
8967 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y','ijbstatus','width=250,height=2,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy- View Status</ulink>
8973 <ulink url="javascript:w=Math.floor(screen.width/2);h=Math.floor(screen.height*0.9);void(window.open('http://www.privoxy.org/actions/index.php?url='+escape(location.href),'Feedback','screenx='+w+',width='+w+',height='+h+',scrollbars=yes,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Submit Actions File Feedback</ulink>
8979 <ulink url="javascript:void(window.open('http://config.privoxy.org/show-url-info?url='+escape(location.href),'Why').focus());">Privoxy - Why?</ulink>
8986 Credit: The site which gave us the general idea for these bookmarklets is
8987 <ulink url="http://www.bookmarklets.com/">www.bookmarklets.com</ulink>. They
8988 have more information about bookmarklets.
8997 <!-- ~~~~~ New section ~~~~~ -->
8999 <title>Chain of Events</title>
9001 Let's take a quick look at how some of <application>Privoxy's</application>
9002 core features are triggered, and the ensuing sequence of events when a web
9003 page is requested by your browser:
9010 First, your web browser requests a web page. The browser knows to send
9011 the request to <application>Privoxy</application>, which will in turn,
9012 relay the request to the remote web server after passing the following
9018 <application>Privoxy</application> traps any request for its own internal CGI
9019 pages (e.g <ulink url="http://p.p/">http://p.p/</ulink>) and sends the CGI page back to the browser.
9024 Next, <application>Privoxy</application> checks to see if the URL
9026 linkend="BLOCK"><quote>+block</quote></link> patterns. If
9027 so, the URL is then blocked, and the remote web server will not be contacted.
9028 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>
9030 <link linkend="HANDLE-AS-EMPTY-DOCUMENT"><quote>+handle-as-empty-document</quote></link>
9031 are then checked, and if there is no match, an
9032 HTML <quote>BLOCKED</quote> page is sent back to the browser. Otherwise, if
9033 it does match, an image is returned for the former, and an empty text
9034 document for the latter. The type of image would depend on the setting of
9035 <link linkend="SET-IMAGE-BLOCKER"><quote>+set-image-blocker</quote></link>
9036 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
9041 Untrusted URLs are blocked. If URLs are being added to the
9042 <filename>trust</filename> file, then that is done.
9047 If the URL pattern matches the <link
9048 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link> action,
9049 it is then processed. Unwanted parts of the requested URL are stripped.
9054 Now the rest of the client browser's request headers are processed. If any
9055 of these match any of the relevant actions (e.g. <link
9056 linkend="HIDE-USER-AGENT"><quote>+hide-user-agent</quote></link>,
9057 etc.), headers are suppressed or forged as determined by these actions and
9063 Now the web server starts sending its response back (i.e. typically a web
9069 First, the server headers are read and processed to determine, among other
9070 things, the MIME type (document type) and encoding. The headers are then
9071 filtered as determined by the
9072 <link linkend="CRUNCH-INCOMING-COOKIES"><quote>+crunch-incoming-cookies</quote></link>,
9073 <link linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>,
9074 and <link linkend="DOWNGRADE-HTTP-VERSION"><quote>+downgrade-http-version</quote></link>
9080 If any <link linkend="FILTER"><quote>+filter</quote></link> action
9082 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
9083 action applies (and the document type fits the action), the rest of the page is
9084 read into memory (up to a configurable limit). Then the filter rules (from
9085 <filename>default.filter</filename> and any other filter files) are
9086 processed against the buffered content. Filters are applied in the order
9087 they are specified in one of the filter files. Animated GIFs, if present,
9088 are reduced to either the first or last frame, depending on the action
9089 setting.The entire page, which is now filtered, is then sent by
9090 <application>Privoxy</application> back to your browser.
9093 If neither a <link linkend="FILTER"><quote>+filter</quote></link> action
9095 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
9096 matches, then <application>Privoxy</application> passes the raw data through
9097 to the client browser as it becomes available.
9102 As the browser receives the now (possibly filtered) page content, it
9103 reads and then requests any URLs that may be embedded within the page
9104 source, e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
9105 frames), sounds, etc. For each of these objects, the browser issues a
9106 separate request (this is easily viewable in <application>Privoxy's</application>
9107 logs). And each such request is in turn processed just as above. Note that a
9108 complex web page will have many, many such embedded URLs. If these
9109 secondary requests are to a different server, then quite possibly a very
9110 differing set of actions is triggered.
9117 NOTE: This is somewhat of a simplistic overview of what happens with each URL
9118 request. For the sake of brevity and simplicity, we have focused on
9119 <application>Privoxy's</application> core features only.
