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 changelog SYSTEM "changelog.sgml">
15 <!entity p-version "3.0.20">
16 <!entity p-status "beta">
17 <!entity % p-authors-formal "INCLUDE"> <!-- include additional text, etc -->
18 <!entity % p-not-stable "INCLUDE">
19 <!entity % p-stable "IGNORE">
20 <!entity % p-text "IGNORE"> <!-- define we are not a text only doc -->
21 <!entity % p-doc "INCLUDE"> <!-- and we are a formal doc -->
22 <!entity % p-readme "IGNORE">
23 <!entity % user-man "IGNORE">
24 <!entity % config-file "IGNORE">
25 <!entity % p-supp-userman "IGNORE"> <!-- Omit some from supported.sgml -->
26 <!entity my-copy "©"> <!-- kludge for docbook2man -->
27 <!entity % draft "IGNORE"> <!-- WIP stuff -->
28 <!entity % seealso-extra "INCLUDE"> <!-- extra stuff from seealso.sgml -->
29 <!entity my-app "<application>Privoxy</application>">
32 File : $Source: /cvsroot/ijbswa/current/doc/source/user-manual.sgml,v $
35 This file belongs into
36 ijbswa.sourceforge.net:/home/groups/i/ij/ijbswa/htdocs/
38 $Id: user-manual.sgml,v 2.166 2013/01/25 14:18:48 fabiankeil Exp $
40 Copyright (C) 2001-2013 Privoxy Developers http://www.privoxy.org/
43 ========================================================================
44 NOTE: Please read developer-manual/documentation.html before touching
45 anything in this, or other Privoxy documentation.
46 ========================================================================
53 <title>Privoxy &p-version; User Manual</title>
57 <!-- Completely the wrong markup, but very little is allowed -->
58 <!-- in this part of an article. FIXME -->
59 <link linkend="copyright">Copyright</link> &my-copy; 2001-2013 by
60 <ulink url="http://www.privoxy.org/">Privoxy Developers</ulink>
64 <pubdate>$Id: user-manual.sgml,v 2.166 2013/01/25 14:18:48 fabiankeil Exp $</pubdate>
68 Note: the following should generate a separate page, and a live link to it,
69 all nicely done. But it doesn't for some mysterious reason. Please leave
70 commented unless it can be fixed proper. For the time being, the
71 copyright/license declarations will be in their own sgml.
84 This is here to keep vim syntax file from breaking :/
85 If I knew enough to fix it, I would.
86 PLEASE DO NOT REMOVE! HB: hal@foobox.net
92 The <citetitle>Privoxy User Manual</citetitle> gives users information on how to
93 install, configure and use <ulink
94 url="http://www.privoxy.org/">Privoxy</ulink>.
97 <!-- Include privoxy.sgml boilerplate: -->
99 <!-- end privoxy.sgml -->
102 You can find the latest version of the <citetitle>Privoxy User Manual</citetitle> at <ulink
103 url="http://www.privoxy.org/user-manual/">http://www.privoxy.org/user-manual/</ulink>.
104 Please see the <link linkend="contact">Contact section</link> on how to
105 contact the developers.
109 <!-- Feel free to send a note to the developers at <email>ijbswa-developers@lists.sourceforge.net</email>. -->
115 <!-- ~~~~~ New section ~~~~~ -->
116 <sect1 label="1" id="introduction"><title>Introduction</title>
118 This documentation is included with the current &p-status; version of
119 <application>Privoxy</application>, v.&p-version;<![%p-not-stable;[,
120 and is mostly complete at this point. The most up to date reference for the
121 time being is still the comments in the source files and in the individual
122 configuration files. Development of a new version is currently nearing
123 completion, and includes significant changes and enhancements over
127 <!-- include only in non-stable versions -->
130 Since this is a &p-status; version, not all new features are well tested. This
131 documentation may be slightly out of sync as a result (especially with
132 CVS sources). And there <emphasis>may be</emphasis> bugs, though hopefully
137 <!-- ~~~~~ New section ~~~~~ -->
138 <sect2 id="features"><title>Features</title>
140 In addition to the core
141 features of ad blocking and
142 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookie</ulink> management,
143 <application>Privoxy</application> provides many supplemental
144 features<![%p-not-stable;[, some of them currently under development]]>,
145 that give the end-user more control, more privacy and more freedom:
147 <!-- Include newfeatures.sgml boilerplate here: -->
149 <!-- end boilerplate -->
154 <!-- ~ End section ~ -->
157 <!-- ~~~~~ New section ~~~~~ -->
158 <sect1 id="installation"><title>Installation</title>
161 <application>Privoxy</application> is available both in convenient pre-compiled
162 packages for a wide range of operating systems, and as raw source code.
163 For most users, we recommend using the packages, which can be downloaded from our
164 <ulink url="http://sourceforge.net/projects/ijbswa/">Privoxy Project
170 On some platforms, the installer may remove previously installed versions, if
171 found. (See below for your platform). In any case <emphasis>be sure to backup
172 your old configuration if it is valuable to you.</emphasis> See the <link
173 linkend="upgradersnote">note to upgraders</link> section below.
176 <!-- ~~~~~ New section ~~~~~ -->
177 <sect2 id="installation-packages"><title>Binary Packages</title>
179 How to install the binary packages depends on your operating system:
182 <!-- XXX: The installation sections should be sorted -->
184 <!-- ~~~~~ New section ~~~~~ -->
185 <sect3 id="installation-deb"><title>Debian and Ubuntu</title>
187 DEBs can be installed with <literal>apt-get install privoxy</literal>,
188 and will use <filename>/etc/privoxy</filename> for the location of
193 <!-- ~~~~~ New section ~~~~~ -->
194 <sect3 id="installation-pack-win"><title>Windows</title>
197 Just double-click the installer, which will guide you through
198 the installation process. You will find the configuration files
199 in the same directory as you installed <application>Privoxy</application> in.
202 Version 3.0.5 beta introduced full <application>Windows</application> service
203 functionality. On Windows only, the <application>Privoxy</application>
204 program has two new command line arguments to install and uninstall
205 <application>Privoxy</application> as a <emphasis>service</emphasis>.
209 <term>Arguments:</term>
212 <replaceable class="parameter">--install</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
215 <replaceable class="parameter">--uninstall</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
221 After invoking <application>Privoxy</application> with
222 <command>--install</command>, you will need to bring up the
223 <application>Windows</application> service console to assign the user you
224 want <application>Privoxy</application> to run under, and whether or not you
225 want it to run whenever the system starts. You can start the
226 <application>Windows</application> services console with the following
227 command: <command>services.msc</command>. If you do not take the manual step
228 of modifying <application>Privoxy's</application> service settings, it will
229 not start. Note too that you will need to give Privoxy a user account that
230 actually exists, or it will not be permitted to
231 write to its log and configuration files.
236 <!-- ~~~~~ New section ~~~~~ -->
237 <sect3 id="installation-os2"><title>OS/2</title>
240 First, make sure that no previous installations of
241 <application>Junkbuster</application> and / or
242 <application>Privoxy</application> are left on your
243 system. Check that no <application>Junkbuster</application>
244 or <application>Privoxy</application> objects are in
250 Then, just double-click the WarpIN self-installing archive, which will
251 guide you through the installation process. A shadow of the
252 <application>Privoxy</application> executable will be placed in your
253 startup folder so it will start automatically whenever OS/2 starts.
257 The directory you choose to install <application>Privoxy</application>
258 into will contain all of the configuration files.
262 <!-- ~~~~~ New section ~~~~~ -->
263 <sect3 id="installation-mac"><title>Mac OS X</title>
265 Installation instructions for the OS X platform depend upon whether
266 you downloaded a ready-built installation package (.pkg or .mpkg) or have
267 downloaded the source code.
270 <sect3 renderas="sect4" id="OS-X-install-from-package">
271 <title>Installation from ready-built package</title>
273 The downloaded file will either be a .pkg (for OS X 10.5 upwards) or a bzipped
274 .mpkg file (for OS X 10.4). The former can be double-clicked as is and the
275 installation will start; double-clicking the latter will unzip the .mpkg file
276 which can then be double-clicked to commence the installation.
279 The privoxy service will automatically start after a successful installation
280 (and thereafter every time your computer starts up) however you will need to
281 configure your web browser(s) to use it. To do so, configure them to use a
282 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
285 To prevent the privoxy service from automatically starting when your computer
286 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
287 (on OS X 10.5 and higher) or the folder named
288 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
291 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
292 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
293 administrator account, using sudo.
296 To uninstall, run /Applications/Privoxy/uninstall.command as sudo from an
297 administrator account.
300 <sect3 renderas="sect4" id="OS-X-install-from-source">
301 <title>Installation from source</title>
303 To build and install the Privoxy source code on OS X you will need to obtain
304 the macsetup module from the Privoxy Sourceforge CVS repository (refer to
305 Sourceforge help for details of how to set up a CVS client to have read-only
306 access to the repository). This module contains scripts that leverage the usual
307 open-source tools (available as part of Apple's free of charge Xcode
308 distribution or via the usual open-source software package managers for OS X
309 (MacPorts, Homebrew, Fink etc.) to build and then install the privoxy binary
310 and associated files. The macsetup module's README file contains complete
311 instructions for its use.
314 The privoxy service will automatically start after a successful installation
315 (and thereafter every time your computer starts up) however you will need to
316 configure your web browser(s) to use it. To do so, configure them to use a
317 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
320 To prevent the privoxy service from automatically starting when your computer
321 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
322 (on OS X 10.5 and higher) or the folder named
323 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
326 To manually start or stop the privoxy service, use the Privoxy Utility
327 for Mac OS X (also part of the macsetup module). This application can start
328 and stop the privoxy service and display its log and configuration files.
331 To uninstall, run the macsetup module's uninstall.sh as sudo from an
332 administrator account.
336 <!-- ~~~~~ New section ~~~~~ -->
337 <sect3 id="installation-tbz"><title>FreeBSD</title>
340 Privoxy is part of FreeBSD's Ports Collection, you can build and install
341 it with <literal>cd /usr/ports/www/privoxy; make install clean</literal>.
344 If you don't use the ports, you can fetch and install
345 the package with <literal>pkg_add -r privoxy</literal>.
348 The port skeleton and the package can also be downloaded from the
349 <ulink url="https://sourceforge.net/project/showfiles.php?group_id=11118">File Release
350 Page</ulink>, but there's no reason to use them unless you're interested in the
351 beta releases which are only available there.
357 <!-- ~~~~~ New section ~~~~~ -->
358 <sect2 id="installation-source"><title>Building from Source</title>
361 The most convenient way to obtain the <application>Privoxy</application> sources
362 is to download the source tarball from our
363 <ulink url="http://sourceforge.net/project/showfiles.php?group_id=11118&package_id=10571">project download
368 If you like to live on the bleeding edge and are not afraid of using
369 possibly unstable development versions, you can check out the up-to-the-minute
370 version directly from <ulink url="http://sourceforge.net/cvs/?group_id=11118">the
371 CVS repository</ulink>.
373 deprecated...out of business.
374 or simply download <ulink
375 url="http://cvs.sourceforge.net/cvstarballs/ijbswa-cvsroot.tar.bz2">the nightly CVS
380 <!-- include buildsource.sgml boilerplate: -->
382 <!-- end boilerplate -->
385 <!-- ~~~~~ New section ~~~~~ -->
386 <sect2 id="installation-keepupdated"><title>Keeping your Installation Up-to-Date</title>
389 If you wish to receive an email notification whenever we release updates of
390 <application>Privoxy</application> or the actions file, <ulink
391 url="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce/">subscribe
392 to our announce mailing list</ulink>, ijbswa-announce@lists.sourceforge.net.
396 In order not to lose your personal changes and adjustments when updating
397 to the latest <literal>default.action</literal> file we <emphasis>strongly
398 recommend</emphasis> that you use <literal>user.action</literal> and
399 <literal>user.filter</literal> for your local
400 customizations of <application>Privoxy</application>. See the <link
401 linkend="actions-file">Chapter on actions files</link> for details.
409 <!-- ~ End section ~ -->
411 <!-- ~~~~~ New section ~~~~~ -->
412 <sect1 id="whatsnew">
413 <title>What's New in this Release</title>
417 <!-- ~~~~~ New section ~~~~~ -->
419 <sect2 id="upgradersnote">
420 <title>Note to Upgraders</title>
423 A quick list of things to be aware of before upgrading from earlier
424 versions of <application>Privoxy</application>:
432 The recommended way to upgrade &my-app; is to backup your old
433 configuration files, install the new ones, verify that &my-app;
434 is working correctly and finally merge back your changes using
435 <application>diff</application> and maybe <application>patch</application>.
438 There are a number of new features in each &my-app; release and
439 most of them have to be explicitly enabled in the configuration
440 files. Old configuration files obviously don't do that and due
441 to syntax changes using old configuration files with a new
442 &my-app; isn't always possible anyway.
447 Note that some installers remove earlier versions completely,
448 including configuration files, therefore you should really save
449 any important configuration files!
454 On the other hand, other installers don't overwrite existing configuration
455 files, thinking you will want to do that yourself.
460 In the default configuration only fatal errors are logged now.
461 You can change that in the <link linkend="DEBUG">debug section</link>
462 of the configuration file. You may also want to enable more verbose
463 logging until you verified that the new &my-app; version is working
470 Three other config file settings are now off by default:
471 <link linkend="enable-remote-toggle">enable-remote-toggle</link>,
472 <link linkend="enable-remote-http-toggle">enable-remote-http-toggle</link>,
473 and <link linkend="enable-edit-actions">enable-edit-actions</link>.
474 If you use or want these, you will need to explicitly enable them, and
475 be aware of the security issues involved.
482 What constitutes a <quote>default</quote> configuration has changed,
483 and you may want to review which actions are <quote>on</quote> by
484 default. This is primarily a matter of emphasis, but some features
485 you may have been used to, may now be <quote>off</quote> by default.
486 There are also a number of new actions and filters you may want to
487 consider, most of which are not fully incorporated into the default
488 settings as yet (see above).
495 The default actions setting is now <literal>Cautious</literal>. Previous
496 releases had a default setting of <literal>Medium</literal>. Experienced
497 users may want to adjust this, as it is fairly conservative by &my-app;
498 standards and past practices. See <ulink
499 url="http://config.privoxy.org/edit-actions-list?f=default">
500 http://config.privoxy.org/edit-actions-list?f=default</ulink>. New users
501 should try the default settings for a while before turning up the volume.
507 The default setting has filtering turned <emphasis>off</emphasis>, which
508 subsequently means that compression is <emphasis>on</emphasis>. Remember
509 that filtering does not work on compressed pages, so if you use, or want to
510 use, filtering, you will need to force compression off. Example:
514 { +<link linkend="filter">filter</link>{google} +<link linkend="prevent-compression">prevent-compression</link> }
518 Or if you use a number of filters, or filter many sites, you may just want
519 to turn off compression for all sites in
520 <filename>default.action</filename> (or
521 <filename>user.action</filename>).
528 Also, <link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> is
529 off by default now. If you've liked this feature in the past, you may want
530 to turn it back on in <filename>user.action</filename> now.
537 Some installers may not automatically start
538 <application>Privoxy</application> after installation.
549 <!-- ~~~~~ New section ~~~~~ -->
550 <sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
556 Install <application>Privoxy</application>. See the <link
557 linkend="installation">Installation Section</link> below for platform specific
564 Advanced users and those who want to offer <application>Privoxy</application>
565 service to more than just their local machine should check the <link
566 linkend="config">main config file</link>, especially the <link
567 linkend="access-control">security-relevant</link> options. These are
574 Start <application>Privoxy</application>, if the installation program has
575 not done this already (may vary according to platform). See the section
576 <link linkend="startup">Starting <application>Privoxy</application></link>.
582 Set your browser to use <application>Privoxy</application> as HTTP and
583 HTTPS (SSL) <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
584 by setting the proxy configuration for address of
585 <literal>127.0.0.1</literal> and port <literal>8118</literal>.
586 <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
587 any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
588 browser from using these protocols.
594 Flush your browser's disk and memory caches, to remove any cached ad images.
595 If using <application>Privoxy</application> to manage
596 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
597 you should remove any currently stored cookies too.
603 A default installation should provide a reasonable starting point for
604 most. There will undoubtedly be occasions where you will want to adjust the
605 configuration, but that can be dealt with as the need arises. Little
606 to no initial configuration is required in most cases, you may want
608 <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
609 Be sure to read the warnings first.
612 See the <link linkend="configuration">Configuration section</link> for more
613 configuration options, and how to customize your installation.
614 You might also want to look at the <link
615 linkend="quickstart-ad-blocking">next section</link> for a quick
616 introduction to how <application>Privoxy</application> blocks ads and
623 If you experience ads that slip through, innocent images that are
624 blocked, or otherwise feel the need to fine-tune
625 <application>Privoxy's</application> behavior, take a look at the <link
626 linkend="actions-file">actions files</link>. As a quick start, you might
627 find the <link linkend="act-examples">richly commented examples</link>
628 helpful. You can also view and edit the actions files through the <ulink
629 url="http://config.privoxy.org">web-based user interface</ulink>. The
630 Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
631 Action</link></quote> has hints on how to understand and debug actions that
632 <quote>misbehave</quote>.
637 Did anyone test these lately?
641 For easy access to &my-app;'s most important controls, drag the provided
642 <link linkend="bookmarklets">Bookmarklets</link> into your browser's
650 Please see the section <link linkend="contact">Contacting the
651 Developers</link> on how to report bugs, problems with websites or to get
658 Now enjoy surfing with enhanced control, comfort and privacy!
666 <!-- ~~~~~ New section ~~~~~ -->
668 <sect2 id="quickstart-ad-blocking">
669 <title>Quickstart to Ad Blocking</title>
671 NOTE: This section is deliberately redundant for those that don't
672 want to read the whole thing (which is getting lengthy).
675 Ad blocking is but one of <application>Privoxy's</application>
676 array of features. Many of these features are for the technically minded advanced
677 user. But, ad and banner blocking is surely common ground for everybody.
680 This section will provide a quick summary of ad blocking so
681 you can get up to speed quickly without having to read the more extensive
682 information provided below, though this is highly recommended.
685 First a bit of a warning ... blocking ads is much like blocking SPAM: the
686 more aggressive you are about it, the more likely you are to block
687 things that were not intended. And the more likely that some things
688 may not work as intended. So there is a trade off here. If you want
689 extreme ad free browsing, be prepared to deal with more
690 <quote>problem</quote> sites, and to spend more time adjusting the
691 configuration to solve these unintended consequences. In short, there is
692 not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
693 the easy way and settle for <emphasis>most</emphasis> ads blocked with the
694 default configuration, or jump in and tweak it for your personal surfing
695 habits and preferences.
698 Secondly, a brief explanation of <application>Privoxy's </application>
699 <quote>actions</quote>. <quote>Actions</quote> in this context, are
700 the directives we use to tell <application>Privoxy</application> to perform
701 some task relating to HTTP transactions (i.e. web browsing). We tell
702 <application>Privoxy</application> to take some <quote>action</quote>. Each
703 action has a unique name and function. While there are many potential
704 <application>actions</application> in <application>Privoxy's</application>
705 arsenal, only a few are used for ad blocking. <link
706 linkend="actions">Actions</link>, and <link linkend="actions-file">action
707 configuration files</link>, are explained in depth below.
710 Actions are specified in <application>Privoxy's</application> configuration,
711 followed by one or more URLs to which the action should apply. URLs
712 can actually be URL type <link linkend="af-patterns">patterns</link> that use
713 wildcards so they can apply potentially to a range of similar URLs. The
714 actions, together with the URL patterns are called a section.
717 When you connect to a website, the full URL will either match one or more
718 of the sections as defined in <application>Privoxy's</application> configuration,
719 or not. If so, then <application>Privoxy</application> will perform the
720 respective actions. If not, then nothing special happens. Furthermore, web
721 pages may contain embedded, secondary URLs that your web browser will
722 use to load additional components of the page, as it parses the
723 original page's HTML content. An ad image for instance, is just an URL
724 embedded in the page somewhere. The image itself may be on the same server,
725 or a server somewhere else on the Internet. Complex web pages will have many
726 such embedded URLs. &my-app; can deal with each URL individually, so, for
727 instance, the main page text is not touched, but images from such-and-such
732 The most important actions for basic ad blocking are: <literal><link
733 linkend="block">block</link></literal>, <literal><link
734 linkend="handle-as-image">handle-as-image</link></literal>,
736 linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
737 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
745 <literal><link linkend="block">block</link></literal> - this is perhaps
746 the single most used action, and is particularly important for ad blocking.
747 This action stops any contact between your browser and any URL patterns
748 that match this action's configuration. It can be used for blocking ads,
749 but also anything that is determined to be unwanted. By itself, it simply
750 stops any communication with the remote server and sends
751 <application>Privoxy</application>'s own built-in BLOCKED page instead to
752 let you now what has happened (with some exceptions, see below).
758 <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
759 tells <application>Privoxy</application> to treat this URL as an image.
760 <application>Privoxy</application>'s default configuration already does this
761 for all common image types (e.g. GIF), but there are many situations where this
762 is not so easy to determine. So we'll force it in these cases. This is particularly
763 important for ad blocking, since only if we know that it's an image of
764 some kind, can we replace it with an image of our choosing, instead of the
765 <application>Privoxy</application> BLOCKED page (which would only result in
766 a <quote>broken image</quote> icon). There are some limitations to this
767 though. For instance, you can't just brute-force an image substitution for
768 an entire HTML page in most situations.
774 <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
775 sends an empty document instead of <application>Privoxy's</application>
776 normal BLOCKED HTML page. This is useful for file types that are neither
777 HTML nor images, such as blocking JavaScript files.
784 linkend="set-image-blocker">set-image-blocker</link></literal> - tells
785 <application>Privoxy</application> what to display in place of an ad image that
786 has hit a block rule. For this to come into play, the URL must match a
787 <literal><link linkend="block">block</link></literal> action somewhere in the
788 configuration, <emphasis>and</emphasis>, it must also match an
789 <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
792 The configuration options on what to display instead of the ad are:
796 <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
797 replacement is obvious. This is the default.
802 <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
803 This is the so-called <quote>invisible</quote> configuration option.
808 <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
809 of the user's choosing (advanced usage).
818 Advanced users will eventually want to explore &my-app;
819 <literal><link linkend="filter">filters</link></literal> as well. Filters
820 are very different from <literal><link
821 linkend="block">blocks</link></literal>.
822 A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
823 are a way of filtering or modifying what is actually on the page. An example
824 filter usage: a text replacement of <quote>no-no</quote> for
825 <quote>nasty-word</quote>. That is a very simple example. This process can be
826 used for ad blocking, but it is more in the realm of advanced usage and has
827 some pitfalls to be wary off.
831 The quickest way to adjust any of these settings is with your browser through
832 the special <application>Privoxy</application> editor at <ulink
833 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
834 (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
835 is an internal page, and does not require Internet access.
839 Note that as of <application>Privoxy</application> 3.0.7 beta the
840 action editor is disabled by default. Check the
841 <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
842 section in the configuration file</ulink> to learn why and in which
843 cases it's safe to enable again.
847 If you decided to enable the action editor, select the appropriate
848 <quote>actions</quote> file, and click
849 <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
850 local preferences in <filename>user.action</filename> since this is not
851 meant to be overwritten during upgrades, and will over-ride the settings in
852 other files. Here you can insert new <quote>actions</quote>, and URLs for ad
853 blocking or other purposes, and make other adjustments to the configuration.
854 <application>Privoxy</application> will detect these changes automatically.
858 A quick and simple step by step example:
866 Right click on the ad image to be blocked, then select
867 <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
875 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
880 Find <filename>user.action</filename> in the top section, and click
881 on <quote><guibutton>Edit</guibutton></quote>:
884 <!-- image of editor and actions files selections -->
886 <figure pgwide="0" float="0"><title>Actions Files in Use</title>
889 <imagedata fileref="files-in-use.jpg" format="jpg">
892 <phrase>[ Screenshot of Actions Files in Use ]</phrase>
901 You should have a section with only
902 <literal><link linkend="block">block</link></literal> listed under
903 <quote>Actions:</quote>.
904 If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
905 button, and in the new section that just appeared, click the
906 <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
907 This will bring up a list of all actions. Find
908 <literal><link linkend="block">block</link></literal> near the top, and click
909 in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
915 Now, in the <literal><link linkend="block">block</link></literal> actions section,
916 click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
917 browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
918 Remove the <literal>http://</literal> at the beginning of the URL. Then, click
919 <quote><guibutton>Submit</guibutton></quote> (or
920 <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
925 Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
926 (or flush all browser caches). The image should be gone now.
