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 2.161 2013/01/12 12:21:38 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 2.161 2013/01/12 12:21:38 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-deb"><title>Debian and Ubuntu</title>
186 DEBs can be installed with <literal>apt-get install privoxy</literal>,
187 and will use <filename>/etc/privoxy</filename> for the location of
192 <!-- ~~~~~ New section ~~~~~ -->
193 <sect3 id="installation-pack-win"><title>Windows</title>
196 Just double-click the installer, which will guide you through
197 the installation process. You will find the configuration files
198 in the same directory as you installed <application>Privoxy</application> in.
201 Version 3.0.5 beta introduced full <application>Windows</application> service
202 functionality. On Windows only, the <application>Privoxy</application>
203 program has two new command line arguments to install and uninstall
204 <application>Privoxy</application> as a <emphasis>service</emphasis>.
208 <term>Arguments:</term>
211 <replaceable class="parameter">--install</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
214 <replaceable class="parameter">--uninstall</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
220 After invoking <application>Privoxy</application> with
221 <command>--install</command>, you will need to bring up the
222 <application>Windows</application> service console to assign the user you
223 want <application>Privoxy</application> to run under, and whether or not you
224 want it to run whenever the system starts. You can start the
225 <application>Windows</application> services console with the following
226 command: <command>services.msc</command>. If you do not take the manual step
227 of modifying <application>Privoxy's</application> service settings, it will
228 not start. Note too that you will need to give Privoxy a user account that
229 actually exists, or it will not be permitted to
230 write to its log and configuration files.
235 <!-- ~~~~~ New section ~~~~~ -->
236 <sect3 id="installation-os2"><title>OS/2</title>
239 First, make sure that no previous installations of
240 <application>Junkbuster</application> and / or
241 <application>Privoxy</application> are left on your
242 system. Check that no <application>Junkbuster</application>
243 or <application>Privoxy</application> objects are in
249 Then, just double-click the WarpIN self-installing archive, which will
250 guide you through the installation process. A shadow of the
251 <application>Privoxy</application> executable will be placed in your
252 startup folder so it will start automatically whenever OS/2 starts.
256 The directory you choose to install <application>Privoxy</application>
257 into will contain all of the configuration files.
261 <!-- ~~~~~ New section ~~~~~ -->
262 <sect3 id="installation-mac"><title>Mac OS X</title>
264 Installation instructions for the OS X platform depend upon whether
265 you downloaded a ready-built installation package (.pkg or .mpkg) or have
266 downloaded the source code.
269 <sect3 renderas="sect4" id="OS-X-install-from-package">
270 <title>Installation from ready-built package</title>
272 The downloaded file will either be a .pkg (for OS X 10.5 upwards) or a bzipped
273 .mpkg file (for OS X 10.4). The former can be double-clicked as is and the
274 installation will start; double-clicking the latter will unzip the .mpkg file
275 which can then be double-clicked to commence the installation.
278 The privoxy service will automatically start after a successful installation
279 (and thereafter every time your computer starts up) however you will need to
280 configure your web browser(s) to use it. To do so, configure them to use a
281 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
284 To prevent the privoxy service from automatically starting when your computer
285 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
286 (on OS X 10.5 and higher) or the folder named
287 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
290 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
291 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
292 administrator account, using sudo.
295 To uninstall, run /Applications/Privoxy/uninstall.command as sudo from an
296 administrator account.
299 <sect3 renderas="sect4" id="OS-X-install-from-source">
300 <title>Installation from source</title>
302 To build and install the Privoxy source code on OS X you will need to obtain
303 the macsetup module from the Privoxy Sourceforge CVS repository (refer to
304 Sourceforge help for details of how to set up a CVS client to have read-only
305 access to the repository). This module contains scripts that leverage the usual
306 open-source tools (available as part of Apple's free of charge Xcode
307 distribution or via the usual open-source software package managers for OS X
308 (MacPorts, Homebrew, Fink etc.) to build and then install the privoxy binary
309 and associated files. The macsetup module's README file contains complete
310 instructions for its use.
313 The privoxy service will automatically start after a successful installation
314 (and thereafter every time your computer starts up) however you will need to
315 configure your web browser(s) to use it. To do so, configure them to use a
316 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
319 To prevent the privoxy service from automatically starting when your computer
320 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
321 (on OS X 10.5 and higher) or the folder named
322 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
325 To manually start or stop the privoxy service, use the Privoxy Utility
326 for Mac OS X (also part of the macsetup module). This application can start
327 and stop the privoxy service and display its log and configuration files.
330 To uninstall, run the macsetup module's uninstall.sh as sudo from an
331 administrator account.
335 <!-- ~~~~~ New section ~~~~~ -->
336 <sect3 id="installation-tbz"><title>FreeBSD</title>
339 Privoxy is part of FreeBSD's Ports Collection, you can build and install
340 it with <literal>cd /usr/ports/www/privoxy; make install clean</literal>.
343 If you don't use the ports, you can fetch and install
344 the package with <literal>pkg_add -r privoxy</literal>.
347 The port skeleton and the package can also be downloaded from the
348 <ulink url="https://sourceforge.net/project/showfiles.php?group_id=11118">File Release
349 Page</ulink>, but there's no reason to use them unless you're interested in the
350 beta releases which are only available there.
356 <!-- ~~~~~ New section ~~~~~ -->
357 <sect2 id="installation-source"><title>Building from Source</title>
360 The most convenient way to obtain the <application>Privoxy</application> sources
361 is to download the source tarball from our
362 <ulink url="http://sourceforge.net/project/showfiles.php?group_id=11118&package_id=10571">project download
367 If you like to live on the bleeding edge and are not afraid of using
368 possibly unstable development versions, you can check out the up-to-the-minute
369 version directly from <ulink url="http://sourceforge.net/cvs/?group_id=11118">the
370 CVS repository</ulink>.
372 deprecated...out of business.
373 or simply download <ulink
374 url="http://cvs.sourceforge.net/cvstarballs/ijbswa-cvsroot.tar.bz2">the nightly CVS
379 <!-- include buildsource.sgml boilerplate: -->
381 <!-- end boilerplate -->
384 <!-- ~~~~~ New section ~~~~~ -->
385 <sect2 id="installation-keepupdated"><title>Keeping your Installation Up-to-Date</title>
388 If you wish to receive an email notification whenever we release updates of
389 <application>Privoxy</application> or the actions file, <ulink
390 url="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce/">subscribe
391 to our announce mailing list</ulink>, ijbswa-announce@lists.sourceforge.net.
395 In order not to lose your personal changes and adjustments when updating
396 to the latest <literal>default.action</literal> file we <emphasis>strongly
397 recommend</emphasis> that you use <literal>user.action</literal> and
398 <literal>user.filter</literal> for your local
399 customizations of <application>Privoxy</application>. See the <link
400 linkend="actions-file">Chapter on actions files</link> for details.
408 <!-- ~ End section ~ -->
410 <!-- ~~~~~ New section ~~~~~ -->
411 <sect1 id="whatsnew">
412 <title>What's New in this Release</title>
414 <application>Privoxy 3.0.20</application> is a beta release.
415 The changes since 3.0.19 stable are:
426 Client sockets are now properly shutdown and drained before being
427 closed. This fixes page truncation issues with clients that aggressively
428 pipeline data on platforms that otherwise discard already written data.
429 The issue mainly affected Opera users and was initially reported
430 by Kevin in #3464439, szotsaki provided additional information to track
436 Fix latency calculation for shared connections (disabled by default).
437 It was broken since their introduction in 2009. The calculated latency
438 for most connections would be 0 in which case the timeout detection
439 failed to account for the real latency.
444 Reject URLs with invalid port. Previously they were parsed incorrectly and
445 characters between the port number and the first slash were silently
446 dropped as shown by curl test 187.
451 The default-server-timeout and socket-timeout directives accept 0 as
457 Fix a race condition on Windows that could cause Privoxy to become
458 unresponsive after toggling it on or off through the taskbar icon.
459 Reported by Tim H. in #3525694.
464 Fix the compilation on Windows when configured without IPv6 support.
469 Fix an assertion that could cause debug builds to abort() in case of
470 socks5 connection failures with "debug 2" enabled.
475 Fix an assertion that could cause debug builds to abort() if a filter
476 contained nul bytes in the replacement text.
484 General improvements:
488 Significantly improved keep-alive support for both client and server
494 New debug log level 65536 which logs all actions that were applied to
500 New directive client-header-order to forward client headers in a
501 different order than the one in which they arrived.
506 New directive tolerate-pipelining to allow client-side pipelining.
507 If enabled (3.0.20 beta enables it by default), Privoxy will keep
508 pipelined client requests around to deal with them once the current
509 request has been served.
514 New --config-test option to let Privoxy exit after checking whether or not
515 the configuration seems valid. The limitations noted in TODO #22 and #23
516 still apply. Based on a patch by Ramkumar Chinchani.
521 New limit-cookie-lifetime{} action to let cookies expire before the end
522 of the session. Suggested by Rick Sykes in #1049575.
527 Increase the hard-coded maximum number of actions and filter files from
528 10 to 30 (each). It doesn't significantly affect Privoxy's memory usage
529 and recompiling wasn't an option for all Privoxy users that reached the
535 Add support for chunk-encoded client request bodies. Previously
536 chunk-encoded request bodies weren't guaranteed to be forwarded correctly,
537 so this can also be considered a bug fix although chunk-encoded request
538 bodies aren't commonly used in the real world.
543 Add support for Tor's optimistic-data SOCKS extension, which can reduce the
544 latency for requests on newly created connections. Currently only the
545 headers are sent optimistically and only if the client request has already
546 been read completely which rules out requests with large bodies.
551 After preventing the client from pipelining, don't signal keep-alive
552 intentions. When looking at the response headers alone, it previously
553 wasn't obvious from the client's perspective that no additional responses
559 Stop considering client sockets tainted after receving a request with body.
560 It hasn't been necessary for a while now and unnecessarily causes test
561 failures when using curl's test suite.
566 Allow HTTP/1.0 clients to signal interest in keep-alive through the
567 Proxy-Connection header. While such client are rare in the real world, it
568 doesn't hurt and couple of curl tests rely on it.
573 Only remove duplicated Content-Type headers when filters are enabled.
574 If they are not it doesn't cause ill effects and the user might not want it.
575 Downgrade the removal message to LOG_LEVEL_HEADER to clarify that it's not
576 an error in Privoxy and is unlikely to cause any problems in general.
577 Anonymously reported in #3599335.
582 Set the socket option SO_LINGER for the client socket.
587 Move several variable declarations to the beginning of their code block.
588 It's required when compiling with gcc 2.95 which is still used on some
589 platforms. Initial patch submitted by Simon South in #3564815.
594 Optionally try to sanity-check strptime() results before trusting them.
595 Broken strptime() implementations have caused problems in the past and
596 the most recent offender seems to be FreeBSD's libc (standards/173421).
601 When filtering is enabled, let Range headers pass if the range starts at
602 the beginning. This should work around (or at least reduce ) the video
603 playback issues with various Apple clients as reported by Duc in #3426305.
608 Do not confuse a client hanging up with a connection time out. If a client
609 closes its side of the connection without sending a request line, do not
610 send the CLIENT_CONNECTION_TIMEOUT_RESPONSE, but report the condition
616 Allow closing curly braces as part of action values as long as they are
622 On Windows, the logfile is now written before showing the GUI error
623 message which blocks until the user acknowledges it.
624 Reported by Adriaan in #3593603.
629 Remove an unreasonable parameter limit in the CGI interface. The new
630 parameter limit depends on the memory available and is currently unlikely
631 to be reachable, due to other limits in both Privoxy and common clients.
632 Reported by Andrew on ijbswa-users@.
637 Decrease the chances of parse failures after requests with unsupported
638 methods were sent to the CGI interface.
646 Action file improvements:
650 Remove the comment that indicated that updated default.action versions
651 are released on their own.
656 Block 'optimize.indieclick.com/' and 'optimized-by.rubiconproject.com/'
661 Unblock 'adjamblog.wordpress.com/' and 'adjamblog.files.wordpress.com/'.
662 Reported by Ryan Farmer in #3496116.
667 Unblock '/.*Bugtracker'. Reported by pwhk in #3522341.
672 Add test URLs for '.freebsd.org' and '.watson.org'.
677 Unblock '.urbandictionary.com/popular'.
687 Block 'farm.plista.com/widgetdata.php'.
692 Block 'rotation.linuxnewmedia.com/'.
697 Block 'reklamy.sfd.pl/'. Reported by kacperdominik in #3399948.
702 Block 'g.adspeed.net/'.
707 Unblock 'websupport.wdc.com/'. Reported by Adam Piggot in #3577851.
712 Block '/openx/www/delivery/'.
717 Disable fast-redirects for '.googleapis.com/'.
722 Block 'imp.double.net/'. Reported by David Bo in #3070411.
727 Block 'gm-link.com/' whis is used for email tracking.
728 Reported by David Bo in #1812733.
733 Verify that requests to "bwp." are blocked. URL taken from #1736879
734 submitted by Francois Marier.
739 Block '/.*bannerid='. Reported by Adam Piggott in #2975779.
744 Block 'cltomedia.info/delivery/' and '.adexprt.com/'.
745 Anonymously reported in #2965254.
750 Block 'de17a.com/'. Reported by David Bo in #3061472.
755 Block 'oskar.tradera.com/'. Reported by David Bo in #3060596.
760 Block '/scripts/webtrends\.js'. Reported by johnd16 in #3002729.
765 Block requests for 'pool.*.adhese.com/'. Reported by johnd16 in #3002716.
770 Update path pattern for Coremetrics and add tests.
771 Pattern and URLs submitted by Adam Piggott #3168443.
776 Enable +fast-redirects{check-decoded-url} for 'tr.anp.se/'.
777 Reported by David Bo in #3268832.
782 Unblock '.conrad.se/newsletter/banners/'. Reported by David Bo in #3413824.
787 Block '.tynt.com/'. Reported by Dan Stahlke in #3421767.
792 Unblock '.bbci.co.uk/radio/'. Reported by Adam Piggott in #3569603.
797 Block requests to 'service.maxymiser.net/'.
798 Reported by johnd16 in #3118401 (with a previous URL).
803 Disable fast-redirects for Google's "let's pretend your computer is
809 Unblock '/.*download' to resolve actionsfile feedback #3498129.
810 Submitted by Steven Kolins (soundcloud.com not working).
815 Unblock '.wlxrs.com/' which is required by hotmail.com.
816 Fixes #3413827 submitted by David Bo.
821 Add two unblock patterns for popup radio and TV players.
822 Submitted by Adam Piggott in #3596089.
830 Filter file improvements & bug fixes:
834 Add a referer tagger.
839 Reduce the likelihood that the google filter messes up HTML-generating
840 JavaScript. Reported by Zeno Kugy in #3520260.
848 Documentation improvements:
852 Revised all OS X sections due to new packaging module (OSXPackageBuilder).
857 Update the list of supported operating systems to clarify that all Windows
858 versions after 95 are expected to work and note that the platform-specific
859 code for AmigaOS and QNX currently isn't maintained.
864 Update 'Signals' section, the only explicitly handled signals are SIGINT,
870 Add Haiku to the list of operating systems on which Privoxy is known to
876 Add DragonFly to the list of BSDs on which Privoxy is known to run.
881 Removed references to redhat-specific documentation set since it no longer
887 Removed references to building PDFs since we no longer do so.
892 Multiple listen-address directives are supported since 3.0.18, correct the
893 documentation to say so.
898 Remove bogus section about long and short being preferable to int.
903 Corrected some Internet JunkBuster references to Privoxy.
908 Removed references to www.junkbusters.com since it is no longer
909 maintained. Reported by Angelina Matson.
914 Various grammar and spelling corrections
919 Add a client-header-tagger{} example for disabling filtering for range
925 Correct a URL in the "Privoxy with Tor" FAQ.
930 Spell 'refresh-tags' correctly. Reported by Don in #3571927.
935 Sort manpage options alphabetically.
940 Remove an incorrect sentence in the toggle section. The toggle state
941 doesn't affect whether or not the Windows version uses the tray icon.
942 Reported by Zeno Kugy in #3596395.
947 Add new contributors since 3.0.19.
955 Log message improvements:
959 When stopping to watch a client socket due to pipelining, additionally log
965 Log the client socket and its condition before closing it. This makes it
966 more obvious that the socket actually gets closed and should help when
967 diagnosing problems like #3464439.
972 In case of SOCKS5 failures, do not explicitly log the server's response.
973 It hasn't helped so far and the response can already be logged by enabling
974 "debug 32768" anyway. This reverts v1.81 and the follow-up bug fix v1.84.
979 Relocate the connection-accepted message from listen_loop() to serve().
980 This way it's printed by the thread that is actually serving the
981 connection which is nice when grepping for thread ids in log files.
993 Remove compatibility layer for versions prior to 3.0 since it has been
994 obsolete for more than 10 years now.
999 Remove the ijb_isupper() and ijb_tolower() macros from parsers.c since
1000 they aren't used in this file.
1005 Removed the 'Functions declared include:' comment sections since they tend
1006 to be incomplete, incorrect and out of date and the benefit seems
1012 Various comment grammar and comprehensibility improvements.
1017 Remove a pointless fflush() call in chat(). Flushing all streams pretty
1018 much all the time for no obvious reason is ridiculous.
1023 Relocate ijb_isupper()'s definition to project.h and get the ijb_tolower()
1024 definition from there, too.
1029 Relocate ijb_isdigit()'s definition to project.h.
1034 Rename ijb_foo macros to privoxy_foo.
1039 Add malloc_or_die() which will allow to simplify code paths where malloc()
1040 failures don't need to be handled gracefully.
1045 Add strdup_or_die() which will allow to simplify code paths where strdup()
1046 failures don't need to be handled gracefully.
1051 Replace strdup() calls with strdup_or_die() calls where it's safe and
1052 simplifies the code.
1057 Fix white-space around parentheses.
1062 Add missing white-space behind if's and the following parentheses.
1067 Unwrap a memcpy() call in resolve_hostname_to_ip().
1072 Declare pcrs_get_delimiter()'s delimiters[] static const.
1077 Various optimisations to remove dead code and merge inefficient code
1078 structures for improved clarity, performance or code compactness.
1083 Various data type corrections.
1088 Change visibility of several code segments when compiling without
1089 FEATURE_CONNECTION_KEEP_ALIVE enabled for clarity.
1094 In pcrs_get_delimiter(), do not use delimiters ouside the ASCII range.
1095 Fixes a clang complaint.
1100 Fix an error message in get_last_url() nobody is supposed to see.
1101 Reported by Matthew Fischer in #3507301.
1106 Fix a typo in the no-zlib-support complaint. Patch submitted by Matthew
1107 Fischer in #3507304.
1112 Shorten ssplit()'s prototype by removing the last two arguments. We always
1113 want to skip empty fields and ignore leading delimiters, so having
1114 parameters for this only complicates the API.
1119 Use an enum for the type of the action value.
1124 Rename action_name's member takes_value to value_type as it isn't used as
1130 Turn family mismatches in match_sockaddr() into fatal errors.
1135 Let enlist_unique_header() verify that the caller didn't pass a header
1136 containing either \r or \n.
1141 Change the hashes used in load_config() to unsigned int. That's what
1142 hash_string() actually returns and using a potentiallly larger type
1148 Use privoxy_tolower() instead of vanilla tolower() with manual casting of
1154 Catch ssplit() failures in parse_cgi_parameters().
1162 Privoxy-Regression-Test:
1166 Add an 'Overwrite condition' directive to skip any matching tests before
1167 it. As it has a global scope, using it is more convenient than clowning
1168 around with the Ignore directive.
1173 Log to STDOUT instead of STDERR.
1178 Include the Privoxy version in the output.
1183 Various grammar and spelling corrections in documentation and code.
1188 Additional tests for range requests with filtering enabled.
1193 Tests with mostly invalid range request.
1198 Add a couple of hide-if-modified-since{} tests with different date formats.
1203 Cleaned up the format of the regression-tests.action file to match the
1204 format of default.action.
1209 Remove the "Copyright" line from print_version(). When using --help, every
1210 line of screen space matters and thus shouldn't be wasted on things the
1211 user doesn't care about.
1223 Improve the --statistics performance by skipping sanity checks for input
1224 that shouldn't affect the results anyway. Add a --strict-checks option
1225 that enables some of the checks again, just in case anybody cares.
1230 The distribution of client requests per connection is included in
1231 the --statistic output.
1236 The --accept-unknown-messages option has been removed and the behavior
1242 Accept and (mostly) highlight new log messages introduced with
1255 Bump generated Firefox version to 17.
1263 GNUmakefile improvements:
1267 The dok-tidy target no longer taints documents with a tidy-mark
1272 Change RA_MODE from 0664 to 0644. Suggested by Markus Dittrich in
1278 Remove tidy's clean flag as it changes the scope of attributes.
1279 Link-specific colors end up being applied to all text. Reported by Adam
1280 Piggott in #3569551.
1285 Leave it up to the user whether or not smart tags are inserted.
1290 Let w3m itself do the line wrapping for the config file. It works better
1291 than fmt as it can honour pre tags causing less unintentional line breaks.
1296 Ditch a pointless '-r' passed to rm to delete files.
1301 The config-file target now requires less manual intervention and updates
1302 the original config.
1307 Change WDUMP to generate ASCII. Add WDUMP_UTF8 to allow UTF-8 in the
1308 AUTHORS file so the names are right.
1313 Stop pretending that lynx and links are supported for the documentation.
1321 configure improvements:
1325 On Haiku, do not pass -lpthread to the compiler. Haiku's pthreads
1326 implementation is contained in its system library, libroot, so no
1327 additional library needs to be searched.
1328 Patch submitted by Simon South in #3564815.
1333 Additional Haiku-specific improvements. Disable checks intended for
1334 multi-user systems as Haiku is presently single-user. Group Haiku-specific
1335 settings in their own section, following the pattern for Solaris, OS/2 and
1336 AmigaOS. Add additional library-related settings to remove the need for
1337 providing configure with custom LDFLAGS.
1338 Submitted by Simon South in #3574538.
1339 *** Version 3.0.19 Stable ***
1351 Prevent a segmentation fault when de-chunking buffered content.
1352 It could be triggered by malicious web servers if Privoxy was
1353 configured to filter the content and running on a platform
1354 where SIZE_T_MAX isn't larger than UINT_MAX, which probably
1355 includes most 32-bit systems. On those platforms, all Privoxy
1356 versions before 3.0.19 appear to be affected.
1357 To be on the safe side, this bug should be presumed to allow
1358 code execution as proving that it doesn't seems unrealistic.
1363 Do not expect a response from the SOCKS4/4A server until it
1364 got something to respond to. This regression was introduced
1365 in 3.0.18 and prevented the SOCKS4/4A negotiation from working.
1366 Reported by qqqqqw in #3459781.
1374 General improvements:
1378 Fix an off-by-one in an error message about connect failures.
1383 Use a GNUMakefile variable for the webserver root directory and
1384 update the path. Sourceforge changed it which broke various
1385 web-related targets.
1390 Update the CODE_STATUS description.
1400 <!-- ~~~~~ New section ~~~~~ -->
1402 <sect2 id="upgradersnote">
1403 <title>Note to Upgraders</title>
1406 A quick list of things to be aware of before upgrading from earlier
1407 versions of <application>Privoxy</application>:
1415 The recommended way to upgrade &my-app; is to backup your old
1416 configuration files, install the new ones, verify that &my-app;
1417 is working correctly and finally merge back your changes using
1418 <application>diff</application> and maybe <application>patch</application>.
1421 There are a number of new features in each &my-app; release and
1422 most of them have to be explicitly enabled in the configuration
1423 files. Old configuration files obviously don't do that and due
1424 to syntax changes using old configuration files with a new
1425 &my-app; isn't always possible anyway.
1430 Note that some installers remove earlier versions completely,
1431 including configuration files, therefore you should really save
1432 any important configuration files!
1437 On the other hand, other installers don't overwrite existing configuration
1438 files, thinking you will want to do that yourself.
1443 <filename>standard.action</filename> has been merged into
1444 the <filename>default.action</filename> file.
1449 In the default configuration only fatal errors are logged now.
1450 You can change that in the <link linkend="DEBUG">debug section</link>
1451 of the configuration file. You may also want to enable more verbose
1452 logging until you verified that the new &my-app; version is working
1459 Three other config file settings are now off by default:
1460 <link linkend="enable-remote-toggle">enable-remote-toggle</link>,
1461 <link linkend="enable-remote-http-toggle">enable-remote-http-toggle</link>,
1462 and <link linkend="enable-edit-actions">enable-edit-actions</link>.
1463 If you use or want these, you will need to explicitly enable them, and
1464 be aware of the security issues involved.
1471 What constitutes a <quote>default</quote> configuration has changed,
1472 and you may want to review which actions are <quote>on</quote> by
1473 default. This is primarily a matter of emphasis, but some features
1474 you may have been used to, may now be <quote>off</quote> by default.
1475 There are also a number of new actions and filters you may want to
1476 consider, most of which are not fully incorporated into the default
1477 settings as yet (see above).
1484 The default actions setting is now <literal>Cautious</literal>. Previous
1485 releases had a default setting of <literal>Medium</literal>. Experienced
1486 users may want to adjust this, as it is fairly conservative by &my-app;
1487 standards and past practices. See <ulink
1488 url="http://config.privoxy.org/edit-actions-list?f=default">
1489 http://config.privoxy.org/edit-actions-list?f=default</ulink>. New users
1490 should try the default settings for a while before turning up the volume.
1496 The default setting has filtering turned <emphasis>off</emphasis>, which
1497 subsequently means that compression is <emphasis>on</emphasis>. Remember
1498 that filtering does not work on compressed pages, so if you use, or want to
1499 use, filtering, you will need to force compression off. Example:
1503 { +<link linkend="filter">filter</link>{google} +<link linkend="prevent-compression">prevent-compression</link> }
1507 Or if you use a number of filters, or filter many sites, you may just want
1508 to turn off compression for all sites in
1509 <filename>default.action</filename> (or
1510 <filename>user.action</filename>).