9125 <!-- ~~~~~ New section ~~~~~ -->
9126 <sect2 id="actionsanat">
9127 <title>Troubleshooting: Anatomy of an Action</title>
9130 The way <application>Privoxy</application> applies
9131 <link linkend="ACTIONS">actions</link> and <link linkend="FILTER">filters</link>
9132 to any given URL can be complex, and not always so
9133 easy to understand what is happening. And sometimes we need to be able to
9134 <emphasis>see</emphasis> just what <application>Privoxy</application> is
9135 doing. Especially, if something <application>Privoxy</application> is doing
9136 is causing us a problem inadvertently. It can be a little daunting to look at
9137 the actions and filters files themselves, since they tend to be filled with
9138 <link linkend="regex">regular expressions</link> whose consequences are not
9143 One quick test to see if <application>Privoxy</application> is causing a problem
9144 or not, is to disable it temporarily. This should be the first troubleshooting
9145 step. See <link linkend="bookmarklets">the Bookmarklets</link> section on a quick
9146 and easy way to do this (be sure to flush caches afterward!). Looking at the
9147 logs is a good idea too. (Note that both the toggle feature and logging are
9148 enabled via <filename>config</filename> file settings, and may need to be
9149 turned <quote>on</quote>.)
9152 Another easy troubleshooting step to try is if you have done any
9153 customization of your installation, revert back to the installed
9154 defaults and see if that helps. There are times the developers get complaints
9155 about one thing or another, and the problem is more related to a customized
9156 configuration issue.
9160 <application>Privoxy</application> also provides the
9161 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
9162 page that can show us very specifically how <application>actions</application>
9163 are being applied to any given URL. This is a big help for troubleshooting.
9167 First, enter one URL (or partial URL) at the prompt, and then
9168 <application>Privoxy</application> will tell us
9169 how the current configuration will handle it. This will not
9170 help with filtering effects (i.e. the <link
9171 linkend="FILTER"><quote>+filter</quote></link> action) from
9172 one of the filter files since this is handled very
9173 differently and not so easy to trap! It also will not tell you about any other
9174 URLs that may be embedded within the URL you are testing. For instance, images
9175 such as ads are expressed as URLs within the raw page source of HTML pages. So
9176 you will only get info for the actual URL that is pasted into the prompt area
9177 -- not any sub-URLs. If you want to know about embedded URLs like ads, you
9178 will have to dig those out of the HTML source. Use your browser's <quote>View
9179 Page Source</quote> option for this. Or right click on the ad, and grab the
9184 Let's try an example, <ulink url="http://google.com">google.com</ulink>,
9185 and look at it one section at a time in a sample configuration (your real
9186 configuration may vary):
9191 Matches for http://www.google.com:
9193 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
9195 {+change-x-forwarded-for{block}
9196 +deanimate-gifs {last}
9197 +fast-redirects {check-decoded-url}
9198 +filter {refresh-tags}
9199 +filter {img-reorder}
9200 +filter {banners-by-size}
9202 +filter {jumping-windows}
9203 +filter {ie-exploits}
9204 +hide-from-header {block}
9205 +hide-referrer {forge}
9206 +session-cookies-only
9207 +set-image-blocker {pattern}
9210 { -session-cookies-only }
9216 In file: user.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
9217 (no matches in this file)
9222 This is telling us how we have defined our
9223 <link linkend="ACTIONS"><quote>actions</quote></link>, and
9224 which ones match for our test case, <quote>google.com</quote>.
9225 Displayed is all the actions that are available to us. Remember,
9226 the <literal>+</literal> sign denotes <quote>on</quote>. <literal>-</literal>
9227 denotes <quote>off</quote>. So some are <quote>on</quote> here, but many
9228 are <quote>off</quote>. Each example we try may provide a slightly different
9229 end result, depending on our configuration directives.
9233 is for our <filename>default.action</filename> file. The large, multi-line
9234 listing, is how the actions are set to match for all URLs, i.e. our default
9235 settings. If you look at your <quote>actions</quote> file, this would be the
9236 section just below the <quote>aliases</quote> section near the top. This
9237 will apply to all URLs as signified by the single forward slash at the end
9238 of the listing -- <quote> / </quote>.
9242 But we have defined additional actions that would be exceptions to these general
9243 rules, and then we list specific URLs (or patterns) that these exceptions
9244 would apply to. Last match wins. Just below this then are two explicit
9245 matches for <quote>.google.com</quote>. The first is negating our previous
9246 cookie setting, which was for <link
9247 linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>
9248 (i.e. not persistent). So we will allow persistent cookies for google, at
9249 least that is how it is in this example. The second turns
9250 <emphasis>off</emphasis> any <link
9251 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link>
9252 action, allowing this to take place unmolested. Note that there is a leading
9253 dot here -- <quote>.google.com</quote>. This will match any hosts and
9254 sub-domains, in the google.com domain also, such as
9255 <quote>www.google.com</quote> or <quote>mail.google.com</quote>. But it would not
9256 match <quote>www.google.de</quote>! So, apparently, we have these two actions
9257 defined as exceptions to the general rules at the top somewhere in the lower
9258 part of our <filename>default.action</filename> file, and
9259 <quote>google.com</quote> is referenced somewhere in these latter sections.