934 This is a very crude and simple example. There might be good reasons to use a
935 wildcard pattern match to include potentially similar images from the same
936 site. For a more extensive explanation of <quote>patterns</quote>, and
937 the entire actions concept, see <link linkend="actions-file">the Actions
942 For advanced users who want to hand edit their config files, you might want
943 to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
944 The ideas explained therein also apply to the web-based editor.
947 There are also various
948 <link linkend="filter">filters</link> that can be used for ad blocking
949 (filters are a special subset of actions). These
950 fall into the <quote>advanced</quote> usage category, and are explained in
951 depth in later sections.
958 <!-- ~ End section ~ -->
961 <!-- ~~~~~ New section ~~~~~ -->
963 <title>Starting Privoxy</title>
965 Before launching <application>Privoxy</application> for the first time, you
966 will want to configure your browser(s) to use
967 <application>Privoxy</application> as a HTTP and HTTPS (SSL)
968 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
969 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
970 used port 8000). This is the one configuration step <emphasis>that must be done
974 Please note that <application>Privoxy</application> can only proxy HTTP and
975 HTTPS traffic. It will not work with FTP or other protocols.
978 <!-- image of Mozilla Proxy configuration -->
980 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
981 Mozilla/Netscape HTTP and HTTPS (SSL) Settings</title>
984 <imagedata fileref="proxy_setup.jpg" format="jpg">
987 <phrase>[ Screenshot of Mozilla Proxy Configuration ]</phrase>
995 With <application>Firefox</application>, this is typically set under:
999 <guibutton>Tools</guibutton> -> <guibutton>Options</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Network</guibutton> -><guibutton>Connection</guibutton> -> <guibutton>Settings</guibutton>
1004 Or optionally on some platforms:
1008 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
1014 With <application>Netscape</application> (and
1015 <application>Mozilla</application>), this can be set under:
1020 <!-- Mix ascii and gui art, something for everybody -->
1021 <!-- spacing on this is tricky -->
1022 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
1027 For <application>Internet Explorer v.5-7</application>:
1031 <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
1035 Then, check <quote>Use Proxy</quote> and fill in the appropriate info
1036 (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
1037 proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
1038 checkboxes like <quote>Use the same proxy server for all protocols</quote> is
1039 <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
1042 <!-- image of IE Proxy configuration -->
1044 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1045 Internet Explorer HTTP and HTTPS (Secure) Settings</title>
1048 <imagedata fileref="proxy2.jpg" format="jpg">
1051 <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
1059 After doing this, flush your browser's disk and memory caches to force a
1060 re-reading of all pages and to get rid of any ads that may be cached. Remove
1061 any <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1062 if you want <application>Privoxy</application> to manage that. You are now
1063 ready to start enjoying the benefits of using
1064 <application>Privoxy</application>!
1068 <application>Privoxy</application> itself is typically started by specifying the
1069 main configuration file to be used on the command line. If no configuration
1070 file is specified on the command line, <application>Privoxy</application>
1071 will look for a file named <filename>config</filename> in the current
1072 directory. Except on Win32 where it will try <filename>config.txt</filename>.
1075 <sect2 id="start-debian">
1076 <title>Debian</title>
1078 We use a script. Note that Debian typically starts &my-app; upon booting per
1079 default. It will use the file
1080 <filename>/etc/privoxy/config</filename> as its main configuration
1085 # /etc/init.d/privoxy start
1090 <sect2 id="start-windows">
1091 <title>Windows</title>
1093 Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
1094 specified on the command line, <application>Privoxy</application> will look
1095 for a file named <filename>config.txt</filename>. Note that Windows will
1096 automatically start &my-app; when the system starts if you chose that option
1100 <application>Privoxy</application> can run with full Windows service functionality.
1101 On Windows only, the &my-app; program has two new command line arguments
1102 to install and uninstall &my-app; as a service. See the
1103 <link linkend="installation-pack-win">Windows Installation
1104 instructions</link> for details.
1108 <sect2 id="start-unices">
1109 <title>Solaris, NetBSD, FreeBSD, HP-UX and others</title>
1111 Example Unix startup command:
1115 # /usr/sbin/privoxy /etc/privoxy/config
1120 <sect2 id="start-os2">
1123 During installation, <application>Privoxy</application> is configured to
1124 start automatically when the system restarts. You can start it manually by
1125 double-clicking on the <application>Privoxy</application> icon in the
1126 <application>Privoxy</application> folder.
1130 <sect2 id="start-macosx">
1131 <title>Mac OS X</title>
1133 After downloading the privoxy software, unzip the downloaded file by
1134 double-clicking on the zip file icon. Then, double-click on the
1135 installer package icon and follow the installation process.
1138 The privoxy service will automatically start after a successful
1139 installation. In addition, the privoxy service will automatically
1140 start every time your computer starts up.
1143 To prevent the privoxy service from automatically starting when your
1144 computer starts up, remove or rename the folder named
1145 /Library/StartupItems/Privoxy.
1148 A simple application named Privoxy Utility has been created which
1149 enables administrators to easily start and stop the privoxy service.
1152 In addition, the Privoxy Utility presents a simple way for
1153 administrators to edit the various privoxy config files. A method
1154 to uninstall the software is also available.
1157 An administrator username and password must be supplied in order for
1158 the Privoxy Utility to perform any of the tasks.
1166 See the section <link linkend="cmdoptions">Command line options</link> for
1170 must find a better place for this paragraph
1173 The included default configuration files should give a reasonable starting
1174 point. Most of the per site configuration is done in the
1175 <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
1176 where various cookie actions are defined, ad and banner blocking, and other
1177 aspects of <application>Privoxy</application> configuration. There are several
1178 such files included, with varying levels of aggressiveness.
1182 You will probably want to keep an eye out for sites for which you may prefer
1183 persistent cookies, and add these to your actions configuration as needed. By
1184 default, most of these will be accepted only during the current browser
1185 session (aka <quote>session cookies</quote>), unless you add them to the
1186 configuration. If you want the browser to handle this instead, you will need
1187 to edit <filename>user.action</filename> (or through the web based interface)
1188 and disable this feature. If you use more than one browser, it would make
1189 more sense to let <application>Privoxy</application> handle this. In which
1190 case, the browser(s) should be set to accept all cookies.
1194 Another feature where you will probably want to define exceptions for trusted
1195 sites is the popup-killing (through <ulink
1196 url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
1197 because your favorite shopping, banking, or leisure site may need
1198 popups (explained below).
1202 <application>Privoxy</application> does not support all of the optional HTTP/1.1
1203 features yet. In the unlikely event that you experience inexplicable problems
1204 with browsers that use HTTP/1.1 per default
1205 (like <application>Mozilla</application> or recent versions of I.E.), you might
1206 try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
1207 Preferences -> Debug -> Networking</literal>.
1208 Alternatively, set the <quote>+downgrade-http-version</quote> config option in
1209 <filename>default.action</filename> which will downgrade your browser's HTTP
1210 requests from HTTP/1.1 to HTTP/1.0 before processing them.
1214 After running <application>Privoxy</application> for a while, you can
1215 start to fine tune the configuration to suit your personal, or site,
1216 preferences and requirements. There are many, many aspects that can
1217 be customized. <quote>Actions</quote>
1218 can be adjusted by pointing your browser to
1219 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1220 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1221 and then follow the link to <quote>View & Change the Current Configuration</quote>.
1222 (This is an internal page and does not require Internet access.)
1226 In fact, various aspects of <application>Privoxy</application>
1227 configuration can be viewed from this page, including
1228 current configuration parameters, source code version numbers,
1229 the browser's request headers, and <quote>actions</quote> that apply
1230 to a given URL. In addition to the actions file
1231 editor mentioned above, <application>Privoxy</application> can also
1232 be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
1236 If you encounter problems, try loading the page without
1237 <application>Privoxy</application>. If that helps, enter the URL where
1238 you have the problems into <ulink url="http://p.p/show-url-info">the browser
1239 based rule tracing utility</ulink>. See which rules apply and why, and
1240 then try turning them off for that site one after the other, until the problem
1241 is gone. When you have found the culprit, you might want to turn the rest on
1246 If the above paragraph sounds gibberish to you, you might want to <link
1247 linkend="actions-file">read more about the actions concept</link>
1248 or even dive deep into the <link linkend="actionsanat">Appendix
1253 If you can't get rid of the problem at all, think you've found a bug in
1254 Privoxy, want to propose a new feature or smarter rules, please see the
1255 section <link linkend="contact"><quote>Contacting the
1256 Developers</quote></link> below.
1261 <!-- ~~~~~ New section ~~~~~ -->
1262 <sect2 id="cmdoptions">
1263 <title>Command Line Options</title>
1265 <application>Privoxy</application> may be invoked with the following
1266 command-line options:
1274 <emphasis>--config-test</emphasis>
1277 Exit after loading the configuration files before binding to
1278 the listen address. The exit code signals whether or not the
1279 configuration files have been successfully loaded.
1282 If the exit code is 1, at least one of the configuration files
1283 is invalid, if it is 0, all the configuration files have been
1284 successfully loaded (but may still contain errors that can
1285 currently only be detected at run time).
1288 This option doesn't affect the log setting, combination with
1289 <emphasis>--no-daemon</emphasis> is recommended if a configured
1290 log file shouldn't be used.
1295 <emphasis>--version</emphasis>
1298 Print version info and exit. Unix only.
1303 <emphasis>--help</emphasis>
1306 Print short usage info and exit. Unix only.
1311 <emphasis>--no-daemon</emphasis>
1314 Don't become a daemon, i.e. don't fork and become process group
1315 leader, and don't detach from controlling tty. Unix only.
1320 <emphasis>--pidfile FILE</emphasis>
1323 On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
1324 <emphasis>FILE</emphasis> on exit. Failure to create or delete the
1325 <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
1326 option is given, no PID file will be used. Unix only.
1331 <emphasis>--user USER[.GROUP]</emphasis>
1334 After (optionally) writing the PID file, assume the user ID of
1335 <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
1336 privileges are not sufficient to do so. Unix only.
1341 <emphasis>--chroot</emphasis>
1344 Before changing to the user ID given in the <emphasis>--user</emphasis> option,
1345 chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
1346 process that the directory tree starts there. If set up carefully, this can limit
1347 the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
1353 <emphasis>--pre-chroot-nslookup hostname</emphasis>
1356 Specifies a hostname to look up before doing a chroot. On some systems, initializing the
1357 resolver library involves reading config files from /etc and/or loading additional shared
1358 libraries from /lib. On these systems, doing a hostname lookup before the chroot reduces
1359 the number of files that must be copied into the chroot tree.
1362 For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
1363 your local name server (listed in /etc/resolv.conf) can resolve without recursion
1364 (that is, without having to ask any other name servers). The hostname need not exist,
1365 but if it doesn't, an error message (which can be ignored) will be output.
1371 <emphasis>configfile</emphasis>
1374 If no <emphasis>configfile</emphasis> is included on the command line,
1375 <application>Privoxy</application> will look for a file named
1376 <quote>config</quote> in the current directory (except on Win32
1377 where it will look for <quote>config.txt</quote> instead). Specify
1378 full path to avoid confusion. If no config file is found,
1379 <application>Privoxy</application> will fail to start.
1387 On <application>MS Windows</application> only there are two additional
1388 command-line options to allow <application>Privoxy</application> to install and
1389 run as a <emphasis>service</emphasis>. See the
1390 <link linkend="installation-pack-win">Window Installation section</link>
1398 <!-- ~ End section ~ -->
1401 <!-- ~~~~~ New section ~~~~~ -->
1402 <sect1 id="configuration"><title>Privoxy Configuration</title>
1404 All <application>Privoxy</application> configuration is stored
1405 in text files. These files can be edited with a text editor.
1406 Many important aspects of <application>Privoxy</application> can
1407 also be controlled easily with a web browser.
1411 <!-- ~~~~~ New section ~~~~~ -->
1414 <title>Controlling Privoxy with Your Web Browser</title>
1416 <application>Privoxy</application>'s user interface can be reached through the special
1417 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1418 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1419 which is a built-in page and works without Internet access.
1420 You will see the following section:
1424 <!-- Needs to be put in a table and colorized -->
1427 <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
1431 ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
1434 ▪ <ulink url="http://config.privoxy.org/show-version">View the source code version numbers</ulink>
1437 ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
1440 ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
1443 ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
1446 ▪ <ulink
1447 url="http://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
1455 This should be self-explanatory. Note the first item leads to an editor for the
1456 <link linkend="actions-file">actions files</link>, which is where the ad, banner,
1457 cookie, and URL blocking magic is configured as well as other advanced features of
1458 <application>Privoxy</application>. This is an easy way to adjust various
1459 aspects of <application>Privoxy</application> configuration. The actions
1460 file, and other configuration files, are explained in detail below.
1464 <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
1465 have problems with your current actions and filters. You can in fact use
1466 it as a test to see whether it is <application>Privoxy</application>
1467 causing the problem or not. <application>Privoxy</application> continues
1468 to run as a proxy in this case, but all manipulation is disabled, i.e.
1469 <application>Privoxy</application> acts like a normal forwarding proxy. There
1470 is even a toggle <link linkend="bookmarklets">Bookmarklet</link> offered, so
1471 that you can toggle <application>Privoxy</application> with one click from
1476 Note that several of the features described above are disabled by default
1477 in <application>Privoxy</application> 3.0.7 beta and later.
1479 <ulink url="config.html">configuration file</ulink> to learn why
1480 and in which cases it's safe to enable them again.
1485 <!-- ~ End section ~ -->
1490 <!-- ~~~~~ New section ~~~~~ -->
1492 <sect2 id="confoverview">
1493 <title>Configuration Files Overview</title>
1495 For Unix, *BSD and Linux, all configuration files are located in
1496 <filename>/etc/privoxy/</filename> by default. For MS Windows, OS/2, and
1497 AmigaOS these are all in the same directory as the
1498 <application>Privoxy</application> executable. <![%p-not-stable;[ The name
1499 and number of configuration files has changed from previous versions, and is
1500 subject to change as development progresses.]]>
1504 The installed defaults provide a reasonable starting point, though
1505 some settings may be aggressive by some standards. For the time being, the
1506 principle configuration files are:
1514 The <link linkend="config">main configuration file</link> is named <filename>config</filename>
1515 on Linux, Unix, BSD, OS/2, and AmigaOS and <filename>config.txt</filename>
1516 on Windows. This is a required file.
1522 <filename>match-all.action</filename> is used to define which <quote>actions</quote>
1523 relating to banner-blocking, images, pop-ups, content modification, cookie handling
1524 etc should be applied by default. It should be the first actions file loaded.
1527 <filename>default.action</filename> defines many exceptions (both positive and negative)
1528 from the default set of actions that's configured in <filename>match-all.action</filename>.
1529 It should be the second actions file loaded and shouldn't be edited by the user.
1532 Multiple actions files may be defined in <filename>config</filename>. These
1533 are processed in the order they are defined. Local customizations and locally
1534 preferred exceptions to the default policies as defined in
1535 <filename>match-all.action</filename> (which you will most probably want
1536 to define sooner or later) are best applied in <filename>user.action</filename>,
1537 where you can preserve them across upgrades. The file isn't installed by all
1538 installers, but you can easily create it yourself with a text editor.
1541 There is also a web based editor that can be accessed from
1543 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1545 url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
1546 various actions files.
1552 <quote>Filter files</quote> (the <link linkend="filter-file">filter
1553 file</link>) can be used to re-write the raw page content, including
1554 viewable text as well as embedded HTML and JavaScript, and whatever else
1555 lurks on any given web page. The filtering jobs are only pre-defined here;
1556 whether to apply them or not is up to the actions files.
1557 <filename>default.filter</filename> includes various filters made
1558 available for use by the developers. Some are much more intrusive than
1559 others, and all should be used with caution. You may define additional
1560 filter files in <filename>config</filename> as you can with
1561 actions files. We suggest <filename>user.filter</filename> for any
1562 locally defined filters or customizations.
1570 The syntax of the configuration and filter files may change between different
1571 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
1572 <!-- Add link to documentation-->
1576 All files use the <quote><literal>#</literal></quote> character to denote a
1577 comment (the rest of the line will be ignored) and understand line continuation
1578 through placing a backslash ("<literal>\</literal>") as the very last character
1579 in a line. If the <literal>#</literal> is preceded by a backslash, it looses
1580 its special function. Placing a <literal>#</literal> in front of an otherwise
1581 valid configuration line to prevent it from being interpreted is called "commenting
1582 out" that line. Blank lines are ignored.
1586 The actions files and filter files
1587 can use Perl style <link linkend="regex">regular expressions</link> for
1588 maximum flexibility.
1592 After making any changes, there is no need to restart
1593 <application>Privoxy</application> in order for the changes to take
1594 effect. <application>Privoxy</application> detects such changes
1595 automatically. Note, however, that it may take one or two additional
1596 requests for the change to take effect. When changing the listening address
1597 of <application>Privoxy</application>, these <quote>wake up</quote> requests
1598 must obviously be sent to the <emphasis>old</emphasis> listening address.
1603 While under development, the configuration content is subject to change.
1604 The below documentation may not be accurate by the time you read this.
1605 Also, what constitutes a <quote>default</quote> setting, may change, so
1606 please check all your configuration files on important issues.
1612 <!-- ~ End section ~ -->
1615 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1617 <!-- **************************************************** -->
1618 <!-- Include config.sgml here -->
1619 <!-- This is where the entire config file is detailed. -->
1621 <!-- end include -->
1624 <!-- ~ End section ~ -->
1628 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1630 <sect1 id="actions-file"><title>Actions Files</title>
1634 XXX: similar descriptions are in the Configuration Files sections.
1635 We should only describe them at one place.
1638 The actions files are used to define what <emphasis>actions</emphasis>
1639 <application>Privoxy</application> takes for which URLs, and thus determines
1640 how ad images, cookies and various other aspects of HTTP content and
1641 transactions are handled, and on which sites (or even parts thereof).
1642 There are a number of such actions, with a wide range of functionality.
1643 Each action does something a little different.
1644 These actions give us a veritable arsenal of tools with which to exert
1645 our control, preferences and independence. Actions can be combined so that
1646 their effects are aggregated when applied against a given set of URLs.
1650 are three action files included with <application>Privoxy</application> with
1657 <filename>match-all.action</filename> - is used to define which
1658 <quote>actions</quote> relating to banner-blocking, images, pop-ups,
1659 content modification, cookie handling etc should be applied by default.
1660 It should be the first actions file loaded
1665 <filename>default.action</filename> - defines many exceptions (both
1666 positive and negative) from the default set of actions that's configured
1667 in <filename>match-all.action</filename>. It is a set of rules that should
1668 work reasonably well as-is for most users. This file is only supposed to
1669 be edited by the developers. It should be the second actions file loaded.
1674 <filename>user.action</filename> - is intended to be for local site
1675 preferences and exceptions. As an example, if your ISP or your bank
1676 has specific requirements, and need special handling, this kind of
1677 thing should go here. This file will not be upgraded.
1682 <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
1685 These have increasing levels of aggressiveness <emphasis>and have no
1686 influence on your browsing unless you select them explicitly in the
1687 editor</emphasis>. A default installation should be pre-set to
1688 <literal>Cautious</literal>. New users should try this for a while before
1689 adjusting the settings to more aggressive levels. The more aggressive
1690 the settings, then the more likelihood there is of problems such as sites
1691 not working as they should.
1694 The <guibutton>Edit</guibutton> button allows you to turn each
1695 action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
1696 button changes the actions list to low/safe settings which will activate
1697 ad blocking and a minimal set of &my-app;'s features, and subsequently
1698 there will be less of a chance for accidental problems. The
1699 <guibutton>Medium</guibutton> button sets the list to a medium level of
1700 other features and a low level set of privacy features. The
1701 <guibutton>Advanced</guibutton> button sets the list to a high level of
1702 ad blocking and medium level of privacy. See the chart below. The latter
1703 three buttons over-ride any changes via with the
1704 <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
1705 lower sections of this internal page.
1708 While the actions file editor allows to enable these settings in all
1709 actions files, they are only supposed to be enabled in the first one
1710 to make sure you don't unintentionally overrule earlier rules.
1713 The default profiles, and their associated actions, as pre-defined in
1714 <filename>default.action</filename> are:
1717 <table frame=all><title>Default Configurations</title>
1718 <tgroup cols=4 align=left colsep=1 rowsep=1>
1719 <colspec colname=c1>
1720 <colspec colname=c2>
1721 <colspec colname=c3>
1722 <colspec colname=c4>
1725 <entry>Feature</entry>
1726 <entry>Cautious</entry>
1727 <entry>Medium</entry>
1728 <entry>Advanced</entry>
1733 <!-- <entry>f1</entry> -->
1734 <!-- <entry>f2</entry> -->
1735 <!-- <entry>f3</entry> -->
1736 <!-- <entry>f4</entry> -->
1742 <entry>Ad-blocking Aggressiveness</entry>
1743 <entry>medium</entry>
1749 <entry>Ad-filtering by size</entry>
1756 <entry>Ad-filtering by link</entry>
1762 <entry>Pop-up killing</entry>
1763 <entry>blocks only</entry>
1764 <entry>blocks only</entry>
1765 <entry>blocks only</entry>
1769 <entry>Privacy Features</entry>
1771 <entry>medium</entry>
1772 <entry>medium/high</entry>
1776 <entry>Cookie handling</entry>
1778 <entry>session-only</entry>
1783 <entry>Referer forging</entry>
1790 <entry>GIF de-animation</entry>
1797 <entry>Fast redirects</entry>
1804 <entry>HTML taming</entry>
1811 <entry>JavaScript taming</entry>
1818 <entry>Web-bug killing</entry>
1825 <entry>Image tag reordering</entry>
1841 The list of actions files to be used are defined in the main configuration
1842 file, and are processed in the order they are defined (e.g.
1843 <filename>default.action</filename> is typically processed before
1844 <filename>user.action</filename>). The content of these can all be viewed and
1846 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1847 The over-riding principle when applying actions, is that the last action that
1848 matches a given URL wins. The broadest, most general rules go first
1849 (defined in <filename>default.action</filename>),
1850 followed by any exceptions (typically also in
1851 <filename>default.action</filename>), which are then followed lastly by any
1852 local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
1853 Generally, <filename>user.action</filename> has the last word.
1857 An actions file typically has multiple sections. If you want to use
1858 <quote>aliases</quote> in an actions file, you have to place the (optional)
1859 <link linkend="aliases">alias section</link> at the top of that file.
1860 Then comes the default set of rules which will apply universally to all
1861 sites and pages (be <emphasis>very careful</emphasis> with using such a
1862 universal set in <filename>user.action</filename> or any other actions file after
1863 <filename>default.action</filename>, because it will override the result
1864 from consulting any previous file). And then below that,
1865 exceptions to the defined universal policies. You can regard
1866 <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
1867 with the advantage that it is a separate file, which makes preserving your
1868 personal settings across <application>Privoxy</application> upgrades easier.
1872 Actions can be used to block anything you want, including ads, banners, or
1873 just some obnoxious URL whose content you would rather not see. Cookies can be accepted
1874 or rejected, or accepted only during the current browser session (i.e. not
1875 written to disk), content can be modified, some JavaScripts tamed, user-tracking
1876 fooled, and much more. See below for a <link linkend="actions">complete list
1880 <!-- ~~~~~ New section ~~~~~ -->
1882 <title>Finding the Right Mix</title>
1884 Note that some <link linkend="actions">actions</link>, like cookie suppression
1885 or script disabling, may render some sites unusable that rely on these
1886 techniques to work properly. Finding the right mix of actions is not always easy and
1887 certainly a matter of personal taste. And, things can always change, requiring
1888 refinements in the configuration. In general, it can be said that the more
1889 <quote>aggressive</quote> your default settings (in the top section of the
1890 actions file) are, the more exceptions for <quote>trusted</quote> sites you
1891 will have to make later. If, for example, you want to crunch all cookies per
1892 default, you'll have to make exceptions from that rule for sites that you
1893 regularly use and that require cookies for actually useful purposes, like maybe
1894 your bank, favorite shop, or newspaper.
1898 We have tried to provide you with reasonable rules to start from in the
1899 distribution actions files. But there is no general rule of thumb on these
1900 things. There just are too many variables, and sites are constantly changing.