1517 Also, <link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> is
1518 off by default now. If you've liked this feature in the past, you may want
1519 to turn it back on in <filename>user.action</filename> now.
1526 Some installers may not automatically start
1527 <application>Privoxy</application> after installation.
1538 <!-- ~~~~~ New section ~~~~~ -->
1539 <sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
1545 Install <application>Privoxy</application>. See the <link
1546 linkend="installation">Installation Section</link> below for platform specific
1553 Advanced users and those who want to offer <application>Privoxy</application>
1554 service to more than just their local machine should check the <link
1555 linkend="config">main config file</link>, especially the <link
1556 linkend="access-control">security-relevant</link> options. These are
1563 Start <application>Privoxy</application>, if the installation program has
1564 not done this already (may vary according to platform). See the section
1565 <link linkend="startup">Starting <application>Privoxy</application></link>.
1571 Set your browser to use <application>Privoxy</application> as HTTP and
1572 HTTPS (SSL) <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
1573 by setting the proxy configuration for address of
1574 <literal>127.0.0.1</literal> and port <literal>8118</literal>.
1575 <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
1576 any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
1577 browser from using these protocols.
1583 Flush your browser's disk and memory caches, to remove any cached ad images.
1584 If using <application>Privoxy</application> to manage
1585 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1586 you should remove any currently stored cookies too.
1592 A default installation should provide a reasonable starting point for
1593 most. There will undoubtedly be occasions where you will want to adjust the
1594 configuration, but that can be dealt with as the need arises. Little
1595 to no initial configuration is required in most cases, you may want
1597 <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
1598 Be sure to read the warnings first.
1601 See the <link linkend="configuration">Configuration section</link> for more
1602 configuration options, and how to customize your installation.
1603 You might also want to look at the <link
1604 linkend="quickstart-ad-blocking">next section</link> for a quick
1605 introduction to how <application>Privoxy</application> blocks ads and
1612 If you experience ads that slip through, innocent images that are
1613 blocked, or otherwise feel the need to fine-tune
1614 <application>Privoxy's</application> behavior, take a look at the <link
1615 linkend="actions-file">actions files</link>. As a quick start, you might
1616 find the <link linkend="act-examples">richly commented examples</link>
1617 helpful. You can also view and edit the actions files through the <ulink
1618 url="http://config.privoxy.org">web-based user interface</ulink>. The
1619 Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
1620 Action</link></quote> has hints on how to understand and debug actions that
1621 <quote>misbehave</quote>.
1626 Did anyone test these lately?
1630 For easy access to &my-app;'s most important controls, drag the provided
1631 <link linkend="bookmarklets">Bookmarklets</link> into your browser's
1639 Please see the section <link linkend="contact">Contacting the
1640 Developers</link> on how to report bugs, problems with websites or to get
1647 Now enjoy surfing with enhanced control, comfort and privacy!
1655 <!-- ~~~~~ New section ~~~~~ -->
1657 <sect2 id="quickstart-ad-blocking">
1658 <title>Quickstart to Ad Blocking</title>
1660 NOTE: This section is deliberately redundant for those that don't
1661 want to read the whole thing (which is getting lengthy).
1664 Ad blocking is but one of <application>Privoxy's</application>
1665 array of features. Many of these features are for the technically minded advanced
1666 user. But, ad and banner blocking is surely common ground for everybody.
1669 This section will provide a quick summary of ad blocking so
1670 you can get up to speed quickly without having to read the more extensive
1671 information provided below, though this is highly recommended.
1674 First a bit of a warning ... blocking ads is much like blocking SPAM: the
1675 more aggressive you are about it, the more likely you are to block
1676 things that were not intended. And the more likely that some things
1677 may not work as intended. So there is a trade off here. If you want
1678 extreme ad free browsing, be prepared to deal with more
1679 <quote>problem</quote> sites, and to spend more time adjusting the
1680 configuration to solve these unintended consequences. In short, there is
1681 not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
1682 the easy way and settle for <emphasis>most</emphasis> ads blocked with the
1683 default configuration, or jump in and tweak it for your personal surfing
1684 habits and preferences.
1687 Secondly, a brief explanation of <application>Privoxy's </application>
1688 <quote>actions</quote>. <quote>Actions</quote> in this context, are
1689 the directives we use to tell <application>Privoxy</application> to perform
1690 some task relating to HTTP transactions (i.e. web browsing). We tell
1691 <application>Privoxy</application> to take some <quote>action</quote>. Each
1692 action has a unique name and function. While there are many potential
1693 <application>actions</application> in <application>Privoxy's</application>
1694 arsenal, only a few are used for ad blocking. <link
1695 linkend="actions">Actions</link>, and <link linkend="actions-file">action
1696 configuration files</link>, are explained in depth below.
1699 Actions are specified in <application>Privoxy's</application> configuration,
1700 followed by one or more URLs to which the action should apply. URLs
1701 can actually be URL type <link linkend="af-patterns">patterns</link> that use
1702 wildcards so they can apply potentially to a range of similar URLs. The
1703 actions, together with the URL patterns are called a section.
1706 When you connect to a website, the full URL will either match one or more
1707 of the sections as defined in <application>Privoxy's</application> configuration,
1708 or not. If so, then <application>Privoxy</application> will perform the
1709 respective actions. If not, then nothing special happens. Furthermore, web
1710 pages may contain embedded, secondary URLs that your web browser will
1711 use to load additional components of the page, as it parses the
1712 original page's HTML content. An ad image for instance, is just an URL
1713 embedded in the page somewhere. The image itself may be on the same server,
1714 or a server somewhere else on the Internet. Complex web pages will have many
1715 such embedded URLs. &my-app; can deal with each URL individually, so, for
1716 instance, the main page text is not touched, but images from such-and-such
1721 The most important actions for basic ad blocking are: <literal><link
1722 linkend="block">block</link></literal>, <literal><link
1723 linkend="handle-as-image">handle-as-image</link></literal>,
1725 linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
1726 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
1734 <literal><link linkend="block">block</link></literal> - this is perhaps
1735 the single most used action, and is particularly important for ad blocking.
1736 This action stops any contact between your browser and any URL patterns
1737 that match this action's configuration. It can be used for blocking ads,
1738 but also anything that is determined to be unwanted. By itself, it simply
1739 stops any communication with the remote server and sends
1740 <application>Privoxy</application>'s own built-in BLOCKED page instead to
1741 let you now what has happened (with some exceptions, see below).
1747 <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
1748 tells <application>Privoxy</application> to treat this URL as an image.
1749 <application>Privoxy</application>'s default configuration already does this
1750 for all common image types (e.g. GIF), but there are many situations where this
1751 is not so easy to determine. So we'll force it in these cases. This is particularly
1752 important for ad blocking, since only if we know that it's an image of
1753 some kind, can we replace it with an image of our choosing, instead of the
1754 <application>Privoxy</application> BLOCKED page (which would only result in
1755 a <quote>broken image</quote> icon). There are some limitations to this
1756 though. For instance, you can't just brute-force an image substitution for
1757 an entire HTML page in most situations.
1763 <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
1764 sends an empty document instead of <application>Privoxy's</application>
1765 normal BLOCKED HTML page. This is useful for file types that are neither
1766 HTML nor images, such as blocking JavaScript files.
1773 linkend="set-image-blocker">set-image-blocker</link></literal> - tells
1774 <application>Privoxy</application> what to display in place of an ad image that
1775 has hit a block rule. For this to come into play, the URL must match a
1776 <literal><link linkend="block">block</link></literal> action somewhere in the
1777 configuration, <emphasis>and</emphasis>, it must also match an
1778 <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
1781 The configuration options on what to display instead of the ad are:
1785 <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
1786 replacement is obvious. This is the default.
1791 <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
1792 This is the so-called <quote>invisible</quote> configuration option.
1797 <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
1798 of the user's choosing (advanced usage).
1807 Advanced users will eventually want to explore &my-app;
1808 <literal><link linkend="filter">filters</link></literal> as well. Filters
1809 are very different from <literal><link
1810 linkend="block">blocks</link></literal>.
1811 A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
1812 are a way of filtering or modifying what is actually on the page. An example
1813 filter usage: a text replacement of <quote>no-no</quote> for
1814 <quote>nasty-word</quote>. That is a very simple example. This process can be
1815 used for ad blocking, but it is more in the realm of advanced usage and has
1816 some pitfalls to be wary off.
1820 The quickest way to adjust any of these settings is with your browser through
1821 the special <application>Privoxy</application> editor at <ulink
1822 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1823 (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
1824 is an internal page, and does not require Internet access.
1828 Note that as of <application>Privoxy</application> 3.0.7 beta the
1829 action editor is disabled by default. Check the
1830 <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
1831 section in the configuration file</ulink> to learn why and in which
1832 cases it's safe to enable again.
1836 If you decided to enable the action editor, select the appropriate
1837 <quote>actions</quote> file, and click
1838 <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
1839 local preferences in <filename>user.action</filename> since this is not
1840 meant to be overwritten during upgrades, and will over-ride the settings in
1841 other files. Here you can insert new <quote>actions</quote>, and URLs for ad
1842 blocking or other purposes, and make other adjustments to the configuration.
1843 <application>Privoxy</application> will detect these changes automatically.
1847 A quick and simple step by step example:
1855 Right click on the ad image to be blocked, then select
1856 <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
1864 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1869 Find <filename>user.action</filename> in the top section, and click
1870 on <quote><guibutton>Edit</guibutton></quote>:
1873 <!-- image of editor and actions files selections -->
1875 <figure pgwide="0" float="0"><title>Actions Files in Use</title>
1878 <imagedata fileref="files-in-use.jpg" format="jpg">
1881 <phrase>[ Screenshot of Actions Files in Use ]</phrase>
1890 You should have a section with only
1891 <literal><link linkend="block">block</link></literal> listed under
1892 <quote>Actions:</quote>.
1893 If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
1894 button, and in the new section that just appeared, click the
1895 <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
1896 This will bring up a list of all actions. Find
1897 <literal><link linkend="block">block</link></literal> near the top, and click
1898 in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
1899 just below the list.
1904 Now, in the <literal><link linkend="block">block</link></literal> actions section,
1905 click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
1906 browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
1907 Remove the <literal>http://</literal> at the beginning of the URL. Then, click
1908 <quote><guibutton>Submit</guibutton></quote> (or
1909 <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
1914 Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
1915 (or flush all browser caches). The image should be gone now.
1923 This is a very crude and simple example. There might be good reasons to use a
1924 wildcard pattern match to include potentially similar images from the same
1925 site. For a more extensive explanation of <quote>patterns</quote>, and
1926 the entire actions concept, see <link linkend="actions-file">the Actions
1931 For advanced users who want to hand edit their config files, you might want
1932 to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
1933 The ideas explained therein also apply to the web-based editor.
1936 There are also various
1937 <link linkend="filter">filters</link> that can be used for ad blocking
1938 (filters are a special subset of actions). These
1939 fall into the <quote>advanced</quote> usage category, and are explained in
1940 depth in later sections.
1947 <!-- ~ End section ~ -->
1950 <!-- ~~~~~ New section ~~~~~ -->
1951 <sect1 id="startup">
1952 <title>Starting Privoxy</title>
1954 Before launching <application>Privoxy</application> for the first time, you
1955 will want to configure your browser(s) to use
1956 <application>Privoxy</application> as a HTTP and HTTPS (SSL)
1957 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
1958 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
1959 used port 8000). This is the one configuration step <emphasis>that must be done
1963 Please note that <application>Privoxy</application> can only proxy HTTP and
1964 HTTPS traffic. It will not work with FTP or other protocols.
1967 <!-- image of Mozilla Proxy configuration -->
1969 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1970 Mozilla/Netscape HTTP and HTTPS (SSL) Settings</title>
1973 <imagedata fileref="proxy_setup.jpg" format="jpg">
1976 <phrase>[ Screenshot of Mozilla Proxy Configuration ]</phrase>
1984 With <application>Firefox</application>, this is typically set under:
1988 <guibutton>Tools</guibutton> -> <guibutton>Options</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Network</guibutton> -><guibutton>Connection</guibutton> -> <guibutton>Settings</guibutton>
1993 Or optionally on some platforms:
1997 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
2003 With <application>Netscape</application> (and
2004 <application>Mozilla</application>), this can be set under:
2009 <!-- Mix ascii and gui art, something for everybody -->
2010 <!-- spacing on this is tricky -->
2011 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
2016 For <application>Internet Explorer v.5-7</application>:
2020 <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
2024 Then, check <quote>Use Proxy</quote> and fill in the appropriate info
2025 (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
2026 proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
2027 checkboxes like <quote>Use the same proxy server for all protocols</quote> is
2028 <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
2031 <!-- image of IE Proxy configuration -->
2033 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
2034 Internet Explorer HTTP and HTTPS (Secure) Settings</title>
2037 <imagedata fileref="proxy2.jpg" format="jpg">
2040 <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
2048 After doing this, flush your browser's disk and memory caches to force a
2049 re-reading of all pages and to get rid of any ads that may be cached. Remove
2050 any <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
2051 if you want <application>Privoxy</application> to manage that. You are now
2052 ready to start enjoying the benefits of using
2053 <application>Privoxy</application>!
2057 <application>Privoxy</application> itself is typically started by specifying the
2058 main configuration file to be used on the command line. If no configuration
2059 file is specified on the command line, <application>Privoxy</application>
2060 will look for a file named <filename>config</filename> in the current
2061 directory. Except on Win32 where it will try <filename>config.txt</filename>.
2064 <sect2 id="start-redhat">
2065 <title>Red Hat and Fedora</title>
2067 A default Red Hat installation may not start &my-app; upon boot. It will use
2068 the file <filename>/etc/privoxy/config</filename> as its main configuration
2073 # /etc/rc.d/init.d/privoxy start
2081 # service privoxy start
2086 <sect2 id="start-debian">
2087 <title>Debian</title>
2089 We use a script. Note that Debian typically starts &my-app; upon booting per
2090 default. It will use the file
2091 <filename>/etc/privoxy/config</filename> as its main configuration
2096 # /etc/init.d/privoxy start
2101 <sect2 id="start-windows">
2102 <title>Windows</title>
2104 Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
2105 specified on the command line, <application>Privoxy</application> will look
2106 for a file named <filename>config.txt</filename>. Note that Windows will
2107 automatically start &my-app; when the system starts if you chose that option
2111 <application>Privoxy</application> can run with full Windows service functionality.
2112 On Windows only, the &my-app; program has two new command line arguments
2113 to install and uninstall &my-app; as a service. See the
2114 <link linkend="installation-pack-win">Windows Installation
2115 instructions</link> for details.
2119 <sect2 id="start-unices">
2120 <title>Solaris, NetBSD, FreeBSD, HP-UX and others</title>
2122 Example Unix startup command:
2126 # /usr/sbin/privoxy /etc/privoxy/config
2131 <sect2 id="start-os2">
2134 During installation, <application>Privoxy</application> is configured to
2135 start automatically when the system restarts. You can start it manually by
2136 double-clicking on the <application>Privoxy</application> icon in the
2137 <application>Privoxy</application> folder.
2141 <sect2 id="start-macosx">
2142 <title>Mac OS X</title>
2144 After downloading the privoxy software, unzip the downloaded file by
2145 double-clicking on the zip file icon. Then, double-click on the
2146 installer package icon and follow the installation process.
2149 The privoxy service will automatically start after a successful
2150 installation. In addition, the privoxy service will automatically
2151 start every time your computer starts up.
2154 To prevent the privoxy service from automatically starting when your
2155 computer starts up, remove or rename the folder named
2156 /Library/StartupItems/Privoxy.
2159 A simple application named Privoxy Utility has been created which
2160 enables administrators to easily start and stop the privoxy service.
2163 In addition, the Privoxy Utility presents a simple way for
2164 administrators to edit the various privoxy config files. A method
2165 to uninstall the software is also available.
2168 An administrator username and password must be supplied in order for
2169 the Privoxy Utility to perform any of the tasks.
2174 <sect2 id="start-amigaos">
2175 <title>AmigaOS</title>
2177 Start <application>Privoxy</application> (with RUN <>NIL:) in your
2178 <filename>startnet</filename> script (AmiTCP), in
2179 <filename>s:user-startup</filename> (RoadShow), as startup program in your
2180 startup script (Genesis), or as startup action (Miami and MiamiDx).
2181 <application>Privoxy</application> will automatically quit when you quit your
2182 TCP/IP stack (just ignore the harmless warning your TCP/IP stack may display that
2183 <application>Privoxy</application> is still running).
2187 <sect2 id="start-gentoo">
2188 <title>Gentoo</title>
2190 A script is again used. It will use the file <filename>/etc/privoxy/config
2191 </filename> as its main configuration file.
2195 /etc/init.d/privoxy start
2199 Note that <application>Privoxy</application> is not automatically started at
2200 boot time by default. You can change this with the <literal>rc-update</literal>
2205 rc-update add privoxy default
2213 See the section <link linkend="cmdoptions">Command line options</link> for
2217 must find a better place for this paragraph
2220 The included default configuration files should give a reasonable starting
2221 point. Most of the per site configuration is done in the
2222 <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
2223 where various cookie actions are defined, ad and banner blocking, and other
2224 aspects of <application>Privoxy</application> configuration. There are several
2225 such files included, with varying levels of aggressiveness.
2229 You will probably want to keep an eye out for sites for which you may prefer
2230 persistent cookies, and add these to your actions configuration as needed. By
2231 default, most of these will be accepted only during the current browser
2232 session (aka <quote>session cookies</quote>), unless you add them to the
2233 configuration. If you want the browser to handle this instead, you will need
2234 to edit <filename>user.action</filename> (or through the web based interface)
2235 and disable this feature. If you use more than one browser, it would make
2236 more sense to let <application>Privoxy</application> handle this. In which
2237 case, the browser(s) should be set to accept all cookies.
2241 Another feature where you will probably want to define exceptions for trusted
2242 sites is the popup-killing (through <ulink
2243 url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
2244 because your favorite shopping, banking, or leisure site may need
2245 popups (explained below).
2249 <application>Privoxy</application> does not support all of the optional HTTP/1.1
2250 features yet. In the unlikely event that you experience inexplicable problems
2251 with browsers that use HTTP/1.1 per default
2252 (like <application>Mozilla</application> or recent versions of I.E.), you might
2253 try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
2254 Preferences -> Debug -> Networking</literal>.
2255 Alternatively, set the <quote>+downgrade-http-version</quote> config option in
2256 <filename>default.action</filename> which will downgrade your browser's HTTP
2257 requests from HTTP/1.1 to HTTP/1.0 before processing them.
2261 After running <application>Privoxy</application> for a while, you can
2262 start to fine tune the configuration to suit your personal, or site,
2263 preferences and requirements. There are many, many aspects that can
2264 be customized. <quote>Actions</quote>
2265 can be adjusted by pointing your browser to
2266 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
2267 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
2268 and then follow the link to <quote>View & Change the Current Configuration</quote>.
2269 (This is an internal page and does not require Internet access.)
2273 In fact, various aspects of <application>Privoxy</application>
2274 configuration can be viewed from this page, including
2275 current configuration parameters, source code version numbers,
2276 the browser's request headers, and <quote>actions</quote> that apply
2277 to a given URL. In addition to the actions file
2278 editor mentioned above, <application>Privoxy</application> can also
2279 be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
2283 If you encounter problems, try loading the page without
2284 <application>Privoxy</application>. If that helps, enter the URL where
2285 you have the problems into <ulink url="http://p.p/show-url-info">the browser
2286 based rule tracing utility</ulink>. See which rules apply and why, and
2287 then try turning them off for that site one after the other, until the problem
2288 is gone. When you have found the culprit, you might want to turn the rest on
2293 If the above paragraph sounds gibberish to you, you might want to <link
2294 linkend="actions-file">read more about the actions concept</link>
2295 or even dive deep into the <link linkend="actionsanat">Appendix
2300 If you can't get rid of the problem at all, think you've found a bug in
2301 Privoxy, want to propose a new feature or smarter rules, please see the
2302 section <link linkend="contact"><quote>Contacting the
2303 Developers</quote></link> below.
2308 <!-- ~~~~~ New section ~~~~~ -->
2309 <sect2 id="cmdoptions">
2310 <title>Command Line Options</title>
2312 <application>Privoxy</application> may be invoked with the following
2313 command-line options:
2321 <emphasis>--config-test</emphasis>
2324 Exit after loading the configuration files before binding to
2325 the listen address. The exit code signals whether or not the
2326 configuration files have been successfully loaded.
2329 If the exit code is 1, at least one of the configuration files
2330 is invalid, if it is 0, all the configuration files have been
2331 successfully loaded (but may still contain errors that can
2332 currently only be detected at run time).
2335 This option doesn't affect the log setting, combination with
2336 <emphasis>--no-daemon</emphasis> is recommended if a configured
2337 log file shouldn't be used.
2342 <emphasis>--version</emphasis>
2345 Print version info and exit. Unix only.
2350 <emphasis>--help</emphasis>
2353 Print short usage info and exit. Unix only.
2358 <emphasis>--no-daemon</emphasis>
2361 Don't become a daemon, i.e. don't fork and become process group
2362 leader, and don't detach from controlling tty. Unix only.
2367 <emphasis>--pidfile FILE</emphasis>
2370 On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
2371 <emphasis>FILE</emphasis> on exit. Failure to create or delete the
2372 <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
2373 option is given, no PID file will be used. Unix only.
2378 <emphasis>--user USER[.GROUP]</emphasis>
2381 After (optionally) writing the PID file, assume the user ID of
2382 <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
2383 privileges are not sufficient to do so. Unix only.
2388 <emphasis>--chroot</emphasis>
2391 Before changing to the user ID given in the <emphasis>--user</emphasis> option,
2392 chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
2393 process that the directory tree starts there. If set up carefully, this can limit
2394 the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
2400 <emphasis>--pre-chroot-nslookup hostname</emphasis>
2403 Specifies a hostname to look up before doing a chroot. On some systems, initializing the
2404 resolver library involves reading config files from /etc and/or loading additional shared
2405 libraries from /lib. On these systems, doing a hostname lookup before the chroot reduces
2406 the number of files that must be copied into the chroot tree.
2409 For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
2410 your local name server (listed in /etc/resolv.conf) can resolve without recursion
2411 (that is, without having to ask any other name servers). The hostname need not exist,
2412 but if it doesn't, an error message (which can be ignored) will be output.
2418 <emphasis>configfile</emphasis>
2421 If no <emphasis>configfile</emphasis> is included on the command line,
2422 <application>Privoxy</application> will look for a file named
2423 <quote>config</quote> in the current directory (except on Win32
2424 where it will look for <quote>config.txt</quote> instead). Specify
2425 full path to avoid confusion. If no config file is found,
2426 <application>Privoxy</application> will fail to start.
2434 On <application>MS Windows</application> only there are two additional
2435 command-line options to allow <application>Privoxy</application> to install and
2436 run as a <emphasis>service</emphasis>. See the
2437 <link linkend="installation-pack-win">Window Installation section</link>
2445 <!-- ~ End section ~ -->
2448 <!-- ~~~~~ New section ~~~~~ -->
2449 <sect1 id="configuration"><title>Privoxy Configuration</title>
2451 All <application>Privoxy</application> configuration is stored
2452 in text files. These files can be edited with a text editor.
2453 Many important aspects of <application>Privoxy</application> can
2454 also be controlled easily with a web browser.
2458 <!-- ~~~~~ New section ~~~~~ -->
2461 <title>Controlling Privoxy with Your Web Browser</title>
2463 <application>Privoxy</application>'s user interface can be reached through the special
2464 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
2465 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
2466 which is a built-in page and works without Internet access.
2467 You will see the following section:
2471 <!-- Needs to be put in a table and colorized -->
2474 <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
2478 ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
2481 ▪ <ulink url="http://config.privoxy.org/show-version">View the source code version numbers</ulink>
2484 ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
2487 ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
2490 ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
2493 ▪ <ulink
2494 url="http://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
2502 This should be self-explanatory. Note the first item leads to an editor for the
2503 <link linkend="actions-file">actions files</link>, which is where the ad, banner,
2504 cookie, and URL blocking magic is configured as well as other advanced features of
2505 <application>Privoxy</application>. This is an easy way to adjust various
2506 aspects of <application>Privoxy</application> configuration. The actions
2507 file, and other configuration files, are explained in detail below.
2511 <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
2512 have problems with your current actions and filters. You can in fact use
2513 it as a test to see whether it is <application>Privoxy</application>
2514 causing the problem or not. <application>Privoxy</application> continues
2515 to run as a proxy in this case, but all manipulation is disabled, i.e.
2516 <application>Privoxy</application> acts like a normal forwarding proxy. There
2517 is even a toggle <link linkend="bookmarklets">Bookmarklet</link> offered, so
2518 that you can toggle <application>Privoxy</application> with one click from
2523 Note that several of the features described above are disabled by default
2524 in <application>Privoxy</application> 3.0.7 beta and later.
2526 <ulink url="config.html">configuration file</ulink> to learn why
2527 and in which cases it's safe to enable them again.
2532 <!-- ~ End section ~ -->
2537 <!-- ~~~~~ New section ~~~~~ -->
2539 <sect2 id="confoverview">
2540 <title>Configuration Files Overview</title>
2542 For Unix, *BSD and Linux, all configuration files are located in
2543 <filename>/etc/privoxy/</filename> by default. For MS Windows, OS/2, and
2544 AmigaOS these are all in the same directory as the
2545 <application>Privoxy</application> executable. <![%p-not-stable;[ The name
2546 and number of configuration files has changed from previous versions, and is
2547 subject to change as development progresses.]]>
2551 The installed defaults provide a reasonable starting point, though
2552 some settings may be aggressive by some standards. For the time being, the
2553 principle configuration files are:
2561 The <link linkend="config">main configuration file</link> is named <filename>config</filename>
2562 on Linux, Unix, BSD, OS/2, and AmigaOS and <filename>config.txt</filename>
2563 on Windows. This is a required file.
2569 <filename>match-all.action</filename> is used to define which <quote>actions</quote>
2570 relating to banner-blocking, images, pop-ups, content modification, cookie handling
2571 etc should be applied by default. It should be the first actions file loaded.