9263 Then, for our <filename>user.action</filename> file, we again have no hits.
9264 So there is nothing google-specific that we might have added to our own, local
9265 configuration. If there was, those actions would over-rule any actions from
9266 previously processed files, such as <filename>default.action</filename>.
9267 <filename>user.action</filename> typically has the last word. This is the
9268 best place to put hard and fast exceptions,
9272 And finally we pull it all together in the bottom section and summarize how
9273 <application>Privoxy</application> is applying all its <quote>actions</quote>
9274 to <quote>google.com</quote>:
9285 +change-x-forwarded-for{block}
9286 -client-header-filter{hide-tor-exit-notation}
9287 -content-type-overwrite
9288 -crunch-client-header
9289 -crunch-if-none-match
9290 -crunch-incoming-cookies
9291 -crunch-outgoing-cookies
9292 -crunch-server-header
9293 +deanimate-gifs {last}
9294 -downgrade-http-version
9297 -filter {content-cookies}
9298 -filter {all-popups}
9299 -filter {banners-by-link}
9300 -filter {tiny-textforms}
9301 -filter {frameset-borders}
9302 -filter {demoronizer}
9303 -filter {shockwave-flash}
9304 -filter {quicktime-kioskmode}
9306 -filter {crude-parental}
9307 -filter {site-specifics}
9308 -filter {js-annoyances}
9309 -filter {html-annoyances}
9310 +filter {refresh-tags}
9311 -filter {unsolicited-popups}
9312 +filter {img-reorder}
9313 +filter {banners-by-size}
9315 +filter {jumping-windows}
9316 +filter {ie-exploits}
9323 -handle-as-empty-document
9325 -hide-accept-language
9326 -hide-content-disposition
9327 +hide-from-header {block}
9328 -hide-if-modified-since
9329 +hide-referrer {forge}
9332 -overwrite-last-modified
9333 -prevent-compression
9335 -server-header-filter{xml-to-html}
9336 -server-header-filter{html-to-xml}
9337 -session-cookies-only
9338 +set-image-blocker {pattern} </screen>
9342 Notice the only difference here to the previous listing, is to
9343 <quote>fast-redirects</quote> and <quote>session-cookies-only</quote>,
9344 which are activated specifically for this site in our configuration,
9345 and thus show in the <quote>Final Results</quote>.
9349 Now another example, <quote>ad.doubleclick.net</quote>:
9355 { +block{Domains starts with "ad"} }
9358 { +block{Domain contains "ad"} }
9361 { +block{Doubleclick banner server} +handle-as-image }
9362 .[a-vx-z]*.doubleclick.net
9367 We'll just show the interesting part here - the explicit matches. It is
9368 matched three different times. Two <quote>+block{}</quote> sections,
9369 and a <quote>+block{} +handle-as-image</quote>,
9370 which is the expanded form of one of our aliases that had been defined as:
9371 <quote>+block-as-image</quote>. (<link
9372 linkend="ALIASES"><quote>Aliases</quote></link> are defined in
9373 the first section of the actions file and typically used to combine more
9378 Any one of these would have done the trick and blocked this as an unwanted
9379 image. This is unnecessarily redundant since the last case effectively
9380 would also cover the first. No point in taking chances with these guys
9381 though ;-) Note that if you want an ad or obnoxious
9382 URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
9383 is done here -- as both a <link
9384 linkend="BLOCK"><quote>+block{}</quote></link>
9385 <emphasis>and</emphasis> an
9386 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>.
9387 The custom alias <quote><literal>+block-as-image</literal></quote> just
9388 simplifies the process and make it more readable.