1901 Sooner or later you will want to change the rules (and read this chapter again :).
1905 <!-- ~~~~~ New section ~~~~~ -->
1907 <title>How to Edit</title>
1909 The easiest way to edit the actions files is with a browser by
1910 using our browser-based editor, which can be reached from <ulink
1911 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1912 Note: the config file option <link
1913 linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
1914 this to work. The editor allows both fine-grained control over every single
1915 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
1916 like <quote>Cautious</quote>, <quote>Medium</quote> or
1917 <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
1918 aggressive, and will be more likely to cause problems for some sites.
1919 Experienced users only!
1923 If you prefer plain text editing to GUIs, you can of course also directly edit the
1924 the actions files with your favorite text editor. Look at
1925 <filename>default.action</filename> which is richly commented with many
1931 <sect2 id="actions-apply">
1932 <title>How Actions are Applied to Requests</title>
1934 Actions files are divided into sections. There are special sections,
1935 like the <quote><link linkend="aliases">alias</link></quote> sections which will
1936 be discussed later. For now let's concentrate on regular sections: They have a
1937 heading line (often split up to multiple lines for readability) which consist
1938 of a list of actions, separated by whitespace and enclosed in curly braces.
1939 Below that, there is a list of URL and tag patterns, each on a separate line.
1943 To determine which actions apply to a request, the URL of the request is
1944 compared to all URL patterns in each <quote>action file</quote>.
1945 Every time it matches, the list of applicable actions for the request is
1946 incrementally updated, using the heading of the section in which the
1947 pattern is located. The same is done again for tags and tag patterns later on.
1951 If multiple applying sections set the same action differently,
1952 the last match wins. If not, the effects are aggregated.
1953 E.g. a URL might match a regular section with a heading line of <literal>{
1954 +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
1955 then later another one with just <literal>{
1956 +<link linkend="block">block</link> }</literal>, resulting
1957 in <emphasis>both</emphasis> actions to apply. And there may well be
1958 cases where you will want to combine actions together. Such a section then
1964 { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
1965 # Block these as if they were images. Send no block page.
1967 media.example.com/.*banners
1968 .example.com/images/ads/</screen>
1972 You can trace this process for URL patterns and any given URL by visiting <ulink
1973 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
1977 Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
1978 Troubleshooting: Anatomy of an Action</link> section.
1982 <!-- ~~~~~ New section ~~~~~ -->
1983 <sect2 id="af-patterns">
1984 <title>Patterns</title>
1986 As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
1987 to determine what <emphasis>actions</emphasis> might apply to which sites and
1988 pages your browser attempts to access. These <quote>patterns</quote> use wild
1989 card type <emphasis>pattern</emphasis> matching to achieve a high degree of
1990 flexibility. This allows one expression to be expanded and potentially match
1991 against many similar patterns.
1995 Generally, an URL pattern has the form
1996 <literal><domain><port>/<path></literal>, where the
1997 <literal><domain></literal>, the <literal><port></literal>
1998 and the <literal><path></literal> are optional. (This is why the special
1999 <literal>/</literal> pattern matches all URLs). Note that the protocol
2000 portion of the URL pattern (e.g. <literal>http://</literal>) should
2001 <emphasis>not</emphasis> be included in the pattern. This is assumed already!
2004 The pattern matching syntax is different for the domain and path parts of
2005 the URL. The domain part uses a simple globbing type matching technique,
2006 while the path part uses more flexible
2007 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2008 Expressions</quote></ulink> (POSIX 1003.2).
2011 The port part of a pattern is a decimal port number preceded by a colon
2012 (<literal>:</literal>). If the domain part contains a numerical IPv6 address,
2013 it has to be put into angle brackets
2014 (<literal><</literal>, <literal>></literal>).
2019 <term><literal>www.example.com/</literal></term>
2022 is a domain-only pattern and will match any request to <literal>www.example.com</literal>,
2023 regardless of which document on that server is requested. So ALL pages in
2024 this domain would be covered by the scope of this action. Note that a
2025 simple <literal>example.com</literal> is different and would NOT match.
2030 <term><literal>www.example.com</literal></term>
2033 means exactly the same. For domain-only patterns, the trailing <literal>/</literal> may
2039 <term><literal>www.example.com/index.html</literal></term>
2042 matches all the documents on <literal>www.example.com</literal>
2043 whose name starts with <literal>/index.html</literal>.
2048 <term><literal>www.example.com/index.html$</literal></term>
2051 matches only the single document <literal>/index.html</literal>
2052 on <literal>www.example.com</literal>.
2057 <term><literal>/index.html$</literal></term>
2060 matches the document <literal>/index.html</literal>, regardless of the domain,
2061 i.e. on <emphasis>any</emphasis> web server anywhere.
2066 <term><literal>/</literal></term>
2069 Matches any URL because there's no requirement for either the
2070 domain or the path to match anything.
2075 <term><literal>:8000/</literal></term>
2078 Matches any URL pointing to TCP port 8000.
2083 <term><literal><2001:db8::1>/</literal></term>
2086 Matches any URL with the host address <literal>2001:db8::1</literal>.
2087 (Note that the real URL uses plain brackets, not angle brackets.)
2092 <term><literal>index.html</literal></term>
2095 matches nothing, since it would be interpreted as a domain name and
2096 there is no top-level domain called <literal>.html</literal>. So its
2104 <!-- ~~~~~ New section ~~~~~ -->
2105 <sect3><title>The Domain Pattern</title>
2108 The matching of the domain part offers some flexible options: if the
2109 domain starts or ends with a dot, it becomes unanchored at that end.
2115 <term><literal>.example.com</literal></term>
2118 matches any domain with first-level domain <literal>com</literal>
2119 and second-level domain <literal>example</literal>.
2120 For example <literal>www.example.com</literal>,
2121 <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
2122 Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
2127 <term><literal>www.</literal></term>
2130 matches any domain that <emphasis>STARTS</emphasis> with
2131 <literal>www.</literal> (It also matches the domain
2132 <literal>www</literal> but most of the time that doesn't matter.)
2137 <term><literal>.example.</literal></term>
2140 matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
2141 And, by the way, also included would be any files or documents that exist
2142 within that domain since no path limitations are specified. (Correctly
2143 speaking: It matches any FQDN that contains <literal>example</literal> as
2144 a domain.) This might be <literal>www.example.com</literal>,
2145 <literal>news.example.de</literal>, or
2146 <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
2154 Additionally, there are wild-cards that you can use in the domain names
2155 themselves. These work similarly to shell globbing type wild-cards:
2156 <quote>*</quote> represents zero or more arbitrary characters (this is
2158 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2159 Expression</quote></ulink> based syntax of <quote>.*</quote>),
2160 <quote>?</quote> represents any single character (this is equivalent to the
2161 regular expression syntax of a simple <quote>.</quote>), and you can define
2162 <quote>character classes</quote> in square brackets which is similar to
2163 the same regular expression technique. All of this can be freely mixed:
2168 <term><literal>ad*.example.com</literal></term>
2171 matches <quote>adserver.example.com</quote>,
2172 <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
2177 <term><literal>*ad*.example.com</literal></term>
2180 matches all of the above, and then some.
2185 <term><literal>.?pix.com</literal></term>
2188 matches <literal>www.ipix.com</literal>,
2189 <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
2194 <term><literal>www[1-9a-ez].example.c*</literal></term>
2197 matches <literal>www1.example.com</literal>,
2198 <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
2199 <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
2200 <literal>wwww.example.com</literal>.
2207 While flexible, this is not the sophistication of full regular expression based syntax.
2212 <!-- ~ End section ~ -->
2215 <!-- ~~~~~ New section ~~~~~ -->
2216 <sect3><title>The Path Pattern</title>
2219 <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
2220 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2221 Expressions</quote></ulink> for matching the path portion (after the slash),
2222 and is thus more flexible.
2226 There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
2227 expressions, you also might want to have a look at your operating system's documentation
2228 on regular expressions (try <literal>man re_format</literal>).
2232 Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
2233 i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
2234 for the beginning of a line).
2238 Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
2239 by default, but you can switch to case sensitive at any point in the pattern by using the
2240 <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
2241 only documents whose path starts with <literal>PaTtErN</literal> in
2242 <emphasis>exactly</emphasis> this capitalization.
2247 <term><literal>.example.com/.*</literal></term>
2250 Is equivalent to just <quote>.example.com</quote>, since any documents
2251 within that domain are matched with or without the <quote>.*</quote>
2252 regular expression. This is redundant
2257 <term><literal>.example.com/.*/index.html$</literal></term>
2260 Will match any page in the domain of <quote>example.com</quote> that is
2261 named <quote>index.html</quote>, and that is part of some path. For
2262 example, it matches <quote>www.example.com/testing/index.html</quote> but
2263 NOT <quote>www.example.com/index.html</quote> because the regular
2264 expression called for at least two <quote>/'s</quote>, thus the path
2265 requirement. It also would match
2266 <quote>www.example.com/testing/index_html</quote>, because of the
2267 special meta-character <quote>.</quote>.
2272 <term><literal>.example.com/(.*/)?index\.html$</literal></term>
2275 This regular expression is conditional so it will match any page
2276 named <quote>index.html</quote> regardless of path which in this case can
2277 have one or more <quote>/'s</quote>. And this one must contain exactly
2278 <quote>.html</quote> (but does not have to end with that!).
2283 <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
2286 This regular expression will match any path of <quote>example.com</quote>
2287 that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
2288 <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
2289 The path does not have to end in these words, just contain them.
2294 <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
2297 This is very much the same as above, except now it must end in either
2298 <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
2299 one is limited to common image formats.
2306 There are many, many good examples to be found in <filename>default.action</filename>,
2307 and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
2312 <!-- ~ End section ~ -->
2315 <!-- ~~~~~ New section ~~~~~ -->
2316 <sect3 id="tag-pattern"><title>The Tag Pattern</title>
2319 Tag patterns are used to change the applying actions based on the
2320 request's tags. Tags can be created with either the
2321 <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
2322 or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
2326 Tag patterns have to start with <quote>TAG:</quote>, so &my-app;
2327 can tell them apart from URL patterns. Everything after the colon
2328 including white space, is interpreted as a regular expression with
2329 path pattern syntax, except that tag patterns aren't left-anchored
2330 automatically (&my-app; doesn't silently add a <quote>^</quote>,
2331 you have to do it yourself if you need it).
2335 To match all requests that are tagged with <quote>foo</quote>
2336 your pattern line should be <quote>TAG:^foo$</quote>,
2337 <quote>TAG:foo</quote> would work as well, but it would also
2338 match requests whose tags contain <quote>foo</quote> somewhere.
2339 <quote>TAG: foo</quote> wouldn't work as it requires white space.
2343 Sections can contain URL and tag patterns at the same time,
2344 but tag patterns are checked after the URL patterns and thus
2345 always overrule them, even if they are located before the URL patterns.
2349 Once a new tag is added, Privoxy checks right away if it's matched by one
2350 of the tag patterns and updates the action settings accordingly. As a result
2351 tags can be used to activate other tagger actions, as long as these other
2352 taggers look for headers that haven't already be parsed.
2356 For example you could tag client requests which use the
2357 <literal>POST</literal> method,
2358 then use this tag to activate another tagger that adds a tag if cookies
2359 are sent, and then use a block action based on the cookie tag. This allows
2360 the outcome of one action, to be input into a subsequent action. However if
2361 you'd reverse the position of the described taggers, and activated the
2362 method tagger based on the cookie tagger, no method tags would be created.
2363 The method tagger would look for the request line, but at the time
2364 the cookie tag is created, the request line has already been parsed.
2368 While this is a limitation you should be aware of, this kind of
2369 indirection is seldom needed anyway and even the example doesn't
2370 make too much sense.
2377 <!-- ~ End section ~ -->
2380 <!-- ~~~~~ New section ~~~~~ -->
2382 <sect2 id="actions">
2383 <title>Actions</title>
2385 All actions are disabled by default, until they are explicitly enabled
2386 somewhere in an actions file. Actions are turned on if preceded with a
2387 <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
2388 <literal>+action</literal> means <quote>do that action</quote>, e.g.
2389 <literal>+block</literal> means <quote>please block URLs that match the
2390 following patterns</quote>, and <literal>-block</literal> means <quote>don't
2391 block URLs that match the following patterns, even if <literal>+block</literal>
2392 previously applied.</quote>
2397 Again, actions are invoked by placing them on a line, enclosed in curly braces and
2398 separated by whitespace, like in
2399 <literal>{+some-action -some-other-action{some-parameter}}</literal>,
2400 followed by a list of URL patterns, one per line, to which they apply.
2401 Together, the actions line and the following pattern lines make up a section
2402 of the actions file.
2406 Actions fall into three categories:
2413 Boolean, i.e the action can only be <quote>enabled</quote> or
2414 <quote>disabled</quote>. Syntax:
2418 +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
2419 -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable></screen>
2422 Example: <literal>+handle-as-image</literal>
2429 Parameterized, where some value is required in order to enable this type of action.
2434 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
2435 # overwriting parameter from previous match if necessary
2436 -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted</screen>
2439 Note that if the URL matches multiple positive forms of a parameterized action,
2440 the last match wins, i.e. the params from earlier matches are simply ignored.
2443 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>
2449 Multi-value. These look exactly like parameterized actions,
2450 but they behave differently: If the action applies multiple times to the
2451 same URL, but with different parameters, <emphasis>all</emphasis> the parameters
2452 from <emphasis>all</emphasis> matches are remembered. This is used for actions
2453 that can be executed for the same request repeatedly, like adding multiple
2454 headers, or filtering through multiple filters. Syntax:
2458 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
2459 -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
2460 # If it was the last one left, disable the action.
2461 <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list</screen>
2464 Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
2465 <literal>+filter{html-annoyances}</literal>
2473 If nothing is specified in any actions file, no <quote>actions</quote> are
2474 taken. So in this case <application>Privoxy</application> would just be a
2475 normal, non-blocking, non-filtering proxy. You must specifically enable the
2476 privacy and blocking features you need (although the provided default actions
2477 files will give a good starting point).
2481 Later defined action sections always over-ride earlier ones of the same type.
2482 So exceptions to any rules you make, should come in the latter part of the file (or
2483 in a file that is processed later when using multiple actions files such
2484 as <filename>user.action</filename>). For multi-valued actions, the actions
2485 are applied in the order they are specified. Actions files are processed in
2486 the order they are defined in <filename>config</filename> (the default
2487 installation has three actions files). It also quite possible for any given
2488 URL to match more than one <quote>pattern</quote> (because of wildcards and
2489 regular expressions), and thus to trigger more than one set of actions! Last
2493 <!-- start actions listing -->
2495 The list of valid <application>Privoxy</application> actions are:
2499 <!-- ********************************************************** -->
2500 <!-- Please note the below defined actions use id's that are -->
2501 <!-- probably linked from other places, so please don't change. -->
2503 <!-- ********************************************************** -->
2506 <!-- ~~~~~ New section ~~~~~ -->
2508 <sect3 renderas="sect4" id="add-header">
2509 <title>add-header</title>
2513 <term>Typical use:</term>
2515 <para>Confuse log analysis, custom applications</para>
2520 <term>Effect:</term>
2523 Sends a user defined HTTP header to the web server.
2530 <!-- boolean, parameterized, Multi-value -->
2532 <para>Multi-value.</para>
2537 <term>Parameter:</term>
2540 Any string value is possible. Validity of the defined HTTP headers is not checked.
2541 It is recommended that you use the <quote><literal>X-</literal></quote> prefix
2551 This action may be specified multiple times, in order to define multiple
2552 headers. This is rarely needed for the typical user. If you don't know what
2553 <quote>HTTP headers</quote> are, you definitely don't need to worry about this
2557 Headers added by this action are not modified by other actions.
2563 <term>Example usage:</term>
2566 <screen>+add-header{X-User-Tracking: sucks}</screen>
2574 <!-- ~~~~~ New section ~~~~~ -->
2575 <sect3 renderas="sect4" id="block">
2576 <title>block</title>
2580 <term>Typical use:</term>
2582 <para>Block ads or other unwanted content</para>
2587 <term>Effect:</term>
2590 Requests for URLs to which this action applies are blocked, i.e. the
2591 requests are trapped by &my-app; and the requested URL is never retrieved,
2592 but is answered locally with a substitute page or image, as determined by
2594 linkend="handle-as-image">handle-as-image</link></literal>,
2596 linkend="set-image-blocker">set-image-blocker</link></literal>, and
2598 linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
2606 <!-- boolean, parameterized, Multi-value -->
2608 <para>Parameterized.</para>
2613 <term>Parameter:</term>
2615 <para>A block reason that should be given to the user.</para>
2623 <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
2624 for requests to blocked pages. This page contains the block reason given as
2625 parameter, a link to find out why the block action applies, and a click-through
2626 to the blocked content (the latter only if the force feature is available and
2630 A very important exception occurs if <emphasis>both</emphasis>
2631 <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
2632 apply to the same request: it will then be replaced by an image. If
2633 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
2634 (see below) also applies, the type of image will be determined by its parameter,
2635 if not, the standard checkerboard pattern is sent.
2638 It is important to understand this process, in order
2639 to understand how <application>Privoxy</application> deals with
2640 ads and other unwanted content. Blocking is a core feature, and one
2641 upon which various other features depend.
2644 The <literal><link linkend="filter">filter</link></literal>
2645 action can perform a very similar task, by <quote>blocking</quote>
2646 banner images and other content through rewriting the relevant URLs in the
2647 document's HTML source, so they don't get requested in the first place.
2648 Note that this is a totally different technique, and it's easy to confuse the two.
2654 <term>Example usage (section):</term>
2657 <screen>{+block{No nasty stuff for you.}}
2658 # Block and replace with "blocked" page
2659 .nasty-stuff.example.com
2661 {+block{Doubleclick banners.} +handle-as-image}
2662 # Block and replace with image
2666 {+block{Layered ads.} +handle-as-empty-document}
2667 # Block and then ignore
2668 adserver.example.net/.*\.js$</screen>
2678 <!-- ~~~~~ New section ~~~~~ -->
2679 <sect3 renderas="sect4" id="change-x-forwarded-for">
2680 <title>change-x-forwarded-for</title>
2684 <term>Typical use:</term>
2686 <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
2691 <term>Effect:</term>
2694 Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
2702 <!-- Boolean, Parameterized, Multi-value -->
2704 <para>Parameterized.</para>
2709 <term>Parameter:</term>
2713 <para><quote>block</quote> to delete the header.</para>
2717 <quote>add</quote> to create the header (or append
2718 the client's IP address to an already existing one).
2729 It is safe and recommended to use <literal>block</literal>.
2732 Forwarding the source address of the request may make
2733 sense in some multi-user setups but is also a privacy risk.
2738 <term>Example usage:</term>
2741 <screen>+change-x-forwarded-for{block}</screen>
2748 <!-- ~~~~~ New section ~~~~~ -->
2749 <sect3 renderas="sect4" id="client-header-filter">
2750 <title>client-header-filter</title>
2754 <term>Typical use:</term>
2757 Rewrite or remove single client headers.
2763 <term>Effect:</term>
2766 All client headers to which this action applies are filtered on-the-fly through
2767 the specified regular expression based substitutions.
2774 <!-- boolean, parameterized, Multi-value -->
2776 <para>Parameterized.</para>
2781 <term>Parameter:</term>
2784 The name of a client-header filter, as defined in one of the
2785 <link linkend="filter-file">filter files</link>.
2794 Client-header filters are applied to each header on its own, not to
2795 all at once. This makes it easier to diagnose problems, but on the downside
2796 you can't write filters that only change header x if header y's value is z.
2797 You can do that by using tags though.
2800 Client-header filters are executed after the other header actions have finished
2801 and use their output as input.
2804 If the request URI gets changed, &my-app; will detect that and use the new
2805 one. This can be used to rewrite the request destination behind the client's
2806 back, for example to specify a Tor exit relay for certain requests.
2809 Please refer to the <link linkend="filter-file">filter file chapter</link>
2810 to learn which client-header filters are available by default, and how to
2818 <term>Example usage (section):</term>
2822 # Hide Tor exit notation in Host and Referer Headers
2823 {+client-header-filter{hide-tor-exit-notation}}
2834 <!-- ~~~~~ New section ~~~~~ -->
2835 <sect3 renderas="sect4" id="client-header-tagger">
2836 <title>client-header-tagger</title>
2840 <term>Typical use:</term>
2843 Block requests based on their headers.
2849 <term>Effect:</term>
2852 Client headers to which this action applies are filtered on-the-fly through
2853 the specified regular expression based substitutions, the result is used as
2861 <!-- boolean, parameterized, Multi-value -->
2863 <para>Parameterized.</para>
2868 <term>Parameter:</term>
2871 The name of a client-header tagger, as defined in one of the
2872 <link linkend="filter-file">filter files</link>.
2881 Client-header taggers are applied to each header on its own,
2882 and as the header isn't modified, each tagger <quote>sees</quote>
2886 Client-header taggers are the first actions that are executed
2887 and their tags can be used to control every other action.
2893 <term>Example usage (section):</term>
2897 # Tag every request with the User-Agent header
2898 {+client-header-tagger{user-agent}}
2901 # Tagging itself doesn't change the action
2902 # settings, sections with TAG patterns do:
2904 # If it's a download agent, use a different forwarding proxy,
2905 # show the real User-Agent and make sure resume works.
2906 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
2907 -hide-if-modified-since \
2908 -overwrite-last-modified \
2913 TAG:^User-Agent: NetBSD-ftp/
2914 TAG:^User-Agent: Novell ZYPP Installer
2915 TAG:^User-Agent: RPM APT-HTTP/
2916 TAG:^User-Agent: fetch libfetch/
2917 TAG:^User-Agent: Ubuntu APT-HTTP/
2918 TAG:^User-Agent: MPlayer/
2923 # Tag all requests with the Range header set
2924 {+client-header-tagger{range-requests}}
2927 # Disable filtering for the tagged requests.
2929 # With filtering enabled Privoxy would remove the Range headers
2930 # to be able to filter the whole response. The downside is that
2931 # it prevents clients from resuming downloads or skipping over
2932 # parts of multimedia files.
2933 {-filter -deanimate-gifs}
2944 <!-- ~~~~~ New section ~~~~~ -->
2945 <sect3 renderas="sect4" id="content-type-overwrite">
2946 <title>content-type-overwrite</title>
2950 <term>Typical use:</term>
2952 <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
2957 <term>Effect:</term>
2960 Replaces the <quote>Content-Type:</quote> HTTP server header.
2967 <!-- Boolean, Parameterized, Multi-value -->
2969 <para>Parameterized.</para>
2974 <term>Parameter:</term>
2986 The <quote>Content-Type:</quote> HTTP server header is used by the
2987 browser to decide what to do with the document. The value of this
2988 header can cause the browser to open a download menu instead of
2989 displaying the document by itself, even if the document's format is
2990 supported by the browser.
2993 The declared content type can also affect which rendering mode
2994 the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
2995 many browsers treat it as yet another broken HTML document.
2996 If it is send as <quote>application/xml</quote>, browsers with
2997 XHTML support will only display it, if the syntax is correct.
3000 If you see a web site that proudly uses XHTML buttons, but sets
3001 <quote>Content-Type: text/html</quote>, you can use &my-app;
3002 to overwrite it with <quote>application/xml</quote> and validate
3003 the web master's claim inside your XHTML-supporting browser.
3004 If the syntax is incorrect, the browser will complain loudly.
3007 You can also go the opposite direction: if your browser prints
3008 error messages instead of rendering a document falsely declared
3009 as XHTML, you can overwrite the content type with
3010 <quote>text/html</quote> and have it rendered as broken HTML document.
3013 By default <literal>content-type-overwrite</literal> only replaces
3014 <quote>Content-Type:</quote> headers that look like some kind of text.
3015 If you want to overwrite it unconditionally, you have to combine it with
3016 <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
3017 This limitation exists for a reason, think twice before circumventing it.
3020 Most of the time it's easier to replace this action with a custom
3021 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3022 It allows you to activate it for every document of a certain site and it will still
3023 only replace the content types you aimed at.
3026 Of course you can apply <literal>content-type-overwrite</literal>
3027 to a whole site and then make URL based exceptions, but it's a lot
3028 more work to get the same precision.