2574 <filename>default.action</filename> defines many exceptions (both positive and negative)
2575 from the default set of actions that's configured in <filename>match-all.action</filename>.
2576 It should be the second actions file loaded and shouldn't be edited by the user.
2579 Multiple actions files may be defined in <filename>config</filename>. These
2580 are processed in the order they are defined. Local customizations and locally
2581 preferred exceptions to the default policies as defined in
2582 <filename>match-all.action</filename> (which you will most probably want
2583 to define sooner or later) are best applied in <filename>user.action</filename>,
2584 where you can preserve them across upgrades. The file isn't installed by all
2585 installers, but you can easily create it yourself with a text editor.
2588 There is also a web based editor that can be accessed from
2590 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2592 url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
2593 various actions files.
2599 <quote>Filter files</quote> (the <link linkend="filter-file">filter
2600 file</link>) can be used to re-write the raw page content, including
2601 viewable text as well as embedded HTML and JavaScript, and whatever else
2602 lurks on any given web page. The filtering jobs are only pre-defined here;
2603 whether to apply them or not is up to the actions files.
2604 <filename>default.filter</filename> includes various filters made
2605 available for use by the developers. Some are much more intrusive than
2606 others, and all should be used with caution. You may define additional
2607 filter files in <filename>config</filename> as you can with
2608 actions files. We suggest <filename>user.filter</filename> for any
2609 locally defined filters or customizations.
2617 The syntax of the configuration and filter files may change between different
2618 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
2619 <!-- Add link to documentation-->
2623 All files use the <quote><literal>#</literal></quote> character to denote a
2624 comment (the rest of the line will be ignored) and understand line continuation
2625 through placing a backslash ("<literal>\</literal>") as the very last character
2626 in a line. If the <literal>#</literal> is preceded by a backslash, it looses
2627 its special function. Placing a <literal>#</literal> in front of an otherwise
2628 valid configuration line to prevent it from being interpreted is called "commenting
2629 out" that line. Blank lines are ignored.
2633 The actions files and filter files
2634 can use Perl style <link linkend="regex">regular expressions</link> for
2635 maximum flexibility.
2639 After making any changes, there is no need to restart
2640 <application>Privoxy</application> in order for the changes to take
2641 effect. <application>Privoxy</application> detects such changes
2642 automatically. Note, however, that it may take one or two additional
2643 requests for the change to take effect. When changing the listening address
2644 of <application>Privoxy</application>, these <quote>wake up</quote> requests
2645 must obviously be sent to the <emphasis>old</emphasis> listening address.
2650 While under development, the configuration content is subject to change.
2651 The below documentation may not be accurate by the time you read this.
2652 Also, what constitutes a <quote>default</quote> setting, may change, so
2653 please check all your configuration files on important issues.
2659 <!-- ~ End section ~ -->
2662 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
2664 <!-- **************************************************** -->
2665 <!-- Include config.sgml here -->
2666 <!-- This is where the entire config file is detailed. -->
2668 <!-- end include -->
2671 <!-- ~ End section ~ -->
2675 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
2677 <sect1 id="actions-file"><title>Actions Files</title>
2681 XXX: similar descriptions are in the Configuration Files sections.
2682 We should only describe them at one place.
2685 The actions files are used to define what <emphasis>actions</emphasis>
2686 <application>Privoxy</application> takes for which URLs, and thus determines
2687 how ad images, cookies and various other aspects of HTTP content and
2688 transactions are handled, and on which sites (or even parts thereof).
2689 There are a number of such actions, with a wide range of functionality.
2690 Each action does something a little different.
2691 These actions give us a veritable arsenal of tools with which to exert
2692 our control, preferences and independence. Actions can be combined so that
2693 their effects are aggregated when applied against a given set of URLs.
2697 are three action files included with <application>Privoxy</application> with
2704 <filename>match-all.action</filename> - is used to define which
2705 <quote>actions</quote> relating to banner-blocking, images, pop-ups,
2706 content modification, cookie handling etc should be applied by default.
2707 It should be the first actions file loaded
2712 <filename>default.action</filename> - defines many exceptions (both
2713 positive and negative) from the default set of actions that's configured
2714 in <filename>match-all.action</filename>. It is a set of rules that should
2715 work reasonably well as-is for most users. This file is only supposed to
2716 be edited by the developers. It should be the second actions file loaded.
2721 <filename>user.action</filename> - is intended to be for local site
2722 preferences and exceptions. As an example, if your ISP or your bank
2723 has specific requirements, and need special handling, this kind of
2724 thing should go here. This file will not be upgraded.
2729 <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
2732 These have increasing levels of aggressiveness <emphasis>and have no
2733 influence on your browsing unless you select them explicitly in the
2734 editor</emphasis>. A default installation should be pre-set to
2735 <literal>Cautious</literal>. New users should try this for a while before
2736 adjusting the settings to more aggressive levels. The more aggressive
2737 the settings, then the more likelihood there is of problems such as sites
2738 not working as they should.
2741 The <guibutton>Edit</guibutton> button allows you to turn each
2742 action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
2743 button changes the actions list to low/safe settings which will activate
2744 ad blocking and a minimal set of &my-app;'s features, and subsequently
2745 there will be less of a chance for accidental problems. The
2746 <guibutton>Medium</guibutton> button sets the list to a medium level of
2747 other features and a low level set of privacy features. The
2748 <guibutton>Advanced</guibutton> button sets the list to a high level of
2749 ad blocking and medium level of privacy. See the chart below. The latter
2750 three buttons over-ride any changes via with the
2751 <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
2752 lower sections of this internal page.
2755 While the actions file editor allows to enable these settings in all
2756 actions files, they are only supposed to be enabled in the first one
2757 to make sure you don't unintentionally overrule earlier rules.
2760 The default profiles, and their associated actions, as pre-defined in
2761 <filename>default.action</filename> are:
2764 <table frame=all><title>Default Configurations</title>
2765 <tgroup cols=4 align=left colsep=1 rowsep=1>
2766 <colspec colname=c1>
2767 <colspec colname=c2>
2768 <colspec colname=c3>
2769 <colspec colname=c4>
2772 <entry>Feature</entry>
2773 <entry>Cautious</entry>
2774 <entry>Medium</entry>
2775 <entry>Advanced</entry>
2780 <!-- <entry>f1</entry> -->
2781 <!-- <entry>f2</entry> -->
2782 <!-- <entry>f3</entry> -->
2783 <!-- <entry>f4</entry> -->
2789 <entry>Ad-blocking Aggressiveness</entry>
2790 <entry>medium</entry>
2796 <entry>Ad-filtering by size</entry>
2803 <entry>Ad-filtering by link</entry>
2809 <entry>Pop-up killing</entry>
2810 <entry>blocks only</entry>
2811 <entry>blocks only</entry>
2812 <entry>blocks only</entry>
2816 <entry>Privacy Features</entry>
2818 <entry>medium</entry>
2819 <entry>medium/high</entry>
2823 <entry>Cookie handling</entry>
2825 <entry>session-only</entry>
2830 <entry>Referer forging</entry>
2837 <entry>GIF de-animation</entry>
2844 <entry>Fast redirects</entry>
2851 <entry>HTML taming</entry>
2858 <entry>JavaScript taming</entry>
2865 <entry>Web-bug killing</entry>
2872 <entry>Image tag reordering</entry>
2888 The list of actions files to be used are defined in the main configuration
2889 file, and are processed in the order they are defined (e.g.
2890 <filename>default.action</filename> is typically processed before
2891 <filename>user.action</filename>). The content of these can all be viewed and
2893 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
2894 The over-riding principle when applying actions, is that the last action that
2895 matches a given URL wins. The broadest, most general rules go first
2896 (defined in <filename>default.action</filename>),
2897 followed by any exceptions (typically also in
2898 <filename>default.action</filename>), which are then followed lastly by any
2899 local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
2900 Generally, <filename>user.action</filename> has the last word.
2904 An actions file typically has multiple sections. If you want to use
2905 <quote>aliases</quote> in an actions file, you have to place the (optional)
2906 <link linkend="aliases">alias section</link> at the top of that file.
2907 Then comes the default set of rules which will apply universally to all
2908 sites and pages (be <emphasis>very careful</emphasis> with using such a
2909 universal set in <filename>user.action</filename> or any other actions file after
2910 <filename>default.action</filename>, because it will override the result
2911 from consulting any previous file). And then below that,
2912 exceptions to the defined universal policies. You can regard
2913 <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
2914 with the advantage that it is a separate file, which makes preserving your
2915 personal settings across <application>Privoxy</application> upgrades easier.
2919 Actions can be used to block anything you want, including ads, banners, or
2920 just some obnoxious URL whose content you would rather not see. Cookies can be accepted
2921 or rejected, or accepted only during the current browser session (i.e. not
2922 written to disk), content can be modified, some JavaScripts tamed, user-tracking
2923 fooled, and much more. See below for a <link linkend="actions">complete list
2927 <!-- ~~~~~ New section ~~~~~ -->
2929 <title>Finding the Right Mix</title>
2931 Note that some <link linkend="actions">actions</link>, like cookie suppression
2932 or script disabling, may render some sites unusable that rely on these
2933 techniques to work properly. Finding the right mix of actions is not always easy and
2934 certainly a matter of personal taste. And, things can always change, requiring
2935 refinements in the configuration. In general, it can be said that the more
2936 <quote>aggressive</quote> your default settings (in the top section of the
2937 actions file) are, the more exceptions for <quote>trusted</quote> sites you
2938 will have to make later. If, for example, you want to crunch all cookies per
2939 default, you'll have to make exceptions from that rule for sites that you
2940 regularly use and that require cookies for actually useful purposes, like maybe
2941 your bank, favorite shop, or newspaper.
2945 We have tried to provide you with reasonable rules to start from in the
2946 distribution actions files. But there is no general rule of thumb on these
2947 things. There just are too many variables, and sites are constantly changing.
2948 Sooner or later you will want to change the rules (and read this chapter again :).
2952 <!-- ~~~~~ New section ~~~~~ -->
2954 <title>How to Edit</title>
2956 The easiest way to edit the actions files is with a browser by
2957 using our browser-based editor, which can be reached from <ulink
2958 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
2959 Note: the config file option <link
2960 linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
2961 this to work. The editor allows both fine-grained control over every single
2962 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
2963 like <quote>Cautious</quote>, <quote>Medium</quote> or
2964 <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
2965 aggressive, and will be more likely to cause problems for some sites.
2966 Experienced users only!
2970 If you prefer plain text editing to GUIs, you can of course also directly edit the
2971 the actions files with your favorite text editor. Look at
2972 <filename>default.action</filename> which is richly commented with many
2978 <sect2 id="actions-apply">
2979 <title>How Actions are Applied to Requests</title>
2981 Actions files are divided into sections. There are special sections,
2982 like the <quote><link linkend="aliases">alias</link></quote> sections which will
2983 be discussed later. For now let's concentrate on regular sections: They have a
2984 heading line (often split up to multiple lines for readability) which consist
2985 of a list of actions, separated by whitespace and enclosed in curly braces.
2986 Below that, there is a list of URL and tag patterns, each on a separate line.
2990 To determine which actions apply to a request, the URL of the request is
2991 compared to all URL patterns in each <quote>action file</quote>.
2992 Every time it matches, the list of applicable actions for the request is
2993 incrementally updated, using the heading of the section in which the
2994 pattern is located. The same is done again for tags and tag patterns later on.
2998 If multiple applying sections set the same action differently,
2999 the last match wins. If not, the effects are aggregated.
3000 E.g. a URL might match a regular section with a heading line of <literal>{
3001 +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
3002 then later another one with just <literal>{
3003 +<link linkend="block">block</link> }</literal>, resulting
3004 in <emphasis>both</emphasis> actions to apply. And there may well be
3005 cases where you will want to combine actions together. Such a section then
3011 { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
3012 # Block these as if they were images. Send no block page.
3014 media.example.com/.*banners
3015 .example.com/images/ads/</screen>
3019 You can trace this process for URL patterns and any given URL by visiting <ulink
3020 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
3024 Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
3025 Troubleshooting: Anatomy of an Action</link> section.
3029 <!-- ~~~~~ New section ~~~~~ -->
3030 <sect2 id="af-patterns">
3031 <title>Patterns</title>
3033 As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
3034 to determine what <emphasis>actions</emphasis> might apply to which sites and
3035 pages your browser attempts to access. These <quote>patterns</quote> use wild
3036 card type <emphasis>pattern</emphasis> matching to achieve a high degree of
3037 flexibility. This allows one expression to be expanded and potentially match
3038 against many similar patterns.
3042 Generally, an URL pattern has the form
3043 <literal><domain><port>/<path></literal>, where the
3044 <literal><domain></literal>, the <literal><port></literal>
3045 and the <literal><path></literal> are optional. (This is why the special
3046 <literal>/</literal> pattern matches all URLs). Note that the protocol
3047 portion of the URL pattern (e.g. <literal>http://</literal>) should
3048 <emphasis>not</emphasis> be included in the pattern. This is assumed already!
3051 The pattern matching syntax is different for the domain and path parts of
3052 the URL. The domain part uses a simple globbing type matching technique,
3053 while the path part uses more flexible
3054 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3055 Expressions</quote></ulink> (POSIX 1003.2).
3058 The port part of a pattern is a decimal port number preceded by a colon
3059 (<literal>:</literal>). If the domain part contains a numerical IPv6 address,
3060 it has to be put into angle brackets
3061 (<literal><</literal>, <literal>></literal>).
3066 <term><literal>www.example.com/</literal></term>
3069 is a domain-only pattern and will match any request to <literal>www.example.com</literal>,
3070 regardless of which document on that server is requested. So ALL pages in
3071 this domain would be covered by the scope of this action. Note that a
3072 simple <literal>example.com</literal> is different and would NOT match.
3077 <term><literal>www.example.com</literal></term>
3080 means exactly the same. For domain-only patterns, the trailing <literal>/</literal> may
3086 <term><literal>www.example.com/index.html</literal></term>
3089 matches all the documents on <literal>www.example.com</literal>
3090 whose name starts with <literal>/index.html</literal>.
3095 <term><literal>www.example.com/index.html$</literal></term>
3098 matches only the single document <literal>/index.html</literal>
3099 on <literal>www.example.com</literal>.
3104 <term><literal>/index.html$</literal></term>
3107 matches the document <literal>/index.html</literal>, regardless of the domain,
3108 i.e. on <emphasis>any</emphasis> web server anywhere.
3113 <term><literal>/</literal></term>
3116 Matches any URL because there's no requirement for either the
3117 domain or the path to match anything.
3122 <term><literal>:8000/</literal></term>
3125 Matches any URL pointing to TCP port 8000.
3130 <term><literal><2001:db8::1>/</literal></term>
3133 Matches any URL with the host address <literal>2001:db8::1</literal>.
3134 (Note that the real URL uses plain brackets, not angle brackets.)
3139 <term><literal>index.html</literal></term>
3142 matches nothing, since it would be interpreted as a domain name and
3143 there is no top-level domain called <literal>.html</literal>. So its
3151 <!-- ~~~~~ New section ~~~~~ -->
3152 <sect3><title>The Domain Pattern</title>
3155 The matching of the domain part offers some flexible options: if the
3156 domain starts or ends with a dot, it becomes unanchored at that end.
3162 <term><literal>.example.com</literal></term>
3165 matches any domain with first-level domain <literal>com</literal>
3166 and second-level domain <literal>example</literal>.
3167 For example <literal>www.example.com</literal>,
3168 <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
3169 Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
3174 <term><literal>www.</literal></term>
3177 matches any domain that <emphasis>STARTS</emphasis> with
3178 <literal>www.</literal> (It also matches the domain
3179 <literal>www</literal> but most of the time that doesn't matter.)
3184 <term><literal>.example.</literal></term>
3187 matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
3188 And, by the way, also included would be any files or documents that exist
3189 within that domain since no path limitations are specified. (Correctly
3190 speaking: It matches any FQDN that contains <literal>example</literal> as
3191 a domain.) This might be <literal>www.example.com</literal>,
3192 <literal>news.example.de</literal>, or
3193 <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
3201 Additionally, there are wild-cards that you can use in the domain names
3202 themselves. These work similarly to shell globbing type wild-cards:
3203 <quote>*</quote> represents zero or more arbitrary characters (this is
3205 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3206 Expression</quote></ulink> based syntax of <quote>.*</quote>),
3207 <quote>?</quote> represents any single character (this is equivalent to the
3208 regular expression syntax of a simple <quote>.</quote>), and you can define
3209 <quote>character classes</quote> in square brackets which is similar to
3210 the same regular expression technique. All of this can be freely mixed:
3215 <term><literal>ad*.example.com</literal></term>
3218 matches <quote>adserver.example.com</quote>,
3219 <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
3224 <term><literal>*ad*.example.com</literal></term>
3227 matches all of the above, and then some.
3232 <term><literal>.?pix.com</literal></term>
3235 matches <literal>www.ipix.com</literal>,
3236 <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
3241 <term><literal>www[1-9a-ez].example.c*</literal></term>
3244 matches <literal>www1.example.com</literal>,
3245 <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
3246 <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
3247 <literal>wwww.example.com</literal>.
3254 While flexible, this is not the sophistication of full regular expression based syntax.
3259 <!-- ~ End section ~ -->
3262 <!-- ~~~~~ New section ~~~~~ -->
3263 <sect3><title>The Path Pattern</title>
3266 <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
3267 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3268 Expressions</quote></ulink> for matching the path portion (after the slash),
3269 and is thus more flexible.
3273 There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
3274 expressions, you also might want to have a look at your operating system's documentation
3275 on regular expressions (try <literal>man re_format</literal>).
3279 Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
3280 i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
3281 for the beginning of a line).
3285 Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
3286 by default, but you can switch to case sensitive at any point in the pattern by using the
3287 <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
3288 only documents whose path starts with <literal>PaTtErN</literal> in
3289 <emphasis>exactly</emphasis> this capitalization.
3294 <term><literal>.example.com/.*</literal></term>
3297 Is equivalent to just <quote>.example.com</quote>, since any documents
3298 within that domain are matched with or without the <quote>.*</quote>
3299 regular expression. This is redundant
3304 <term><literal>.example.com/.*/index.html$</literal></term>
3307 Will match any page in the domain of <quote>example.com</quote> that is
3308 named <quote>index.html</quote>, and that is part of some path. For
3309 example, it matches <quote>www.example.com/testing/index.html</quote> but
3310 NOT <quote>www.example.com/index.html</quote> because the regular
3311 expression called for at least two <quote>/'s</quote>, thus the path
3312 requirement. It also would match
3313 <quote>www.example.com/testing/index_html</quote>, because of the
3314 special meta-character <quote>.</quote>.
3319 <term><literal>.example.com/(.*/)?index\.html$</literal></term>
3322 This regular expression is conditional so it will match any page
3323 named <quote>index.html</quote> regardless of path which in this case can
3324 have one or more <quote>/'s</quote>. And this one must contain exactly
3325 <quote>.html</quote> (but does not have to end with that!).
3330 <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
3333 This regular expression will match any path of <quote>example.com</quote>
3334 that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
3335 <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
3336 The path does not have to end in these words, just contain them.
3341 <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
3344 This is very much the same as above, except now it must end in either
3345 <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
3346 one is limited to common image formats.
3353 There are many, many good examples to be found in <filename>default.action</filename>,
3354 and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
3359 <!-- ~ End section ~ -->
3362 <!-- ~~~~~ New section ~~~~~ -->
3363 <sect3 id="tag-pattern"><title>The Tag Pattern</title>
3366 Tag patterns are used to change the applying actions based on the
3367 request's tags. Tags can be created with either the
3368 <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
3369 or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
3373 Tag patterns have to start with <quote>TAG:</quote>, so &my-app;
3374 can tell them apart from URL patterns. Everything after the colon
3375 including white space, is interpreted as a regular expression with
3376 path pattern syntax, except that tag patterns aren't left-anchored
3377 automatically (&my-app; doesn't silently add a <quote>^</quote>,
3378 you have to do it yourself if you need it).
3382 To match all requests that are tagged with <quote>foo</quote>
3383 your pattern line should be <quote>TAG:^foo$</quote>,
3384 <quote>TAG:foo</quote> would work as well, but it would also
3385 match requests whose tags contain <quote>foo</quote> somewhere.
3386 <quote>TAG: foo</quote> wouldn't work as it requires white space.
3390 Sections can contain URL and tag patterns at the same time,
3391 but tag patterns are checked after the URL patterns and thus
3392 always overrule them, even if they are located before the URL patterns.
3396 Once a new tag is added, Privoxy checks right away if it's matched by one
3397 of the tag patterns and updates the action settings accordingly. As a result
3398 tags can be used to activate other tagger actions, as long as these other
3399 taggers look for headers that haven't already be parsed.
3403 For example you could tag client requests which use the
3404 <literal>POST</literal> method,
3405 then use this tag to activate another tagger that adds a tag if cookies
3406 are sent, and then use a block action based on the cookie tag. This allows
3407 the outcome of one action, to be input into a subsequent action. However if
3408 you'd reverse the position of the described taggers, and activated the
3409 method tagger based on the cookie tagger, no method tags would be created.
3410 The method tagger would look for the request line, but at the time
3411 the cookie tag is created, the request line has already been parsed.
3415 While this is a limitation you should be aware of, this kind of
3416 indirection is seldom needed anyway and even the example doesn't
3417 make too much sense.
3424 <!-- ~ End section ~ -->
3427 <!-- ~~~~~ New section ~~~~~ -->
3429 <sect2 id="actions">
3430 <title>Actions</title>
3432 All actions are disabled by default, until they are explicitly enabled
3433 somewhere in an actions file. Actions are turned on if preceded with a
3434 <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
3435 <literal>+action</literal> means <quote>do that action</quote>, e.g.
3436 <literal>+block</literal> means <quote>please block URLs that match the
3437 following patterns</quote>, and <literal>-block</literal> means <quote>don't
3438 block URLs that match the following patterns, even if <literal>+block</literal>
3439 previously applied.</quote>
3444 Again, actions are invoked by placing them on a line, enclosed in curly braces and
3445 separated by whitespace, like in
3446 <literal>{+some-action -some-other-action{some-parameter}}</literal>,
3447 followed by a list of URL patterns, one per line, to which they apply.
3448 Together, the actions line and the following pattern lines make up a section
3449 of the actions file.
3453 Actions fall into three categories:
3460 Boolean, i.e the action can only be <quote>enabled</quote> or
3461 <quote>disabled</quote>. Syntax:
3465 +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
3466 -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable></screen>
3469 Example: <literal>+handle-as-image</literal>
3476 Parameterized, where some value is required in order to enable this type of action.
3481 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
3482 # overwriting parameter from previous match if necessary
3483 -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted</screen>
3486 Note that if the URL matches multiple positive forms of a parameterized action,
3487 the last match wins, i.e. the params from earlier matches are simply ignored.
3490 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>
3496 Multi-value. These look exactly like parameterized actions,
3497 but they behave differently: If the action applies multiple times to the
3498 same URL, but with different parameters, <emphasis>all</emphasis> the parameters
3499 from <emphasis>all</emphasis> matches are remembered. This is used for actions
3500 that can be executed for the same request repeatedly, like adding multiple
3501 headers, or filtering through multiple filters. Syntax:
3505 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
3506 -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
3507 # If it was the last one left, disable the action.
3508 <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list</screen>
3511 Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
3512 <literal>+filter{html-annoyances}</literal>
3520 If nothing is specified in any actions file, no <quote>actions</quote> are
3521 taken. So in this case <application>Privoxy</application> would just be a
3522 normal, non-blocking, non-filtering proxy. You must specifically enable the
3523 privacy and blocking features you need (although the provided default actions
3524 files will give a good starting point).
3528 Later defined action sections always over-ride earlier ones of the same type.
3529 So exceptions to any rules you make, should come in the latter part of the file (or
3530 in a file that is processed later when using multiple actions files such
3531 as <filename>user.action</filename>). For multi-valued actions, the actions
3532 are applied in the order they are specified. Actions files are processed in
3533 the order they are defined in <filename>config</filename> (the default
3534 installation has three actions files). It also quite possible for any given
3535 URL to match more than one <quote>pattern</quote> (because of wildcards and
3536 regular expressions), and thus to trigger more than one set of actions! Last
3540 <!-- start actions listing -->
3542 The list of valid <application>Privoxy</application> actions are:
3546 <!-- ********************************************************** -->
3547 <!-- Please note the below defined actions use id's that are -->
3548 <!-- probably linked from other places, so please don't change. -->
3550 <!-- ********************************************************** -->
3553 <!-- ~~~~~ New section ~~~~~ -->
3555 <sect3 renderas="sect4" id="add-header">
3556 <title>add-header</title>
3560 <term>Typical use:</term>
3562 <para>Confuse log analysis, custom applications</para>
3567 <term>Effect:</term>
3570 Sends a user defined HTTP header to the web server.
3577 <!-- boolean, parameterized, Multi-value -->
3579 <para>Multi-value.</para>
3584 <term>Parameter:</term>
3587 Any string value is possible. Validity of the defined HTTP headers is not checked.
3588 It is recommended that you use the <quote><literal>X-</literal></quote> prefix
3598 This action may be specified multiple times, in order to define multiple
3599 headers. This is rarely needed for the typical user. If you don't know what
3600 <quote>HTTP headers</quote> are, you definitely don't need to worry about this
3604 Headers added by this action are not modified by other actions.
3610 <term>Example usage:</term>
3613 <screen>+add-header{X-User-Tracking: sucks}</screen>
3621 <!-- ~~~~~ New section ~~~~~ -->
3622 <sect3 renderas="sect4" id="block">
3623 <title>block</title>
3627 <term>Typical use:</term>
3629 <para>Block ads or other unwanted content</para>
3634 <term>Effect:</term>
3637 Requests for URLs to which this action applies are blocked, i.e. the
3638 requests are trapped by &my-app; and the requested URL is never retrieved,
3639 but is answered locally with a substitute page or image, as determined by
3641 linkend="handle-as-image">handle-as-image</link></literal>,
3643 linkend="set-image-blocker">set-image-blocker</link></literal>, and
3645 linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
3653 <!-- boolean, parameterized, Multi-value -->
3655 <para>Parameterized.</para>
3660 <term>Parameter:</term>
3662 <para>A block reason that should be given to the user.</para>
3670 <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
3671 for requests to blocked pages. This page contains the block reason given as
3672 parameter, a link to find out why the block action applies, and a click-through
3673 to the blocked content (the latter only if the force feature is available and
3677 A very important exception occurs if <emphasis>both</emphasis>
3678 <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
3679 apply to the same request: it will then be replaced by an image. If
3680 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
3681 (see below) also applies, the type of image will be determined by its parameter,
3682 if not, the standard checkerboard pattern is sent.