9392 One last example. Let's try <quote>http://www.example.net/adsl/HOWTO/</quote>.
9393 This one is giving us problems. We are getting a blank page. Hmmm ...
9399 Matches for http://www.example.net/adsl/HOWTO/:
9401 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
9405 +change-x-forwarded-for{block}
9406 -client-header-filter{hide-tor-exit-notation}
9407 -content-type-overwrite
9408 -crunch-client-header
9409 -crunch-if-none-match
9410 -crunch-incoming-cookies
9411 -crunch-outgoing-cookies
9412 -crunch-server-header
9414 -downgrade-http-version
9415 +fast-redirects {check-decoded-url}
9417 -filter {content-cookies}
9418 -filter {all-popups}
9419 -filter {banners-by-link}
9420 -filter {tiny-textforms}
9421 -filter {frameset-borders}
9422 -filter {demoronizer}
9423 -filter {shockwave-flash}
9424 -filter {quicktime-kioskmode}
9426 -filter {crude-parental}
9427 -filter {site-specifics}
9428 -filter {js-annoyances}
9429 -filter {html-annoyances}
9430 +filter {refresh-tags}
9431 -filter {unsolicited-popups}
9432 +filter {img-reorder}
9433 +filter {banners-by-size}
9435 +filter {jumping-windows}
9436 +filter {ie-exploits}
9443 -handle-as-empty-document
9445 -hide-accept-language
9446 -hide-content-disposition
9447 +hide-from-header{block}
9448 +hide-referer{forge}
9450 -overwrite-last-modified
9451 +prevent-compression
9453 -server-header-filter{xml-to-html}
9454 -server-header-filter{html-to-xml}
9455 +session-cookies-only
9456 +set-image-blocker{blank} }
9459 { +block{Path contains "ads".} +handle-as-image }
9465 Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote> in our
9466 configuration! But we did not want this at all! Now we see why we get the
9467 blank page. It is actually triggering two different actions here, and
9468 the effects are aggregated so that the URL is blocked, and &my-app; is told
9469 to treat the block as if it were an image. But this is, of course, all wrong.
9470 We could now add a new action below this (or better in our own
9471 <filename>user.action</filename> file) that explicitly
9472 <emphasis>un</emphasis> blocks (
9473 <link linkend="BLOCK"><quote>{-block}</quote></link>) paths with
9474 <quote>adsl</quote> in them (remember, last match in the configuration
9475 wins). There are various ways to handle such exceptions. Example:
9487 Now the page displays ;-)
9488 Remember to flush your browser's caches when making these kinds of changes to
9489 your configuration to insure that you get a freshly delivered page! Or, try
9490 using <literal>Shift+Reload</literal>.
9494 But now what about a situation where we get no explicit matches like
9501 { +block{Path starts with "ads".} +handle-as-image }
9507 That actually was very helpful and pointed us quickly to where the problem
9508 was. If you don't get this kind of match, then it means one of the default
9509 rules in the first section of <filename>default.action</filename> is causing
9510 the problem. This would require some guesswork, and maybe a little trial and
9511 error to isolate the offending rule. One likely cause would be one of the
9512 <link linkend="FILTER"><quote>+filter</quote></link> actions.
9513 These tend to be harder to troubleshoot.
9514 Try adding the URL for the site to one of aliases that turn off
9515 <link linkend="FILTER"><quote>+filter</quote></link>:
9523 .worldpay.com # for quietpc.com
9531 <quote><literal>{ shop }</literal></quote> is an <quote>alias</quote> that expands to
9532 <quote><literal>{ -filter -session-cookies-only }</literal></quote>.
9533 Or you could do your own exception to negate filtering:
9541 # Disable ALL filter actions for sites in this section
9549 This would turn off all filtering for these sites. This is best
9550 put in <filename>user.action</filename>, for local site
9551 exceptions. Note that when a simple domain pattern is used by itself (without
9552 the subsequent path portion), all sub-pages within that domain are included
9553 automatically in the scope of the action.
9557 Images that are inexplicably being blocked, may well be hitting the
9558 <link linkend="FILTER-BANNERS-BY-SIZE"><quote>+filter{banners-by-size}</quote></link>
9560 that images of certain sizes are ad banners (works well
9561 <emphasis>most of the time</emphasis> since these tend to be standardized).
9565 <quote><literal>{ fragile }</literal></quote> is an alias that disables most
9566 actions that are the most likely to cause trouble. This can be used as a
9567 last resort for problem sites.
9573 # Handle with care: easy to break
9575 mybank.example.com</screen>
9580 <emphasis>Remember to flush caches!</emphasis> Note that the
9581 <literal>mail.google</literal> reference lacks the TLD portion (e.g.
9582 <quote>.com</quote>). This will effectively match any TLD with
9583 <literal>google</literal> in it, such as <literal>mail.google.de.</literal>,
9587 If this still does not work, you will have to go through the remaining
9588 actions one by one to find which one(s) is causing the problem.
9597 This program is free software; you can redistribute it
9598 and/or modify it under the terms of the GNU General
9599 Public License as published by the Free Software
9600 Foundation; either version 2 of the License, or (at
9601 your option) any later version.
9603 This program is distributed in the hope that it will
9604 be useful, but WITHOUT ANY WARRANTY; without even the
9605 implied warranty of MERCHANTABILITY or FITNESS FOR A
9606 PARTICULAR PURPOSE. See the GNU General Public
9607 License for more details.
9609 The GNU General Public License should be included with
9610 this file. If not, you can view it at
9611 http://www.gnu.org/copyleft/gpl.html
9612 or write to the Free Software Foundation, Inc.,
9613 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
projects / privoxy.git / blob