3034 <term>Example usage (sections):</term>
3037 <screen># Check if www.example.net/ really uses valid XHTML
3038 { +content-type-overwrite{application/xml} }
3041 # but leave the content type unmodified if the URL looks like a style sheet
3042 {-content-type-overwrite}
3043 www.example.net/.*\.css$
3044 www.example.net/.*style
3053 <!-- ~~~~~ New section ~~~~~ -->
3054 <sect3 renderas="sect4" id="crunch-client-header">
3058 <title>crunch-client-header</title>
3062 <term>Typical use:</term>
3064 <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
3069 <term>Effect:</term>
3072 Deletes every header sent by the client that contains the string the user supplied as parameter.
3079 <!-- Boolean, Parameterized, Multi-value -->
3081 <para>Parameterized.</para>
3086 <term>Parameter:</term>
3098 This action allows you to block client headers for which no dedicated
3099 <application>Privoxy</application> action exists.
3100 <application>Privoxy</application> will remove every client header that
3101 contains the string you supplied as parameter.
3104 Regular expressions are <emphasis>not supported</emphasis> and you can't
3105 use this action to block different headers in the same request, unless
3106 they contain the same string.
3109 <literal>crunch-client-header</literal> is only meant for quick tests.
3110 If you have to block several different headers, or only want to modify
3111 parts of them, you should use a
3112 <literal><link linkend="client-header-filter">client-header filter</link></literal>.
3116 Don't block any header without understanding the consequences.
3123 <term>Example usage (section):</term>
3126 <screen># Block the non-existent "Privacy-Violation:" client header
3127 { +crunch-client-header{Privacy-Violation:} }
3137 <!-- ~~~~~ New section ~~~~~ -->
3138 <sect3 renderas="sect4" id="crunch-if-none-match">
3139 <title>crunch-if-none-match</title>
3145 <term>Typical use:</term>
3147 <para>Prevent yet another way to track the user's steps between sessions.</para>
3152 <term>Effect:</term>
3155 Deletes the <quote>If-None-Match:</quote> HTTP client header.
3162 <!-- Boolean, Parameterized, Multi-value -->
3164 <para>Boolean.</para>
3169 <term>Parameter:</term>
3181 Removing the <quote>If-None-Match:</quote> HTTP client header
3182 is useful for filter testing, where you want to force a real
3183 reload instead of getting status code <quote>304</quote> which
3184 would cause the browser to use a cached copy of the page.
3187 It is also useful to make sure the header isn't used as a cookie
3188 replacement (unlikely but possible).
3191 Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
3192 caching problems, as long as the <quote>If-Modified-Since:</quote> header
3193 isn't blocked or missing as well.
3196 It is recommended to use this action together with
3197 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
3199 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
3205 <term>Example usage (section):</term>
3208 <screen># Let the browser revalidate cached documents but don't
3209 # allow the server to use the revalidation headers for user tracking.
3210 {+hide-if-modified-since{-60} \
3211 +overwrite-last-modified{randomize} \
3212 +crunch-if-none-match}
3221 <!-- ~~~~~ New section ~~~~~ -->
3222 <sect3 renderas="sect4" id="crunch-incoming-cookies">
3223 <title>crunch-incoming-cookies</title>
3227 <term>Typical use:</term>
3230 Prevent the web server from setting HTTP cookies on your system
3236 <term>Effect:</term>
3239 Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
3246 <!-- Boolean, Parameterized, Multi-value -->
3248 <para>Boolean.</para>
3253 <term>Parameter:</term>
3265 This action is only concerned with <emphasis>incoming</emphasis> HTTP cookies. For
3266 <emphasis>outgoing</emphasis> HTTP cookies, use
3267 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
3268 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3271 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3272 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3273 since it would prevent the session cookies from being set. See also
3274 <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
3280 <term>Example usage:</term>
3283 <screen>+crunch-incoming-cookies</screen>
3291 <!-- ~~~~~ New section ~~~~~ -->
3292 <sect3 renderas="sect4" id="crunch-server-header">
3293 <title>crunch-server-header</title>
3299 <term>Typical use:</term>
3301 <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
3306 <term>Effect:</term>
3309 Deletes every header sent by the server that contains the string the user supplied as parameter.
3316 <!-- Boolean, Parameterized, Multi-value -->
3318 <para>Parameterized.</para>
3323 <term>Parameter:</term>
3335 This action allows you to block server headers for which no dedicated
3336 <application>Privoxy</application> action exists. <application>Privoxy</application>
3337 will remove every server header that contains the string you supplied as parameter.
3340 Regular expressions are <emphasis>not supported</emphasis> and you can't
3341 use this action to block different headers in the same request, unless
3342 they contain the same string.
3345 <literal>crunch-server-header</literal> is only meant for quick tests.
3346 If you have to block several different headers, or only want to modify
3347 parts of them, you should use a custom
3348 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3352 Don't block any header without understanding the consequences.
3359 <term>Example usage (section):</term>
3362 <screen># Crunch server headers that try to prevent caching
3363 { +crunch-server-header{no-cache} }
3372 <!-- ~~~~~ New section ~~~~~ -->
3373 <sect3 renderas="sect4" id="crunch-outgoing-cookies">
3374 <title>crunch-outgoing-cookies</title>
3378 <term>Typical use:</term>
3381 Prevent the web server from reading any HTTP cookies from your system
3387 <term>Effect:</term>
3390 Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
3397 <!-- Boolean, Parameterized, Multi-value -->
3399 <para>Boolean.</para>
3404 <term>Parameter:</term>
3416 This action is only concerned with <emphasis>outgoing</emphasis> HTTP cookies. For
3417 <emphasis>incoming</emphasis> HTTP cookies, use
3418 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
3419 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3422 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3423 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3424 since it would prevent the session cookies from being read.
3430 <term>Example usage:</term>
3433 <screen>+crunch-outgoing-cookies</screen>
3442 <!-- ~~~~~ New section ~~~~~ -->
3443 <sect3 renderas="sect4" id="deanimate-gifs">
3444 <title>deanimate-gifs</title>
3448 <term>Typical use:</term>
3450 <para>Stop those annoying, distracting animated GIF images.</para>
3455 <term>Effect:</term>
3458 De-animate GIF animations, i.e. reduce them to their first or last image.
3465 <!-- boolean, parameterized, Multi-value -->
3467 <para>Parameterized.</para>
3472 <term>Parameter:</term>
3475 <quote>last</quote> or <quote>first</quote>
3484 This will also shrink the images considerably (in bytes, not pixels!). If
3485 the option <quote>first</quote> is given, the first frame of the animation
3486 is used as the replacement. If <quote>last</quote> is given, the last
3487 frame of the animation is used instead, which probably makes more sense for
3488 most banner animations, but also has the risk of not showing the entire
3489 last frame (if it is only a delta to an earlier frame).
3492 You can safely use this action with patterns that will also match non-GIF
3493 objects, because no attempt will be made at anything that doesn't look like
3500 <term>Example usage:</term>
3503 <screen>+deanimate-gifs{last}</screen>
3510 <!-- ~~~~~ New section ~~~~~ -->
3511 <sect3 renderas="sect4" id="downgrade-http-version">
3512 <title>downgrade-http-version</title>
3516 <term>Typical use:</term>
3518 <para>Work around (very rare) problems with HTTP/1.1</para>
3523 <term>Effect:</term>
3526 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
3533 <!-- boolean, parameterized, Multi-value -->
3535 <para>Boolean.</para>
3540 <term>Parameter:</term>
3552 This is a left-over from the time when <application>Privoxy</application>
3553 didn't support important HTTP/1.1 features well. It is left here for the
3554 unlikely case that you experience HTTP/1.1-related problems with some server
3558 Note that enabling this action is only a workaround. It should not
3559 be enabled for sites that work without it. While it shouldn't break
3560 any pages, it has an (usually negative) performance impact.
3563 If you come across a site where enabling this action helps, please report it,
3564 so the cause of the problem can be analyzed. If the problem turns out to be
3565 caused by a bug in <application>Privoxy</application> it should be
3566 fixed so the following release works without the work around.
3572 <term>Example usage (section):</term>
3575 <screen>{+downgrade-http-version}
3576 problem-host.example.com</screen>
3584 <!-- ~~~~~ New section ~~~~~ -->
3585 <sect3 renderas="sect4" id="fast-redirects">
3586 <title>fast-redirects</title>
3590 <term>Typical use:</term>
3592 <para>Fool some click-tracking scripts and speed up indirect links.</para>
3597 <term>Effect:</term>
3600 Detects redirection URLs and redirects the browser without contacting
3601 the redirection server first.
3608 <!-- boolean, parameterized, Multi-value -->
3610 <para>Parameterized.</para>
3615 <term>Parameter:</term>
3620 <quote>simple-check</quote> to just search for the string <quote>http://</quote>
3621 to detect redirection URLs.
3626 <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
3627 for redirection URLs.
3638 Many sites, like yahoo.com, don't just link to other sites. Instead, they
3639 will link to some script on their own servers, giving the destination as a
3640 parameter, which will then redirect you to the final target. URLs
3641 resulting from this scheme typically look like:
3642 <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
3645 Sometimes, there are even multiple consecutive redirects encoded in the
3646 URL. These redirections via scripts make your web browsing more traceable,
3647 since the server from which you follow such a link can see where you go
3648 to. Apart from that, valuable bandwidth and time is wasted, while your
3649 browser asks the server for one redirect after the other. Plus, it feeds
3653 This feature is currently not very smart and is scheduled for improvement.
3654 If it is enabled by default, you will have to create some exceptions to
3655 this action. It can lead to failures in several ways:
3658 Not every URLs with other URLs as parameters is evil.
3659 Some sites offer a real service that requires this information to work.
3660 For example a validation service needs to know, which document to validate.
3661 <literal>fast-redirects</literal> assumes that every URL parameter that
3662 looks like another URL is a redirection target, and will always redirect to
3663 the last one. Most of the time the assumption is correct, but if it isn't,
3664 the user gets redirected anyway.
3667 Another failure occurs if the URL contains other parameters after the URL parameter.
3669 <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
3670 contains the redirection URL <quote>http://www.example.net/</quote>,
3671 followed by another parameter. <literal>fast-redirects</literal> doesn't know that
3672 and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
3673 Depending on the target server configuration, the parameter will be silently ignored
3674 or lead to a <quote>page not found</quote> error. You can prevent this problem by
3675 first using the <literal><link linkend="redirect">redirect</link></literal> action
3676 to remove the last part of the URL, but it requires a little effort.
3679 To detect a redirection URL, <literal>fast-redirects</literal> only
3680 looks for the string <quote>http://</quote>, either in plain text
3681 (invalid but often used) or encoded as <quote>http%3a//</quote>.
3682 Some sites use their own URL encoding scheme, encrypt the address
3683 of the target server or replace it with a database id. In theses cases
3684 <literal>fast-redirects</literal> is fooled and the request reaches the
3685 redirection server where it probably gets logged.
3691 <term>Example usage:</term>
3695 { +fast-redirects{simple-check} }
3698 { +fast-redirects{check-decoded-url} }
3699 another.example.com/testing</screen>
3708 <!-- ~~~~~ New section ~~~~~ -->
3709 <sect3 renderas="sect4" id="filter">
3710 <title>filter</title>
3714 <term>Typical use:</term>
3716 <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
3717 do fun text replacements, add personalized effects, etc.</para>
3722 <term>Effect:</term>
3725 All instances of text-based type, most notably HTML and JavaScript, to which
3726 this action applies, can be filtered on-the-fly through the specified regular
3727 expression based substitutions. (Note: as of version 3.0.3 plain text documents
3728 are exempted from filtering, because web servers often use the
3729 <literal>text/plain</literal> MIME type for all files whose type they don't know.)
3736 <!-- boolean, parameterized, Multi-value -->
3738 <para>Parameterized.</para>
3743 <term>Parameter:</term>
3746 The name of a content filter, as defined in the <link linkend="filter-file">filter file</link>.
3747 Filters can be defined in one or more files as defined by the
3748 <literal><link linkend="filterfile">filterfile</link></literal>
3749 option in the <link linkend="config">config file</link>.
3750 <filename>default.filter</filename> is the collection of filters
3751 supplied by the developers. Locally defined filters should go
3752 in their own file, such as <filename>user.filter</filename>.
3755 When used in its negative form,
3756 and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
3765 For your convenience, there are a number of pre-defined filters available
3766 in the distribution filter file that you can use. See the examples below for
3770 Filtering requires buffering the page content, which may appear to
3771 slow down page rendering since nothing is displayed until all content has
3772 passed the filters. (The total time until the page is completely rendered
3773 doesn't change much, but it may be perceived as slower since the page is
3774 not incrementally displayed.)
3775 This effect will be more noticeable on slower connections.
3778 <quote>Rolling your own</quote>
3779 filters requires a knowledge of
3780 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3781 Expressions</quote></ulink> and
3782 <ulink url="http://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
3783 This is very powerful feature, and potentially very intrusive.
3784 Filters should be used with caution, and where an equivalent
3785 <quote>action</quote> is not available.
3788 The amount of data that can be filtered is limited to the
3789 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
3790 option in the main <link linkend="config">config file</link>. The
3791 default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
3792 data, and all pending data, is passed through unfiltered.
3795 Inappropriate MIME types, such as zipped files, are not filtered at all.
3796 (Again, only text-based types except plain text). Encrypted SSL data
3797 (from HTTPS servers) cannot be filtered either, since this would violate
3798 the integrity of the secure transaction. In some situations it might
3799 be necessary to protect certain text, like source code, from filtering
3800 by defining appropriate <literal>-filter</literal> exceptions.
3803 Compressed content can't be filtered either, but if &my-app;
3804 is compiled with zlib support and a supported compression algorithm
3805 is used (gzip or deflate), &my-app; can first decompress the content
3809 If you use a &my-app; version without zlib support, but want filtering to work on
3810 as much documents as possible, even those that would normally be sent compressed,
3811 you must use the <literal><link linkend="prevent-compression">prevent-compression</link></literal>
3812 action in conjunction with <literal>filter</literal>.
3815 Content filtering can achieve some of the same effects as the
3816 <literal><link linkend="block">block</link></literal>
3817 action, i.e. it can be used to block ads and banners. But the mechanism
3818 works quite differently. One effective use, is to block ad banners
3819 based on their size (see below), since many of these seem to be somewhat
3823 <link linkend="contact">Feedback</link> with suggestions for new or
3824 improved filters is particularly welcome!
3827 The below list has only the names and a one-line description of each
3828 predefined filter. There are <link linkend="predefined-filters">more
3829 verbose explanations</link> of what these filters do in the <link
3830 linkend="filter-file">filter file chapter</link>.
3836 <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
3837 See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
3838 more explanation on each:</term>
3841 <anchor id="filter-js-annoyances">
3842 <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse.</screen>
3845 <anchor id="filter-js-events">
3846 <screen>+filter{js-events} # Kill all JS event bindings and timers (Radically destructive! Only for extra nasty sites).</screen>
3849 <anchor id="filter-html-annoyances">
3850 <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse.</screen>
3853 <anchor id="filter-content-cookies">
3854 <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content.</screen>
3857 <anchor id="filter-refresh-tags">
3858 <screen>+filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups).</screen>
3861 <anchor id="filter-unsolicited-popups">
3862 <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability.</screen>
3865 <anchor id="filter-all-popups">
3866 <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability.</screen>
3869 <anchor id="filter-img-reorder">
3870 <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective.</screen>
3873 <anchor id="filter-banners-by-size">
3874 <screen>+filter{banners-by-size} # Kill banners by size.</screen>
3877 <anchor id="filter-banners-by-link">
3878 <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers.</screen>
3881 <anchor id="filter-webbugs">
3882 <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking).</screen>
3885 <anchor id="filter-tiny-textforms">
3886 <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap.</screen>
3889 <anchor id="filter-jumping-windows">
3890 <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves.</screen>
3893 <anchor id="filter-frameset-borders">
3894 <screen>+filter{frameset-borders} # Give frames a border and make them resizable.</screen>
3897 <anchor id="filter-demoronizer">
3898 <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets.</screen>
3901 <anchor id="filter-shockwave-flash">
3902 <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects.</screen>
3905 <anchor id="filter-quicktime-kioskmode">
3906 <screen>+filter{quicktime-kioskmode} # Make Quicktime movies saveable.</screen>
3909 <anchor id="filter-fun">
3910 <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
3913 <anchor id="filter-crude-parental">
3914 <screen>+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably.</screen>
3917 <anchor id="filter-ie-exploits">
3918 <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits.</screen>
3921 <anchor id="filter-site-specifics">
3922 <screen>+filter{site-specifics} # Cure for site-specific problems. Don't apply generally!</screen>
3925 <anchor id="filter-no-ping">
3926 <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
3929 <anchor id="filter-google">
3930 <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
3933 <anchor id="filter-yahoo">
3934 <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
3937 <anchor id="filter-msn">
3938 <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
3941 <anchor id="filter-blogspot">
3942 <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</screen>
3950 <!-- ~~~~~ New section ~~~~~ -->
3951 <sect3 renderas="sect4" id="force-text-mode">
3952 <title>force-text-mode</title>
3958 <term>Typical use:</term>
3960 <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
3965 <term>Effect:</term>
3968 Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
3975 <!-- Boolean, Parameterized, Multi-value -->
3977 <para>Boolean.</para>
3982 <term>Parameter:</term>
3994 As explained <literal><link linkend="filter">above</link></literal>,
3995 <application>Privoxy</application> tries to only filter files that are
3996 in some kind of text format. The same restrictions apply to
3997 <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
3998 <literal>force-text-mode</literal> declares a document as text,
3999 without looking at the <quote>Content-Type:</quote> first.
4003 Think twice before activating this action. Filtering binary data
4004 with regular expressions can cause file damage.
4011 <term>Example usage:</term>
4024 <!-- ~~~~~ New section ~~~~~ -->
4025 <sect3 renderas="sect4" id="forward-override">
4026 <title>forward-override</title>
4032 <term>Typical use:</term>
4034 <para>Change the forwarding settings based on User-Agent or request origin</para>
4039 <term>Effect:</term>
4042 Overrules the forward directives in the configuration file.
4049 <!-- Boolean, Parameterized, Multi-value -->
4051 <para>Multi-value.</para>
4056 <term>Parameter:</term>
4060 <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
4064 <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
4069 <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
4070 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
4071 to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4072 for socks5 connections (with remote DNS resolution).
4077 <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
4078 listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
4079 Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
4080 (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4081 for socks5 connections (with remote DNS resolution).
4092 This action takes parameters similar to the
4093 <link linkend="forwarding">forward</link> directives in the configuration
4094 file, but without the URL pattern. It can be used as replacement, but normally it's only
4095 used in cases where matching based on the request URL isn't sufficient.
4099 Please read the description for the <link linkend="forwarding">forward</link> directives before
4100 using this action. Forwarding to the wrong people will reduce your privacy and increase the
4101 chances of man-in-the-middle attacks.
4104 If the ports are missing or invalid, default values will be used. This might change
4105 in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
4109 Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
4110 to verify that your forward settings do what you thought the do.
4117 <term>Example usage:</term>
4121 # Always use direct connections for requests previously tagged as
4122 # <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
4123 # resuming downloads continues to work.
4124 # This way you can continue to use Tor for your normal browsing,
4125 # without overloading the Tor network with your FreeBSD ports updates
4126 # or downloads of bigger files like ISOs.
4127 # Note that HTTP headers are easy to fake and therefore their
4128 # values are as (un)trustworthy as your clients and users.
4129 {+forward-override{forward .} \
4130 -hide-if-modified-since \
4131 -overwrite-last-modified \
4133 TAG:^User-Agent: fetch libfetch/2\.0$
4142 <!-- ~~~~~ New section ~~~~~ -->
4143 <sect3 renderas="sect4" id="handle-as-empty-document">
4144 <title>handle-as-empty-document</title>
4150 <term>Typical use:</term>
4152 <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
4157 <term>Effect:</term>
4160 This action alone doesn't do anything noticeable. It just marks URLs.
4161 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4162 the presence or absence of this mark decides whether an HTML <quote>BLOCKED</quote>
4163 page, or an empty document will be sent to the client as a substitute for the blocked content.
4164 The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
4171 <!-- Boolean, Parameterized, Multi-value -->
4173 <para>Boolean.</para>
4178 <term>Parameter:</term>
4190 Some browsers complain about syntax errors if JavaScript documents
4191 are blocked with <application>Privoxy's</application>
4192 default HTML page; this option can be used to silence them.
4193 And of course this action can also be used to eliminate the &my-app;
4194 BLOCKED message in frames.
4197 The content type for the empty document can be specified with
4198 <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
4199 but usually this isn't necessary.
4205 <term>Example usage:</term>
4208 <screen># Block all documents on example.org that end with ".js",
4209 # but send an empty document instead of the usual HTML message.
4210 {+block{Blocked JavaScript} +handle-as-empty-document}
4220 <!-- ~~~~~ New section ~~~~~ -->
4221 <sect3 renderas="sect4" id="handle-as-image">
4222 <title>handle-as-image</title>
4226 <term>Typical use:</term>
4228 <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>
4233 <term>Effect:</term>
4236 This action alone doesn't do anything noticeable. It just marks URLs as images.
4237 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4238 the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
4239 page, or a replacement image (as determined by the <literal><link
4240 linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
4241 client as a substitute for the blocked content.
4248 <!-- Boolean, Parameterized, Multi-value -->
4250 <para>Boolean.</para>
4255 <term>Parameter:</term>
4267 The below generic example section is actually part of <filename>default.action</filename>.
4268 It marks all URLs with well-known image file name extensions as images and should
4272 Users will probably only want to use the handle-as-image action in conjunction with
4273 <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
4274 reflect the file type, like in the second example section.
4277 Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
4278 frames require an HTML page to be sent, or they won't display properly.
4279 Forcing <literal>handle-as-image</literal> in this situation will not replace the
4280 ad frame with an image, but lead to error messages.
4286 <term>Example usage (sections):</term>
4289 <screen># Generic image extensions:
4292 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
4294 # These don't look like images, but they're banners and should be
4295 # blocked as images:
4297 {+block{Nasty banners.} +handle-as-image}
4298 nasty-banner-server.example.com/junk.cgi\?output=trash
4307 <!-- ~~~~~ New section ~~~~~ -->
4308 <sect3 renderas="sect4" id="hide-accept-language">
4309 <title>hide-accept-language</title>
4315 <term>Typical use:</term>
4317 <para>Pretend to use different language settings.</para>
4322 <term>Effect:</term>
4325 Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
4332 <!-- Boolean, Parameterized, Multi-value -->
4334 <para>Parameterized.</para>
4339 <term>Parameter:</term>
4342 Keyword: <quote>block</quote>, or any user defined value.
4351 Faking the browser's language settings can be useful to make a
4352 foreign User-Agent set with
4353 <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
4357 However some sites with content in different languages check the
4358 <quote>Accept-Language:</quote> to decide which one to take by default.
4359 Sometimes it isn't possible to later switch to another language without
4360 changing the <quote>Accept-Language:</quote> header first.
4363 Therefore it's a good idea to either only change the
4364 <quote>Accept-Language:</quote> header to languages you understand,
4365 or to languages that aren't wide spread.
4368 Before setting the <quote>Accept-Language:</quote> header
4369 to a rare language, you should consider that it helps to
4370 make your requests unique and thus easier to trace.
4371 If you don't plan to change this header frequently,
4372 you should stick to a common language.
4378 <term>Example usage (section):</term>
4381 <screen># Pretend to use Canadian language settings.
4382 {+hide-accept-language{en-ca} \
4383 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
4393 <!-- ~~~~~ New section ~~~~~ -->
4394 <sect3 renderas="sect4" id="hide-content-disposition">
4395 <title>hide-content-disposition</title>
4401 <term>Typical use:</term>
4403 <para>Prevent download menus for content you prefer to view inside the browser.</para>
4408 <term>Effect:</term>
4411 Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
4418 <!-- Boolean, Parameterized, Multi-value -->
4420 <para>Parameterized.</para>
4425 <term>Parameter:</term>
4428 Keyword: <quote>block</quote>, or any user defined value.
4437 Some servers set the <quote>Content-Disposition:</quote> HTTP header for
4438 documents they assume you want to save locally before viewing them.
4439 The <quote>Content-Disposition:</quote> header contains the file name
4440 the browser is supposed to use by default.
4443 In most browsers that understand this header, it makes it impossible to
4444 <emphasis>just view</emphasis> the document, without downloading it first,
4445 even if it's just a simple text file or an image.