3685 It is important to understand this process, in order
3686 to understand how <application>Privoxy</application> deals with
3687 ads and other unwanted content. Blocking is a core feature, and one
3688 upon which various other features depend.
3691 The <literal><link linkend="filter">filter</link></literal>
3692 action can perform a very similar task, by <quote>blocking</quote>
3693 banner images and other content through rewriting the relevant URLs in the
3694 document's HTML source, so they don't get requested in the first place.
3695 Note that this is a totally different technique, and it's easy to confuse the two.
3701 <term>Example usage (section):</term>
3704 <screen>{+block{No nasty stuff for you.}}
3705 # Block and replace with "blocked" page
3706 .nasty-stuff.example.com
3708 {+block{Doubleclick banners.} +handle-as-image}
3709 # Block and replace with image
3713 {+block{Layered ads.} +handle-as-empty-document}
3714 # Block and then ignore
3715 adserver.example.net/.*\.js$</screen>
3725 <!-- ~~~~~ New section ~~~~~ -->
3726 <sect3 renderas="sect4" id="change-x-forwarded-for">
3727 <title>change-x-forwarded-for</title>
3731 <term>Typical use:</term>
3733 <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
3738 <term>Effect:</term>
3741 Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
3749 <!-- Boolean, Parameterized, Multi-value -->
3751 <para>Parameterized.</para>
3756 <term>Parameter:</term>
3760 <para><quote>block</quote> to delete the header.</para>
3764 <quote>add</quote> to create the header (or append
3765 the client's IP address to an already existing one).
3776 It is safe and recommended to use <literal>block</literal>.
3779 Forwarding the source address of the request may make
3780 sense in some multi-user setups but is also a privacy risk.
3785 <term>Example usage:</term>
3788 <screen>+change-x-forwarded-for{block}</screen>
3795 <!-- ~~~~~ New section ~~~~~ -->
3796 <sect3 renderas="sect4" id="client-header-filter">
3797 <title>client-header-filter</title>
3801 <term>Typical use:</term>
3804 Rewrite or remove single client headers.
3810 <term>Effect:</term>
3813 All client headers to which this action applies are filtered on-the-fly through
3814 the specified regular expression based substitutions.
3821 <!-- boolean, parameterized, Multi-value -->
3823 <para>Parameterized.</para>
3828 <term>Parameter:</term>
3831 The name of a client-header filter, as defined in one of the
3832 <link linkend="filter-file">filter files</link>.
3841 Client-header filters are applied to each header on its own, not to
3842 all at once. This makes it easier to diagnose problems, but on the downside
3843 you can't write filters that only change header x if header y's value is z.
3844 You can do that by using tags though.
3847 Client-header filters are executed after the other header actions have finished
3848 and use their output as input.
3851 If the request URI gets changed, &my-app; will detect that and use the new
3852 one. This can be used to rewrite the request destination behind the client's
3853 back, for example to specify a Tor exit relay for certain requests.
3856 Please refer to the <link linkend="filter-file">filter file chapter</link>
3857 to learn which client-header filters are available by default, and how to
3865 <term>Example usage (section):</term>
3869 # Hide Tor exit notation in Host and Referer Headers
3870 {+client-header-filter{hide-tor-exit-notation}}
3881 <!-- ~~~~~ New section ~~~~~ -->
3882 <sect3 renderas="sect4" id="client-header-tagger">
3883 <title>client-header-tagger</title>
3887 <term>Typical use:</term>
3890 Block requests based on their headers.
3896 <term>Effect:</term>
3899 Client headers to which this action applies are filtered on-the-fly through
3900 the specified regular expression based substitutions, the result is used as
3908 <!-- boolean, parameterized, Multi-value -->
3910 <para>Parameterized.</para>
3915 <term>Parameter:</term>
3918 The name of a client-header tagger, as defined in one of the
3919 <link linkend="filter-file">filter files</link>.
3928 Client-header taggers are applied to each header on its own,
3929 and as the header isn't modified, each tagger <quote>sees</quote>
3933 Client-header taggers are the first actions that are executed
3934 and their tags can be used to control every other action.
3940 <term>Example usage (section):</term>
3944 # Tag every request with the User-Agent header
3945 {+client-header-tagger{user-agent}}
3948 # Tagging itself doesn't change the action
3949 # settings, sections with TAG patterns do:
3951 # If it's a download agent, use a different forwarding proxy,
3952 # show the real User-Agent and make sure resume works.
3953 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
3954 -hide-if-modified-since \
3955 -overwrite-last-modified \
3960 TAG:^User-Agent: NetBSD-ftp/
3961 TAG:^User-Agent: Novell ZYPP Installer
3962 TAG:^User-Agent: RPM APT-HTTP/
3963 TAG:^User-Agent: fetch libfetch/
3964 TAG:^User-Agent: Ubuntu APT-HTTP/
3965 TAG:^User-Agent: MPlayer/
3970 # Tag all requests with the Range header set
3971 {+client-header-tagger{range-requests}}
3974 # Disable filtering for the tagged requests.
3976 # With filtering enabled Privoxy would remove the Range headers
3977 # to be able to filter the whole response. The downside is that
3978 # it prevents clients from resuming downloads or skipping over
3979 # parts of multimedia files.
3980 {-filter -deanimate-gifs}
3991 <!-- ~~~~~ New section ~~~~~ -->
3992 <sect3 renderas="sect4" id="content-type-overwrite">
3993 <title>content-type-overwrite</title>
3997 <term>Typical use:</term>
3999 <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
4004 <term>Effect:</term>
4007 Replaces the <quote>Content-Type:</quote> HTTP server header.
4014 <!-- Boolean, Parameterized, Multi-value -->
4016 <para>Parameterized.</para>
4021 <term>Parameter:</term>
4033 The <quote>Content-Type:</quote> HTTP server header is used by the
4034 browser to decide what to do with the document. The value of this
4035 header can cause the browser to open a download menu instead of
4036 displaying the document by itself, even if the document's format is
4037 supported by the browser.
4040 The declared content type can also affect which rendering mode
4041 the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
4042 many browsers treat it as yet another broken HTML document.
4043 If it is send as <quote>application/xml</quote>, browsers with
4044 XHTML support will only display it, if the syntax is correct.
4047 If you see a web site that proudly uses XHTML buttons, but sets
4048 <quote>Content-Type: text/html</quote>, you can use &my-app;
4049 to overwrite it with <quote>application/xml</quote> and validate
4050 the web master's claim inside your XHTML-supporting browser.
4051 If the syntax is incorrect, the browser will complain loudly.
4054 You can also go the opposite direction: if your browser prints
4055 error messages instead of rendering a document falsely declared
4056 as XHTML, you can overwrite the content type with
4057 <quote>text/html</quote> and have it rendered as broken HTML document.
4060 By default <literal>content-type-overwrite</literal> only replaces
4061 <quote>Content-Type:</quote> headers that look like some kind of text.
4062 If you want to overwrite it unconditionally, you have to combine it with
4063 <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
4064 This limitation exists for a reason, think twice before circumventing it.
4067 Most of the time it's easier to replace this action with a custom
4068 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
4069 It allows you to activate it for every document of a certain site and it will still
4070 only replace the content types you aimed at.
4073 Of course you can apply <literal>content-type-overwrite</literal>
4074 to a whole site and then make URL based exceptions, but it's a lot
4075 more work to get the same precision.
4081 <term>Example usage (sections):</term>
4084 <screen># Check if www.example.net/ really uses valid XHTML
4085 { +content-type-overwrite{application/xml} }
4088 # but leave the content type unmodified if the URL looks like a style sheet
4089 {-content-type-overwrite}
4090 www.example.net/.*\.css$
4091 www.example.net/.*style
4100 <!-- ~~~~~ New section ~~~~~ -->
4101 <sect3 renderas="sect4" id="crunch-client-header">
4105 <title>crunch-client-header</title>
4109 <term>Typical use:</term>
4111 <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
4116 <term>Effect:</term>
4119 Deletes every header sent by the client that contains the string the user supplied as parameter.
4126 <!-- Boolean, Parameterized, Multi-value -->
4128 <para>Parameterized.</para>
4133 <term>Parameter:</term>
4145 This action allows you to block client headers for which no dedicated
4146 <application>Privoxy</application> action exists.
4147 <application>Privoxy</application> will remove every client header that
4148 contains the string you supplied as parameter.
4151 Regular expressions are <emphasis>not supported</emphasis> and you can't
4152 use this action to block different headers in the same request, unless
4153 they contain the same string.
4156 <literal>crunch-client-header</literal> is only meant for quick tests.
4157 If you have to block several different headers, or only want to modify
4158 parts of them, you should use a
4159 <literal><link linkend="client-header-filter">client-header filter</link></literal>.
4163 Don't block any header without understanding the consequences.
4170 <term>Example usage (section):</term>
4173 <screen># Block the non-existent "Privacy-Violation:" client header
4174 { +crunch-client-header{Privacy-Violation:} }
4184 <!-- ~~~~~ New section ~~~~~ -->
4185 <sect3 renderas="sect4" id="crunch-if-none-match">
4186 <title>crunch-if-none-match</title>
4192 <term>Typical use:</term>
4194 <para>Prevent yet another way to track the user's steps between sessions.</para>
4199 <term>Effect:</term>
4202 Deletes the <quote>If-None-Match:</quote> HTTP client header.
4209 <!-- Boolean, Parameterized, Multi-value -->
4211 <para>Boolean.</para>
4216 <term>Parameter:</term>
4228 Removing the <quote>If-None-Match:</quote> HTTP client header
4229 is useful for filter testing, where you want to force a real
4230 reload instead of getting status code <quote>304</quote> which
4231 would cause the browser to use a cached copy of the page.
4234 It is also useful to make sure the header isn't used as a cookie
4235 replacement (unlikely but possible).
4238 Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
4239 caching problems, as long as the <quote>If-Modified-Since:</quote> header
4240 isn't blocked or missing as well.
4243 It is recommended to use this action together with
4244 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
4246 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
4252 <term>Example usage (section):</term>
4255 <screen># Let the browser revalidate cached documents but don't
4256 # allow the server to use the revalidation headers for user tracking.
4257 {+hide-if-modified-since{-60} \
4258 +overwrite-last-modified{randomize} \
4259 +crunch-if-none-match}
4268 <!-- ~~~~~ New section ~~~~~ -->
4269 <sect3 renderas="sect4" id="crunch-incoming-cookies">
4270 <title>crunch-incoming-cookies</title>
4274 <term>Typical use:</term>
4277 Prevent the web server from setting HTTP cookies on your system
4283 <term>Effect:</term>
4286 Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
4293 <!-- Boolean, Parameterized, Multi-value -->
4295 <para>Boolean.</para>
4300 <term>Parameter:</term>
4312 This action is only concerned with <emphasis>incoming</emphasis> HTTP cookies. For
4313 <emphasis>outgoing</emphasis> HTTP cookies, use
4314 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
4315 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
4318 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
4319 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
4320 since it would prevent the session cookies from being set. See also
4321 <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
4327 <term>Example usage:</term>
4330 <screen>+crunch-incoming-cookies</screen>
4338 <!-- ~~~~~ New section ~~~~~ -->
4339 <sect3 renderas="sect4" id="crunch-server-header">
4340 <title>crunch-server-header</title>
4346 <term>Typical use:</term>
4348 <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
4353 <term>Effect:</term>
4356 Deletes every header sent by the server that contains the string the user supplied as parameter.
4363 <!-- Boolean, Parameterized, Multi-value -->
4365 <para>Parameterized.</para>
4370 <term>Parameter:</term>
4382 This action allows you to block server headers for which no dedicated
4383 <application>Privoxy</application> action exists. <application>Privoxy</application>
4384 will remove every server header that contains the string you supplied as parameter.
4387 Regular expressions are <emphasis>not supported</emphasis> and you can't
4388 use this action to block different headers in the same request, unless
4389 they contain the same string.
4392 <literal>crunch-server-header</literal> is only meant for quick tests.
4393 If you have to block several different headers, or only want to modify
4394 parts of them, you should use a custom
4395 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
4399 Don't block any header without understanding the consequences.
4406 <term>Example usage (section):</term>
4409 <screen># Crunch server headers that try to prevent caching
4410 { +crunch-server-header{no-cache} }
4419 <!-- ~~~~~ New section ~~~~~ -->
4420 <sect3 renderas="sect4" id="crunch-outgoing-cookies">
4421 <title>crunch-outgoing-cookies</title>
4425 <term>Typical use:</term>
4428 Prevent the web server from reading any HTTP cookies from your system
4434 <term>Effect:</term>
4437 Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
4444 <!-- Boolean, Parameterized, Multi-value -->
4446 <para>Boolean.</para>
4451 <term>Parameter:</term>
4463 This action is only concerned with <emphasis>outgoing</emphasis> HTTP cookies. For
4464 <emphasis>incoming</emphasis> HTTP cookies, use
4465 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
4466 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
4469 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
4470 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
4471 since it would prevent the session cookies from being read.
4477 <term>Example usage:</term>
4480 <screen>+crunch-outgoing-cookies</screen>
4489 <!-- ~~~~~ New section ~~~~~ -->
4490 <sect3 renderas="sect4" id="deanimate-gifs">
4491 <title>deanimate-gifs</title>
4495 <term>Typical use:</term>
4497 <para>Stop those annoying, distracting animated GIF images.</para>
4502 <term>Effect:</term>
4505 De-animate GIF animations, i.e. reduce them to their first or last image.
4512 <!-- boolean, parameterized, Multi-value -->
4514 <para>Parameterized.</para>
4519 <term>Parameter:</term>
4522 <quote>last</quote> or <quote>first</quote>
4531 This will also shrink the images considerably (in bytes, not pixels!). If
4532 the option <quote>first</quote> is given, the first frame of the animation
4533 is used as the replacement. If <quote>last</quote> is given, the last
4534 frame of the animation is used instead, which probably makes more sense for
4535 most banner animations, but also has the risk of not showing the entire
4536 last frame (if it is only a delta to an earlier frame).
4539 You can safely use this action with patterns that will also match non-GIF
4540 objects, because no attempt will be made at anything that doesn't look like
4547 <term>Example usage:</term>
4550 <screen>+deanimate-gifs{last}</screen>
4557 <!-- ~~~~~ New section ~~~~~ -->
4558 <sect3 renderas="sect4" id="downgrade-http-version">
4559 <title>downgrade-http-version</title>
4563 <term>Typical use:</term>
4565 <para>Work around (very rare) problems with HTTP/1.1</para>
4570 <term>Effect:</term>
4573 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
4580 <!-- boolean, parameterized, Multi-value -->
4582 <para>Boolean.</para>
4587 <term>Parameter:</term>
4599 This is a left-over from the time when <application>Privoxy</application>
4600 didn't support important HTTP/1.1 features well. It is left here for the
4601 unlikely case that you experience HTTP/1.1-related problems with some server
4605 Note that enabling this action is only a workaround. It should not
4606 be enabled for sites that work without it. While it shouldn't break
4607 any pages, it has an (usually negative) performance impact.
4610 If you come across a site where enabling this action helps, please report it,
4611 so the cause of the problem can be analyzed. If the problem turns out to be
4612 caused by a bug in <application>Privoxy</application> it should be
4613 fixed so the following release works without the work around.
4619 <term>Example usage (section):</term>
4622 <screen>{+downgrade-http-version}
4623 problem-host.example.com</screen>
4631 <!-- ~~~~~ New section ~~~~~ -->
4632 <sect3 renderas="sect4" id="fast-redirects">
4633 <title>fast-redirects</title>
4637 <term>Typical use:</term>
4639 <para>Fool some click-tracking scripts and speed up indirect links.</para>
4644 <term>Effect:</term>
4647 Detects redirection URLs and redirects the browser without contacting
4648 the redirection server first.
4655 <!-- boolean, parameterized, Multi-value -->
4657 <para>Parameterized.</para>
4662 <term>Parameter:</term>
4667 <quote>simple-check</quote> to just search for the string <quote>http://</quote>
4668 to detect redirection URLs.
4673 <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
4674 for redirection URLs.
4685 Many sites, like yahoo.com, don't just link to other sites. Instead, they
4686 will link to some script on their own servers, giving the destination as a
4687 parameter, which will then redirect you to the final target. URLs
4688 resulting from this scheme typically look like:
4689 <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
4692 Sometimes, there are even multiple consecutive redirects encoded in the
4693 URL. These redirections via scripts make your web browsing more traceable,
4694 since the server from which you follow such a link can see where you go
4695 to. Apart from that, valuable bandwidth and time is wasted, while your
4696 browser asks the server for one redirect after the other. Plus, it feeds
4700 This feature is currently not very smart and is scheduled for improvement.
4701 If it is enabled by default, you will have to create some exceptions to
4702 this action. It can lead to failures in several ways:
4705 Not every URLs with other URLs as parameters is evil.
4706 Some sites offer a real service that requires this information to work.
4707 For example a validation service needs to know, which document to validate.
4708 <literal>fast-redirects</literal> assumes that every URL parameter that
4709 looks like another URL is a redirection target, and will always redirect to
4710 the last one. Most of the time the assumption is correct, but if it isn't,
4711 the user gets redirected anyway.
4714 Another failure occurs if the URL contains other parameters after the URL parameter.
4716 <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
4717 contains the redirection URL <quote>http://www.example.net/</quote>,
4718 followed by another parameter. <literal>fast-redirects</literal> doesn't know that
4719 and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
4720 Depending on the target server configuration, the parameter will be silently ignored
4721 or lead to a <quote>page not found</quote> error. You can prevent this problem by
4722 first using the <literal><link linkend="redirect">redirect</link></literal> action
4723 to remove the last part of the URL, but it requires a little effort.
4726 To detect a redirection URL, <literal>fast-redirects</literal> only
4727 looks for the string <quote>http://</quote>, either in plain text
4728 (invalid but often used) or encoded as <quote>http%3a//</quote>.
4729 Some sites use their own URL encoding scheme, encrypt the address
4730 of the target server or replace it with a database id. In theses cases
4731 <literal>fast-redirects</literal> is fooled and the request reaches the
4732 redirection server where it probably gets logged.
4738 <term>Example usage:</term>
4742 { +fast-redirects{simple-check} }
4745 { +fast-redirects{check-decoded-url} }
4746 another.example.com/testing</screen>
4755 <!-- ~~~~~ New section ~~~~~ -->
4756 <sect3 renderas="sect4" id="filter">
4757 <title>filter</title>
4761 <term>Typical use:</term>
4763 <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
4764 do fun text replacements, add personalized effects, etc.</para>
4769 <term>Effect:</term>
4772 All instances of text-based type, most notably HTML and JavaScript, to which
4773 this action applies, can be filtered on-the-fly through the specified regular
4774 expression based substitutions. (Note: as of version 3.0.3 plain text documents
4775 are exempted from filtering, because web servers often use the
4776 <literal>text/plain</literal> MIME type for all files whose type they don't know.)
4783 <!-- boolean, parameterized, Multi-value -->
4785 <para>Parameterized.</para>
4790 <term>Parameter:</term>
4793 The name of a content filter, as defined in the <link linkend="filter-file">filter file</link>.
4794 Filters can be defined in one or more files as defined by the
4795 <literal><link linkend="filterfile">filterfile</link></literal>
4796 option in the <link linkend="config">config file</link>.
4797 <filename>default.filter</filename> is the collection of filters
4798 supplied by the developers. Locally defined filters should go
4799 in their own file, such as <filename>user.filter</filename>.
4802 When used in its negative form,
4803 and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
4812 For your convenience, there are a number of pre-defined filters available
4813 in the distribution filter file that you can use. See the examples below for
4817 Filtering requires buffering the page content, which may appear to
4818 slow down page rendering since nothing is displayed until all content has
4819 passed the filters. (The total time until the page is completely rendered
4820 doesn't change much, but it may be perceived as slower since the page is
4821 not incrementally displayed.)
4822 This effect will be more noticeable on slower connections.
4825 <quote>Rolling your own</quote>
4826 filters requires a knowledge of
4827 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
4828 Expressions</quote></ulink> and
4829 <ulink url="http://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
4830 This is very powerful feature, and potentially very intrusive.
4831 Filters should be used with caution, and where an equivalent
4832 <quote>action</quote> is not available.
4835 The amount of data that can be filtered is limited to the
4836 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
4837 option in the main <link linkend="config">config file</link>. The
4838 default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
4839 data, and all pending data, is passed through unfiltered.
4842 Inappropriate MIME types, such as zipped files, are not filtered at all.
4843 (Again, only text-based types except plain text). Encrypted SSL data
4844 (from HTTPS servers) cannot be filtered either, since this would violate
4845 the integrity of the secure transaction. In some situations it might
4846 be necessary to protect certain text, like source code, from filtering
4847 by defining appropriate <literal>-filter</literal> exceptions.
4850 Compressed content can't be filtered either, but if &my-app;
4851 is compiled with zlib support and a supported compression algorithm
4852 is used (gzip or deflate), &my-app; can first decompress the content
4856 If you use a &my-app; version without zlib support, but want filtering to work on
4857 as much documents as possible, even those that would normally be sent compressed,
4858 you must use the <literal><link linkend="prevent-compression">prevent-compression</link></literal>
4859 action in conjunction with <literal>filter</literal>.
4862 Content filtering can achieve some of the same effects as the
4863 <literal><link linkend="block">block</link></literal>
4864 action, i.e. it can be used to block ads and banners. But the mechanism
4865 works quite differently. One effective use, is to block ad banners
4866 based on their size (see below), since many of these seem to be somewhat
4870 <link linkend="contact">Feedback</link> with suggestions for new or
4871 improved filters is particularly welcome!
4874 The below list has only the names and a one-line description of each
4875 predefined filter. There are <link linkend="predefined-filters">more
4876 verbose explanations</link> of what these filters do in the <link
4877 linkend="filter-file">filter file chapter</link>.
4883 <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
4884 See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
4885 more explanation on each:</term>
4888 <anchor id="filter-js-annoyances">
4889 <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse.</screen>
4892 <anchor id="filter-js-events">
4893 <screen>+filter{js-events} # Kill all JS event bindings and timers (Radically destructive! Only for extra nasty sites).</screen>
4896 <anchor id="filter-html-annoyances">
4897 <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse.</screen>
4900 <anchor id="filter-content-cookies">
4901 <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content.</screen>
4904 <anchor id="filter-refresh-tags">
4905 <screen>+filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups).</screen>
4908 <anchor id="filter-unsolicited-popups">
4909 <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability.</screen>
4912 <anchor id="filter-all-popups">
4913 <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability.</screen>
4916 <anchor id="filter-img-reorder">
4917 <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective.</screen>
4920 <anchor id="filter-banners-by-size">
4921 <screen>+filter{banners-by-size} # Kill banners by size.</screen>
4924 <anchor id="filter-banners-by-link">
4925 <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers.</screen>
4928 <anchor id="filter-webbugs">
4929 <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking).</screen>
4932 <anchor id="filter-tiny-textforms">
4933 <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap.</screen>
4936 <anchor id="filter-jumping-windows">
4937 <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves.</screen>
4940 <anchor id="filter-frameset-borders">
4941 <screen>+filter{frameset-borders} # Give frames a border and make them resizable.</screen>
4944 <anchor id="filter-demoronizer">
4945 <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets.</screen>
4948 <anchor id="filter-shockwave-flash">
4949 <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects.</screen>
4952 <anchor id="filter-quicktime-kioskmode">
4953 <screen>+filter{quicktime-kioskmode} # Make Quicktime movies saveable.</screen>
4956 <anchor id="filter-fun">
4957 <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
4960 <anchor id="filter-crude-parental">
4961 <screen>+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably.</screen>
4964 <anchor id="filter-ie-exploits">
4965 <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits.</screen>
4968 <anchor id="filter-site-specifics">
4969 <screen>+filter{site-specifics} # Cure for site-specific problems. Don't apply generally!</screen>
4972 <anchor id="filter-no-ping">
4973 <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
4976 <anchor id="filter-google">
4977 <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
4980 <anchor id="filter-yahoo">
4981 <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
4984 <anchor id="filter-msn">
4985 <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
4988 <anchor id="filter-blogspot">
4989 <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</screen>
4997 <!-- ~~~~~ New section ~~~~~ -->
4998 <sect3 renderas="sect4" id="force-text-mode">
4999 <title>force-text-mode</title>
5005 <term>Typical use:</term>
5007 <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
5012 <term>Effect:</term>
5015 Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
5022 <!-- Boolean, Parameterized, Multi-value -->
5024 <para>Boolean.</para>
5029 <term>Parameter:</term>
5041 As explained <literal><link linkend="filter">above</link></literal>,
5042 <application>Privoxy</application> tries to only filter files that are
5043 in some kind of text format. The same restrictions apply to
5044 <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
5045 <literal>force-text-mode</literal> declares a document as text,
5046 without looking at the <quote>Content-Type:</quote> first.
5050 Think twice before activating this action. Filtering binary data
5051 with regular expressions can cause file damage.
5058 <term>Example usage:</term>
5071 <!-- ~~~~~ New section ~~~~~ -->
5072 <sect3 renderas="sect4" id="forward-override">
5073 <title>forward-override</title>
5079 <term>Typical use:</term>
5081 <para>Change the forwarding settings based on User-Agent or request origin</para>
5086 <term>Effect:</term>
5089 Overrules the forward directives in the configuration file.
5096 <!-- Boolean, Parameterized, Multi-value -->
5098 <para>Multi-value.</para>
5103 <term>Parameter:</term>
5107 <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
5111 <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
5116 <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
5117 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
5118 to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
5119 for socks5 connections (with remote DNS resolution).
5124 <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
5125 listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
5126 Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
5127 (with local DNS resolution) instead, use <quote>forward-socks5</quote>
5128 for socks5 connections (with remote DNS resolution).
5139 This action takes parameters similar to the
5140 <link linkend="forwarding">forward</link> directives in the configuration
5141 file, but without the URL pattern. It can be used as replacement, but normally it's only
5142 used in cases where matching based on the request URL isn't sufficient.
5146 Please read the description for the <link linkend="forwarding">forward</link> directives before
5147 using this action. Forwarding to the wrong people will reduce your privacy and increase the
5148 chances of man-in-the-middle attacks.
5151 If the ports are missing or invalid, default values will be used. This might change
5152 in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
5156 Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
5157 to verify that your forward settings do what you thought the do.
5164 <term>Example usage:</term>
5168 # Always use direct connections for requests previously tagged as
5169 # <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
5170 # resuming downloads continues to work.
5171 # This way you can continue to use Tor for your normal browsing,
5172 # without overloading the Tor network with your FreeBSD ports updates
5173 # or downloads of bigger files like ISOs.
5174 # Note that HTTP headers are easy to fake and therefore their
5175 # values are as (un)trustworthy as your clients and users.
5176 {+forward-override{forward .} \
5177 -hide-if-modified-since \
5178 -overwrite-last-modified \
5180 TAG:^User-Agent: fetch libfetch/2\.0$
5189 <!-- ~~~~~ New section ~~~~~ -->
5190 <sect3 renderas="sect4" id="handle-as-empty-document">
5191 <title>handle-as-empty-document</title>
5197 <term>Typical use:</term>
5199 <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
5204 <term>Effect:</term>
5207 This action alone doesn't do anything noticeable. It just marks URLs.
5208 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
5209 the presence or absence of this mark decides whether an HTML <quote>BLOCKED</quote>
5210 page, or an empty document will be sent to the client as a substitute for the blocked content.
5211 The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
5218 <!-- Boolean, Parameterized, Multi-value -->
5220 <para>Boolean.</para>
5225 <term>Parameter:</term>
5237 Some browsers complain about syntax errors if JavaScript documents
5238 are blocked with <application>Privoxy's</application>
5239 default HTML page; this option can be used to silence them.
5240 And of course this action can also be used to eliminate the &my-app;
5241 BLOCKED message in frames.
5244 The content type for the empty document can be specified with
5245 <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
5246 but usually this isn't necessary.
5252 <term>Example usage:</term>
5255 <screen># Block all documents on example.org that end with ".js",
5256 # but send an empty document instead of the usual HTML message.
5257 {+block{Blocked JavaScript} +handle-as-empty-document}
5267 <!-- ~~~~~ New section ~~~~~ -->
5268 <sect3 renderas="sect4" id="handle-as-image">
5269 <title>handle-as-image</title>
5273 <term>Typical use:</term>
5275 <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>
5280 <term>Effect:</term>
5283 This action alone doesn't do anything noticeable. It just marks URLs as images.
5284 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
5285 the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
5286 page, or a replacement image (as determined by the <literal><link
5287 linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
5288 client as a substitute for the blocked content.
5295 <!-- Boolean, Parameterized, Multi-value -->
5297 <para>Boolean.</para>
5302 <term>Parameter:</term>
5314 The below generic example section is actually part of <filename>default.action</filename>.
5315 It marks all URLs with well-known image file name extensions as images and should
5319 Users will probably only want to use the handle-as-image action in conjunction with
5320 <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
5321 reflect the file type, like in the second example section.
5324 Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
5325 frames require an HTML page to be sent, or they won't display properly.
5326 Forcing <literal>handle-as-image</literal> in this situation will not replace the
5327 ad frame with an image, but lead to error messages.
5333 <term>Example usage (sections):</term>
5336 <screen># Generic image extensions:
5339 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
5341 # These don't look like images, but they're banners and should be
5342 # blocked as images:
5344 {+block{Nasty banners.} +handle-as-image}
5345 nasty-banner-server.example.com/junk.cgi\?output=trash
5354 <!-- ~~~~~ New section ~~~~~ -->
5355 <sect3 renderas="sect4" id="hide-accept-language">
5356 <title>hide-accept-language</title>
5362 <term>Typical use:</term>
5364 <para>Pretend to use different language settings.</para>
5369 <term>Effect:</term>
5372 Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
5379 <!-- Boolean, Parameterized, Multi-value -->
5381 <para>Parameterized.</para>
5386 <term>Parameter:</term>
5389 Keyword: <quote>block</quote>, or any user defined value.
5398 Faking the browser's language settings can be useful to make a
5399 foreign User-Agent set with
5400 <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
5404 However some sites with content in different languages check the
5405 <quote>Accept-Language:</quote> to decide which one to take by default.
5406 Sometimes it isn't possible to later switch to another language without
5407 changing the <quote>Accept-Language:</quote> header first.
5410 Therefore it's a good idea to either only change the
5411 <quote>Accept-Language:</quote> header to languages you understand,
5412 or to languages that aren't wide spread.
5415 Before setting the <quote>Accept-Language:</quote> header
5416 to a rare language, you should consider that it helps to
5417 make your requests unique and thus easier to trace.
5418 If you don't plan to change this header frequently,
5419 you should stick to a common language.
5425 <term>Example usage (section):</term>
5428 <screen># Pretend to use Canadian language settings.
5429 {+hide-accept-language{en-ca} \
5430 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
5440 <!-- ~~~~~ New section ~~~~~ -->
5441 <sect3 renderas="sect4" id="hide-content-disposition">
5442 <title>hide-content-disposition</title>
5448 <term>Typical use:</term>
5450 <para>Prevent download menus for content you prefer to view inside the browser.</para>
5455 <term>Effect:</term>
5458 Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
5465 <!-- Boolean, Parameterized, Multi-value -->
5467 <para>Parameterized.</para>
5472 <term>Parameter:</term>
5475 Keyword: <quote>block</quote>, or any user defined value.
5484 Some servers set the <quote>Content-Disposition:</quote> HTTP header for
5485 documents they assume you want to save locally before viewing them.
5486 The <quote>Content-Disposition:</quote> header contains the file name
5487 the browser is supposed to use by default.
5490 In most browsers that understand this header, it makes it impossible to
5491 <emphasis>just view</emphasis> the document, without downloading it first,
5492 even if it's just a simple text file or an image.
5495 Removing the <quote>Content-Disposition:</quote> header helps
5496 to prevent this annoyance, but some browsers additionally check the
5497 <quote>Content-Type:</quote> header, before they decide if they can
5498 display a document without saving it first. In these cases, you have
5499 to change this header as well, before the browser stops displaying
5503 It is also possible to change the server's file name suggestion
5504 to another one, but in most cases it isn't worth the time to set
5508 This action will probably be removed in the future,
5509 use server-header filters instead.
5515 <term>Example usage:</term>
5518 <screen># Disarm the download link in Sourceforge's patch tracker
5520 +content-type-overwrite{text/plain}\
5521 +hide-content-disposition{block} }
5522 .sourceforge.net/tracker/download\.php</screen>
5530 <!-- ~~~~~ New section ~~~~~ -->
5531 <sect3 renderas="sect4" id="hide-if-modified-since">
5532 <title>hide-if-modified-since</title>
5538 <term>Typical use:</term>
5540 <para>Prevent yet another way to track the user's steps between sessions.</para>
5545 <term>Effect:</term>
5548 Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
5555 <!-- Boolean, Parameterized, Multi-value -->
5557 <para>Parameterized.</para>
5562 <term>Parameter:</term>
5565 Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
5574 Removing this header is useful for filter testing, where you want to force a real
5575 reload instead of getting status code <quote>304</quote>, which would cause the
5576 browser to use a cached copy of the page.
5579 Instead of removing the header, <literal>hide-if-modified-since</literal> can
5580 also add or subtract a random amount of time to/from the header's value.
5581 You specify a range of minutes where the random factor should be chosen from and
5582 <application>Privoxy</application> does the rest. A negative value means
5583 subtracting, a positive value adding.
5586 Randomizing the value of the <quote>If-Modified-Since:</quote> makes
5587 it less likely that the server can use the time as a cookie replacement,
5588 but you will run into caching problems if the random range is too high.
5591 It is a good idea to only use a small negative value and let
5592 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
5593 handle the greater changes.
5596 It is also recommended to use this action together with
5597 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>,
5598 otherwise it's more or less pointless.
5604 <term>Example usage (section):</term>
5607 <screen># Let the browser revalidate but make tracking based on the time less likely.
5608 {+hide-if-modified-since{-60} \
5609 +overwrite-last-modified{randomize} \
5610 +crunch-if-none-match}
5619 <!-- ~~~~~ New section ~~~~~ -->
5620 <sect3 renderas="sect4" id="hide-from-header">
5621 <title>hide-from-header</title>
5625 <term>Typical use:</term>
5627 <para>Keep your (old and ill) browser from telling web servers your email address</para>
5632 <term>Effect:</term>
5635 Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
5643 <!-- Boolean, Parameterized, Multi-value -->
5645 <para>Parameterized.</para>
5650 <term>Parameter:</term>
5653 Keyword: <quote>block</quote>, or any user defined value.
5662 The keyword <quote>block</quote> will completely remove the header
5663 (not to be confused with the <literal><link linkend="block">block</link></literal>
5667 Alternately, you can specify any value you prefer to be sent to the web
5668 server. If you do, it is a matter of fairness not to use any address that
5669 is actually used by a real person.
5672 This action is rarely needed, as modern web browsers don't send
5673 <quote>From:</quote> headers anymore.
5679 <term>Example usage:</term>
5682 <screen>+hide-from-header{block}</screen> or
5683 <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
5691 <!-- ~~~~~ New section ~~~~~ -->
5692 <sect3 renderas="sect4" id="hide-referrer">
5693 <title>hide-referrer</title>
5694 <anchor id="hide-referer">
5697 <term>Typical use:</term>
5699 <para>Conceal which link you followed to get to a particular site</para>
5704 <term>Effect:</term>
5707 Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
5708 or replaces it with a forged one.
5715 <!-- Boolean, Parameterized, Multi-value -->
5717 <para>Parameterized.</para>
5722 <term>Parameter:</term>
5726 <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
5729 <para><quote>conditional-forge</quote> to forge the header if the host has changed.</para>
5732 <para><quote>block</quote> to delete the header unconditionally.</para>
5735 <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
5738 <para>Any other string to set a user defined referrer.</para>
5748 <literal>conditional-block</literal> is the only parameter,
5749 that isn't easily detected in the server's log file. If it blocks the
5750 referrer, the request will look like the visitor used a bookmark or
5751 typed in the address directly.
5754 Leaving the referrer unmodified for requests on the same host
5755 allows the server owner to see the visitor's <quote>click path</quote>,
5756 but in most cases she could also get that information by comparing
5757 other parts of the log file: for example the User-Agent if it isn't
5758 a very common one, or the user's IP address if it doesn't change between
5762 Always blocking the referrer, or using a custom one, can lead to
5763 failures on servers that check the referrer before they answer any
5764 requests, in an attempt to prevent their content from being
5765 embedded or linked to elsewhere.
5768 Both <literal>conditional-block</literal> and <literal>forge</literal>
5769 will work with referrer checks, as long as content and valid referring page
5770 are on the same host. Most of the time that's the case.
5773 <literal>hide-referer</literal> is an alternate spelling of
5774 <literal>hide-referrer</literal> and the two can be can be freely
5775 substituted with each other. (<quote>referrer</quote> is the
5776 correct English spelling, however the HTTP specification has a bug - it
5777 requires it to be spelled as <quote>referer</quote>.)
5783 <term>Example usage:</term>
5786 <screen>+hide-referrer{forge}</screen> or
5787 <screen>+hide-referrer{http://www.yahoo.com/}</screen>
5795 <!-- ~~~~~ New section ~~~~~ -->
5796 <sect3 renderas="sect4" id="hide-user-agent">
5797 <title>hide-user-agent</title>
5801 <term>Typical use:</term>
5803 <para>Try to conceal your type of browser and client operating system</para>
5808 <term>Effect:</term>
5811 Replaces the value of the <quote>User-Agent:</quote> HTTP header
5812 in client requests with the specified value.
5819 <!-- Boolean, Parameterized, Multi-value -->
5821 <para>Parameterized.</para>
5826 <term>Parameter:</term>
5829 Any user-defined string.
5839 This can lead to problems on web sites that depend on looking at this header in
5840 order to customize their content for different browsers (which, by the
5841 way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
5842 work browser-independently).
5846 Using this action in multi-user setups or wherever different types of
5847 browsers will access the same <application>Privoxy</application> is
5848 <emphasis>not recommended</emphasis>. In single-user, single-browser
5849 setups, you might use it to delete your OS version information from
5850 the headers, because it is an invitation to exploit known bugs for your
5851 OS. It is also occasionally useful to forge this in order to access
5852 sites that won't let you in otherwise (though there may be a good
5853 reason in some cases).
5856 More information on known user-agent strings can be found at
5857 <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
5859 <ulink url="http://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
5865 <term>Example usage:</term>
5868 <screen>+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}</screen>
5876 <!-- ~~~~~ New section ~~~~~ -->
5877 <sect3 renderas="sect4" id="limit-connect">
5878 <title>limit-connect</title>
5882 <term>Typical use:</term>
5884 <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
5889 <term>Effect:</term>
5892 Specifies to which ports HTTP CONNECT requests are allowable.
5899 <!-- Boolean, Parameterized, Multi-value -->
5901 <para>Parameterized.</para>
5906 <term>Parameter:</term>
5909 A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
5910 defaulting to 0 and the maximum to 65K).
5919 By default, i.e. if no <literal>limit-connect</literal> action applies,
5920 <application>Privoxy</application> allows HTTP CONNECT requests to all
5921 ports. Use <literal>limit-connect</literal> if fine-grained control
5922 is desired for some or all destinations.
5925 The CONNECT methods exists in HTTP to allow access to secure websites
5926 (<quote>https://</quote> URLs) through proxies. It works very simply:
5927 the proxy connects to the server on the specified port, and then
5928 short-circuits its connections to the client and to the remote server.
5929 This means CONNECT-enabled proxies can be used as TCP relays very easily.
5932 <application>Privoxy</application> relays HTTPS traffic without seeing
5933 the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
5934 filters. By specifying an invalid port range you can disable HTTPS entirely.
5940 <term>Example usages:</term>
5942 <!-- I had trouble getting the spacing to look right in my browser -->
5943 <!-- I probably have the wrong font setup, bollocks. -->
5944 <!-- Apparently the emphasis tag uses a proportional font no matter what -->
5946 <screen>+limit-connect{443} # Port 443 is OK.
5947 +limit-connect{80,443} # Ports 80 and 443 are OK.
5948 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
5949 +limit-connect{-} # All ports are OK
5950 +limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
5958 <!-- ~~~~~ New section ~~~~~ -->
5959 <sect3 renderas="sect4" id="limit-cookie-lifetime">
5960 <title>limit-cookie-lifetime</title>
5964 <term>Typical use:</term>
5966 <para>Limit the lifetime of HTTP cookies to a couple of minutes or hours.</para>
5971 <term>Effect:</term>
5974 Overwrites the expires field in Set-Cookie server headers if it's above the specified limit.
5981 <!-- Boolean, Parameterized, Multi-value -->
5983 <para>Parameterized.</para>
5988 <term>Parameter:</term>
5991 The lifetime limit in minutes, or 0.
6000 This action reduces the lifetime of HTTP cookies coming from the
6001 server to the specified number of minutes, starting from the time
6002 the cookie passes Privoxy.
6005 Cookies with a lifetime below the limit are not modified.
6006 The lifetime of session cookies is set to the specified limit.
6009 The effect of this action depends on the server.
6012 In case of servers which refresh their cookies with each response
6013 (or at least frequently), the lifetime limit set by this action
6015 Thus, a session associated with the cookie continues to work with
6016 this action enabled, as long as a new request is made before the
6017 last limit set is reached.
6020 However, some servers send their cookies once, with a lifetime of several
6021 years (the year 2037 is a popular choice), and do not refresh them
6022 until a certain event in the future, for example the user logging out.
6023 In this case this action may limit the absolute lifetime of the session,
6024 even if requests are made frequently.
6027 If the parameter is <quote>0</quote>, this action behaves like
6028 <literal><link linkend="session-cookies-only">session-cookies-only</link></literal>.
6034 <term>Example usages:</term>
6037 <screen>+limit-cookie-lifetime{60}
6045 <!-- ~~~~~ New section ~~~~~ -->
6046 <sect3 renderas="sect4" id="prevent-compression">
6047 <title>prevent-compression</title>
6051 <term>Typical use:</term>
6054 Ensure that servers send the content uncompressed, so it can be
6055 passed through <literal><link linkend="filter">filter</link></literal>s.
6061 <term>Effect:</term>
6064 Removes the Accept-Encoding header which can be used to ask for compressed transfer.
6071 <!-- Boolean, Parameterized, Multi-value -->
6073 <para>Boolean.</para>
6078 <term>Parameter:</term>
6090 More and more websites send their content compressed by default, which
6091 is generally a good idea and saves bandwidth. But the <literal><link
6092 linkend="filter">filter</link></literal> and
6093 <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
6094 actions need access to the uncompressed data.
6097 When compiled with zlib support (available since &my-app; 3.0.7), content that should be
6098 filtered is decompressed on-the-fly and you don't have to worry about this action.
6099 If you are using an older &my-app; version, or one that hasn't been compiled with zlib
6100 support, this action can be used to convince the server to send the content uncompressed.
6103 Most text-based instances compress very well, the size is seldom decreased by less than 50%,
6104 for markup-heavy instances like news feeds saving more than 90% of the original size isn't
6108 Not using compression will therefore slow down the transfer, and you should only
6109 enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
6110 predefined action settings.
6113 Note that some (rare) ill-configured sites don't handle requests for uncompressed
6114 documents correctly. Broken PHP applications tend to send an empty document body,
6115 some IIS versions only send the beginning of the content. If you enable
6116 <literal>prevent-compression</literal> per default, you might want to add
6117 exceptions for those sites. See the example for how to do that.
6123 <term>Example usage (sections):</term>
6127 # Selectively turn off compression, and enable a filter
6129 { +filter{tiny-textforms} +prevent-compression }
6130 # Match only these sites
6135 # Or instead, we could set a universal default:
6137 { +prevent-compression }
6140 # Then maybe make exceptions for broken sites:
6142 { -prevent-compression }
6143 .compusa.com/</screen>
6152 <!-- ~~~~~ New section ~~~~~ -->
6153 <sect3 renderas="sect4" id="overwrite-last-modified">
6154 <title>overwrite-last-modified</title>
6160 <term>Typical use:</term>
6162 <para>Prevent yet another way to track the user's steps between sessions.</para>
6167 <term>Effect:</term>
6170 Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
6177 <!-- Boolean, Parameterized, Multi-value -->
6179 <para>Parameterized.</para>
6184 <term>Parameter:</term>
6187 One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
6188 and <quote>randomize</quote>
6197 Removing the <quote>Last-Modified:</quote> header is useful for filter
6198 testing, where you want to force a real reload instead of getting status
6199 code <quote>304</quote>, which would cause the browser to reuse the old
6200 version of the page.
6203 The <quote>randomize</quote> option overwrites the value of the
6204 <quote>Last-Modified:</quote> header with a randomly chosen time
6205 between the original value and the current time. In theory the server
6206 could send each document with a different <quote>Last-Modified:</quote>
6207 header to track visits without using cookies. <quote>Randomize</quote>
6208 makes it impossible and the browser can still revalidate cached documents.
6211 <quote>reset-to-request-time</quote> overwrites the value of the
6212 <quote>Last-Modified:</quote> header with the current time. You could use
6213 this option together with
6214 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
6215 to further customize your random range.
6218 The preferred parameter here is <quote>randomize</quote>. It is safe
6219 to use, as long as the time settings are more or less correct.
6220 If the server sets the <quote>Last-Modified:</quote> header to the time
6221 of the request, the random range becomes zero and the value stays the same.
6222 Therefore you should later randomize it a second time with
6223 <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
6227 It is also recommended to use this action together with
6228 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
6234 <term>Example usage:</term>
6237 <screen># Let the browser revalidate without being tracked across sessions
6238 { +hide-if-modified-since{-60} \
6239 +overwrite-last-modified{randomize} \
6240 +crunch-if-none-match}
6249 <!-- ~~~~~ New section ~~~~~ -->
6250 <sect3 renderas="sect4" id="redirect">
6251 <title>redirect</title>
6257 <term>Typical use:</term>
6260 Redirect requests to other sites.
6266 <term>Effect:</term>
6269 Convinces the browser that the requested document has been moved
6270 to another location and the browser should get it from there.
6277 <!-- Boolean, Parameterized, Multi-value -->
6279 <para>Parameterized</para>
6284 <term>Parameter:</term>
6287 An absolute URL or a single pcrs command.
6296 Requests to which this action applies are answered with a
6297 HTTP redirect to URLs of your choosing. The new URL is
6298 either provided as parameter, or derived by applying a
6299 single pcrs command to the original URL.
6302 The syntax for pcrs commands is documented in the
6303 <link linkend="filter-file">filter file</link> section.
6306 This action will be ignored if you use it together with
6307 <literal><link linkend="block">block</link></literal>.
6308 It can be combined with
6309 <literal><link linkend="fast-redirects">fast-redirects{check-decoded-url}</link></literal>
6310 to redirect to a decoded version of a rewritten URL.
6313 Use this action carefully, make sure not to create redirection loops
6314 and be aware that using your own redirects might make it
6315 possible to fingerprint your requests.
6318 In case of problems with your redirects, or simply to watch
6319 them working, enable <link linkend="DEBUG">debug 128</link>.
6325 <term>Example usages:</term>
6328 <screen># Replace example.com's style sheet with another one
6329 { +redirect{http://localhost/css-replacements/example.com.css} }
6330 example.com/stylesheet\.css
6332 # Create a short, easy to remember nickname for a favorite site
6333 # (relies on the browser accept and forward invalid URLs to &my-app;)
6334 { +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
6337 # Always use the expanded view for Undeadly.org articles
6338 # (Note the $ at the end of the URL pattern to make sure
6339 # the request for the rewritten URL isn't redirected as well)
6340 {+redirect{s@$@&mode=expanded@}}
6341 undeadly.org/cgi\?action=article&sid=\d*$
6343 # Redirect Google search requests to MSN
6344 {+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}}
6347 # Redirect MSN search requests to Yahoo
6348 {+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}}
6349 search.msn.com//results\.aspx\?q=
6351 # Redirect remote requests for this manual
6352 # to the local version delivered by Privoxy
6353 {+redirect{s@^http://www@http://config@}}
6354 www.privoxy.org/user-manual/</screen>
6363 <!-- ~~~~~ New section ~~~~~ -->
6364 <sect3 renderas="sect4" id="server-header-filter">
6365 <title>server-header-filter</title>
6369 <term>Typical use:</term>
6372 Rewrite or remove single server headers.
6378 <term>Effect:</term>
6381 All server headers to which this action applies are filtered on-the-fly
6382 through the specified regular expression based substitutions.
6389 <!-- boolean, parameterized, Multi-value -->
6391 <para>Parameterized.</para>
6396 <term>Parameter:</term>
6399 The name of a server-header filter, as defined in one of the
6400 <link linkend="filter-file">filter files</link>.
6409 Server-header filters are applied to each header on its own, not to
6410 all at once. This makes it easier to diagnose problems, but on the downside
6411 you can't write filters that only change header x if header y's value is z.
6412 You can do that by using tags though.
6415 Server-header filters are executed after the other header actions have finished
6416 and use their output as input.
6419 Please refer to the <link linkend="filter-file">filter file chapter</link>
6420 to learn which server-header filters are available by default, and how to
6427 <term>Example usage (section):</term>
6431 {+server-header-filter{html-to-xml}}
6432 example.org/xml-instance-that-is-delivered-as-html
6434 {+server-header-filter{xml-to-html}}
6435 example.org/instance-that-is-delivered-as-xml-but-is-not
6445 <!-- ~~~~~ New section ~~~~~ -->
6446 <sect3 renderas="sect4" id="server-header-tagger">
6447 <title>server-header-tagger</title>
6451 <term>Typical use:</term>
6454 Enable or disable filters based on the Content-Type header.
6460 <term>Effect:</term>
6463 Server headers to which this action applies are filtered on-the-fly through
6464 the specified regular expression based substitutions, the result is used as
6472 <!-- boolean, parameterized, Multi-value -->
6474 <para>Parameterized.</para>
6479 <term>Parameter:</term>
6482 The name of a server-header tagger, as defined in one of the
6483 <link linkend="filter-file">filter files</link>.
6492 Server-header taggers are applied to each header on its own,
6493 and as the header isn't modified, each tagger <quote>sees</quote>
6497 Server-header taggers are executed before all other header actions
6498 that modify server headers. Their tags can be used to control
6499 all of the other server-header actions, the content filters
6500 and the crunch actions (<link linkend="redirect">redirect</link>
6501 and <link linkend="block">block</link>).
6504 Obviously crunching based on tags created by server-header taggers
6505 doesn't prevent the request from showing up in the server's log file.
6512 <term>Example usage (section):</term>
6516 # Tag every request with the content type declared by the server
6517 {+server-header-tagger{content-type}}
6528 <!-- ~~~~~ New section ~~~~~ -->
6529 <sect3 renderas="sect4" id="session-cookies-only">
6530 <title>session-cookies-only</title>
6534 <term>Typical use:</term>
6537 Allow only temporary <quote>session</quote> cookies (for the current
6538 browser session <emphasis>only</emphasis>).
6544 <term>Effect:</term>
6547 Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
6548 server headers. Most browsers will not store such cookies permanently and
6549 forget them in between sessions.
6556 <!-- Boolean, Parameterized, Multi-value -->
6558 <para>Boolean.</para>
6563 <term>Parameter:</term>
6575 This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
6576 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
6577 websites that insist or rely on setting cookies, without compromising your privacy too badly.
6580 Most browsers will not permanently store cookies that have been processed by
6581 <literal>session-cookies-only</literal> and will forget about them between sessions.
6582 This makes profiling cookies useless, but won't break sites which require cookies so
6583 that you can log in for transactions. This is generally turned on for all
6584 sites, and is the recommended setting.