4448 Removing the <quote>Content-Disposition:</quote> header helps
4449 to prevent this annoyance, but some browsers additionally check the
4450 <quote>Content-Type:</quote> header, before they decide if they can
4451 display a document without saving it first. In these cases, you have
4452 to change this header as well, before the browser stops displaying
4456 It is also possible to change the server's file name suggestion
4457 to another one, but in most cases it isn't worth the time to set
4461 This action will probably be removed in the future,
4462 use server-header filters instead.
4468 <term>Example usage:</term>
4471 <screen># Disarm the download link in Sourceforge's patch tracker
4473 +content-type-overwrite{text/plain}\
4474 +hide-content-disposition{block} }
4475 .sourceforge.net/tracker/download\.php</screen>
4483 <!-- ~~~~~ New section ~~~~~ -->
4484 <sect3 renderas="sect4" id="hide-if-modified-since">
4485 <title>hide-if-modified-since</title>
4491 <term>Typical use:</term>
4493 <para>Prevent yet another way to track the user's steps between sessions.</para>
4498 <term>Effect:</term>
4501 Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
4508 <!-- Boolean, Parameterized, Multi-value -->
4510 <para>Parameterized.</para>
4515 <term>Parameter:</term>
4518 Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
4527 Removing this header is useful for filter testing, where you want to force a real
4528 reload instead of getting status code <quote>304</quote>, which would cause the
4529 browser to use a cached copy of the page.
4532 Instead of removing the header, <literal>hide-if-modified-since</literal> can
4533 also add or subtract a random amount of time to/from the header's value.
4534 You specify a range of minutes where the random factor should be chosen from and
4535 <application>Privoxy</application> does the rest. A negative value means
4536 subtracting, a positive value adding.
4539 Randomizing the value of the <quote>If-Modified-Since:</quote> makes
4540 it less likely that the server can use the time as a cookie replacement,
4541 but you will run into caching problems if the random range is too high.
4544 It is a good idea to only use a small negative value and let
4545 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
4546 handle the greater changes.
4549 It is also recommended to use this action together with
4550 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>,
4551 otherwise it's more or less pointless.
4557 <term>Example usage (section):</term>
4560 <screen># Let the browser revalidate but make tracking based on the time less likely.
4561 {+hide-if-modified-since{-60} \
4562 +overwrite-last-modified{randomize} \
4563 +crunch-if-none-match}
4572 <!-- ~~~~~ New section ~~~~~ -->
4573 <sect3 renderas="sect4" id="hide-from-header">
4574 <title>hide-from-header</title>
4578 <term>Typical use:</term>
4580 <para>Keep your (old and ill) browser from telling web servers your email address</para>
4585 <term>Effect:</term>
4588 Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
4596 <!-- Boolean, Parameterized, Multi-value -->
4598 <para>Parameterized.</para>
4603 <term>Parameter:</term>
4606 Keyword: <quote>block</quote>, or any user defined value.
4615 The keyword <quote>block</quote> will completely remove the header
4616 (not to be confused with the <literal><link linkend="block">block</link></literal>
4620 Alternately, you can specify any value you prefer to be sent to the web
4621 server. If you do, it is a matter of fairness not to use any address that
4622 is actually used by a real person.
4625 This action is rarely needed, as modern web browsers don't send
4626 <quote>From:</quote> headers anymore.
4632 <term>Example usage:</term>
4635 <screen>+hide-from-header{block}</screen> or
4636 <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
4644 <!-- ~~~~~ New section ~~~~~ -->
4645 <sect3 renderas="sect4" id="hide-referrer">
4646 <title>hide-referrer</title>
4647 <anchor id="hide-referer">
4650 <term>Typical use:</term>
4652 <para>Conceal which link you followed to get to a particular site</para>
4657 <term>Effect:</term>
4660 Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
4661 or replaces it with a forged one.
4668 <!-- Boolean, Parameterized, Multi-value -->
4670 <para>Parameterized.</para>
4675 <term>Parameter:</term>
4679 <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
4682 <para><quote>conditional-forge</quote> to forge the header if the host has changed.</para>
4685 <para><quote>block</quote> to delete the header unconditionally.</para>
4688 <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
4691 <para>Any other string to set a user defined referrer.</para>
4701 <literal>conditional-block</literal> is the only parameter,
4702 that isn't easily detected in the server's log file. If it blocks the
4703 referrer, the request will look like the visitor used a bookmark or
4704 typed in the address directly.
4707 Leaving the referrer unmodified for requests on the same host
4708 allows the server owner to see the visitor's <quote>click path</quote>,
4709 but in most cases she could also get that information by comparing
4710 other parts of the log file: for example the User-Agent if it isn't
4711 a very common one, or the user's IP address if it doesn't change between
4715 Always blocking the referrer, or using a custom one, can lead to
4716 failures on servers that check the referrer before they answer any
4717 requests, in an attempt to prevent their content from being
4718 embedded or linked to elsewhere.
4721 Both <literal>conditional-block</literal> and <literal>forge</literal>
4722 will work with referrer checks, as long as content and valid referring page
4723 are on the same host. Most of the time that's the case.
4726 <literal>hide-referer</literal> is an alternate spelling of
4727 <literal>hide-referrer</literal> and the two can be can be freely
4728 substituted with each other. (<quote>referrer</quote> is the
4729 correct English spelling, however the HTTP specification has a bug - it
4730 requires it to be spelled as <quote>referer</quote>.)
4736 <term>Example usage:</term>
4739 <screen>+hide-referrer{forge}</screen> or
4740 <screen>+hide-referrer{http://www.yahoo.com/}</screen>
4748 <!-- ~~~~~ New section ~~~~~ -->
4749 <sect3 renderas="sect4" id="hide-user-agent">
4750 <title>hide-user-agent</title>
4754 <term>Typical use:</term>
4756 <para>Try to conceal your type of browser and client operating system</para>
4761 <term>Effect:</term>
4764 Replaces the value of the <quote>User-Agent:</quote> HTTP header
4765 in client requests with the specified value.
4772 <!-- Boolean, Parameterized, Multi-value -->
4774 <para>Parameterized.</para>
4779 <term>Parameter:</term>
4782 Any user-defined string.
4792 This can lead to problems on web sites that depend on looking at this header in
4793 order to customize their content for different browsers (which, by the
4794 way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
4795 work browser-independently).
4799 Using this action in multi-user setups or wherever different types of
4800 browsers will access the same <application>Privoxy</application> is
4801 <emphasis>not recommended</emphasis>. In single-user, single-browser
4802 setups, you might use it to delete your OS version information from
4803 the headers, because it is an invitation to exploit known bugs for your
4804 OS. It is also occasionally useful to forge this in order to access
4805 sites that won't let you in otherwise (though there may be a good
4806 reason in some cases).
4809 More information on known user-agent strings can be found at
4810 <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
4812 <ulink url="http://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
4818 <term>Example usage:</term>
4821 <screen>+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}</screen>
4829 <!-- ~~~~~ New section ~~~~~ -->
4830 <sect3 renderas="sect4" id="limit-connect">
4831 <title>limit-connect</title>
4835 <term>Typical use:</term>
4837 <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
4842 <term>Effect:</term>
4845 Specifies to which ports HTTP CONNECT requests are allowable.
4852 <!-- Boolean, Parameterized, Multi-value -->
4854 <para>Parameterized.</para>
4859 <term>Parameter:</term>
4862 A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
4863 defaulting to 0 and the maximum to 65K).
4872 By default, i.e. if no <literal>limit-connect</literal> action applies,
4873 <application>Privoxy</application> allows HTTP CONNECT requests to all
4874 ports. Use <literal>limit-connect</literal> if fine-grained control
4875 is desired for some or all destinations.
4878 The CONNECT methods exists in HTTP to allow access to secure websites
4879 (<quote>https://</quote> URLs) through proxies. It works very simply:
4880 the proxy connects to the server on the specified port, and then
4881 short-circuits its connections to the client and to the remote server.
4882 This means CONNECT-enabled proxies can be used as TCP relays very easily.
4885 <application>Privoxy</application> relays HTTPS traffic without seeing
4886 the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
4887 filters. By specifying an invalid port range you can disable HTTPS entirely.
4893 <term>Example usages:</term>
4895 <!-- I had trouble getting the spacing to look right in my browser -->
4896 <!-- I probably have the wrong font setup, bollocks. -->
4897 <!-- Apparently the emphasis tag uses a proportional font no matter what -->
4899 <screen>+limit-connect{443} # Port 443 is OK.
4900 +limit-connect{80,443} # Ports 80 and 443 are OK.
4901 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
4902 +limit-connect{-} # All ports are OK
4903 +limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
4911 <!-- ~~~~~ New section ~~~~~ -->
4912 <sect3 renderas="sect4" id="limit-cookie-lifetime">
4913 <title>limit-cookie-lifetime</title>
4917 <term>Typical use:</term>
4919 <para>Limit the lifetime of HTTP cookies to a couple of minutes or hours.</para>
4924 <term>Effect:</term>
4927 Overwrites the expires field in Set-Cookie server headers if it's above the specified limit.
4934 <!-- Boolean, Parameterized, Multi-value -->
4936 <para>Parameterized.</para>
4941 <term>Parameter:</term>
4944 The lifetime limit in minutes, or 0.
4953 This action reduces the lifetime of HTTP cookies coming from the
4954 server to the specified number of minutes, starting from the time
4955 the cookie passes Privoxy.
4958 Cookies with a lifetime below the limit are not modified.
4959 The lifetime of session cookies is set to the specified limit.
4962 The effect of this action depends on the server.
4965 In case of servers which refresh their cookies with each response
4966 (or at least frequently), the lifetime limit set by this action
4968 Thus, a session associated with the cookie continues to work with
4969 this action enabled, as long as a new request is made before the
4970 last limit set is reached.
4973 However, some servers send their cookies once, with a lifetime of several
4974 years (the year 2037 is a popular choice), and do not refresh them
4975 until a certain event in the future, for example the user logging out.
4976 In this case this action may limit the absolute lifetime of the session,
4977 even if requests are made frequently.
4980 If the parameter is <quote>0</quote>, this action behaves like
4981 <literal><link linkend="session-cookies-only">session-cookies-only</link></literal>.
4987 <term>Example usages:</term>
4990 <screen>+limit-cookie-lifetime{60}
4998 <!-- ~~~~~ New section ~~~~~ -->
4999 <sect3 renderas="sect4" id="prevent-compression">
5000 <title>prevent-compression</title>
5004 <term>Typical use:</term>
5007 Ensure that servers send the content uncompressed, so it can be
5008 passed through <literal><link linkend="filter">filter</link></literal>s.
5014 <term>Effect:</term>
5017 Removes the Accept-Encoding header which can be used to ask for compressed transfer.
5024 <!-- Boolean, Parameterized, Multi-value -->
5026 <para>Boolean.</para>
5031 <term>Parameter:</term>
5043 More and more websites send their content compressed by default, which
5044 is generally a good idea and saves bandwidth. But the <literal><link
5045 linkend="filter">filter</link></literal> and
5046 <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
5047 actions need access to the uncompressed data.
5050 When compiled with zlib support (available since &my-app; 3.0.7), content that should be
5051 filtered is decompressed on-the-fly and you don't have to worry about this action.
5052 If you are using an older &my-app; version, or one that hasn't been compiled with zlib
5053 support, this action can be used to convince the server to send the content uncompressed.
5056 Most text-based instances compress very well, the size is seldom decreased by less than 50%,
5057 for markup-heavy instances like news feeds saving more than 90% of the original size isn't
5061 Not using compression will therefore slow down the transfer, and you should only
5062 enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
5063 predefined action settings.
5066 Note that some (rare) ill-configured sites don't handle requests for uncompressed
5067 documents correctly. Broken PHP applications tend to send an empty document body,
5068 some IIS versions only send the beginning of the content. If you enable
5069 <literal>prevent-compression</literal> per default, you might want to add
5070 exceptions for those sites. See the example for how to do that.
5076 <term>Example usage (sections):</term>
5080 # Selectively turn off compression, and enable a filter
5082 { +filter{tiny-textforms} +prevent-compression }
5083 # Match only these sites
5088 # Or instead, we could set a universal default:
5090 { +prevent-compression }
5093 # Then maybe make exceptions for broken sites:
5095 { -prevent-compression }
5096 .compusa.com/</screen>
5105 <!-- ~~~~~ New section ~~~~~ -->
5106 <sect3 renderas="sect4" id="overwrite-last-modified">
5107 <title>overwrite-last-modified</title>
5113 <term>Typical use:</term>
5115 <para>Prevent yet another way to track the user's steps between sessions.</para>
5120 <term>Effect:</term>
5123 Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
5130 <!-- Boolean, Parameterized, Multi-value -->
5132 <para>Parameterized.</para>
5137 <term>Parameter:</term>
5140 One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
5141 and <quote>randomize</quote>
5150 Removing the <quote>Last-Modified:</quote> header is useful for filter
5151 testing, where you want to force a real reload instead of getting status
5152 code <quote>304</quote>, which would cause the browser to reuse the old
5153 version of the page.
5156 The <quote>randomize</quote> option overwrites the value of the
5157 <quote>Last-Modified:</quote> header with a randomly chosen time
5158 between the original value and the current time. In theory the server
5159 could send each document with a different <quote>Last-Modified:</quote>
5160 header to track visits without using cookies. <quote>Randomize</quote>
5161 makes it impossible and the browser can still revalidate cached documents.
5164 <quote>reset-to-request-time</quote> overwrites the value of the
5165 <quote>Last-Modified:</quote> header with the current time. You could use
5166 this option together with
5167 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
5168 to further customize your random range.
5171 The preferred parameter here is <quote>randomize</quote>. It is safe
5172 to use, as long as the time settings are more or less correct.
5173 If the server sets the <quote>Last-Modified:</quote> header to the time
5174 of the request, the random range becomes zero and the value stays the same.
5175 Therefore you should later randomize it a second time with
5176 <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
5180 It is also recommended to use this action together with
5181 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
5187 <term>Example usage:</term>
5190 <screen># Let the browser revalidate without being tracked across sessions
5191 { +hide-if-modified-since{-60} \
5192 +overwrite-last-modified{randomize} \
5193 +crunch-if-none-match}
5202 <!-- ~~~~~ New section ~~~~~ -->
5203 <sect3 renderas="sect4" id="redirect">
5204 <title>redirect</title>
5210 <term>Typical use:</term>
5213 Redirect requests to other sites.
5219 <term>Effect:</term>
5222 Convinces the browser that the requested document has been moved
5223 to another location and the browser should get it from there.
5230 <!-- Boolean, Parameterized, Multi-value -->
5232 <para>Parameterized</para>
5237 <term>Parameter:</term>
5240 An absolute URL or a single pcrs command.
5249 Requests to which this action applies are answered with a
5250 HTTP redirect to URLs of your choosing. The new URL is
5251 either provided as parameter, or derived by applying a
5252 single pcrs command to the original URL.
5255 The syntax for pcrs commands is documented in the
5256 <link linkend="filter-file">filter file</link> section.
5259 This action will be ignored if you use it together with
5260 <literal><link linkend="block">block</link></literal>.
5261 It can be combined with
5262 <literal><link linkend="fast-redirects">fast-redirects{check-decoded-url}</link></literal>
5263 to redirect to a decoded version of a rewritten URL.
5266 Use this action carefully, make sure not to create redirection loops
5267 and be aware that using your own redirects might make it
5268 possible to fingerprint your requests.
5271 In case of problems with your redirects, or simply to watch
5272 them working, enable <link linkend="DEBUG">debug 128</link>.
5278 <term>Example usages:</term>
5281 <screen># Replace example.com's style sheet with another one
5282 { +redirect{http://localhost/css-replacements/example.com.css} }
5283 example.com/stylesheet\.css
5285 # Create a short, easy to remember nickname for a favorite site
5286 # (relies on the browser accept and forward invalid URLs to &my-app;)
5287 { +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
5290 # Always use the expanded view for Undeadly.org articles
5291 # (Note the $ at the end of the URL pattern to make sure
5292 # the request for the rewritten URL isn't redirected as well)
5293 {+redirect{s@$@&mode=expanded@}}
5294 undeadly.org/cgi\?action=article&sid=\d*$
5296 # Redirect Google search requests to MSN
5297 {+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}}
5300 # Redirect MSN search requests to Yahoo
5301 {+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}}
5302 search.msn.com//results\.aspx\?q=
5304 # Redirect remote requests for this manual
5305 # to the local version delivered by Privoxy
5306 {+redirect{s@^http://www@http://config@}}
5307 www.privoxy.org/user-manual/</screen>
5316 <!-- ~~~~~ New section ~~~~~ -->
5317 <sect3 renderas="sect4" id="server-header-filter">
5318 <title>server-header-filter</title>
5322 <term>Typical use:</term>
5325 Rewrite or remove single server headers.
5331 <term>Effect:</term>
5334 All server headers to which this action applies are filtered on-the-fly
5335 through the specified regular expression based substitutions.
5342 <!-- boolean, parameterized, Multi-value -->
5344 <para>Parameterized.</para>
5349 <term>Parameter:</term>
5352 The name of a server-header filter, as defined in one of the
5353 <link linkend="filter-file">filter files</link>.
5362 Server-header filters are applied to each header on its own, not to
5363 all at once. This makes it easier to diagnose problems, but on the downside
5364 you can't write filters that only change header x if header y's value is z.
5365 You can do that by using tags though.
5368 Server-header filters are executed after the other header actions have finished
5369 and use their output as input.
5372 Please refer to the <link linkend="filter-file">filter file chapter</link>
5373 to learn which server-header filters are available by default, and how to
5380 <term>Example usage (section):</term>
5384 {+server-header-filter{html-to-xml}}
5385 example.org/xml-instance-that-is-delivered-as-html
5387 {+server-header-filter{xml-to-html}}
5388 example.org/instance-that-is-delivered-as-xml-but-is-not
5398 <!-- ~~~~~ New section ~~~~~ -->
5399 <sect3 renderas="sect4" id="server-header-tagger">
5400 <title>server-header-tagger</title>
5404 <term>Typical use:</term>
5407 Enable or disable filters based on the Content-Type header.
5413 <term>Effect:</term>
5416 Server headers to which this action applies are filtered on-the-fly through
5417 the specified regular expression based substitutions, the result is used as
5425 <!-- boolean, parameterized, Multi-value -->
5427 <para>Parameterized.</para>
5432 <term>Parameter:</term>
5435 The name of a server-header tagger, as defined in one of the
5436 <link linkend="filter-file">filter files</link>.
5445 Server-header taggers are applied to each header on its own,
5446 and as the header isn't modified, each tagger <quote>sees</quote>
5450 Server-header taggers are executed before all other header actions
5451 that modify server headers. Their tags can be used to control
5452 all of the other server-header actions, the content filters
5453 and the crunch actions (<link linkend="redirect">redirect</link>
5454 and <link linkend="block">block</link>).
5457 Obviously crunching based on tags created by server-header taggers
5458 doesn't prevent the request from showing up in the server's log file.
5465 <term>Example usage (section):</term>
5469 # Tag every request with the content type declared by the server
5470 {+server-header-tagger{content-type}}
5481 <!-- ~~~~~ New section ~~~~~ -->
5482 <sect3 renderas="sect4" id="session-cookies-only">
5483 <title>session-cookies-only</title>
5487 <term>Typical use:</term>
5490 Allow only temporary <quote>session</quote> cookies (for the current
5491 browser session <emphasis>only</emphasis>).
5497 <term>Effect:</term>
5500 Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
5501 server headers. Most browsers will not store such cookies permanently and
5502 forget them in between sessions.
5509 <!-- Boolean, Parameterized, Multi-value -->
5511 <para>Boolean.</para>
5516 <term>Parameter:</term>
5528 This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
5529 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
5530 websites that insist or rely on setting cookies, without compromising your privacy too badly.
5533 Most browsers will not permanently store cookies that have been processed by
5534 <literal>session-cookies-only</literal> and will forget about them between sessions.
5535 This makes profiling cookies useless, but won't break sites which require cookies so
5536 that you can log in for transactions. This is generally turned on for all
5537 sites, and is the recommended setting.
5540 It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
5541 together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
5542 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
5543 will be plainly killed.
5546 Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
5547 field. If you use an exotic browser, you might want to try it out to be sure.
5550 This setting also has no effect on cookies that may have been stored
5551 previously by the browser before starting <application>Privoxy</application>.
5552 These would have to be removed manually.
5555 <application>Privoxy</application> also uses
5556 the <link linkend="filter-content-cookies">content-cookies filter</link>
5557 to block some types of cookies. Content cookies are not effected by
5558 <literal>session-cookies-only</literal>.
5564 <term>Example usage:</term>
5567 <screen>+session-cookies-only</screen>
5575 <!-- ~~~~~ New section ~~~~~ -->
5576 <sect3 renderas="sect4" id="set-image-blocker">
5577 <title>set-image-blocker</title>
5581 <term>Typical use:</term>
5583 <para>Choose the replacement for blocked images</para>
5588 <term>Effect:</term>
5591 This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
5592 <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
5593 linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
5594 apply, i.e. if the request is to be blocked as an image,
5595 <emphasis>then</emphasis> the parameter of this action decides what will be
5596 sent as a replacement.
5603 <!-- Boolean, Parameterized, Multi-value -->
5605 <para>Parameterized.</para>
5610 <term>Parameter:</term>
5615 <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
5616 decent, scales very well, and makes it obvious where banners were busted.
5621 <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
5622 completely, but makes it hard to detect where <application>Privoxy</application> has blocked
5623 images on a given page and complicates troubleshooting if <application>Privoxy</application>
5624 has blocked innocent images, like navigation icons.
5629 <quote><replaceable class="parameter">target-url</replaceable></quote> to
5630 send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
5631 to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
5632 (But note that not all browsers support redirecting to a local file system).
5635 A good application of redirects is to use special <application>Privoxy</application>-built-in
5636 URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
5637 This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
5638 the first place, but enables your browser to cache the replacement image, instead of requesting
5639 it over and over again.
5650 The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
5651 class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
5652 either <quote>blank</quote> or <quote>pattern</quote>.
5655 There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
5656 used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
5657 Auto will select the type of image that would have applied to the referring page, had it been an image.
5663 <term>Example usage:</term>
5669 <screen>+set-image-blocker{pattern}</screen>
5672 Redirect to the BSD daemon:
5675 <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
5678 Redirect to the built-in pattern for better caching:
5681 <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
5689 <!-- ~~~~~ New section ~~~~~ -->
5691 <title>Summary</title>
5693 Note that many of these actions have the potential to cause a page to
5694 misbehave, possibly even not to display at all. There are many ways
5695 a site designer may choose to design his site, and what HTTP header
5696 content, and other criteria, he may depend on. There is no way to have hard
5697 and fast rules for all sites. See the <link
5698 linkend="ACTIONSANAT">Appendix</link> for a brief example on troubleshooting
5704 <!-- ~~~~~ New section ~~~~~ -->
5705 <sect2 id="aliases">
5706 <title>Aliases</title>
5708 Custom <quote>actions</quote>, known to <application>Privoxy</application>
5709 as <quote>aliases</quote>, can be defined by combining other actions.
5710 These can in turn be invoked just like the built-in actions.
5711 Currently, an alias name can contain any character except space, tab,
5713 <quote>{</quote> and <quote>}</quote>, but we <emphasis>strongly
5714 recommend</emphasis> that you only use <quote>a</quote> to <quote>z</quote>,
5715 <quote>0</quote> to <quote>9</quote>, <quote>+</quote>, and <quote>-</quote>.
5716 Alias names are not case sensitive, and are not required to start with a
5717 <quote>+</quote> or <quote>-</quote> sign, since they are merely textually
5721 Aliases can be used throughout the actions file, but they <emphasis>must be
5722 defined in a special section at the top of the file!</emphasis>
5723 And there can only be one such section per actions file. Each actions file may
5724 have its own alias section, and the aliases defined in it are only visible
5728 There are two main reasons to use aliases: One is to save typing for frequently
5729 used combinations of actions, the other one is a gain in flexibility: If you
5730 decide once how you want to handle shops by defining an alias called
5731 <quote>shop</quote>, you can later change your policy on shops in
5732 <emphasis>one</emphasis> place, and your changes will take effect everywhere
5733 in the actions file where the <quote>shop</quote> alias is used. Calling aliases
5734 by their purpose also makes your actions files more readable.