6587 It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
6588 together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
6589 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
6590 will be plainly killed.
6593 Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
6594 field. If you use an exotic browser, you might want to try it out to be sure.
6597 This setting also has no effect on cookies that may have been stored
6598 previously by the browser before starting <application>Privoxy</application>.
6599 These would have to be removed manually.
6602 <application>Privoxy</application> also uses
6603 the <link linkend="filter-content-cookies">content-cookies filter</link>
6604 to block some types of cookies. Content cookies are not effected by
6605 <literal>session-cookies-only</literal>.
6611 <term>Example usage:</term>
6614 <screen>+session-cookies-only</screen>
6622 <!-- ~~~~~ New section ~~~~~ -->
6623 <sect3 renderas="sect4" id="set-image-blocker">
6624 <title>set-image-blocker</title>
6628 <term>Typical use:</term>
6630 <para>Choose the replacement for blocked images</para>
6635 <term>Effect:</term>
6638 This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
6639 <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
6640 linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
6641 apply, i.e. if the request is to be blocked as an image,
6642 <emphasis>then</emphasis> the parameter of this action decides what will be
6643 sent as a replacement.
6650 <!-- Boolean, Parameterized, Multi-value -->
6652 <para>Parameterized.</para>
6657 <term>Parameter:</term>
6662 <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
6663 decent, scales very well, and makes it obvious where banners were busted.
6668 <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
6669 completely, but makes it hard to detect where <application>Privoxy</application> has blocked
6670 images on a given page and complicates troubleshooting if <application>Privoxy</application>
6671 has blocked innocent images, like navigation icons.
6676 <quote><replaceable class="parameter">target-url</replaceable></quote> to
6677 send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
6678 to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
6679 (But note that not all browsers support redirecting to a local file system).
6682 A good application of redirects is to use special <application>Privoxy</application>-built-in
6683 URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
6684 This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
6685 the first place, but enables your browser to cache the replacement image, instead of requesting
6686 it over and over again.
6697 The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
6698 class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
6699 either <quote>blank</quote> or <quote>pattern</quote>.
6702 There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
6703 used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
6704 Auto will select the type of image that would have applied to the referring page, had it been an image.
6710 <term>Example usage:</term>
6716 <screen>+set-image-blocker{pattern}</screen>
6719 Redirect to the BSD daemon:
6722 <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
6725 Redirect to the built-in pattern for better caching:
6728 <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
6736 <!-- ~~~~~ New section ~~~~~ -->
6738 <title>Summary</title>
6740 Note that many of these actions have the potential to cause a page to
6741 misbehave, possibly even not to display at all. There are many ways
6742 a site designer may choose to design his site, and what HTTP header
6743 content, and other criteria, he may depend on. There is no way to have hard
6744 and fast rules for all sites. See the <link
6745 linkend="ACTIONSANAT">Appendix</link> for a brief example on troubleshooting
6751 <!-- ~~~~~ New section ~~~~~ -->
6752 <sect2 id="aliases">
6753 <title>Aliases</title>
6755 Custom <quote>actions</quote>, known to <application>Privoxy</application>
6756 as <quote>aliases</quote>, can be defined by combining other actions.
6757 These can in turn be invoked just like the built-in actions.
6758 Currently, an alias name can contain any character except space, tab,
6760 <quote>{</quote> and <quote>}</quote>, but we <emphasis>strongly
6761 recommend</emphasis> that you only use <quote>a</quote> to <quote>z</quote>,
6762 <quote>0</quote> to <quote>9</quote>, <quote>+</quote>, and <quote>-</quote>.
6763 Alias names are not case sensitive, and are not required to start with a
6764 <quote>+</quote> or <quote>-</quote> sign, since they are merely textually
6768 Aliases can be used throughout the actions file, but they <emphasis>must be
6769 defined in a special section at the top of the file!</emphasis>
6770 And there can only be one such section per actions file. Each actions file may
6771 have its own alias section, and the aliases defined in it are only visible
6775 There are two main reasons to use aliases: One is to save typing for frequently
6776 used combinations of actions, the other one is a gain in flexibility: If you
6777 decide once how you want to handle shops by defining an alias called
6778 <quote>shop</quote>, you can later change your policy on shops in
6779 <emphasis>one</emphasis> place, and your changes will take effect everywhere
6780 in the actions file where the <quote>shop</quote> alias is used. Calling aliases
6781 by their purpose also makes your actions files more readable.
6784 Currently, there is one big drawback to using aliases, though:
6785 <application>Privoxy</application>'s built-in web-based action file
6786 editor honors aliases when reading the actions files, but it expands
6787 them before writing. So the effects of your aliases are of course preserved,
6788 but the aliases themselves are lost when you edit sections that use aliases
6793 Now let's define some aliases...
6798 # Useful custom aliases we can use later.
6800 # Note the (required!) section header line and that this section
6801 # must be at the top of the actions file!
6805 # These aliases just save typing later:
6806 # (Note that some already use other aliases!)
6808 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6809 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6810 +block-as-image = +block{Blocked image.} +handle-as-image
6811 allow-all-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
6813 # These aliases define combinations of actions
6814 # that are useful for certain types of sites:
6816 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>
6818 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link>
6820 # Short names for other aliases, for really lazy people ;-)
6822 c0 = +crunch-all-cookies
6823 c1 = -crunch-all-cookies</screen>
6827 ...and put them to use. These sections would appear in the lower part of an
6828 actions file and define exceptions to the default actions (as specified further
6829 up for the <quote>/</quote> pattern):
6834 # These sites are either very complex or very keen on
6835 # user data and require minimal interference to work:
6838 .office.microsoft.com
6839 .windowsupdate.microsoft.com
6840 # Gmail is really mail.google.com, not gmail.com
6844 # Allow cookies (for setting and retrieving your customer data)
6848 .worldpay.com # for quietpc.com
6851 # These shops require pop-ups:
6853 {-filter{all-popups} -filter{unsolicited-popups}}
6855 .overclockers.co.uk</screen>
6859 Aliases like <quote>shop</quote> and <quote>fragile</quote> are typically used for
6860 <quote>problem</quote> sites that require more than one action to be disabled
6861 in order to function properly.
6867 <!-- ~~~~~ New section ~~~~~ -->
6868 <sect2 id="act-examples">
6869 <title>Actions Files Tutorial</title>
6871 The above chapters have shown <link linkend="actions-file">which actions files
6872 there are and how they are organized</link>, how actions are <link
6873 linkend="actions">specified</link> and <link linkend="actions-apply">applied
6874 to URLs</link>, how <link linkend="af-patterns">patterns</link> work, and how to
6875 define and use <link linkend="aliases">aliases</link>. Now, let's look at an
6876 example <filename>match-all.action</filename>, <filename>default.action</filename>
6877 and <filename>user.action</filename> file and see how all these pieces come together:
6881 <title>match-all.action</title>
6883 Remember <emphasis>all actions are disabled when matching starts</emphasis>,
6884 so we have to explicitly enable the ones we want.
6888 While the <filename>match-all.action</filename> file only contains a
6889 single section, it is probably the most important one. It has only one
6890 pattern, <quote><literal>/</literal></quote>, but this pattern
6891 <link linkend="af-patterns">matches all URLs</link>. Therefore, the set of
6892 actions used in this <quote>default</quote> section <emphasis>will
6893 be applied to all requests as a start</emphasis>. It can be partly or
6894 wholly overridden by other actions files like <filename>default.action</filename>
6895 and <filename>user.action</filename>, but it will still be largely responsible
6896 for your overall browsing experience.
6900 Again, at the start of matching, all actions are disabled, so there is
6901 no need to disable any actions here. (Remember: a <quote>+</quote>
6902 preceding the action name enables the action, a <quote>-</quote> disables!).
6903 Also note how this long line has been made more readable by splitting it into
6904 multiple lines with line continuation.
6910 +<link linkend="CHANGE-X-FORWARDED-FOR">change-x-forwarded-for{block}</link> \
6911 +<link linkend="HIDE-FROM-HEADER">hide-from-header{block}</link> \
6912 +<link linkend="SET-IMAGE-BLOCKER">set-image-blocker{pattern}</link> \
6919 The default behavior is now set.
6924 <title>default.action</title>
6927 If you aren't a developer, there's no need for you to edit the
6928 <filename>default.action</filename> file. It is maintained by
6929 the &my-app; developers and if you disagree with some of the
6930 sections, you should overrule them in your <filename>user.action</filename>.
6934 Understanding the <filename>default.action</filename> file can
6935 help you with your <filename>user.action</filename>, though.
6939 The first section in this file is a special section for internal use
6940 that prevents older &my-app; versions from reading the file:
6945 ##########################################################################
6946 # Settings -- Don't change! For internal Privoxy use ONLY.
6947 ##########################################################################
6949 for-privoxy-version=3.0.11</screen>
6953 After that comes the (optional) alias section. We'll use the example
6954 section from the above <link linkend="aliases">chapter on aliases</link>,
6955 that also explains why and how aliases are used:
6960 ##########################################################################
6962 ##########################################################################
6965 # These aliases just save typing later:
6966 # (Note that some already use other aliases!)
6968 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6969 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6970 +block-as-image = +block{Blocked image.} +handle-as-image
6971 mercy-for-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
6973 # These aliases define combinations of actions
6974 # that are useful for certain types of sites:
6976 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>
6977 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link></screen>
6981 The first of our specialized sections is concerned with <quote>fragile</quote>
6982 sites, i.e. sites that require minimum interference, because they are either
6983 very complex or very keen on tracking you (and have mechanisms in place that
6984 make them unusable for people who avoid being tracked). We will simply use
6985 our pre-defined <literal>fragile</literal> alias instead of stating the list
6986 of actions explicitly:
6991 ##########################################################################
6992 # Exceptions for sites that'll break under the default action set:
6993 ##########################################################################
6995 # "Fragile" Use a minimum set of actions for these sites (see alias above):
6998 .office.microsoft.com # surprise, surprise!
6999 .windowsupdate.microsoft.com
7000 mail.google.com</screen>
7004 Shopping sites are not as fragile, but they typically
7005 require cookies to log in, and pop-up windows for shopping
7006 carts or item details. Again, we'll use a pre-defined alias:
7015 .worldpay.com # for quietpc.com
7017 .scan.co.uk</screen>
7021 The <literal><link linkend="FAST-REDIRECTS">fast-redirects</link></literal>
7022 action, which may have been enabled in <filename>match-all.action</filename>,
7023 breaks some sites. So disable it for popular sites where we know it misbehaves:
7028 { -<link linkend="FAST-REDIRECTS">fast-redirects</link> }
7032 .altavista.com/.*(like|url|link):http
7033 .altavista.com/trans.*urltext=http
7034 .nytimes.com</screen>
7038 It is important that <application>Privoxy</application> knows which
7039 URLs belong to images, so that <emphasis>if</emphasis> they are to
7040 be blocked, a substitute image can be sent, rather than an HTML page.
7041 Contacting the remote site to find out is not an option, since it
7042 would destroy the loading time advantage of banner blocking, and it
7043 would feed the advertisers information about you. We can mark any
7044 URL as an image with the <literal><link
7045 linkend="handle-as-image">handle-as-image</link></literal> action,
7046 and marking all URLs that end in a known image file extension is a
7052 ##########################################################################
7054 ##########################################################################
7056 # Define which file types will be treated as images, in case they get
7057 # blocked further down this file:
7059 { +<link linkend="HANDLE-AS-IMAGE">handle-as-image</link> }
7060 /.*\.(gif|jpe?g|png|bmp|ico)$</screen>
7064 And then there are known banner sources. They often use scripts to
7065 generate the banners, so it won't be visible from the URL that the
7066 request is for an image. Hence we block them <emphasis>and</emphasis>
7067 mark them as images in one go, with the help of our
7068 <literal>+block-as-image</literal> alias defined above. (We could of
7069 course just as well use <literal>+<link linkend="block">block</link>
7070 +<link linkend="handle-as-image">handle-as-image</link></literal> here.)
7071 Remember that the type of the replacement image is chosen by the
7072 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
7073 action. Since all URLs have matched the default section with its
7074 <literal>+<link linkend="set-image-blocker">set-image-blocker</link>{pattern}</literal>
7075 action before, it still applies and needn't be repeated:
7080 # Known ad generators:
7085 .ad.*.doubleclick.net
7086 .a.yimg.com/(?:(?!/i/).)*$
7087 .a[0-9].yimg.com/(?:(?!/i/).)*$
7093 One of the most important jobs of <application>Privoxy</application>
7094 is to block banners. Many of these can be <quote>blocked</quote>
7095 by the <literal><link linkend="filter">filter</link>{banners-by-size}</literal>
7096 action, which we enabled above, and which deletes the references to banner
7097 images from the pages while they are loaded, so the browser doesn't request
7098 them anymore, and hence they don't need to be blocked here. But this naturally
7099 doesn't catch all banners, and some people choose not to use filters, so we
7100 need a comprehensive list of patterns for banner URLs here, and apply the
7101 <literal><link linkend="block">block</link></literal> action to them.
7104 First comes many generic patterns, which do most of the work, by
7105 matching typical domain and path name components of banners. Then comes
7106 a list of individual patterns for specific sites, which is omitted here
7107 to keep the example short:
7112 ##########################################################################
7113 # Block these fine banners:
7114 ##########################################################################
7115 { <link linkend="BLOCK">+block{Banner ads.}</link> }
7123 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
7124 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
7126 # Site-specific patterns (abbreviated):
7128 .hitbox.com</screen>
7132 It's quite remarkable how many advertisers actually call their banner
7133 servers ads.<replaceable>company</replaceable>.com, or call the directory
7134 in which the banners are stored simply <quote>banners</quote>. So the above
7135 generic patterns are surprisingly effective.
7138 But being very generic, they necessarily also catch URLs that we don't want
7139 to block. The pattern <literal>.*ads.</literal> e.g. catches
7140 <quote>nasty-<emphasis>ads</emphasis>.nasty-corp.com</quote> as intended,
7141 but also <quote>downlo<emphasis>ads</emphasis>.sourcefroge.net</quote> or
7142 <quote><emphasis>ads</emphasis>l.some-provider.net.</quote> So here come some
7143 well-known exceptions to the <literal>+<link linkend="BLOCK">block</link></literal>
7147 Note that these are exceptions to exceptions from the default! Consider the URL
7148 <quote>downloads.sourcefroge.net</quote>: Initially, all actions are deactivated,
7149 so it wouldn't get blocked. Then comes the defaults section, which matches the
7150 URL, but just deactivates the <literal><link linkend="BLOCK">block</link></literal>
7151 action once again. Then it matches <literal>.*ads.</literal>, an exception to the
7152 general non-blocking policy, and suddenly
7153 <literal><link linkend="BLOCK">+block</link></literal> applies. And now, it'll match
7154 <literal>.*loads.</literal>, where <literal><link linkend="BLOCK">-block</link></literal>
7155 applies, so (unless it matches <emphasis>again</emphasis> further down) it ends up
7156 with no <literal><link linkend="BLOCK">block</link></literal> action applying.
7161 ##########################################################################
7162 # Save some innocent victims of the above generic block patterns:
7163 ##########################################################################
7167 { -<link linkend="BLOCK">block</link> }
7168 adv[io]*. # (for advogato.org and advice.*)
7169 adsl. # (has nothing to do with ads)
7170 adobe. # (has nothing to do with ads either)
7171 ad[ud]*. # (adult.* and add.*)
7172 .edu # (universities don't host banners (yet!))
7173 .*loads. # (downloads, uploads etc)
7181 www.globalintersec.com/adv # (adv = advanced)
7182 www.ugu.com/sui/ugu/adv</screen>
7186 Filtering source code can have nasty side effects,
7187 so make an exception for our friends at sourceforge.net,
7188 and all paths with <quote>cvs</quote> in them. Note that
7189 <literal>-<link linkend="FILTER">filter</link></literal>
7190 disables <emphasis>all</emphasis> filters in one fell swoop!
7195 # Don't filter code!
7197 { -<link linkend="FILTER">filter</link> }
7202 .sourceforge.net</screen>
7206 The actual <filename>default.action</filename> is of course much more
7207 comprehensive, but we hope this example made clear how it works.
7212 <sect3><title>user.action</title>
7215 So far we are painting with a broad brush by setting general policies,
7216 which would be a reasonable starting point for many people. Now,
7217 you might want to be more specific and have customized rules that
7218 are more suitable to your personal habits and preferences. These would
7219 be for narrowly defined situations like your ISP or your bank, and should
7220 be placed in <filename>user.action</filename>, which is parsed after all other
7221 actions files and hence has the last word, over-riding any previously
7222 defined actions. <filename>user.action</filename> is also a
7223 <emphasis>safe</emphasis> place for your personal settings, since
7224 <filename>default.action</filename> is actively maintained by the
7225 <application>Privoxy</application> developers and you'll probably want
7226 to install updated versions from time to time.
7230 So let's look at a few examples of things that one might typically do in
7231 <filename>user.action</filename>:
7235 <!-- brief sample user.action here -->
7239 # My user.action file. <fred@example.com></screen>
7243 As <link linkend="aliases">aliases</link> are local to the actions
7244 file that they are defined in, you can't use the ones from
7245 <filename>default.action</filename>, unless you repeat them here:
7250 # Aliases are local to the file they are defined in.
7251 # (Re-)define aliases for this file:
7255 # These aliases just save typing later, and the alias names should
7256 # be self explanatory.
7258 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
7259 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
7260 allow-all-cookies = -crunch-all-cookies -session-cookies-only
7261 allow-popups = -filter{all-popups}
7262 +block-as-image = +block{Blocked as image.} +handle-as-image
7263 -block-as-image = -block
7265 # These aliases define combinations of actions that are useful for
7266 # certain types of sites:
7268 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer
7269 shop = -crunch-all-cookies allow-popups
7271 # Allow ads for selected useful free sites:
7273 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
7275 # Alias for specific file types that are text, but might have conflicting
7276 # MIME types. We want the browser to force these to be text documents.
7277 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>
7282 Say you have accounts on some sites that you visit regularly, and
7283 you don't want to have to log in manually each time. So you'd like
7284 to allow persistent cookies for these sites. The
7285 <literal>allow-all-cookies</literal> alias defined above does exactly
7286 that, i.e. it disables crunching of cookies in any direction, and the
7287 processing of cookies to make them only temporary.
7292 { allow-all-cookies }
7296 .redhat.com</screen>
7300 Your bank is allergic to some filter, but you don't know which, so you disable them all:
7305 { -<link linkend="FILTER">filter</link> }
7306 .your-home-banking-site.com</screen>
7310 Some file types you may not want to filter for various reasons:
7315 # Technical documentation is likely to contain strings that might
7316 # erroneously get altered by the JavaScript-oriented filters:
7321 # And this stupid host sends streaming video with a wrong MIME type,
7322 # so that Privoxy thinks it is getting HTML and starts filtering:
7324 stupid-server.example.com/</screen>
7328 Example of a simple <link linkend="BLOCK">block</link> action. Say you've
7329 seen an ad on your favourite page on example.com that you want to get rid of.
7330 You have right-clicked the image, selected <quote>copy image location</quote>
7331 and pasted the URL below while removing the leading http://, into a
7332 <literal>{ +block{} }</literal> section. Note that <literal>{ +handle-as-image
7333 }</literal> need not be specified, since all URLs ending in
7334 <literal>.gif</literal> will be tagged as images by the general rules as set
7335 in default.action anyway:
7340 { +<link linkend="BLOCK">block</link>{Nasty ads.} }
7341 www.example.com/nasty-ads/sponsor\.gif
7342 another.example.net/more/junk/here/</screen>
7346 The URLs of dynamically generated banners, especially from large banner
7347 farms, often don't use the well-known image file name extensions, which
7348 makes it impossible for <application>Privoxy</application> to guess
7349 the file type just by looking at the URL.
7350 You can use the <literal>+block-as-image</literal> alias defined above for
7352 Note that objects which match this rule but then turn out NOT to be an
7353 image are typically rendered as a <quote>broken image</quote> icon by the
7354 browser. Use cautiously.
7363 ar.atwola.com/</screen>
7367 Now you noticed that the default configuration breaks Forbes Magazine,
7368 but you were too lazy to find out which action is the culprit, and you
7369 were again too lazy to give <link linkend="contact">feedback</link>, so
7370 you just used the <literal>fragile</literal> alias on the site, and
7371 -- <emphasis>whoa!</emphasis> -- it worked. The <literal>fragile</literal>
7372 aliases disables those actions that are most likely to break a site. Also,
7373 good for testing purposes to see if it is <application>Privoxy</application>
7374 that is causing the problem or not. We later find other regular sites
7375 that misbehave, and add those to our personalized list of troublemakers:
7383 .mybank.com</screen>
7387 You like the <quote>fun</quote> text replacements in <filename>default.filter</filename>,
7388 but it is disabled in the distributed actions file.
7389 So you'd like to turn it on in your private,
7390 update-safe config, once and for all:
7395 { +<link linkend="filter-fun">filter{fun}</link> }
7396 / # For ALL sites!</screen>
7400 Note that the above is not really a good idea: There are exceptions
7401 to the filters in <filename>default.action</filename> for things that
7402 really shouldn't be filtered, like code on CVS->Web interfaces. Since
7403 <filename>user.action</filename> has the last word, these exceptions
7404 won't be valid for the <quote>fun</quote> filtering specified here.
7408 You might also worry about how your favourite free websites are
7409 funded, and find that they rely on displaying banner advertisements
7410 to survive. So you might want to specifically allow banners for those
7411 sites that you feel provide value to you:
7423 Note that <literal>allow-ads</literal> has been aliased to
7424 <literal>-<link linkend="block">block</link></literal>,
7425 <literal>-<link linkend="filter-banners-by-size">filter{banners-by-size}</link></literal>, and
7426 <literal>-<link linkend="filter-banners-by-link">filter{banners-by-link}</link></literal> above.
7430 Invoke another alias here to force an over-ride of the MIME type <literal>
7431 application/x-sh</literal> which typically would open a download type
7432 dialog. In my case, I want to look at the shell script, and then I can save
7433 it should I choose to.
7443 <filename>user.action</filename> is generally the best place to define
7444 exceptions and additions to the default policies of
7445 <filename>default.action</filename>. Some actions are safe to have their
7446 default policies set here though. So let's set a default policy to have a
7447 <quote>blank</quote> image as opposed to the checkerboard pattern for
7448 <emphasis>ALL</emphasis> sites. <quote>/</quote> of course matches all URL
7454 { +<link linkend="set-image-blocker">set-image-blocker{blank}</link> }
7455 / # ALL sites</screen>
7461 <!-- ~ End section ~ -->
7465 <!-- ~ End section ~ -->
7467 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7469 <sect1 id="filter-file">
7470 <title>Filter Files</title>
7473 On-the-fly text substitutions need
7474 to be defined in a <quote>filter file</quote>. Once defined, they
7475 can then be invoked as an <quote>action</quote>.
7479 &my-app; supports three different filter actions:
7480 <literal><link linkend="filter">filter</link></literal> to
7481 rewrite the content that is send to the client,
7482 <literal><link linkend="client-header-filter">client-header-filter</link></literal>
7483 to rewrite headers that are send by the client, and
7484 <literal><link linkend="server-header-filter">server-header-filter</link></literal>
7485 to rewrite headers that are send by the server.
7489 &my-app; also supports two tagger actions:
7490 <literal><link linkend="client-header-tagger">client-header-tagger</link></literal>
7492 <literal><link linkend="server-header-tagger">server-header-tagger</link></literal>.
7493 Taggers and filters use the same syntax in the filter files, the difference
7494 is that taggers don't modify the text they are filtering, but use a rewritten
7495 version of the filtered text as tag. The tags can then be used to change the
7496 applying actions through sections with <link linkend="tag-pattern">tag-patterns</link>.
7501 Multiple filter files can be defined through the <literal> <link
7502 linkend="filterfile">filterfile</link></literal> config directive. The filters
7503 as supplied by the developers are located in
7504 <filename>default.filter</filename>. It is recommended that any locally
7505 defined or modified filters go in a separately defined file such as
7506 <filename>user.filter</filename>.
7510 Common tasks for content filters are to eliminate common annoyances in
7511 HTML and JavaScript, such as pop-up windows,
7512 exit consoles, crippled windows without navigation tools, the
7513 infamous <BLINK> tag etc, to suppress images with certain
7514 width and height attributes (standard banner sizes or web-bugs),
7515 or just to have fun.
7519 Enabled content filters are applied to any content whose
7520 <quote>Content Type</quote> header is recognised as a sign
7521 of text-based content, with the exception of <literal>text/plain</literal>.
7522 Use the <link linkend="FORCE-TEXT-MODE">force-text-mode</link> action
7523 to also filter other content.
7527 Substitutions are made at the source level, so if you want to <quote>roll
7528 your own</quote> filters, you should first be familiar with HTML syntax,
7529 and, of course, regular expressions.
7533 Just like the <link linkend="actions-file">actions files</link>, the
7534 filter file is organized in sections, which are called <emphasis>filters</emphasis>
7535 here. Each filter consists of a heading line, that starts with one of the
7536 <emphasis>keywords</emphasis> <literal>FILTER:</literal>,
7537 <literal>CLIENT-HEADER-FILTER:</literal> or <literal>SERVER-HEADER-FILTER:</literal>
7538 followed by the filter's <emphasis>name</emphasis>, and a short (one line)
7539 <emphasis>description</emphasis> of what it does. Below that line
7540 come the <emphasis>jobs</emphasis>, i.e. lines that define the actual
7541 text substitutions. By convention, the name of a filter
7542 should describe what the filter <emphasis>eliminates</emphasis>. The
7543 comment is used in the <ulink url="http://config.privoxy.org/">web-based
7544 user interface</ulink>.
7548 Once a filter called <replaceable>name</replaceable> has been defined
7549 in the filter file, it can be invoked by using an action of the form
7550 +<literal><link linkend="filter">filter</link>{<replaceable>name</replaceable>}</literal>
7551 in any <link linkend="actions-file">actions file</link>.
7555 Filter definitions start with a header line that contains the filter
7556 type, the filter name and the filter description.
7557 A content filter header line for a filter called <quote>foo</quote> could look
7562 <screen>FILTER: foo Replace all "foo" with "bar"</screen>
7566 Below that line, and up to the next header line, come the jobs that
7567 define what text replacements the filter executes. They are specified
7568 in a syntax that imitates <ulink url="http://www.perl.org/">Perl</ulink>'s
7569 <literal>s///</literal> operator. If you are familiar with Perl, you
7570 will find this to be quite intuitive, and may want to look at the
7571 PCRS documentation for the subtle differences to Perl behaviour. Most
7572 notably, the non-standard option letter <literal>U</literal> is supported,
7573 which turns the default to ungreedy matching.
7578 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
7579 Expressions</quote></ulink>, you might want to take a look at
7580 the <link linkend="regex">Appendix on regular expressions</link>, and
7581 see the <ulink url="http://perldoc.perl.org/perlre.html">Perl
7583 <ulink url="http://perldoc.perl.org/perlop.html">the
7584 <literal>s///</literal> operator's syntax</ulink> and <ulink
7585 url="http://perldoc.perl.org/perlre.html">Perl-style regular
7586 expressions</ulink> in general.
7587 The below examples might also help to get you started.
7591 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7593 <sect2><title>Filter File Tutorial</title>
7595 Now, let's complete our <quote>foo</quote> content filter. We have already defined
7596 the heading, but the jobs are still missing. Since all it does is to replace
7597 <quote>foo</quote> with <quote>bar</quote>, there is only one (trivial) job
7602 <screen>s/foo/bar/</screen>
7606 But wait! Didn't the comment say that <emphasis>all</emphasis> occurrences
7607 of <quote>foo</quote> should be replaced? Our current job will only take
7608 care of the first <quote>foo</quote> on each page. For global substitution,
7609 we'll need to add the <literal>g</literal> option:
7613 <screen>s/foo/bar/g</screen>
7617 Our complete filter now looks like this:
7620 <screen>FILTER: foo Replace all "foo" with "bar"
7621 s/foo/bar/g</screen>
7625 Let's look at some real filters for more interesting examples. Here you see
7626 a filter that protects against some common annoyances that arise from JavaScript
7627 abuse. Let's look at its jobs one after the other:
7633 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
7635 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
7637 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg</screen>
7641 Following the header line and a comment, you see the job. Note that it uses
7642 <literal>|</literal> as the delimiter instead of <literal>/</literal>, because
7643 the pattern contains a forward slash, which would otherwise have to be escaped
7644 by a backslash (<literal>\</literal>).
7648 Now, let's examine the pattern: it starts with the text <literal><script.*</literal>
7649 enclosed in parentheses. Since the dot matches any character, and <literal>*</literal>
7650 means: <quote>Match an arbitrary number of the element left of myself</quote>, this
7651 matches <quote><script</quote>, followed by <emphasis>any</emphasis> text, i.e.
7652 it matches the whole page, from the start of the first <script> tag.
7656 That's more than we want, but the pattern continues: <literal>document\.referrer</literal>
7657 matches only the exact string <quote>document.referrer</quote>. The dot needed to
7658 be <emphasis>escaped</emphasis>, i.e. preceded by a backslash, to take away its
7659 special meaning as a joker, and make it just a regular dot. So far, the meaning is:
7660 Match from the start of the first <script> tag in a the page, up to, and including,
7661 the text <quote>document.referrer</quote>, if <emphasis>both</emphasis> are present
7662 in the page (and appear in that order).
7666 But there's still more pattern to go. The next element, again enclosed in parentheses,
7667 is <literal>.*</script></literal>. You already know what <literal>.*</literal>
7668 means, so the whole pattern translates to: Match from the start of the first <script>
7669 tag in a page to the end of the last <script> tag, provided that the text
7670 <quote>document.referrer</quote> appears somewhere in between.
7674 This is still not the whole story, since we have ignored the options and the parentheses:
7675 The portions of the page matched by sub-patterns that are enclosed in parentheses, will be
7676 remembered and be available through the variables <literal>$1, $2, ...</literal> in
7677 the substitute. The <literal>U</literal> option switches to ungreedy matching, which means
7678 that the first <literal>.*</literal> in the pattern will only <quote>eat up</quote> all
7679 text in between <quote><script</quote> and the <emphasis>first</emphasis> occurrence
7680 of <quote>document.referrer</quote>, and that the second <literal>.*</literal> will
7681 only span the text up to the <emphasis>first</emphasis> <quote></script></quote>
7682 tag. Furthermore, the <literal>s</literal> option says that the match may span
7683 multiple lines in the page, and the <literal>g</literal> option again means that the
7684 substitution is global.
7688 So, to summarize, the pattern means: Match all scripts that contain the text
7689 <quote>document.referrer</quote>. Remember the parts of the script from
7690 (and including) the start tag up to (and excluding) the string
7691 <quote>document.referrer</quote> as <literal>$1</literal>, and the part following
7692 that string, up to and including the closing tag, as <literal>$2</literal>.
7696 Now the pattern is deciphered, but wasn't this about substituting things? So
7697 lets look at the substitute: <literal>$1"Not Your Business!"$2</literal> is
7698 easy to read: The text remembered as <literal>$1</literal>, followed by
7699 <literal>"Not Your Business!"</literal> (<emphasis>including</emphasis>
7700 the quotation marks!), followed by the text remembered as <literal>$2</literal>.
7701 This produces an exact copy of the original string, with the middle part
7702 (the <quote>document.referrer</quote>) replaced by <literal>"Not Your
7703 Business!"</literal>.
7707 The whole job now reads: Replace <quote>document.referrer</quote> by
7708 <literal>"Not Your Business!"</literal> wherever it appears inside a
7709 <script> tag. Note that this job won't break JavaScript syntax,
7710 since both the original and the replacement are syntactically valid
7711 string objects. The script just won't have access to the referrer
7712 information anymore.
7716 We'll show you two other jobs from the JavaScript taming department, but
7717 this time only point out the constructs of special interest:
7722 # The status bar is for displaying link targets, not pointless blahblah
7724 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig</screen>
7728 <literal>\s</literal> stands for whitespace characters (space, tab, newline,
7729 carriage return, form feed), so that <literal>\s*</literal> means: <quote>zero
7730 or more whitespace</quote>. The <literal>?</literal> in <literal>.*?</literal>
7731 makes this matching of arbitrary text ungreedy. (Note that the <literal>U</literal>
7732 option is not set). The <literal>['"]</literal> construct means: <quote>a single
7733 <emphasis>or</emphasis> a double quote</quote>. Finally, <literal>\1</literal> is
7734 a back-reference to the first parenthesis just like <literal>$1</literal> above,
7735 with the difference that in the <emphasis>pattern</emphasis>, a backslash indicates
7736 a back-reference, whereas in the <emphasis>substitute</emphasis>, it's the dollar.
7740 So what does this job do? It replaces assignments of single- or double-quoted
7741 strings to the <quote>window.status</quote> object with a dummy assignment
7742 (using a variable name that is hopefully odd enough not to conflict with
7743 real variables in scripts). Thus, it catches many cases where e.g. pointless
7744 descriptions are displayed in the status bar instead of the link target when
7745 you move your mouse over links.
7750 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
7752 s/(<body [^>]*)onunload(.*>)/$1never$2/iU</screen>
7757 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">OnUnload
7758 event binding</ulink> in the HTML DOM was a <emphasis>CRIME</emphasis>.
7759 When I close a browser window, I want it to close and die. Basta.
7760 This job replaces the <quote>onunload</quote> attribute in
7761 <quote><body></quote> tags with the dummy word <literal>never</literal>.
7762 Note that the <literal>i</literal> option makes the pattern matching
7763 case-insensitive. Also note that ungreedy matching alone doesn't always guarantee
7764 a minimal match: In the first parenthesis, we had to use <literal>[^>]*</literal>
7765 instead of <literal>.*</literal> to prevent the match from exceeding the
7766 <body> tag if it doesn't contain <quote>OnUnload</quote>, but the page's
7771 The last example is from the fun department:
7776 FILTER: fun Fun text replacements
7778 # Spice the daily news:
7780 s/microsoft(?!\.com)/MicroSuck/ig</screen>
7784 Note the <literal>(?!\.com)</literal> part (a so-called negative lookahead)
7785 in the job's pattern, which means: Don't match, if the string
7786 <quote>.com</quote> appears directly following <quote>microsoft</quote>
7787 in the page. This prevents links to microsoft.com from being trashed, while
7788 still replacing the word everywhere else.
7793 # Buzzword Bingo (example for extended regex syntax)
7795 s* industry[ -]leading \
7797 | customer[ -]focused \
7798 | market[ -]driven \
7799 | award[ -]winning # Comments are OK, too! \
7800 | high[ -]performance \
7801 | solutions[ -]based \
7805 *<font color="red"><b>BINGO!</b></font> \
7810 The <literal>x</literal> option in this job turns on extended syntax, and allows for
7811 e.g. the liberal use of (non-interpreted!) whitespace for nicer formatting.
7819 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7821 <sect2 id="predefined-filters"><title>The Pre-defined Filters</title>
7825 Note each filter is also listed in the +filter action section above. Please
7826 keep these listings in sync.
7831 The distribution <filename>default.filter</filename> file contains a selection of
7832 pre-defined filters for your convenience:
7837 <term><emphasis>js-annoyances</emphasis></term>
7840 The purpose of this filter is to get rid of particularly annoying JavaScript abuse.
7845 replaces JavaScript references to the browser's referrer information
7846 with the string "Not Your Business!". This compliments the <literal><link
7847 linkend="hide-referrer">hide-referrer</link></literal> action on the content level.
7852 removes the bindings to the DOM's
7853 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">unload
7854 event</ulink> which we feel has no right to exist and is responsible for most <quote>exit consoles</quote>, i.e.
7855 nasty windows that pop up when you close another one.
7860 removes code that causes new windows to be opened with undesired properties, such as being
7861 full-screen, non-resizeable, without location, status or menu bar etc.
7867 Use with caution. This is an aggressive filter, and can break sites that
7868 rely heavily on JavaScript.
7874 <term><emphasis>js-events</emphasis></term>
7877 This is a very radical measure. It removes virtually all JavaScript event bindings, which
7878 means that scripts can not react to user actions such as mouse movements or clicks, window
7879 resizing etc, anymore. Use with caution!
7882 We <emphasis>strongly discourage</emphasis> using this filter as a default since it breaks
7883 many legitimate scripts. It is meant for use only on extra-nasty sites (should you really
7890 <term><emphasis>html-annoyances</emphasis></term>
7893 This filter will undo many common instances of HTML based abuse.
7896 The <literal>BLINK</literal> and <literal>MARQUEE</literal> tags
7897 are neutralized (yeah baby!), and browser windows will be created as
7898 resizeable (as of course they should be!), and will have location,
7899 scroll and menu bars -- even if specified otherwise.
7905 <term><emphasis>content-cookies</emphasis></term>
7908 Most cookies are set in the HTTP dialog, where they can be intercepted
7910 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>
7911 and <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>
7912 actions. But web sites increasingly make use of HTML meta tags and JavaScript
7913 to sneak cookies to the browser on the content level.
7916 This filter disables most HTML and JavaScript code that reads or sets
7917 cookies. It cannot detect all clever uses of these types of code, so it
7918 should not be relied on as an absolute fix. Use it wherever you would also
7919 use the cookie crunch actions.
7925 <term><emphasis>refresh-tags</emphasis></term>
7928 Disable any refresh tags if the interval is greater than nine seconds (so
7929 that redirections done via refresh tags are not destroyed). This is useful
7930 for dial-on-demand setups, or for those who find this HTML feature
7937 <term><emphasis>unsolicited-popups</emphasis></term>
7940 This filter attempts to prevent only <quote>unsolicited</quote> pop-up
7941 windows from opening, yet still allow pop-up windows that the user
7942 has explicitly chosen to open. It was added in version 3.0.1,
7943 as an improvement over earlier such filters.
7946 Technical note: The filter works by redefining the window.open JavaScript
7947 function to a dummy function, <literal>PrivoxyWindowOpen()</literal>,
7948 during the loading and rendering phase of each HTML page access, and
7949 restoring the function afterward.
7952 This is recommended only for browsers that cannot perform this function
7953 reliably themselves. And be aware that some sites require such windows
7954 in order to function normally. Use with caution.
7960 <term><emphasis>all-popups</emphasis></term>
7963 Attempt to prevent <emphasis>all</emphasis> pop-up windows from opening.
7964 Note this should be used with even more discretion than the above, since
7965 it is more likely to break some sites that require pop-ups for normal
7966 usage. Use with caution.
7972 <term><emphasis>img-reorder</emphasis></term>
7975 This is a helper filter that has no value if used alone. It makes the
7976 <literal>banners-by-size</literal> and <literal>banners-by-link</literal>
7977 (see below) filters more effective and should be enabled together with them.
7983 <term><emphasis>banners-by-size</emphasis></term>
7986 This filter removes image tags purely based on what size they are. Fortunately
7987 for us, many ads and banner images tend to conform to certain standardized
7988 sizes, which makes this filter quite effective for ad stripping purposes.
7991 Occasionally this filter will cause false positives on images that are not ads,
7992 but just happen to be of one of the standard banner sizes.
7995 Recommended only for those who require extreme ad blocking. The default
7996 block rules should catch 95+% of all ads <emphasis>without</emphasis> this filter enabled.
8002 <term><emphasis>banners-by-link</emphasis></term>
8005 This is an experimental filter that attempts to kill any banners if
8006 their URLs seem to point to known or suspected click trackers. It is currently
8007 not of much value and is not recommended for use by default.
8013 <term><emphasis>webbugs</emphasis></term>
8016 Webbugs are small, invisible images (technically 1X1 GIF images), that
8017 are used to track users across websites, and collect information on them.
8018 As an HTML page is loaded by the browser, an embedded image tag causes the
8019 browser to contact a third-party site, disclosing the tracking information
8020 through the requested URL and/or cookies for that third-party domain, without
8021 the user ever becoming aware of the interaction with the third-party site.
8022 HTML-ized spam also uses a similar technique to verify email addresses.
8025 This filter removes the HTML code that loads such <quote>webbugs</quote>.
8031 <term><emphasis>tiny-textforms</emphasis></term>
8034 A rather special-purpose filter that can be used to enlarge textareas (those
8035 multi-line text boxes in web forms) and turn off hard word wrap in them.
8036 It was written for the sourceforge.net tracker system where such boxes are
8037 a nuisance, but it can be handy on other sites, too.
8040 It is not recommended to use this filter as a default.
8046 <term><emphasis>jumping-windows</emphasis></term>
8049 Many consider windows that move, or resize themselves to be abusive. This filter
8050 neutralizes the related JavaScript code. Note that some sites might not display
8051 or behave as intended when using this filter. Use with caution.
8057 <term><emphasis>frameset-borders</emphasis></term>
8060 Some web designers seem to assume that everyone in the world will view their
8061 web sites using the same browser brand and version, screen resolution etc,
8062 because only that assumption could explain why they'd use static frame sizes,
8063 yet prevent their frames from being resized by the user, should they be too
8064 small to show their whole content.
8067 This filter removes the related HTML code. It should only be applied to sites
8074 <term><emphasis>demoronizer</emphasis></term>
8077 Many Microsoft products that generate HTML use non-standard extensions (read:
8078 violations) of the ISO 8859-1 aka Latin-1 character set. This can cause those
8079 HTML documents to display with errors on standard-compliant platforms.
8082 This filter translates the MS-only characters into Latin-1 equivalents.
8083 It is not necessary when using MS products, and will cause corruption of
8084 all documents that use 8-bit character sets other than Latin-1. It's mostly
8085 worthwhile for Europeans on non-MS platforms, if weird garbage characters
8086 sometimes appear on some pages, or user agents that don't correct for this on
8089 My version of Mozilla (ancient) shows litte square boxes for quote
8090 characters, and apostrophes on moronized pages. So many pages have this, I
8091 can read them fine now. HB 08/27/06
8098 <term><emphasis>shockwave-flash</emphasis></term>
8101 A filter for shockwave haters. As the name suggests, this filter strips code
8102 out of web pages that is used to embed shockwave flash objects.
8110 <term><emphasis>quicktime-kioskmode</emphasis></term>
8113 Change HTML code that embeds Quicktime objects so that kioskmode, which
8114 prevents saving, is disabled.
8120 <term><emphasis>fun</emphasis></term>
8123 Text replacements for subversive browsing fun. Make fun of your favorite
8124 Monopolist or play buzzword bingo.
8130 <term><emphasis>crude-parental</emphasis></term>
8133 A demonstration-only filter that shows how <application>Privoxy</application>
8134 can be used to delete web content on a keyword basis.
8140 <term><emphasis>ie-exploits</emphasis></term>
8143 An experimental collection of text replacements to disable malicious HTML and JavaScript
8144 code that exploits known security holes in Internet Explorer.
8147 Presently, it only protects against Nimda and a cross-site scripting bug, and
8148 would need active maintenance to provide more substantial protection.
8154 <term><emphasis>site-specifics</emphasis></term>
8157 Some web sites have very specific problems, the cure for which doesn't apply
8158 anywhere else, or could even cause damage on other sites.
8161 This is a collection of such site-specific cures which should only be applied
8162 to the sites they were intended for, which is what the supplied
8163 <filename>default.action</filename> file does. Users shouldn't need to change
8164 anything regarding this filter.
8170 <term><emphasis>google</emphasis></term>
8173 A CSS based block for Google text ads. Also removes a width limitation
8174 and the toolbar advertisement.
8180 <term><emphasis>yahoo</emphasis></term>
8183 Another CSS based block, this time for Yahoo text ads. And removes
8184 a width limitation as well.
8190 <term><emphasis>msn</emphasis></term>
8193 Another CSS based block, this time for MSN text ads. And removes
8194 tracking URLs, as well as a width limitation.
8200 <term><emphasis>blogspot</emphasis></term>
8203 Cleans up some Blogspot blogs. Read the fine print before using this one!
8206 This filter also intentionally removes some navigation stuff and sets the
8207 page width to 100%. As a result, some rounded <quote>corners</quote> would
8208 appear to early or not at all and as fixing this would require a browser
8209 that understands background-size (CSS3), they are removed instead.
8215 <term><emphasis>xml-to-html</emphasis></term>
8218 Server-header filter to change the Content-Type from xml to html.
8224 <term><emphasis>html-to-xml</emphasis></term>
8227 Server-header filter to change the Content-Type from html to xml.
8233 <term><emphasis>no-ping</emphasis></term>
8236 Removes the non-standard <literal>ping</literal> attribute from
8237 anchor and area HTML tags.
8243 <term><emphasis>hide-tor-exit-notation</emphasis></term>
8246 Client-header filter to remove the <command>Tor</command> exit node notation
8247 found in Host and Referer headers.
8250 If &my-app; and <command>Tor</command> are chained and &my-app;
8251 is configured to use socks4a, one can use <quote>http://www.example.org.foobar.exit/</quote>
8252 to access the host <quote>www.example.org</quote> through the
8253 <command>Tor</command> exit node <quote>foobar</quote>.
8256 As the HTTP client isn't aware of this notation, it treats the
8257 whole string <quote>www.example.org.foobar.exit</quote> as host and uses it
8258 for the <quote>Host</quote> and <quote>Referer</quote> headers. From the
8259 server's point of view the resulting headers are invalid and can cause problems.
8262 An invalid <quote>Referer</quote> header can trigger <quote>hot-linking</quote>
8263 protections, an invalid <quote>Host</quote> header will make it impossible for
8264 the server to find the right vhost (several domains hosted on the same IP address).
8267 This client-header filter removes the <quote>foo.exit</quote> part in those headers
8268 to prevent the mentioned problems. Note that it only modifies
8269 the HTTP headers, it doesn't make it impossible for the server
8270 to detect your <command>Tor</command> exit node based on the IP address
8271 the request is coming from.
8278 <term><emphasis> </emphasis></term>
8292 <!-- ~ End section ~ -->
8296 <!-- ~~~~~ New section ~~~~~ -->
8298 <sect1 id="templates">
8299 <title>Privoxy's Template Files</title>
8301 All <application>Privoxy</application> built-in pages, i.e. error pages such as the
8302 <ulink url="http://show-the-404-error.page"><quote>404 - No Such Domain</quote>
8303 error page</ulink>, the <ulink
8304 url="http://ads.bannerserver.example.com/nasty-ads/sponsor.html"><quote>BLOCKED</quote>
8306 and all pages of its <ulink url="http://config.privoxy.org/">web-based
8307 user interface</ulink>, are generated from <emphasis>templates</emphasis>.
8308 (<application>Privoxy</application> must be running for the above links to work as
8313 These templates are stored in a subdirectory of the <link linkend="confdir">configuration
8314 directory</link> called <filename>templates</filename>. On Unixish platforms,
8316 <ulink url="file:///etc/privoxy/templates/"><filename>/etc/privoxy/templates/</filename></ulink>.
8320 The templates are basically normal HTML files, but with place-holders (called symbols
8321 or exports), which <application>Privoxy</application> fills at run time. It
8322 is possible to edit the templates with a normal text editor, should you want
8323 to customize them. (<emphasis>Not recommended for the casual
8324 user</emphasis>). Should you create your own custom templates, you should use
8325 the <filename>config</filename> setting <link linkend="templdir">templdir</link>
8326 to specify an alternate location, so your templates do not get overwritten
8330 Note that just like in configuration files, lines starting
8331 with <literal>#</literal> are ignored when the templates are filled in.
8335 The place-holders are of the form <literal>@name@</literal>, and you will
8336 find a list of available symbols, which vary from template to template,
8337 in the comments at the start of each file. Note that these comments are not
8338 always accurate, and that it's probably best to look at the existing HTML
8339 code to find out which symbols are supported and what they are filled in with.
8343 A special application of this substitution mechanism is to make whole
8344 blocks of HTML code disappear when a specific symbol is set. We use this
8345 for many purposes, one of them being to include the beta warning in all
8346 our user interface (CGI) pages when <application>Privoxy</application>
8347 is in an alpha or beta development stage:
8352 <!-- @if-unstable-start -->
8354 ... beta warning HTML code goes here ...
8356 <!-- if-unstable-end@ --></screen>
8360 If the "unstable" symbol is set, everything in between and including
8361 <literal>@if-unstable-start</literal> and <literal>if-unstable-end@</literal>
8362 will disappear, leaving nothing but an empty comment:
8366 <screen><!-- --></screen>
8370 There's also an if-then-else construct and an <literal>#include</literal>
8371 mechanism, but you'll sure find out if you are inclined to edit the
8376 All templates refer to a style located at
8377 <ulink url="http://config.privoxy.org/send-stylesheet"><literal>http://config.privoxy.org/send-stylesheet</literal></ulink>.
8378 This is, of course, locally served by <application>Privoxy</application>
8379 and the source for it can be found and edited in the
8380 <filename>cgi-style.css</filename> template.
8385 <!-- ~ End section ~ -->
8389 <!-- ~~~~~ New section ~~~~~ -->
8391 <sect1 id="contact"><title>Contacting the Developers, Bug Reporting and Feature
8394 <!-- Include contacting.sgml boilerplate: -->
8396 <!-- end boilerplate -->
8400 <!-- ~ End section ~ -->
8403 <!-- ~~~~~ New section ~~~~~ -->
8404 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
8406 <!-- Include copyright.sgml: -->
8408 <!-- end copyright -->
8410 <!-- ~~~~~ New section ~~~~~ -->
8411 <sect2><title>License</title>
8412 <!-- Include copyright.sgml: -->
8414 <!-- end copyright -->
8416 <!-- ~ End section ~ -->
8419 <!-- ~~~~~ New section ~~~~~ -->
8421 <sect2 id="history"><title>History</title>
8422 <!-- Include history.sgml: -->
8424 <!-- end history -->
8427 <sect2 id="authors"><title>Authors</title>
8428 <!-- Include p-authors.sgml: -->
8430 <!-- end authors -->
8435 <!-- ~ End section ~ -->
8438 <!-- ~~~~~ New section ~~~~~ -->
8439 <sect1 id="seealso"><title>See Also</title>
8440 <!-- Include seealso.sgml: -->
8442 <!-- end seealso -->
8447 <!-- ~~~~~ New section ~~~~~ -->
8448 <sect1 id="appendix"><title>Appendix</title>
8451 <!-- ~~~~~ New section ~~~~~ -->
8453 <title>Regular Expressions</title>
8455 <application>Privoxy</application> uses Perl-style <quote>regular
8456 expressions</quote> in its <link linkend="actions-file">actions
8457 files</link> and <link linkend="filter-file">filter file</link>,
8458 through the <ulink url="http://www.pcre.org/">PCRE</ulink> and
8461 <ulink url="http://www.oesterhelt.org/pcrs/">PCRS</ulink> libraries.
8463 <application>PCRS</application> libraries.
8467 If you are reading this, you probably don't understand what <quote>regular
8468 expressions</quote> are, or what they can do. So this will be a very brief
8469 introduction only. A full explanation would require a <ulink
8470 url="http://www.oreilly.com/catalog/regex/">book</ulink> ;-)
8474 Regular expressions provide a language to describe patterns that can be
8475 run against strings of characters (letter, numbers, etc), to see if they
8476 match the string or not. The patterns are themselves (sometimes complex)
8477 strings of literal characters, combined with wild-cards, and other special
8478 characters, called meta-characters. The <quote>meta-characters</quote> have
8479 special meanings and are used to build complex patterns to be matched against.
8480 Perl Compatible Regular Expressions are an especially convenient
8481 <quote>dialect</quote> of the regular expression language.
8485 To make a simple analogy, we do something similar when we use wild-card
8486 characters when listing files with the <command>dir</command> command in DOS.
8487 <literal>*.*</literal> matches all filenames. The <quote>special</quote>
8488 character here is the asterisk which matches any and all characters. We can be
8489 more specific and use <literal>?</literal> to match just individual
8490 characters. So <quote>dir file?.text</quote> would match
8491 <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
8492 matching, using a similar technique to <quote>regular expressions</quote>!