5737 Currently, there is one big drawback to using aliases, though:
5738 <application>Privoxy</application>'s built-in web-based action file
5739 editor honors aliases when reading the actions files, but it expands
5740 them before writing. So the effects of your aliases are of course preserved,
5741 but the aliases themselves are lost when you edit sections that use aliases
5746 Now let's define some aliases...
5751 # Useful custom aliases we can use later.
5753 # Note the (required!) section header line and that this section
5754 # must be at the top of the actions file!
5758 # These aliases just save typing later:
5759 # (Note that some already use other aliases!)
5761 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5762 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5763 +block-as-image = +block{Blocked image.} +handle-as-image
5764 allow-all-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
5766 # These aliases define combinations of actions
5767 # that are useful for certain types of sites:
5769 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>
5771 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link>
5773 # Short names for other aliases, for really lazy people ;-)
5775 c0 = +crunch-all-cookies
5776 c1 = -crunch-all-cookies</screen>
5780 ...and put them to use. These sections would appear in the lower part of an
5781 actions file and define exceptions to the default actions (as specified further
5782 up for the <quote>/</quote> pattern):
5787 # These sites are either very complex or very keen on
5788 # user data and require minimal interference to work:
5791 .office.microsoft.com
5792 .windowsupdate.microsoft.com
5793 # Gmail is really mail.google.com, not gmail.com
5797 # Allow cookies (for setting and retrieving your customer data)
5801 .worldpay.com # for quietpc.com
5804 # These shops require pop-ups:
5806 {-filter{all-popups} -filter{unsolicited-popups}}
5808 .overclockers.co.uk</screen>
5812 Aliases like <quote>shop</quote> and <quote>fragile</quote> are typically used for
5813 <quote>problem</quote> sites that require more than one action to be disabled
5814 in order to function properly.
5820 <!-- ~~~~~ New section ~~~~~ -->
5821 <sect2 id="act-examples">
5822 <title>Actions Files Tutorial</title>
5824 The above chapters have shown <link linkend="actions-file">which actions files
5825 there are and how they are organized</link>, how actions are <link
5826 linkend="actions">specified</link> and <link linkend="actions-apply">applied
5827 to URLs</link>, how <link linkend="af-patterns">patterns</link> work, and how to
5828 define and use <link linkend="aliases">aliases</link>. Now, let's look at an
5829 example <filename>match-all.action</filename>, <filename>default.action</filename>
5830 and <filename>user.action</filename> file and see how all these pieces come together:
5834 <title>match-all.action</title>
5836 Remember <emphasis>all actions are disabled when matching starts</emphasis>,
5837 so we have to explicitly enable the ones we want.
5841 While the <filename>match-all.action</filename> file only contains a
5842 single section, it is probably the most important one. It has only one
5843 pattern, <quote><literal>/</literal></quote>, but this pattern
5844 <link linkend="af-patterns">matches all URLs</link>. Therefore, the set of
5845 actions used in this <quote>default</quote> section <emphasis>will
5846 be applied to all requests as a start</emphasis>. It can be partly or
5847 wholly overridden by other actions files like <filename>default.action</filename>
5848 and <filename>user.action</filename>, but it will still be largely responsible
5849 for your overall browsing experience.
5853 Again, at the start of matching, all actions are disabled, so there is
5854 no need to disable any actions here. (Remember: a <quote>+</quote>
5855 preceding the action name enables the action, a <quote>-</quote> disables!).
5856 Also note how this long line has been made more readable by splitting it into
5857 multiple lines with line continuation.
5863 +<link linkend="CHANGE-X-FORWARDED-FOR">change-x-forwarded-for{block}</link> \
5864 +<link linkend="HIDE-FROM-HEADER">hide-from-header{block}</link> \
5865 +<link linkend="SET-IMAGE-BLOCKER">set-image-blocker{pattern}</link> \
5872 The default behavior is now set.
5877 <title>default.action</title>
5880 If you aren't a developer, there's no need for you to edit the
5881 <filename>default.action</filename> file. It is maintained by
5882 the &my-app; developers and if you disagree with some of the
5883 sections, you should overrule them in your <filename>user.action</filename>.
5887 Understanding the <filename>default.action</filename> file can
5888 help you with your <filename>user.action</filename>, though.
5892 The first section in this file is a special section for internal use
5893 that prevents older &my-app; versions from reading the file:
5898 ##########################################################################
5899 # Settings -- Don't change! For internal Privoxy use ONLY.
5900 ##########################################################################
5902 for-privoxy-version=3.0.11</screen>
5906 After that comes the (optional) alias section. We'll use the example
5907 section from the above <link linkend="aliases">chapter on aliases</link>,
5908 that also explains why and how aliases are used:
5913 ##########################################################################
5915 ##########################################################################
5918 # These aliases just save typing later:
5919 # (Note that some already use other aliases!)
5921 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5922 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5923 +block-as-image = +block{Blocked image.} +handle-as-image
5924 mercy-for-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
5926 # These aliases define combinations of actions
5927 # that are useful for certain types of sites:
5929 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>
5930 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link></screen>
5934 The first of our specialized sections is concerned with <quote>fragile</quote>
5935 sites, i.e. sites that require minimum interference, because they are either
5936 very complex or very keen on tracking you (and have mechanisms in place that
5937 make them unusable for people who avoid being tracked). We will simply use
5938 our pre-defined <literal>fragile</literal> alias instead of stating the list
5939 of actions explicitly:
5944 ##########################################################################
5945 # Exceptions for sites that'll break under the default action set:
5946 ##########################################################################
5948 # "Fragile" Use a minimum set of actions for these sites (see alias above):
5951 .office.microsoft.com # surprise, surprise!
5952 .windowsupdate.microsoft.com
5953 mail.google.com</screen>
5957 Shopping sites are not as fragile, but they typically
5958 require cookies to log in, and pop-up windows for shopping
5959 carts or item details. Again, we'll use a pre-defined alias:
5968 .worldpay.com # for quietpc.com
5970 .scan.co.uk</screen>
5974 The <literal><link linkend="FAST-REDIRECTS">fast-redirects</link></literal>
5975 action, which may have been enabled in <filename>match-all.action</filename>,
5976 breaks some sites. So disable it for popular sites where we know it misbehaves:
5981 { -<link linkend="FAST-REDIRECTS">fast-redirects</link> }
5985 .altavista.com/.*(like|url|link):http
5986 .altavista.com/trans.*urltext=http
5987 .nytimes.com</screen>
5991 It is important that <application>Privoxy</application> knows which
5992 URLs belong to images, so that <emphasis>if</emphasis> they are to
5993 be blocked, a substitute image can be sent, rather than an HTML page.
5994 Contacting the remote site to find out is not an option, since it
5995 would destroy the loading time advantage of banner blocking, and it
5996 would feed the advertisers information about you. We can mark any
5997 URL as an image with the <literal><link
5998 linkend="handle-as-image">handle-as-image</link></literal> action,
5999 and marking all URLs that end in a known image file extension is a
6005 ##########################################################################
6007 ##########################################################################
6009 # Define which file types will be treated as images, in case they get
6010 # blocked further down this file:
6012 { +<link linkend="HANDLE-AS-IMAGE">handle-as-image</link> }
6013 /.*\.(gif|jpe?g|png|bmp|ico)$</screen>
6017 And then there are known banner sources. They often use scripts to
6018 generate the banners, so it won't be visible from the URL that the
6019 request is for an image. Hence we block them <emphasis>and</emphasis>
6020 mark them as images in one go, with the help of our
6021 <literal>+block-as-image</literal> alias defined above. (We could of
6022 course just as well use <literal>+<link linkend="block">block</link>
6023 +<link linkend="handle-as-image">handle-as-image</link></literal> here.)
6024 Remember that the type of the replacement image is chosen by the
6025 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
6026 action. Since all URLs have matched the default section with its
6027 <literal>+<link linkend="set-image-blocker">set-image-blocker</link>{pattern}</literal>
6028 action before, it still applies and needn't be repeated:
6033 # Known ad generators:
6038 .ad.*.doubleclick.net
6039 .a.yimg.com/(?:(?!/i/).)*$
6040 .a[0-9].yimg.com/(?:(?!/i/).)*$
6046 One of the most important jobs of <application>Privoxy</application>
6047 is to block banners. Many of these can be <quote>blocked</quote>
6048 by the <literal><link linkend="filter">filter</link>{banners-by-size}</literal>
6049 action, which we enabled above, and which deletes the references to banner
6050 images from the pages while they are loaded, so the browser doesn't request
6051 them anymore, and hence they don't need to be blocked here. But this naturally
6052 doesn't catch all banners, and some people choose not to use filters, so we
6053 need a comprehensive list of patterns for banner URLs here, and apply the
6054 <literal><link linkend="block">block</link></literal> action to them.
6057 First comes many generic patterns, which do most of the work, by
6058 matching typical domain and path name components of banners. Then comes
6059 a list of individual patterns for specific sites, which is omitted here
6060 to keep the example short:
6065 ##########################################################################
6066 # Block these fine banners:
6067 ##########################################################################
6068 { <link linkend="BLOCK">+block{Banner ads.}</link> }
6076 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
6077 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
6079 # Site-specific patterns (abbreviated):
6081 .hitbox.com</screen>
6085 It's quite remarkable how many advertisers actually call their banner
6086 servers ads.<replaceable>company</replaceable>.com, or call the directory
6087 in which the banners are stored simply <quote>banners</quote>. So the above
6088 generic patterns are surprisingly effective.
6091 But being very generic, they necessarily also catch URLs that we don't want
6092 to block. The pattern <literal>.*ads.</literal> e.g. catches
6093 <quote>nasty-<emphasis>ads</emphasis>.nasty-corp.com</quote> as intended,
6094 but also <quote>downlo<emphasis>ads</emphasis>.sourcefroge.net</quote> or
6095 <quote><emphasis>ads</emphasis>l.some-provider.net.</quote> So here come some
6096 well-known exceptions to the <literal>+<link linkend="BLOCK">block</link></literal>
6100 Note that these are exceptions to exceptions from the default! Consider the URL
6101 <quote>downloads.sourcefroge.net</quote>: Initially, all actions are deactivated,
6102 so it wouldn't get blocked. Then comes the defaults section, which matches the
6103 URL, but just deactivates the <literal><link linkend="BLOCK">block</link></literal>
6104 action once again. Then it matches <literal>.*ads.</literal>, an exception to the
6105 general non-blocking policy, and suddenly
6106 <literal><link linkend="BLOCK">+block</link></literal> applies. And now, it'll match
6107 <literal>.*loads.</literal>, where <literal><link linkend="BLOCK">-block</link></literal>
6108 applies, so (unless it matches <emphasis>again</emphasis> further down) it ends up
6109 with no <literal><link linkend="BLOCK">block</link></literal> action applying.
6114 ##########################################################################
6115 # Save some innocent victims of the above generic block patterns:
6116 ##########################################################################
6120 { -<link linkend="BLOCK">block</link> }
6121 adv[io]*. # (for advogato.org and advice.*)
6122 adsl. # (has nothing to do with ads)
6123 adobe. # (has nothing to do with ads either)
6124 ad[ud]*. # (adult.* and add.*)
6125 .edu # (universities don't host banners (yet!))
6126 .*loads. # (downloads, uploads etc)
6134 www.globalintersec.com/adv # (adv = advanced)
6135 www.ugu.com/sui/ugu/adv</screen>
6139 Filtering source code can have nasty side effects,
6140 so make an exception for our friends at sourceforge.net,
6141 and all paths with <quote>cvs</quote> in them. Note that
6142 <literal>-<link linkend="FILTER">filter</link></literal>
6143 disables <emphasis>all</emphasis> filters in one fell swoop!
6148 # Don't filter code!
6150 { -<link linkend="FILTER">filter</link> }
6155 .sourceforge.net</screen>
6159 The actual <filename>default.action</filename> is of course much more
6160 comprehensive, but we hope this example made clear how it works.
6165 <sect3><title>user.action</title>
6168 So far we are painting with a broad brush by setting general policies,
6169 which would be a reasonable starting point for many people. Now,
6170 you might want to be more specific and have customized rules that
6171 are more suitable to your personal habits and preferences. These would
6172 be for narrowly defined situations like your ISP or your bank, and should
6173 be placed in <filename>user.action</filename>, which is parsed after all other
6174 actions files and hence has the last word, over-riding any previously
6175 defined actions. <filename>user.action</filename> is also a
6176 <emphasis>safe</emphasis> place for your personal settings, since
6177 <filename>default.action</filename> is actively maintained by the
6178 <application>Privoxy</application> developers and you'll probably want
6179 to install updated versions from time to time.
6183 So let's look at a few examples of things that one might typically do in
6184 <filename>user.action</filename>:
6188 <!-- brief sample user.action here -->
6192 # My user.action file. <fred@example.com></screen>
6196 As <link linkend="aliases">aliases</link> are local to the actions
6197 file that they are defined in, you can't use the ones from
6198 <filename>default.action</filename>, unless you repeat them here:
6203 # Aliases are local to the file they are defined in.
6204 # (Re-)define aliases for this file:
6208 # These aliases just save typing later, and the alias names should
6209 # be self explanatory.
6211 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
6212 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
6213 allow-all-cookies = -crunch-all-cookies -session-cookies-only
6214 allow-popups = -filter{all-popups}
6215 +block-as-image = +block{Blocked as image.} +handle-as-image
6216 -block-as-image = -block
6218 # These aliases define combinations of actions that are useful for
6219 # certain types of sites:
6221 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer
6222 shop = -crunch-all-cookies allow-popups
6224 # Allow ads for selected useful free sites:
6226 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
6228 # Alias for specific file types that are text, but might have conflicting
6229 # MIME types. We want the browser to force these to be text documents.
6230 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>
6235 Say you have accounts on some sites that you visit regularly, and
6236 you don't want to have to log in manually each time. So you'd like
6237 to allow persistent cookies for these sites. The
6238 <literal>allow-all-cookies</literal> alias defined above does exactly
6239 that, i.e. it disables crunching of cookies in any direction, and the
6240 processing of cookies to make them only temporary.
6245 { allow-all-cookies }
6249 .redhat.com</screen>
6253 Your bank is allergic to some filter, but you don't know which, so you disable them all:
6258 { -<link linkend="FILTER">filter</link> }
6259 .your-home-banking-site.com</screen>
6263 Some file types you may not want to filter for various reasons:
6268 # Technical documentation is likely to contain strings that might
6269 # erroneously get altered by the JavaScript-oriented filters:
6274 # And this stupid host sends streaming video with a wrong MIME type,
6275 # so that Privoxy thinks it is getting HTML and starts filtering:
6277 stupid-server.example.com/</screen>
6281 Example of a simple <link linkend="BLOCK">block</link> action. Say you've
6282 seen an ad on your favourite page on example.com that you want to get rid of.
6283 You have right-clicked the image, selected <quote>copy image location</quote>
6284 and pasted the URL below while removing the leading http://, into a
6285 <literal>{ +block{} }</literal> section. Note that <literal>{ +handle-as-image
6286 }</literal> need not be specified, since all URLs ending in
6287 <literal>.gif</literal> will be tagged as images by the general rules as set
6288 in default.action anyway:
6293 { +<link linkend="BLOCK">block</link>{Nasty ads.} }
6294 www.example.com/nasty-ads/sponsor\.gif
6295 another.example.net/more/junk/here/</screen>
6299 The URLs of dynamically generated banners, especially from large banner
6300 farms, often don't use the well-known image file name extensions, which
6301 makes it impossible for <application>Privoxy</application> to guess
6302 the file type just by looking at the URL.
6303 You can use the <literal>+block-as-image</literal> alias defined above for
6305 Note that objects which match this rule but then turn out NOT to be an
6306 image are typically rendered as a <quote>broken image</quote> icon by the
6307 browser. Use cautiously.
6316 ar.atwola.com/</screen>
6320 Now you noticed that the default configuration breaks Forbes Magazine,
6321 but you were too lazy to find out which action is the culprit, and you
6322 were again too lazy to give <link linkend="contact">feedback</link>, so
6323 you just used the <literal>fragile</literal> alias on the site, and
6324 -- <emphasis>whoa!</emphasis> -- it worked. The <literal>fragile</literal>
6325 aliases disables those actions that are most likely to break a site. Also,
6326 good for testing purposes to see if it is <application>Privoxy</application>
6327 that is causing the problem or not. We later find other regular sites
6328 that misbehave, and add those to our personalized list of troublemakers:
6336 .mybank.com</screen>
6340 You like the <quote>fun</quote> text replacements in <filename>default.filter</filename>,
6341 but it is disabled in the distributed actions file.
6342 So you'd like to turn it on in your private,
6343 update-safe config, once and for all:
6348 { +<link linkend="filter-fun">filter{fun}</link> }
6349 / # For ALL sites!</screen>
6353 Note that the above is not really a good idea: There are exceptions
6354 to the filters in <filename>default.action</filename> for things that
6355 really shouldn't be filtered, like code on CVS->Web interfaces. Since
6356 <filename>user.action</filename> has the last word, these exceptions
6357 won't be valid for the <quote>fun</quote> filtering specified here.
6361 You might also worry about how your favourite free websites are
6362 funded, and find that they rely on displaying banner advertisements
6363 to survive. So you might want to specifically allow banners for those
6364 sites that you feel provide value to you:
6376 Note that <literal>allow-ads</literal> has been aliased to
6377 <literal>-<link linkend="block">block</link></literal>,
6378 <literal>-<link linkend="filter-banners-by-size">filter{banners-by-size}</link></literal>, and
6379 <literal>-<link linkend="filter-banners-by-link">filter{banners-by-link}</link></literal> above.
6383 Invoke another alias here to force an over-ride of the MIME type <literal>
6384 application/x-sh</literal> which typically would open a download type
6385 dialog. In my case, I want to look at the shell script, and then I can save
6386 it should I choose to.
6396 <filename>user.action</filename> is generally the best place to define
6397 exceptions and additions to the default policies of
6398 <filename>default.action</filename>. Some actions are safe to have their
6399 default policies set here though. So let's set a default policy to have a
6400 <quote>blank</quote> image as opposed to the checkerboard pattern for
6401 <emphasis>ALL</emphasis> sites. <quote>/</quote> of course matches all URL
6407 { +<link linkend="set-image-blocker">set-image-blocker{blank}</link> }
6408 / # ALL sites</screen>
6414 <!-- ~ End section ~ -->
6418 <!-- ~ End section ~ -->
6420 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6422 <sect1 id="filter-file">
6423 <title>Filter Files</title>
6426 On-the-fly text substitutions need
6427 to be defined in a <quote>filter file</quote>. Once defined, they
6428 can then be invoked as an <quote>action</quote>.
6432 &my-app; supports three different filter actions:
6433 <literal><link linkend="filter">filter</link></literal> to
6434 rewrite the content that is send to the client,
6435 <literal><link linkend="client-header-filter">client-header-filter</link></literal>
6436 to rewrite headers that are send by the client, and
6437 <literal><link linkend="server-header-filter">server-header-filter</link></literal>
6438 to rewrite headers that are send by the server.
6442 &my-app; also supports two tagger actions:
6443 <literal><link linkend="client-header-tagger">client-header-tagger</link></literal>
6445 <literal><link linkend="server-header-tagger">server-header-tagger</link></literal>.
6446 Taggers and filters use the same syntax in the filter files, the difference
6447 is that taggers don't modify the text they are filtering, but use a rewritten
6448 version of the filtered text as tag. The tags can then be used to change the
6449 applying actions through sections with <link linkend="tag-pattern">tag-patterns</link>.
6454 Multiple filter files can be defined through the <literal> <link
6455 linkend="filterfile">filterfile</link></literal> config directive. The filters
6456 as supplied by the developers are located in
6457 <filename>default.filter</filename>. It is recommended that any locally
6458 defined or modified filters go in a separately defined file such as
6459 <filename>user.filter</filename>.
6463 Common tasks for content filters are to eliminate common annoyances in
6464 HTML and JavaScript, such as pop-up windows,
6465 exit consoles, crippled windows without navigation tools, the
6466 infamous <BLINK> tag etc, to suppress images with certain
6467 width and height attributes (standard banner sizes or web-bugs),
6468 or just to have fun.
6472 Enabled content filters are applied to any content whose
6473 <quote>Content Type</quote> header is recognised as a sign
6474 of text-based content, with the exception of <literal>text/plain</literal>.
6475 Use the <link linkend="FORCE-TEXT-MODE">force-text-mode</link> action
6476 to also filter other content.
6480 Substitutions are made at the source level, so if you want to <quote>roll
6481 your own</quote> filters, you should first be familiar with HTML syntax,
6482 and, of course, regular expressions.
6486 Just like the <link linkend="actions-file">actions files</link>, the
6487 filter file is organized in sections, which are called <emphasis>filters</emphasis>
6488 here. Each filter consists of a heading line, that starts with one of the
6489 <emphasis>keywords</emphasis> <literal>FILTER:</literal>,
6490 <literal>CLIENT-HEADER-FILTER:</literal> or <literal>SERVER-HEADER-FILTER:</literal>
6491 followed by the filter's <emphasis>name</emphasis>, and a short (one line)
6492 <emphasis>description</emphasis> of what it does. Below that line
6493 come the <emphasis>jobs</emphasis>, i.e. lines that define the actual
6494 text substitutions. By convention, the name of a filter
6495 should describe what the filter <emphasis>eliminates</emphasis>. The
6496 comment is used in the <ulink url="http://config.privoxy.org/">web-based
6497 user interface</ulink>.
6501 Once a filter called <replaceable>name</replaceable> has been defined
6502 in the filter file, it can be invoked by using an action of the form
6503 +<literal><link linkend="filter">filter</link>{<replaceable>name</replaceable>}</literal>
6504 in any <link linkend="actions-file">actions file</link>.
6508 Filter definitions start with a header line that contains the filter
6509 type, the filter name and the filter description.
6510 A content filter header line for a filter called <quote>foo</quote> could look
6515 <screen>FILTER: foo Replace all "foo" with "bar"</screen>
6519 Below that line, and up to the next header line, come the jobs that
6520 define what text replacements the filter executes. They are specified
6521 in a syntax that imitates <ulink url="http://www.perl.org/">Perl</ulink>'s
6522 <literal>s///</literal> operator. If you are familiar with Perl, you
6523 will find this to be quite intuitive, and may want to look at the
6524 PCRS documentation for the subtle differences to Perl behaviour. Most
6525 notably, the non-standard option letter <literal>U</literal> is supported,
6526 which turns the default to ungreedy matching.
6531 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
6532 Expressions</quote></ulink>, you might want to take a look at
6533 the <link linkend="regex">Appendix on regular expressions</link>, and
6534 see the <ulink url="http://perldoc.perl.org/perlre.html">Perl
6536 <ulink url="http://perldoc.perl.org/perlop.html">the
6537 <literal>s///</literal> operator's syntax</ulink> and <ulink
6538 url="http://perldoc.perl.org/perlre.html">Perl-style regular
6539 expressions</ulink> in general.
6540 The below examples might also help to get you started.
6544 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6546 <sect2><title>Filter File Tutorial</title>
6548 Now, let's complete our <quote>foo</quote> content filter. We have already defined
6549 the heading, but the jobs are still missing. Since all it does is to replace
6550 <quote>foo</quote> with <quote>bar</quote>, there is only one (trivial) job
6555 <screen>s/foo/bar/</screen>
6559 But wait! Didn't the comment say that <emphasis>all</emphasis> occurrences
6560 of <quote>foo</quote> should be replaced? Our current job will only take
6561 care of the first <quote>foo</quote> on each page. For global substitution,
6562 we'll need to add the <literal>g</literal> option:
6566 <screen>s/foo/bar/g</screen>
6570 Our complete filter now looks like this:
6573 <screen>FILTER: foo Replace all "foo" with "bar"
6574 s/foo/bar/g</screen>
6578 Let's look at some real filters for more interesting examples. Here you see
6579 a filter that protects against some common annoyances that arise from JavaScript
6580 abuse. Let's look at its jobs one after the other:
6586 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
6588 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
6590 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg</screen>
6594 Following the header line and a comment, you see the job. Note that it uses
6595 <literal>|</literal> as the delimiter instead of <literal>/</literal>, because
6596 the pattern contains a forward slash, which would otherwise have to be escaped
6597 by a backslash (<literal>\</literal>).
6601 Now, let's examine the pattern: it starts with the text <literal><script.*</literal>
6602 enclosed in parentheses. Since the dot matches any character, and <literal>*</literal>
6603 means: <quote>Match an arbitrary number of the element left of myself</quote>, this
6604 matches <quote><script</quote>, followed by <emphasis>any</emphasis> text, i.e.
6605 it matches the whole page, from the start of the first <script> tag.
6609 That's more than we want, but the pattern continues: <literal>document\.referrer</literal>
6610 matches only the exact string <quote>document.referrer</quote>. The dot needed to
6611 be <emphasis>escaped</emphasis>, i.e. preceded by a backslash, to take away its
6612 special meaning as a joker, and make it just a regular dot. So far, the meaning is:
6613 Match from the start of the first <script> tag in a the page, up to, and including,
6614 the text <quote>document.referrer</quote>, if <emphasis>both</emphasis> are present
6615 in the page (and appear in that order).
6619 But there's still more pattern to go. The next element, again enclosed in parentheses,
6620 is <literal>.*</script></literal>. You already know what <literal>.*</literal>
6621 means, so the whole pattern translates to: Match from the start of the first <script>
6622 tag in a page to the end of the last <script> tag, provided that the text
6623 <quote>document.referrer</quote> appears somewhere in between.
6627 This is still not the whole story, since we have ignored the options and the parentheses:
6628 The portions of the page matched by sub-patterns that are enclosed in parentheses, will be
6629 remembered and be available through the variables <literal>$1, $2, ...</literal> in
6630 the substitute. The <literal>U</literal> option switches to ungreedy matching, which means
6631 that the first <literal>.*</literal> in the pattern will only <quote>eat up</quote> all
6632 text in between <quote><script</quote> and the <emphasis>first</emphasis> occurrence
6633 of <quote>document.referrer</quote>, and that the second <literal>.*</literal> will
6634 only span the text up to the <emphasis>first</emphasis> <quote></script></quote>
6635 tag. Furthermore, the <literal>s</literal> option says that the match may span
6636 multiple lines in the page, and the <literal>g</literal> option again means that the
6637 substitution is global.
6641 So, to summarize, the pattern means: Match all scripts that contain the text
6642 <quote>document.referrer</quote>. Remember the parts of the script from
6643 (and including) the start tag up to (and excluding) the string
6644 <quote>document.referrer</quote> as <literal>$1</literal>, and the part following
6645 that string, up to and including the closing tag, as <literal>$2</literal>.
6649 Now the pattern is deciphered, but wasn't this about substituting things? So
6650 lets look at the substitute: <literal>$1"Not Your Business!"$2</literal> is
6651 easy to read: The text remembered as <literal>$1</literal>, followed by
6652 <literal>"Not Your Business!"</literal> (<emphasis>including</emphasis>
6653 the quotation marks!), followed by the text remembered as <literal>$2</literal>.
6654 This produces an exact copy of the original string, with the middle part
6655 (the <quote>document.referrer</quote>) replaced by <literal>"Not Your
6656 Business!"</literal>.
6660 The whole job now reads: Replace <quote>document.referrer</quote> by
6661 <literal>"Not Your Business!"</literal> wherever it appears inside a
6662 <script> tag. Note that this job won't break JavaScript syntax,
6663 since both the original and the replacement are syntactically valid
6664 string objects. The script just won't have access to the referrer
6665 information anymore.
6669 We'll show you two other jobs from the JavaScript taming department, but
6670 this time only point out the constructs of special interest:
6675 # The status bar is for displaying link targets, not pointless blahblah
6677 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig</screen>
6681 <literal>\s</literal> stands for whitespace characters (space, tab, newline,
6682 carriage return, form feed), so that <literal>\s*</literal> means: <quote>zero
6683 or more whitespace</quote>. The <literal>?</literal> in <literal>.*?</literal>
6684 makes this matching of arbitrary text ungreedy. (Note that the <literal>U</literal>
6685 option is not set). The <literal>['"]</literal> construct means: <quote>a single
6686 <emphasis>or</emphasis> a double quote</quote>. Finally, <literal>\1</literal> is
6687 a back-reference to the first parenthesis just like <literal>$1</literal> above,
6688 with the difference that in the <emphasis>pattern</emphasis>, a backslash indicates
6689 a back-reference, whereas in the <emphasis>substitute</emphasis>, it's the dollar.
6693 So what does this job do? It replaces assignments of single- or double-quoted
6694 strings to the <quote>window.status</quote> object with a dummy assignment
6695 (using a variable name that is hopefully odd enough not to conflict with
6696 real variables in scripts). Thus, it catches many cases where e.g. pointless
6697 descriptions are displayed in the status bar instead of the link target when
6698 you move your mouse over links.
6703 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
6705 s/(<body [^>]*)onunload(.*>)/$1never$2/iU</screen>
6710 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">OnUnload
6711 event binding</ulink> in the HTML DOM was a <emphasis>CRIME</emphasis>.
6712 When I close a browser window, I want it to close and die. Basta.
6713 This job replaces the <quote>onunload</quote> attribute in
6714 <quote><body></quote> tags with the dummy word <literal>never</literal>.
6715 Note that the <literal>i</literal> option makes the pattern matching
6716 case-insensitive. Also note that ungreedy matching alone doesn't always guarantee
6717 a minimal match: In the first parenthesis, we had to use <literal>[^>]*</literal>
6718 instead of <literal>.*</literal> to prevent the match from exceeding the
6719 <body> tag if it doesn't contain <quote>OnUnload</quote>, but the page's
6724 The last example is from the fun department:
6729 FILTER: fun Fun text replacements
6731 # Spice the daily news:
6733 s/microsoft(?!\.com)/MicroSuck/ig</screen>
6737 Note the <literal>(?!\.com)</literal> part (a so-called negative lookahead)
6738 in the job's pattern, which means: Don't match, if the string
6739 <quote>.com</quote> appears directly following <quote>microsoft</quote>
6740 in the page. This prevents links to microsoft.com from being trashed, while
6741 still replacing the word everywhere else.
6746 # Buzzword Bingo (example for extended regex syntax)
6748 s* industry[ -]leading \
6750 | customer[ -]focused \
6751 | market[ -]driven \
6752 | award[ -]winning # Comments are OK, too! \
6753 | high[ -]performance \
6754 | solutions[ -]based \
6758 *<font color="red"><b>BINGO!</b></font> \
6763 The <literal>x</literal> option in this job turns on extended syntax, and allows for
6764 e.g. the liberal use of (non-interpreted!) whitespace for nicer formatting.
6772 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6774 <sect2 id="predefined-filters"><title>The Pre-defined Filters</title>
6778 Note each filter is also listed in the +filter action section above. Please
6779 keep these listings in sync.
6784 The distribution <filename>default.filter</filename> file contains a selection of
6785 pre-defined filters for your convenience:
6790 <term><emphasis>js-annoyances</emphasis></term>
6793 The purpose of this filter is to get rid of particularly annoying JavaScript abuse.
6798 replaces JavaScript references to the browser's referrer information
6799 with the string "Not Your Business!". This compliments the <literal><link
6800 linkend="hide-referrer">hide-referrer</link></literal> action on the content level.
6805 removes the bindings to the DOM's
6806 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">unload
6807 event</ulink> which we feel has no right to exist and is responsible for most <quote>exit consoles</quote>, i.e.
6808 nasty windows that pop up when you close another one.
6813 removes code that causes new windows to be opened with undesired properties, such as being
6814 full-screen, non-resizeable, without location, status or menu bar etc.
6820 Use with caution. This is an aggressive filter, and can break sites that
6821 rely heavily on JavaScript.
6827 <term><emphasis>js-events</emphasis></term>
6830 This is a very radical measure. It removes virtually all JavaScript event bindings, which
6831 means that scripts can not react to user actions such as mouse movements or clicks, window
6832 resizing etc, anymore. Use with caution!
6835 We <emphasis>strongly discourage</emphasis> using this filter as a default since it breaks
6836 many legitimate scripts. It is meant for use only on extra-nasty sites (should you really
6843 <term><emphasis>html-annoyances</emphasis></term>
6846 This filter will undo many common instances of HTML based abuse.
6849 The <literal>BLINK</literal> and <literal>MARQUEE</literal> tags
6850 are neutralized (yeah baby!), and browser windows will be created as
6851 resizeable (as of course they should be!), and will have location,
6852 scroll and menu bars -- even if specified otherwise.
6858 <term><emphasis>content-cookies</emphasis></term>
6861 Most cookies are set in the HTTP dialog, where they can be intercepted
6863 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>
6864 and <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>
6865 actions. But web sites increasingly make use of HTML meta tags and JavaScript
6866 to sneak cookies to the browser on the content level.
6869 This filter disables most HTML and JavaScript code that reads or sets
6870 cookies. It cannot detect all clever uses of these types of code, so it
6871 should not be relied on as an absolute fix. Use it wherever you would also
6872 use the cookie crunch actions.
6878 <term><emphasis>refresh-tags</emphasis></term>
6881 Disable any refresh tags if the interval is greater than nine seconds (so
6882 that redirections done via refresh tags are not destroyed). This is useful
6883 for dial-on-demand setups, or for those who find this HTML feature
6890 <term><emphasis>unsolicited-popups</emphasis></term>
6893 This filter attempts to prevent only <quote>unsolicited</quote> pop-up
6894 windows from opening, yet still allow pop-up windows that the user
6895 has explicitly chosen to open. It was added in version 3.0.1,
6896 as an improvement over earlier such filters.
6899 Technical note: The filter works by redefining the window.open JavaScript
6900 function to a dummy function, <literal>PrivoxyWindowOpen()</literal>,
6901 during the loading and rendering phase of each HTML page access, and
6902 restoring the function afterward.
6905 This is recommended only for browsers that cannot perform this function
6906 reliably themselves. And be aware that some sites require such windows
6907 in order to function normally. Use with caution.
6913 <term><emphasis>all-popups</emphasis></term>
6916 Attempt to prevent <emphasis>all</emphasis> pop-up windows from opening.
6917 Note this should be used with even more discretion than the above, since
6918 it is more likely to break some sites that require pop-ups for normal
6919 usage. Use with caution.
6925 <term><emphasis>img-reorder</emphasis></term>
6928 This is a helper filter that has no value if used alone. It makes the
6929 <literal>banners-by-size</literal> and <literal>banners-by-link</literal>
6930 (see below) filters more effective and should be enabled together with them.
6936 <term><emphasis>banners-by-size</emphasis></term>
6939 This filter removes image tags purely based on what size they are. Fortunately
6940 for us, many ads and banner images tend to conform to certain standardized
6941 sizes, which makes this filter quite effective for ad stripping purposes.
6944 Occasionally this filter will cause false positives on images that are not ads,
6945 but just happen to be of one of the standard banner sizes.
6948 Recommended only for those who require extreme ad blocking. The default
6949 block rules should catch 95+% of all ads <emphasis>without</emphasis> this filter enabled.
6955 <term><emphasis>banners-by-link</emphasis></term>
6958 This is an experimental filter that attempts to kill any banners if
6959 their URLs seem to point to known or suspected click trackers. It is currently
6960 not of much value and is not recommended for use by default.
6966 <term><emphasis>webbugs</emphasis></term>
6969 Webbugs are small, invisible images (technically 1X1 GIF images), that
6970 are used to track users across websites, and collect information on them.
6971 As an HTML page is loaded by the browser, an embedded image tag causes the
6972 browser to contact a third-party site, disclosing the tracking information
6973 through the requested URL and/or cookies for that third-party domain, without
6974 the user ever becoming aware of the interaction with the third-party site.
6975 HTML-ized spam also uses a similar technique to verify email addresses.
6978 This filter removes the HTML code that loads such <quote>webbugs</quote>.
6984 <term><emphasis>tiny-textforms</emphasis></term>
6987 A rather special-purpose filter that can be used to enlarge textareas (those
6988 multi-line text boxes in web forms) and turn off hard word wrap in them.
6989 It was written for the sourceforge.net tracker system where such boxes are
6990 a nuisance, but it can be handy on other sites, too.
6993 It is not recommended to use this filter as a default.
6999 <term><emphasis>jumping-windows</emphasis></term>
7002 Many consider windows that move, or resize themselves to be abusive. This filter
7003 neutralizes the related JavaScript code. Note that some sites might not display
7004 or behave as intended when using this filter. Use with caution.
7010 <term><emphasis>frameset-borders</emphasis></term>
7013 Some web designers seem to assume that everyone in the world will view their
7014 web sites using the same browser brand and version, screen resolution etc,
7015 because only that assumption could explain why they'd use static frame sizes,
7016 yet prevent their frames from being resized by the user, should they be too
7017 small to show their whole content.
7020 This filter removes the related HTML code. It should only be applied to sites
7027 <term><emphasis>demoronizer</emphasis></term>
7030 Many Microsoft products that generate HTML use non-standard extensions (read:
7031 violations) of the ISO 8859-1 aka Latin-1 character set. This can cause those
7032 HTML documents to display with errors on standard-compliant platforms.
7035 This filter translates the MS-only characters into Latin-1 equivalents.
7036 It is not necessary when using MS products, and will cause corruption of
7037 all documents that use 8-bit character sets other than Latin-1. It's mostly
7038 worthwhile for Europeans on non-MS platforms, if weird garbage characters
7039 sometimes appear on some pages, or user agents that don't correct for this on
7042 My version of Mozilla (ancient) shows litte square boxes for quote
7043 characters, and apostrophes on moronized pages. So many pages have this, I
7044 can read them fine now. HB 08/27/06
7051 <term><emphasis>shockwave-flash</emphasis></term>
7054 A filter for shockwave haters. As the name suggests, this filter strips code
7055 out of web pages that is used to embed shockwave flash objects.
7063 <term><emphasis>quicktime-kioskmode</emphasis></term>
7066 Change HTML code that embeds Quicktime objects so that kioskmode, which
7067 prevents saving, is disabled.
7073 <term><emphasis>fun</emphasis></term>
7076 Text replacements for subversive browsing fun. Make fun of your favorite
7077 Monopolist or play buzzword bingo.
7083 <term><emphasis>crude-parental</emphasis></term>
7086 A demonstration-only filter that shows how <application>Privoxy</application>
7087 can be used to delete web content on a keyword basis.
7093 <term><emphasis>ie-exploits</emphasis></term>
7096 An experimental collection of text replacements to disable malicious HTML and JavaScript
7097 code that exploits known security holes in Internet Explorer.
7100 Presently, it only protects against Nimda and a cross-site scripting bug, and
7101 would need active maintenance to provide more substantial protection.
7107 <term><emphasis>site-specifics</emphasis></term>
7110 Some web sites have very specific problems, the cure for which doesn't apply
7111 anywhere else, or could even cause damage on other sites.
7114 This is a collection of such site-specific cures which should only be applied
7115 to the sites they were intended for, which is what the supplied
7116 <filename>default.action</filename> file does. Users shouldn't need to change
7117 anything regarding this filter.
7123 <term><emphasis>google</emphasis></term>
7126 A CSS based block for Google text ads. Also removes a width limitation
7127 and the toolbar advertisement.
7133 <term><emphasis>yahoo</emphasis></term>
7136 Another CSS based block, this time for Yahoo text ads. And removes
7137 a width limitation as well.
7143 <term><emphasis>msn</emphasis></term>
7146 Another CSS based block, this time for MSN text ads. And removes
7147 tracking URLs, as well as a width limitation.
7153 <term><emphasis>blogspot</emphasis></term>
7156 Cleans up some Blogspot blogs. Read the fine print before using this one!
7159 This filter also intentionally removes some navigation stuff and sets the
7160 page width to 100%. As a result, some rounded <quote>corners</quote> would
7161 appear to early or not at all and as fixing this would require a browser
7162 that understands background-size (CSS3), they are removed instead.
7168 <term><emphasis>xml-to-html</emphasis></term>
7171 Server-header filter to change the Content-Type from xml to html.
7177 <term><emphasis>html-to-xml</emphasis></term>
7180 Server-header filter to change the Content-Type from html to xml.
7186 <term><emphasis>no-ping</emphasis></term>
7189 Removes the non-standard <literal>ping</literal> attribute from
7190 anchor and area HTML tags.
7196 <term><emphasis>hide-tor-exit-notation</emphasis></term>
7199 Client-header filter to remove the <command>Tor</command> exit node notation
7200 found in Host and Referer headers.
7203 If &my-app; and <command>Tor</command> are chained and &my-app;
7204 is configured to use socks4a, one can use <quote>http://www.example.org.foobar.exit/</quote>
7205 to access the host <quote>www.example.org</quote> through the
7206 <command>Tor</command> exit node <quote>foobar</quote>.
7209 As the HTTP client isn't aware of this notation, it treats the
7210 whole string <quote>www.example.org.foobar.exit</quote> as host and uses it
7211 for the <quote>Host</quote> and <quote>Referer</quote> headers. From the
7212 server's point of view the resulting headers are invalid and can cause problems.
7215 An invalid <quote>Referer</quote> header can trigger <quote>hot-linking</quote>
7216 protections, an invalid <quote>Host</quote> header will make it impossible for
7217 the server to find the right vhost (several domains hosted on the same IP address).
7220 This client-header filter removes the <quote>foo.exit</quote> part in those headers
7221 to prevent the mentioned problems. Note that it only modifies
7222 the HTTP headers, it doesn't make it impossible for the server
7223 to detect your <command>Tor</command> exit node based on the IP address
7224 the request is coming from.
7231 <term><emphasis> </emphasis></term>
7245 <!-- ~ End section ~ -->
7249 <!-- ~~~~~ New section ~~~~~ -->
7251 <sect1 id="templates">
7252 <title>Privoxy's Template Files</title>
7254 All <application>Privoxy</application> built-in pages, i.e. error pages such as the
7255 <ulink url="http://show-the-404-error.page"><quote>404 - No Such Domain</quote>
7256 error page</ulink>, the <ulink
7257 url="http://ads.bannerserver.example.com/nasty-ads/sponsor.html"><quote>BLOCKED</quote>
7259 and all pages of its <ulink url="http://config.privoxy.org/">web-based
7260 user interface</ulink>, are generated from <emphasis>templates</emphasis>.
7261 (<application>Privoxy</application> must be running for the above links to work as
7266 These templates are stored in a subdirectory of the <link linkend="confdir">configuration
7267 directory</link> called <filename>templates</filename>. On Unixish platforms,
7269 <ulink url="file:///etc/privoxy/templates/"><filename>/etc/privoxy/templates/</filename></ulink>.
7273 The templates are basically normal HTML files, but with place-holders (called symbols
7274 or exports), which <application>Privoxy</application> fills at run time. It
7275 is possible to edit the templates with a normal text editor, should you want
7276 to customize them. (<emphasis>Not recommended for the casual
7277 user</emphasis>). Should you create your own custom templates, you should use
7278 the <filename>config</filename> setting <link linkend="templdir">templdir</link>
7279 to specify an alternate location, so your templates do not get overwritten
7283 Note that just like in configuration files, lines starting
7284 with <literal>#</literal> are ignored when the templates are filled in.
7288 The place-holders are of the form <literal>@name@</literal>, and you will
7289 find a list of available symbols, which vary from template to template,
7290 in the comments at the start of each file. Note that these comments are not
7291 always accurate, and that it's probably best to look at the existing HTML
7292 code to find out which symbols are supported and what they are filled in with.
7296 A special application of this substitution mechanism is to make whole
7297 blocks of HTML code disappear when a specific symbol is set. We use this
7298 for many purposes, one of them being to include the beta warning in all
7299 our user interface (CGI) pages when <application>Privoxy</application>
7300 is in an alpha or beta development stage:
7305 <!-- @if-unstable-start -->
7307 ... beta warning HTML code goes here ...
7309 <!-- if-unstable-end@ --></screen>
7313 If the "unstable" symbol is set, everything in between and including
7314 <literal>@if-unstable-start</literal> and <literal>if-unstable-end@</literal>
7315 will disappear, leaving nothing but an empty comment:
7319 <screen><!-- --></screen>
7323 There's also an if-then-else construct and an <literal>#include</literal>
7324 mechanism, but you'll sure find out if you are inclined to edit the
7329 All templates refer to a style located at
7330 <ulink url="http://config.privoxy.org/send-stylesheet"><literal>http://config.privoxy.org/send-stylesheet</literal></ulink>.
7331 This is, of course, locally served by <application>Privoxy</application>
7332 and the source for it can be found and edited in the
7333 <filename>cgi-style.css</filename> template.
7338 <!-- ~ End section ~ -->
7342 <!-- ~~~~~ New section ~~~~~ -->
7344 <sect1 id="contact"><title>Contacting the Developers, Bug Reporting and Feature
7347 <!-- Include contacting.sgml boilerplate: -->
7349 <!-- end boilerplate -->
7353 <!-- ~ End section ~ -->
7356 <!-- ~~~~~ New section ~~~~~ -->
7357 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
7359 <!-- Include copyright.sgml: -->
7361 <!-- end copyright -->
7363 <!-- ~~~~~ New section ~~~~~ -->
7364 <sect2><title>License</title>
7365 <!-- Include copyright.sgml: -->
7367 <!-- end copyright -->
7369 <!-- ~ End section ~ -->
7372 <!-- ~~~~~ New section ~~~~~ -->
7374 <sect2 id="history"><title>History</title>
7375 <!-- Include history.sgml: -->
7377 <!-- end history -->
7380 <sect2 id="authors"><title>Authors</title>
7381 <!-- Include p-authors.sgml: -->
7383 <!-- end authors -->
7388 <!-- ~ End section ~ -->
7391 <!-- ~~~~~ New section ~~~~~ -->
7392 <sect1 id="seealso"><title>See Also</title>
7393 <!-- Include seealso.sgml: -->
7395 <!-- end seealso -->
7400 <!-- ~~~~~ New section ~~~~~ -->
7401 <sect1 id="appendix"><title>Appendix</title>
7404 <!-- ~~~~~ New section ~~~~~ -->
7406 <title>Regular Expressions</title>
7408 <application>Privoxy</application> uses Perl-style <quote>regular
7409 expressions</quote> in its <link linkend="actions-file">actions
7410 files</link> and <link linkend="filter-file">filter file</link>,
7411 through the <ulink url="http://www.pcre.org/">PCRE</ulink> and
7414 <ulink url="http://www.oesterhelt.org/pcrs/">PCRS</ulink> libraries.
7416 <application>PCRS</application> libraries.
7420 If you are reading this, you probably don't understand what <quote>regular
7421 expressions</quote> are, or what they can do. So this will be a very brief
7422 introduction only. A full explanation would require a <ulink
7423 url="http://www.oreilly.com/catalog/regex/">book</ulink> ;-)
7427 Regular expressions provide a language to describe patterns that can be
7428 run against strings of characters (letter, numbers, etc), to see if they
7429 match the string or not. The patterns are themselves (sometimes complex)
7430 strings of literal characters, combined with wild-cards, and other special
7431 characters, called meta-characters. The <quote>meta-characters</quote> have
7432 special meanings and are used to build complex patterns to be matched against.
7433 Perl Compatible Regular Expressions are an especially convenient
7434 <quote>dialect</quote> of the regular expression language.
7438 To make a simple analogy, we do something similar when we use wild-card
7439 characters when listing files with the <command>dir</command> command in DOS.
7440 <literal>*.*</literal> matches all filenames. The <quote>special</quote>
7441 character here is the asterisk which matches any and all characters. We can be
7442 more specific and use <literal>?</literal> to match just individual
7443 characters. So <quote>dir file?.text</quote> would match
7444 <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
7445 matching, using a similar technique to <quote>regular expressions</quote>!
7449 Regular expressions do essentially the same thing, but are much, much more
7450 powerful. There are many more <quote>special characters</quote> and ways of
7451 building complex patterns however. Let's look at a few of the common ones,
7452 and then some examples:
7457 <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
7458 <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
7460 </simplelist></para>
7464 <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
7467 </simplelist></para>
7471 <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
7474 </simplelist></para>
7478 <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
7481 </simplelist></para>
7485 <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
7486 the following character should be taken literally. This is used where one of the
7487 special characters (e.g. <quote>.</quote>) needs to be taken literally and
7488 not as a special meta-character. Example: <quote>example\.com</quote>, makes
7489 sure the period is recognized only as a period (and not expanded to its
7490 meta-character meaning of any single character).
7492 </simplelist></para>
7496 <emphasis>[ ]</emphasis> - Characters enclosed in brackets will be matched if
7497 any of the enclosed characters are encountered. For instance, <quote>[0-9]</quote>
7498 matches any numeric digit (zero through nine). As an example, we can combine
7499 this with <quote>+</quote> to match any digit one of more times: <quote>[0-9]+</quote>.