8496 Regular expressions do essentially the same thing, but are much, much more
8497 powerful. There are many more <quote>special characters</quote> and ways of
8498 building complex patterns however. Let's look at a few of the common ones,
8499 and then some examples:
8504 <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
8505 <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
8507 </simplelist></para>
8511 <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
8514 </simplelist></para>
8518 <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
8521 </simplelist></para>
8525 <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
8528 </simplelist></para>
8532 <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
8533 the following character should be taken literally. This is used where one of the
8534 special characters (e.g. <quote>.</quote>) needs to be taken literally and
8535 not as a special meta-character. Example: <quote>example\.com</quote>, makes
8536 sure the period is recognized only as a period (and not expanded to its
8537 meta-character meaning of any single character).
8539 </simplelist></para>
8543 <emphasis>[ ]</emphasis> - Characters enclosed in brackets will be matched if
8544 any of the enclosed characters are encountered. For instance, <quote>[0-9]</quote>
8545 matches any numeric digit (zero through nine). As an example, we can combine
8546 this with <quote>+</quote> to match any digit one of more times: <quote>[0-9]+</quote>.
8548 </simplelist></para>
8552 <emphasis>( )</emphasis> - parentheses are used to group a sub-expression,
8553 or multiple sub-expressions.
8555 </simplelist></para>
8559 <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
8560 <quote>or</quote> conditional statement. A match is successful if the
8561 sub-expression on either side of <quote>|</quote> matches. As an example:
8562 <quote>/(this|that) example/</quote> uses grouping and the bar character
8563 and would match either <quote>this example</quote> or <quote>that
8564 example</quote>, and nothing else.
8566 </simplelist></para>
8569 These are just some of the ones you are likely to use when matching URLs with
8570 <application>Privoxy</application>, and is a long way from a definitive
8571 list. This is enough to get us started with a few simple examples which may
8572 be more illuminating:
8576 <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
8577 that uses the common combination of <quote>.</quote> and <quote>*</quote> to
8578 denote any character, zero or more times. In other words, any string at all.
8579 So we start with a literal forward slash, then our regular expression pattern
8580 (<quote>.*</quote>) another literal forward slash, the string
8581 <quote>banners</quote>, another forward slash, and lastly another
8582 <quote>.*</quote>. We are building
8583 a directory path here. This will match any file with the path that has a
8584 directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
8585 any characters, and this could conceivably be more forward slashes, so it
8586 might expand into a much longer looking path. For example, this could match:
8587 <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
8588 <quote>/banners/annoying.html</quote>, or almost an infinite number of other
8589 possible combinations, just so it has <quote>banners</quote> in the path
8594 And now something a little more complex:
8598 <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
8599 We have several literal forward slashes again (<quote>/</quote>), so we are
8600 building another expression that is a file path statement. We have another
8601 <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
8602 it matches our expression. The only true literal that <emphasis>must
8603 match</emphasis> our pattern is <application>adv</application>, together with
8604 the forward slashes. What comes after the <quote>adv</quote> string is the
8609 Remember the <quote>?</quote> means the preceding expression (either a
8610 literal character or anything grouped with <quote>(...)</quote> in this case)
8611 can exist or not, since this means either zero or one match. So
8612 <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
8613 individual sub-expressions: <quote>(er)</quote>,
8614 <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
8615 means <quote>or</quote>. We have two of those. For instance,
8616 <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
8617 <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
8618 attempt at matching as many variations of <quote>advertisement</quote>, and
8619 similar, as possible. So this would expand to match just <quote>adv</quote>,
8620 or <quote>advert</quote>, or <quote>adverts</quote>, or
8621 <quote>advertising</quote>, or <quote>advertisement</quote>, or
8622 <quote>advertisements</quote>. You get the idea. But it would not match
8623 <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
8624 changing our regular expression to:
8625 <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
8630 <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
8631 another path statement with forward slashes. Anything in the square brackets
8632 <quote>[ ]</quote> can be matched. This is using <quote>0-9</quote> as a
8633 shorthand expression to mean any digit one through nine. It is the same as
8634 saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
8635 means one or more of the preceding expression must be included. The preceding
8636 expression here is what is in the square brackets -- in this case, any digit
8637 one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
8638 This includes a <quote>|</quote>, so this needs to match the expression on
8639 either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
8640 side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
8641 since the <quote>?</quote> means the letter <quote>e</quote> is optional and
8642 can be matched once or not at all. So we are building an expression here to
8643 match image GIF or JPEG type image file. It must include the literal
8644 string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
8645 (which is now a literal, and not a special character, since it is escaped
8646 with <quote>\</quote>), and lastly either <quote>gif</quote>, or
8647 <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
8648 include: <quote>//advert1.jpg</quote>,
8649 <quote>/nasty/ads/advert1234.gif</quote>,
8650 <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
8651 <quote>advert1.gif</quote> (no leading slash), or
8652 <quote>/adverts232.jpg</quote> (the expression does not include an
8653 <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
8654 in the expression anywhere).
8658 We are barely scratching the surface of regular expressions here so that you
8659 can understand the default <application>Privoxy</application>
8660 configuration files, and maybe use this knowledge to customize your own
8661 installation. There is much, much more that can be done with regular
8662 expressions. Now that you know enough to get started, you can learn more on
8667 More reading on Perl Compatible Regular expressions:
8668 <ulink url="http://perldoc.perl.org/perlre.html">http://perldoc.perl.org/perlre.html</ulink>
8672 For information on regular expression based substitutions and their applications
8673 in filters, please see the <link linkend="filter-file">filter file tutorial</link>
8678 <!-- ~ End section ~ -->
8681 <!-- ~~~~~ New section ~~~~~ -->
8683 <title>Privoxy's Internal Pages</title>
8686 Since <application>Privoxy</application> proxies each requested
8687 web page, it is easy for <application>Privoxy</application> to
8688 trap certain special URLs. In this way, we can talk directly to
8689 <application>Privoxy</application>, and see how it is
8690 configured, see how our rules are being applied, change these
8691 rules and other configuration options, and even turn
8692 <application>Privoxy's</application> filtering off, all with
8698 The URLs listed below are the special ones that allow direct access
8699 to <application>Privoxy</application>. Of course,
8700 <application>Privoxy</application> must be running to access these. If
8701 not, you will get a friendly error message. Internet access is not
8714 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
8718 There is a shortcut: <ulink url="http://p.p/">http://p.p/</ulink> (But it
8719 doesn't provide a fall-back to a real page, in case the request is not
8720 sent through <application>Privoxy</application>)
8726 Show information about the current configuration, including viewing and
8727 editing of actions files:
8731 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
8738 Show the source code version numbers:
8742 <ulink url="http://config.privoxy.org/show-version">http://config.privoxy.org/show-version</ulink>
8749 Show the browser's request headers:
8753 <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
8760 Show which actions apply to a URL and why:
8764 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8771 Toggle Privoxy on or off. This feature can be turned off/on in the main
8772 <filename>config</filename> file. When toggled <quote>off</quote>, <quote>Privoxy</quote>
8773 continues to run, but only as a pass-through proxy, with no actions taking
8778 <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
8782 Short cuts. Turn off, then on:
8786 <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
8791 <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
8800 These may be bookmarked for quick reference. See next.
8804 <sect3 id="bookmarklets">
8805 <title>Bookmarklets</title>
8807 Below are some <quote>bookmarklets</quote> to allow you to easily access a
8808 <quote>mini</quote> version of some of <application>Privoxy's</application>
8809 special pages. They are designed for MS Internet Explorer, but should work
8810 equally well in Netscape, Mozilla, and other browsers which support
8811 JavaScript. They are designed to run directly from your bookmarks - not by
8812 clicking the links below (although that should work for testing).
8815 To save them, right-click the link and choose <quote>Add to Favorites</quote>
8816 (IE) or <quote>Add Bookmark</quote> (Netscape). You will get a warning that
8817 the bookmark <quote>may not be safe</quote> - just click OK. Then you can run the
8818 Bookmarklet directly from your favorites/bookmarks. For even faster access,
8819 you can put them on the <quote>Links</quote> bar (IE) or the <quote>Personal
8820 Toolbar</quote> (Netscape), and run them with a single click.
8829 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>
8836 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>
8843 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)
8850 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>
8856 <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>
8862 <ulink url="javascript:void(window.open('http://config.privoxy.org/show-url-info?url='+escape(location.href),'Why').focus());">Privoxy - Why?</ulink>
8869 Credit: The site which gave us the general idea for these bookmarklets is
8870 <ulink url="http://www.bookmarklets.com/">www.bookmarklets.com</ulink>. They
8871 have more information about bookmarklets.
8880 <!-- ~~~~~ New section ~~~~~ -->
8882 <title>Chain of Events</title>
8884 Let's take a quick look at how some of <application>Privoxy's</application>
8885 core features are triggered, and the ensuing sequence of events when a web
8886 page is requested by your browser:
8893 First, your web browser requests a web page. The browser knows to send
8894 the request to <application>Privoxy</application>, which will in turn,
8895 relay the request to the remote web server after passing the following
8901 <application>Privoxy</application> traps any request for its own internal CGI
8902 pages (e.g <ulink url="http://p.p/">http://p.p/</ulink>) and sends the CGI page back to the browser.
8907 Next, <application>Privoxy</application> checks to see if the URL
8909 linkend="BLOCK"><quote>+block</quote></link> patterns. If
8910 so, the URL is then blocked, and the remote web server will not be contacted.
8911 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>
8913 <link linkend="HANDLE-AS-EMPTY-DOCUMENT"><quote>+handle-as-empty-document</quote></link>
8914 are then checked, and if there is no match, an
8915 HTML <quote>BLOCKED</quote> page is sent back to the browser. Otherwise, if
8916 it does match, an image is returned for the former, and an empty text
8917 document for the latter. The type of image would depend on the setting of
8918 <link linkend="SET-IMAGE-BLOCKER"><quote>+set-image-blocker</quote></link>
8919 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
8924 Untrusted URLs are blocked. If URLs are being added to the
8925 <filename>trust</filename> file, then that is done.
8930 If the URL pattern matches the <link
8931 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link> action,
8932 it is then processed. Unwanted parts of the requested URL are stripped.
8937 Now the rest of the client browser's request headers are processed. If any
8938 of these match any of the relevant actions (e.g. <link
8939 linkend="HIDE-USER-AGENT"><quote>+hide-user-agent</quote></link>,
8940 etc.), headers are suppressed or forged as determined by these actions and
8946 Now the web server starts sending its response back (i.e. typically a web
8952 First, the server headers are read and processed to determine, among other
8953 things, the MIME type (document type) and encoding. The headers are then
8954 filtered as determined by the
8955 <link linkend="CRUNCH-INCOMING-COOKIES"><quote>+crunch-incoming-cookies</quote></link>,
8956 <link linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>,
8957 and <link linkend="DOWNGRADE-HTTP-VERSION"><quote>+downgrade-http-version</quote></link>
8963 If any <link linkend="FILTER"><quote>+filter</quote></link> action
8965 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
8966 action applies (and the document type fits the action), the rest of the page is
8967 read into memory (up to a configurable limit). Then the filter rules (from
8968 <filename>default.filter</filename> and any other filter files) are
8969 processed against the buffered content. Filters are applied in the order
8970 they are specified in one of the filter files. Animated GIFs, if present,
8971 are reduced to either the first or last frame, depending on the action
8972 setting.The entire page, which is now filtered, is then sent by
8973 <application>Privoxy</application> back to your browser.
8976 If neither a <link linkend="FILTER"><quote>+filter</quote></link> action
8978 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
8979 matches, then <application>Privoxy</application> passes the raw data through
8980 to the client browser as it becomes available.
8985 As the browser receives the now (possibly filtered) page content, it
8986 reads and then requests any URLs that may be embedded within the page
8987 source, e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
8988 frames), sounds, etc. For each of these objects, the browser issues a
8989 separate request (this is easily viewable in <application>Privoxy's</application>
8990 logs). And each such request is in turn processed just as above. Note that a
8991 complex web page will have many, many such embedded URLs. If these
8992 secondary requests are to a different server, then quite possibly a very
8993 differing set of actions is triggered.
9000 NOTE: This is somewhat of a simplistic overview of what happens with each URL
9001 request. For the sake of brevity and simplicity, we have focused on
9002 <application>Privoxy's</application> core features only.
9008 <!-- ~~~~~ New section ~~~~~ -->
9009 <sect2 id="actionsanat">
9010 <title>Troubleshooting: Anatomy of an Action</title>
9013 The way <application>Privoxy</application> applies
9014 <link linkend="ACTIONS">actions</link> and <link linkend="FILTER">filters</link>
9015 to any given URL can be complex, and not always so
9016 easy to understand what is happening. And sometimes we need to be able to
9017 <emphasis>see</emphasis> just what <application>Privoxy</application> is
9018 doing. Especially, if something <application>Privoxy</application> is doing
9019 is causing us a problem inadvertently. It can be a little daunting to look at
9020 the actions and filters files themselves, since they tend to be filled with
9021 <link linkend="regex">regular expressions</link> whose consequences are not
9026 One quick test to see if <application>Privoxy</application> is causing a problem
9027 or not, is to disable it temporarily. This should be the first troubleshooting
9028 step. See <link linkend="bookmarklets">the Bookmarklets</link> section on a quick
9029 and easy way to do this (be sure to flush caches afterward!). Looking at the
9030 logs is a good idea too. (Note that both the toggle feature and logging are
9031 enabled via <filename>config</filename> file settings, and may need to be
9032 turned <quote>on</quote>.)
9035 Another easy troubleshooting step to try is if you have done any
9036 customization of your installation, revert back to the installed
9037 defaults and see if that helps. There are times the developers get complaints
9038 about one thing or another, and the problem is more related to a customized
9039 configuration issue.
9043 <application>Privoxy</application> also provides the
9044 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
9045 page that can show us very specifically how <application>actions</application>
9046 are being applied to any given URL. This is a big help for troubleshooting.
9050 First, enter one URL (or partial URL) at the prompt, and then
9051 <application>Privoxy</application> will tell us
9052 how the current configuration will handle it. This will not
9053 help with filtering effects (i.e. the <link
9054 linkend="FILTER"><quote>+filter</quote></link> action) from
9055 one of the filter files since this is handled very
9056 differently and not so easy to trap! It also will not tell you about any other
9057 URLs that may be embedded within the URL you are testing. For instance, images
9058 such as ads are expressed as URLs within the raw page source of HTML pages. So
9059 you will only get info for the actual URL that is pasted into the prompt area
9060 -- not any sub-URLs. If you want to know about embedded URLs like ads, you
9061 will have to dig those out of the HTML source. Use your browser's <quote>View
9062 Page Source</quote> option for this. Or right click on the ad, and grab the
9067 Let's try an example, <ulink url="http://google.com">google.com</ulink>,
9068 and look at it one section at a time in a sample configuration (your real
9069 configuration may vary):
9074 Matches for http://www.google.com:
9076 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
9078 {+change-x-forwarded-for{block}
9079 +deanimate-gifs {last}
9080 +fast-redirects {check-decoded-url}
9081 +filter {refresh-tags}
9082 +filter {img-reorder}
9083 +filter {banners-by-size}
9085 +filter {jumping-windows}
9086 +filter {ie-exploits}
9087 +hide-from-header {block}
9088 +hide-referrer {forge}
9089 +session-cookies-only
9090 +set-image-blocker {pattern}
9093 { -session-cookies-only }
9099 In file: user.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
9100 (no matches in this file)
9105 This is telling us how we have defined our
9106 <link linkend="ACTIONS"><quote>actions</quote></link>, and
9107 which ones match for our test case, <quote>google.com</quote>.
9108 Displayed is all the actions that are available to us. Remember,
9109 the <literal>+</literal> sign denotes <quote>on</quote>. <literal>-</literal>
9110 denotes <quote>off</quote>. So some are <quote>on</quote> here, but many
9111 are <quote>off</quote>. Each example we try may provide a slightly different
9112 end result, depending on our configuration directives.
9116 is for our <filename>default.action</filename> file. The large, multi-line
9117 listing, is how the actions are set to match for all URLs, i.e. our default
9118 settings. If you look at your <quote>actions</quote> file, this would be the
9119 section just below the <quote>aliases</quote> section near the top. This
9120 will apply to all URLs as signified by the single forward slash at the end
9121 of the listing -- <quote> / </quote>.
9125 But we have defined additional actions that would be exceptions to these general
9126 rules, and then we list specific URLs (or patterns) that these exceptions
9127 would apply to. Last match wins. Just below this then are two explicit
9128 matches for <quote>.google.com</quote>. The first is negating our previous
9129 cookie setting, which was for <link
9130 linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>
9131 (i.e. not persistent). So we will allow persistent cookies for google, at
9132 least that is how it is in this example. The second turns
9133 <emphasis>off</emphasis> any <link
9134 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link>
9135 action, allowing this to take place unmolested. Note that there is a leading
9136 dot here -- <quote>.google.com</quote>. This will match any hosts and
9137 sub-domains, in the google.com domain also, such as
9138 <quote>www.google.com</quote> or <quote>mail.google.com</quote>. But it would not
9139 match <quote>www.google.de</quote>! So, apparently, we have these two actions
9140 defined as exceptions to the general rules at the top somewhere in the lower
9141 part of our <filename>default.action</filename> file, and
9142 <quote>google.com</quote> is referenced somewhere in these latter sections.
9146 Then, for our <filename>user.action</filename> file, we again have no hits.
9147 So there is nothing google-specific that we might have added to our own, local
9148 configuration. If there was, those actions would over-rule any actions from
9149 previously processed files, such as <filename>default.action</filename>.
9150 <filename>user.action</filename> typically has the last word. This is the
9151 best place to put hard and fast exceptions,
9155 And finally we pull it all together in the bottom section and summarize how
9156 <application>Privoxy</application> is applying all its <quote>actions</quote>
9157 to <quote>google.com</quote>:
9168 +change-x-forwarded-for{block}
9169 -client-header-filter{hide-tor-exit-notation}
9170 -content-type-overwrite
9171 -crunch-client-header
9172 -crunch-if-none-match
9173 -crunch-incoming-cookies
9174 -crunch-outgoing-cookies
9175 -crunch-server-header
9176 +deanimate-gifs {last}
9177 -downgrade-http-version
9180 -filter {content-cookies}
9181 -filter {all-popups}
9182 -filter {banners-by-link}
9183 -filter {tiny-textforms}
9184 -filter {frameset-borders}
9185 -filter {demoronizer}
9186 -filter {shockwave-flash}
9187 -filter {quicktime-kioskmode}
9189 -filter {crude-parental}
9190 -filter {site-specifics}
9191 -filter {js-annoyances}
9192 -filter {html-annoyances}
9193 +filter {refresh-tags}
9194 -filter {unsolicited-popups}
9195 +filter {img-reorder}
9196 +filter {banners-by-size}
9198 +filter {jumping-windows}
9199 +filter {ie-exploits}
9206 -handle-as-empty-document
9208 -hide-accept-language
9209 -hide-content-disposition
9210 +hide-from-header {block}
9211 -hide-if-modified-since
9212 +hide-referrer {forge}
9215 -overwrite-last-modified
9216 -prevent-compression
9218 -server-header-filter{xml-to-html}
9219 -server-header-filter{html-to-xml}
9220 -session-cookies-only
9221 +set-image-blocker {pattern} </screen>
9225 Notice the only difference here to the previous listing, is to
9226 <quote>fast-redirects</quote> and <quote>session-cookies-only</quote>,
9227 which are activated specifically for this site in our configuration,
9228 and thus show in the <quote>Final Results</quote>.
9232 Now another example, <quote>ad.doubleclick.net</quote>:
9238 { +block{Domains starts with "ad"} }
9241 { +block{Domain contains "ad"} }
9244 { +block{Doubleclick banner server} +handle-as-image }
9245 .[a-vx-z]*.doubleclick.net
9250 We'll just show the interesting part here - the explicit matches. It is
9251 matched three different times. Two <quote>+block{}</quote> sections,
9252 and a <quote>+block{} +handle-as-image</quote>,
9253 which is the expanded form of one of our aliases that had been defined as:
9254 <quote>+block-as-image</quote>. (<link
9255 linkend="ALIASES"><quote>Aliases</quote></link> are defined in
9256 the first section of the actions file and typically used to combine more
9261 Any one of these would have done the trick and blocked this as an unwanted
9262 image. This is unnecessarily redundant since the last case effectively
9263 would also cover the first. No point in taking chances with these guys
9264 though ;-) Note that if you want an ad or obnoxious
9265 URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
9266 is done here -- as both a <link
9267 linkend="BLOCK"><quote>+block{}</quote></link>
9268 <emphasis>and</emphasis> an
9269 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>.
9270 The custom alias <quote><literal>+block-as-image</literal></quote> just
9271 simplifies the process and make it more readable.
9275 One last example. Let's try <quote>http://www.example.net/adsl/HOWTO/</quote>.
9276 This one is giving us problems. We are getting a blank page. Hmmm ...
9282 Matches for http://www.example.net/adsl/HOWTO/:
9284 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
9288 +change-x-forwarded-for{block}
9289 -client-header-filter{hide-tor-exit-notation}
9290 -content-type-overwrite
9291 -crunch-client-header
9292 -crunch-if-none-match
9293 -crunch-incoming-cookies
9294 -crunch-outgoing-cookies
9295 -crunch-server-header
9297 -downgrade-http-version
9298 +fast-redirects {check-decoded-url}
9300 -filter {content-cookies}
9301 -filter {all-popups}
9302 -filter {banners-by-link}
9303 -filter {tiny-textforms}
9304 -filter {frameset-borders}
9305 -filter {demoronizer}
9306 -filter {shockwave-flash}
9307 -filter {quicktime-kioskmode}
9309 -filter {crude-parental}
9310 -filter {site-specifics}
9311 -filter {js-annoyances}
9312 -filter {html-annoyances}
9313 +filter {refresh-tags}
9314 -filter {unsolicited-popups}
9315 +filter {img-reorder}
9316 +filter {banners-by-size}
9318 +filter {jumping-windows}
9319 +filter {ie-exploits}
9326 -handle-as-empty-document
9328 -hide-accept-language
9329 -hide-content-disposition
9330 +hide-from-header{block}
9331 +hide-referer{forge}
9333 -overwrite-last-modified
9334 +prevent-compression
9336 -server-header-filter{xml-to-html}
9337 -server-header-filter{html-to-xml}
9338 +session-cookies-only
9339 +set-image-blocker{blank} }
9342 { +block{Path contains "ads".} +handle-as-image }
9348 Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote> in our
9349 configuration! But we did not want this at all! Now we see why we get the
9350 blank page. It is actually triggering two different actions here, and
9351 the effects are aggregated so that the URL is blocked, and &my-app; is told
9352 to treat the block as if it were an image. But this is, of course, all wrong.
9353 We could now add a new action below this (or better in our own
9354 <filename>user.action</filename> file) that explicitly
9355 <emphasis>un</emphasis> blocks (
9356 <link linkend="BLOCK"><quote>{-block}</quote></link>) paths with
9357 <quote>adsl</quote> in them (remember, last match in the configuration
9358 wins). There are various ways to handle such exceptions. Example:
9370 Now the page displays ;-)
9371 Remember to flush your browser's caches when making these kinds of changes to
9372 your configuration to insure that you get a freshly delivered page! Or, try
9373 using <literal>Shift+Reload</literal>.
9377 But now what about a situation where we get no explicit matches like
9384 { +block{Path starts with "ads".} +handle-as-image }
9390 That actually was very helpful and pointed us quickly to where the problem
9391 was. If you don't get this kind of match, then it means one of the default
9392 rules in the first section of <filename>default.action</filename> is causing
9393 the problem. This would require some guesswork, and maybe a little trial and
9394 error to isolate the offending rule. One likely cause would be one of the
9395 <link linkend="FILTER"><quote>+filter</quote></link> actions.
9396 These tend to be harder to troubleshoot.
9397 Try adding the URL for the site to one of aliases that turn off
9398 <link linkend="FILTER"><quote>+filter</quote></link>:
9406 .worldpay.com # for quietpc.com
9414 <quote><literal>{ shop }</literal></quote> is an <quote>alias</quote> that expands to
9415 <quote><literal>{ -filter -session-cookies-only }</literal></quote>.
9416 Or you could do your own exception to negate filtering:
9424 # Disable ALL filter actions for sites in this section
9432 This would turn off all filtering for these sites. This is best
9433 put in <filename>user.action</filename>, for local site
9434 exceptions. Note that when a simple domain pattern is used by itself (without
9435 the subsequent path portion), all sub-pages within that domain are included
9436 automatically in the scope of the action.
9440 Images that are inexplicably being blocked, may well be hitting the
9441 <link linkend="FILTER-BANNERS-BY-SIZE"><quote>+filter{banners-by-size}</quote></link>
9443 that images of certain sizes are ad banners (works well
9444 <emphasis>most of the time</emphasis> since these tend to be standardized).
9448 <quote><literal>{ fragile }</literal></quote> is an alias that disables most
9449 actions that are the most likely to cause trouble. This can be used as a
9450 last resort for problem sites.
9456 # Handle with care: easy to break
9458 mybank.example.com</screen>
9463 <emphasis>Remember to flush caches!</emphasis> Note that the
9464 <literal>mail.google</literal> reference lacks the TLD portion (e.g.
9465 <quote>.com</quote>). This will effectively match any TLD with
9466 <literal>google</literal> in it, such as <literal>mail.google.de.</literal>,
9470 If this still does not work, you will have to go through the remaining
9471 actions one by one to find which one(s) is causing the problem.
9480 This program is free software; you can redistribute it
9481 and/or modify it under the terms of the GNU General
9482 Public License as published by the Free Software
9483 Foundation; either version 2 of the License, or (at
9484 your option) any later version.
9486 This program is distributed in the hope that it will
9487 be useful, but WITHOUT ANY WARRANTY; without even the
9488 implied warranty of MERCHANTABILITY or FITNESS FOR A
9489 PARTICULAR PURPOSE. See the GNU General Public
9490 License for more details.
9492 The GNU General Public License should be included with
9493 this file. If not, you can view it at
9494 http://www.gnu.org/copyleft/gpl.html
9495 or write to the Free Software Foundation, Inc.,
9496 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
projects / privoxy.git / blob