7501 </simplelist></para>
7505 <emphasis>( )</emphasis> - parentheses are used to group a sub-expression,
7506 or multiple sub-expressions.
7508 </simplelist></para>
7512 <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
7513 <quote>or</quote> conditional statement. A match is successful if the
7514 sub-expression on either side of <quote>|</quote> matches. As an example:
7515 <quote>/(this|that) example/</quote> uses grouping and the bar character
7516 and would match either <quote>this example</quote> or <quote>that
7517 example</quote>, and nothing else.
7519 </simplelist></para>
7522 These are just some of the ones you are likely to use when matching URLs with
7523 <application>Privoxy</application>, and is a long way from a definitive
7524 list. This is enough to get us started with a few simple examples which may
7525 be more illuminating:
7529 <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
7530 that uses the common combination of <quote>.</quote> and <quote>*</quote> to
7531 denote any character, zero or more times. In other words, any string at all.
7532 So we start with a literal forward slash, then our regular expression pattern
7533 (<quote>.*</quote>) another literal forward slash, the string
7534 <quote>banners</quote>, another forward slash, and lastly another
7535 <quote>.*</quote>. We are building
7536 a directory path here. This will match any file with the path that has a
7537 directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
7538 any characters, and this could conceivably be more forward slashes, so it
7539 might expand into a much longer looking path. For example, this could match:
7540 <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
7541 <quote>/banners/annoying.html</quote>, or almost an infinite number of other
7542 possible combinations, just so it has <quote>banners</quote> in the path
7547 And now something a little more complex:
7551 <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
7552 We have several literal forward slashes again (<quote>/</quote>), so we are
7553 building another expression that is a file path statement. We have another
7554 <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
7555 it matches our expression. The only true literal that <emphasis>must
7556 match</emphasis> our pattern is <application>adv</application>, together with
7557 the forward slashes. What comes after the <quote>adv</quote> string is the
7562 Remember the <quote>?</quote> means the preceding expression (either a
7563 literal character or anything grouped with <quote>(...)</quote> in this case)
7564 can exist or not, since this means either zero or one match. So
7565 <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
7566 individual sub-expressions: <quote>(er)</quote>,
7567 <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
7568 means <quote>or</quote>. We have two of those. For instance,
7569 <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
7570 <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
7571 attempt at matching as many variations of <quote>advertisement</quote>, and
7572 similar, as possible. So this would expand to match just <quote>adv</quote>,
7573 or <quote>advert</quote>, or <quote>adverts</quote>, or
7574 <quote>advertising</quote>, or <quote>advertisement</quote>, or
7575 <quote>advertisements</quote>. You get the idea. But it would not match
7576 <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
7577 changing our regular expression to:
7578 <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
7583 <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
7584 another path statement with forward slashes. Anything in the square brackets
7585 <quote>[ ]</quote> can be matched. This is using <quote>0-9</quote> as a
7586 shorthand expression to mean any digit one through nine. It is the same as
7587 saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
7588 means one or more of the preceding expression must be included. The preceding
7589 expression here is what is in the square brackets -- in this case, any digit
7590 one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
7591 This includes a <quote>|</quote>, so this needs to match the expression on
7592 either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
7593 side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
7594 since the <quote>?</quote> means the letter <quote>e</quote> is optional and
7595 can be matched once or not at all. So we are building an expression here to
7596 match image GIF or JPEG type image file. It must include the literal
7597 string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
7598 (which is now a literal, and not a special character, since it is escaped
7599 with <quote>\</quote>), and lastly either <quote>gif</quote>, or
7600 <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
7601 include: <quote>//advert1.jpg</quote>,
7602 <quote>/nasty/ads/advert1234.gif</quote>,
7603 <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
7604 <quote>advert1.gif</quote> (no leading slash), or
7605 <quote>/adverts232.jpg</quote> (the expression does not include an
7606 <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
7607 in the expression anywhere).
7611 We are barely scratching the surface of regular expressions here so that you
7612 can understand the default <application>Privoxy</application>
7613 configuration files, and maybe use this knowledge to customize your own
7614 installation. There is much, much more that can be done with regular
7615 expressions. Now that you know enough to get started, you can learn more on
7620 More reading on Perl Compatible Regular expressions:
7621 <ulink url="http://perldoc.perl.org/perlre.html">http://perldoc.perl.org/perlre.html</ulink>
7625 For information on regular expression based substitutions and their applications
7626 in filters, please see the <link linkend="filter-file">filter file tutorial</link>
7631 <!-- ~ End section ~ -->
7634 <!-- ~~~~~ New section ~~~~~ -->
7636 <title>Privoxy's Internal Pages</title>
7639 Since <application>Privoxy</application> proxies each requested
7640 web page, it is easy for <application>Privoxy</application> to
7641 trap certain special URLs. In this way, we can talk directly to
7642 <application>Privoxy</application>, and see how it is
7643 configured, see how our rules are being applied, change these
7644 rules and other configuration options, and even turn
7645 <application>Privoxy's</application> filtering off, all with
7651 The URLs listed below are the special ones that allow direct access
7652 to <application>Privoxy</application>. Of course,
7653 <application>Privoxy</application> must be running to access these. If
7654 not, you will get a friendly error message. Internet access is not
7667 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
7671 There is a shortcut: <ulink url="http://p.p/">http://p.p/</ulink> (But it
7672 doesn't provide a fall-back to a real page, in case the request is not
7673 sent through <application>Privoxy</application>)
7679 Show information about the current configuration, including viewing and
7680 editing of actions files:
7684 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
7691 Show the source code version numbers:
7695 <ulink url="http://config.privoxy.org/show-version">http://config.privoxy.org/show-version</ulink>
7702 Show the browser's request headers:
7706 <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
7713 Show which actions apply to a URL and why:
7717 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
7724 Toggle Privoxy on or off. This feature can be turned off/on in the main
7725 <filename>config</filename> file. When toggled <quote>off</quote>, <quote>Privoxy</quote>
7726 continues to run, but only as a pass-through proxy, with no actions taking
7731 <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
7735 Short cuts. Turn off, then on:
7739 <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
7744 <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
7753 These may be bookmarked for quick reference. See next.
7757 <sect3 id="bookmarklets">
7758 <title>Bookmarklets</title>
7760 Below are some <quote>bookmarklets</quote> to allow you to easily access a
7761 <quote>mini</quote> version of some of <application>Privoxy's</application>
7762 special pages. They are designed for MS Internet Explorer, but should work
7763 equally well in Netscape, Mozilla, and other browsers which support
7764 JavaScript. They are designed to run directly from your bookmarks - not by
7765 clicking the links below (although that should work for testing).
7768 To save them, right-click the link and choose <quote>Add to Favorites</quote>
7769 (IE) or <quote>Add Bookmark</quote> (Netscape). You will get a warning that
7770 the bookmark <quote>may not be safe</quote> - just click OK. Then you can run the
7771 Bookmarklet directly from your favorites/bookmarks. For even faster access,
7772 you can put them on the <quote>Links</quote> bar (IE) or the <quote>Personal
7773 Toolbar</quote> (Netscape), and run them with a single click.
7782 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>
7789 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>
7796 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)
7803 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>
7809 <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>
7815 <ulink url="javascript:void(window.open('http://config.privoxy.org/show-url-info?url='+escape(location.href),'Why').focus());">Privoxy - Why?</ulink>
7822 Credit: The site which gave us the general idea for these bookmarklets is
7823 <ulink url="http://www.bookmarklets.com/">www.bookmarklets.com</ulink>. They
7824 have more information about bookmarklets.
7833 <!-- ~~~~~ New section ~~~~~ -->
7835 <title>Chain of Events</title>
7837 Let's take a quick look at how some of <application>Privoxy's</application>
7838 core features are triggered, and the ensuing sequence of events when a web
7839 page is requested by your browser:
7846 First, your web browser requests a web page. The browser knows to send
7847 the request to <application>Privoxy</application>, which will in turn,
7848 relay the request to the remote web server after passing the following
7854 <application>Privoxy</application> traps any request for its own internal CGI
7855 pages (e.g <ulink url="http://p.p/">http://p.p/</ulink>) and sends the CGI page back to the browser.
7860 Next, <application>Privoxy</application> checks to see if the URL
7862 linkend="BLOCK"><quote>+block</quote></link> patterns. If
7863 so, the URL is then blocked, and the remote web server will not be contacted.
7864 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>
7866 <link linkend="HANDLE-AS-EMPTY-DOCUMENT"><quote>+handle-as-empty-document</quote></link>
7867 are then checked, and if there is no match, an
7868 HTML <quote>BLOCKED</quote> page is sent back to the browser. Otherwise, if
7869 it does match, an image is returned for the former, and an empty text
7870 document for the latter. The type of image would depend on the setting of
7871 <link linkend="SET-IMAGE-BLOCKER"><quote>+set-image-blocker</quote></link>
7872 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
7877 Untrusted URLs are blocked. If URLs are being added to the
7878 <filename>trust</filename> file, then that is done.
7883 If the URL pattern matches the <link
7884 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link> action,
7885 it is then processed. Unwanted parts of the requested URL are stripped.
7890 Now the rest of the client browser's request headers are processed. If any
7891 of these match any of the relevant actions (e.g. <link
7892 linkend="HIDE-USER-AGENT"><quote>+hide-user-agent</quote></link>,
7893 etc.), headers are suppressed or forged as determined by these actions and
7899 Now the web server starts sending its response back (i.e. typically a web
7905 First, the server headers are read and processed to determine, among other
7906 things, the MIME type (document type) and encoding. The headers are then
7907 filtered as determined by the
7908 <link linkend="CRUNCH-INCOMING-COOKIES"><quote>+crunch-incoming-cookies</quote></link>,
7909 <link linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>,
7910 and <link linkend="DOWNGRADE-HTTP-VERSION"><quote>+downgrade-http-version</quote></link>
7916 If any <link linkend="FILTER"><quote>+filter</quote></link> action
7918 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
7919 action applies (and the document type fits the action), the rest of the page is
7920 read into memory (up to a configurable limit). Then the filter rules (from
7921 <filename>default.filter</filename> and any other filter files) are
7922 processed against the buffered content. Filters are applied in the order
7923 they are specified in one of the filter files. Animated GIFs, if present,
7924 are reduced to either the first or last frame, depending on the action
7925 setting.The entire page, which is now filtered, is then sent by
7926 <application>Privoxy</application> back to your browser.
7929 If neither a <link linkend="FILTER"><quote>+filter</quote></link> action
7931 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
7932 matches, then <application>Privoxy</application> passes the raw data through
7933 to the client browser as it becomes available.
7938 As the browser receives the now (possibly filtered) page content, it
7939 reads and then requests any URLs that may be embedded within the page
7940 source, e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
7941 frames), sounds, etc. For each of these objects, the browser issues a
7942 separate request (this is easily viewable in <application>Privoxy's</application>
7943 logs). And each such request is in turn processed just as above. Note that a
7944 complex web page will have many, many such embedded URLs. If these
7945 secondary requests are to a different server, then quite possibly a very
7946 differing set of actions is triggered.
7953 NOTE: This is somewhat of a simplistic overview of what happens with each URL
7954 request. For the sake of brevity and simplicity, we have focused on
7955 <application>Privoxy's</application> core features only.
7961 <!-- ~~~~~ New section ~~~~~ -->
7962 <sect2 id="actionsanat">
7963 <title>Troubleshooting: Anatomy of an Action</title>
7966 The way <application>Privoxy</application> applies
7967 <link linkend="ACTIONS">actions</link> and <link linkend="FILTER">filters</link>
7968 to any given URL can be complex, and not always so
7969 easy to understand what is happening. And sometimes we need to be able to
7970 <emphasis>see</emphasis> just what <application>Privoxy</application> is
7971 doing. Especially, if something <application>Privoxy</application> is doing
7972 is causing us a problem inadvertently. It can be a little daunting to look at
7973 the actions and filters files themselves, since they tend to be filled with
7974 <link linkend="regex">regular expressions</link> whose consequences are not
7979 One quick test to see if <application>Privoxy</application> is causing a problem
7980 or not, is to disable it temporarily. This should be the first troubleshooting
7981 step. See <link linkend="bookmarklets">the Bookmarklets</link> section on a quick
7982 and easy way to do this (be sure to flush caches afterward!). Looking at the
7983 logs is a good idea too. (Note that both the toggle feature and logging are
7984 enabled via <filename>config</filename> file settings, and may need to be
7985 turned <quote>on</quote>.)
7988 Another easy troubleshooting step to try is if you have done any
7989 customization of your installation, revert back to the installed
7990 defaults and see if that helps. There are times the developers get complaints
7991 about one thing or another, and the problem is more related to a customized
7992 configuration issue.
7996 <application>Privoxy</application> also provides the
7997 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
7998 page that can show us very specifically how <application>actions</application>
7999 are being applied to any given URL. This is a big help for troubleshooting.
8003 First, enter one URL (or partial URL) at the prompt, and then
8004 <application>Privoxy</application> will tell us
8005 how the current configuration will handle it. This will not
8006 help with filtering effects (i.e. the <link
8007 linkend="FILTER"><quote>+filter</quote></link> action) from
8008 one of the filter files since this is handled very
8009 differently and not so easy to trap! It also will not tell you about any other
8010 URLs that may be embedded within the URL you are testing. For instance, images
8011 such as ads are expressed as URLs within the raw page source of HTML pages. So
8012 you will only get info for the actual URL that is pasted into the prompt area
8013 -- not any sub-URLs. If you want to know about embedded URLs like ads, you
8014 will have to dig those out of the HTML source. Use your browser's <quote>View
8015 Page Source</quote> option for this. Or right click on the ad, and grab the
8020 Let's try an example, <ulink url="http://google.com">google.com</ulink>,
8021 and look at it one section at a time in a sample configuration (your real
8022 configuration may vary):
8027 Matches for http://www.google.com:
8029 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8031 {+change-x-forwarded-for{block}
8032 +deanimate-gifs {last}
8033 +fast-redirects {check-decoded-url}
8034 +filter {refresh-tags}
8035 +filter {img-reorder}
8036 +filter {banners-by-size}
8038 +filter {jumping-windows}
8039 +filter {ie-exploits}
8040 +hide-from-header {block}
8041 +hide-referrer {forge}
8042 +session-cookies-only
8043 +set-image-blocker {pattern}
8046 { -session-cookies-only }
8052 In file: user.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8053 (no matches in this file)
8058 This is telling us how we have defined our
8059 <link linkend="ACTIONS"><quote>actions</quote></link>, and
8060 which ones match for our test case, <quote>google.com</quote>.
8061 Displayed is all the actions that are available to us. Remember,
8062 the <literal>+</literal> sign denotes <quote>on</quote>. <literal>-</literal>
8063 denotes <quote>off</quote>. So some are <quote>on</quote> here, but many
8064 are <quote>off</quote>. Each example we try may provide a slightly different
8065 end result, depending on our configuration directives.
8069 is for our <filename>default.action</filename> file. The large, multi-line
8070 listing, is how the actions are set to match for all URLs, i.e. our default
8071 settings. If you look at your <quote>actions</quote> file, this would be the
8072 section just below the <quote>aliases</quote> section near the top. This
8073 will apply to all URLs as signified by the single forward slash at the end
8074 of the listing -- <quote> / </quote>.
8078 But we have defined additional actions that would be exceptions to these general
8079 rules, and then we list specific URLs (or patterns) that these exceptions
8080 would apply to. Last match wins. Just below this then are two explicit
8081 matches for <quote>.google.com</quote>. The first is negating our previous
8082 cookie setting, which was for <link
8083 linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>
8084 (i.e. not persistent). So we will allow persistent cookies for google, at
8085 least that is how it is in this example. The second turns
8086 <emphasis>off</emphasis> any <link
8087 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link>
8088 action, allowing this to take place unmolested. Note that there is a leading
8089 dot here -- <quote>.google.com</quote>. This will match any hosts and
8090 sub-domains, in the google.com domain also, such as
8091 <quote>www.google.com</quote> or <quote>mail.google.com</quote>. But it would not
8092 match <quote>www.google.de</quote>! So, apparently, we have these two actions
8093 defined as exceptions to the general rules at the top somewhere in the lower
8094 part of our <filename>default.action</filename> file, and
8095 <quote>google.com</quote> is referenced somewhere in these latter sections.
8099 Then, for our <filename>user.action</filename> file, we again have no hits.
8100 So there is nothing google-specific that we might have added to our own, local
8101 configuration. If there was, those actions would over-rule any actions from
8102 previously processed files, such as <filename>default.action</filename>.
8103 <filename>user.action</filename> typically has the last word. This is the
8104 best place to put hard and fast exceptions,
8108 And finally we pull it all together in the bottom section and summarize how
8109 <application>Privoxy</application> is applying all its <quote>actions</quote>
8110 to <quote>google.com</quote>:
8121 +change-x-forwarded-for{block}
8122 -client-header-filter{hide-tor-exit-notation}
8123 -content-type-overwrite
8124 -crunch-client-header
8125 -crunch-if-none-match
8126 -crunch-incoming-cookies
8127 -crunch-outgoing-cookies
8128 -crunch-server-header
8129 +deanimate-gifs {last}
8130 -downgrade-http-version
8133 -filter {content-cookies}
8134 -filter {all-popups}
8135 -filter {banners-by-link}
8136 -filter {tiny-textforms}
8137 -filter {frameset-borders}
8138 -filter {demoronizer}
8139 -filter {shockwave-flash}
8140 -filter {quicktime-kioskmode}
8142 -filter {crude-parental}
8143 -filter {site-specifics}
8144 -filter {js-annoyances}
8145 -filter {html-annoyances}
8146 +filter {refresh-tags}
8147 -filter {unsolicited-popups}
8148 +filter {img-reorder}
8149 +filter {banners-by-size}
8151 +filter {jumping-windows}
8152 +filter {ie-exploits}
8159 -handle-as-empty-document
8161 -hide-accept-language
8162 -hide-content-disposition
8163 +hide-from-header {block}
8164 -hide-if-modified-since
8165 +hide-referrer {forge}
8168 -overwrite-last-modified
8169 -prevent-compression
8171 -server-header-filter{xml-to-html}
8172 -server-header-filter{html-to-xml}
8173 -session-cookies-only
8174 +set-image-blocker {pattern} </screen>
8178 Notice the only difference here to the previous listing, is to
8179 <quote>fast-redirects</quote> and <quote>session-cookies-only</quote>,
8180 which are activated specifically for this site in our configuration,
8181 and thus show in the <quote>Final Results</quote>.
8185 Now another example, <quote>ad.doubleclick.net</quote>:
8191 { +block{Domains starts with "ad"} }
8194 { +block{Domain contains "ad"} }
8197 { +block{Doubleclick banner server} +handle-as-image }
8198 .[a-vx-z]*.doubleclick.net
8203 We'll just show the interesting part here - the explicit matches. It is
8204 matched three different times. Two <quote>+block{}</quote> sections,
8205 and a <quote>+block{} +handle-as-image</quote>,
8206 which is the expanded form of one of our aliases that had been defined as:
8207 <quote>+block-as-image</quote>. (<link
8208 linkend="ALIASES"><quote>Aliases</quote></link> are defined in
8209 the first section of the actions file and typically used to combine more
8214 Any one of these would have done the trick and blocked this as an unwanted
8215 image. This is unnecessarily redundant since the last case effectively
8216 would also cover the first. No point in taking chances with these guys
8217 though ;-) Note that if you want an ad or obnoxious
8218 URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
8219 is done here -- as both a <link
8220 linkend="BLOCK"><quote>+block{}</quote></link>
8221 <emphasis>and</emphasis> an
8222 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>.
8223 The custom alias <quote><literal>+block-as-image</literal></quote> just
8224 simplifies the process and make it more readable.
8228 One last example. Let's try <quote>http://www.example.net/adsl/HOWTO/</quote>.
8229 This one is giving us problems. We are getting a blank page. Hmmm ...
8235 Matches for http://www.example.net/adsl/HOWTO/:
8237 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8241 +change-x-forwarded-for{block}
8242 -client-header-filter{hide-tor-exit-notation}
8243 -content-type-overwrite
8244 -crunch-client-header
8245 -crunch-if-none-match
8246 -crunch-incoming-cookies
8247 -crunch-outgoing-cookies
8248 -crunch-server-header
8250 -downgrade-http-version
8251 +fast-redirects {check-decoded-url}
8253 -filter {content-cookies}
8254 -filter {all-popups}
8255 -filter {banners-by-link}
8256 -filter {tiny-textforms}
8257 -filter {frameset-borders}
8258 -filter {demoronizer}
8259 -filter {shockwave-flash}
8260 -filter {quicktime-kioskmode}
8262 -filter {crude-parental}
8263 -filter {site-specifics}
8264 -filter {js-annoyances}
8265 -filter {html-annoyances}
8266 +filter {refresh-tags}
8267 -filter {unsolicited-popups}
8268 +filter {img-reorder}
8269 +filter {banners-by-size}
8271 +filter {jumping-windows}
8272 +filter {ie-exploits}
8279 -handle-as-empty-document
8281 -hide-accept-language
8282 -hide-content-disposition
8283 +hide-from-header{block}
8284 +hide-referer{forge}
8286 -overwrite-last-modified
8287 +prevent-compression
8289 -server-header-filter{xml-to-html}
8290 -server-header-filter{html-to-xml}
8291 +session-cookies-only
8292 +set-image-blocker{blank} }
8295 { +block{Path contains "ads".} +handle-as-image }
8301 Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote> in our
8302 configuration! But we did not want this at all! Now we see why we get the
8303 blank page. It is actually triggering two different actions here, and
8304 the effects are aggregated so that the URL is blocked, and &my-app; is told
8305 to treat the block as if it were an image. But this is, of course, all wrong.
8306 We could now add a new action below this (or better in our own
8307 <filename>user.action</filename> file) that explicitly
8308 <emphasis>un</emphasis> blocks (
8309 <link linkend="BLOCK"><quote>{-block}</quote></link>) paths with
8310 <quote>adsl</quote> in them (remember, last match in the configuration
8311 wins). There are various ways to handle such exceptions. Example:
8323 Now the page displays ;-)
8324 Remember to flush your browser's caches when making these kinds of changes to
8325 your configuration to insure that you get a freshly delivered page! Or, try
8326 using <literal>Shift+Reload</literal>.
8330 But now what about a situation where we get no explicit matches like
8337 { +block{Path starts with "ads".} +handle-as-image }
8343 That actually was very helpful and pointed us quickly to where the problem
8344 was. If you don't get this kind of match, then it means one of the default
8345 rules in the first section of <filename>default.action</filename> is causing
8346 the problem. This would require some guesswork, and maybe a little trial and
8347 error to isolate the offending rule. One likely cause would be one of the
8348 <link linkend="FILTER"><quote>+filter</quote></link> actions.
8349 These tend to be harder to troubleshoot.
8350 Try adding the URL for the site to one of aliases that turn off
8351 <link linkend="FILTER"><quote>+filter</quote></link>:
8359 .worldpay.com # for quietpc.com
8367 <quote><literal>{ shop }</literal></quote> is an <quote>alias</quote> that expands to
8368 <quote><literal>{ -filter -session-cookies-only }</literal></quote>.
8369 Or you could do your own exception to negate filtering:
8377 # Disable ALL filter actions for sites in this section
8385 This would turn off all filtering for these sites. This is best
8386 put in <filename>user.action</filename>, for local site
8387 exceptions. Note that when a simple domain pattern is used by itself (without
8388 the subsequent path portion), all sub-pages within that domain are included
8389 automatically in the scope of the action.
8393 Images that are inexplicably being blocked, may well be hitting the
8394 <link linkend="FILTER-BANNERS-BY-SIZE"><quote>+filter{banners-by-size}</quote></link>
8396 that images of certain sizes are ad banners (works well
8397 <emphasis>most of the time</emphasis> since these tend to be standardized).
8401 <quote><literal>{ fragile }</literal></quote> is an alias that disables most
8402 actions that are the most likely to cause trouble. This can be used as a
8403 last resort for problem sites.
8409 # Handle with care: easy to break
8411 mybank.example.com</screen>
8416 <emphasis>Remember to flush caches!</emphasis> Note that the
8417 <literal>mail.google</literal> reference lacks the TLD portion (e.g.
8418 <quote>.com</quote>). This will effectively match any TLD with
8419 <literal>google</literal> in it, such as <literal>mail.google.de.</literal>,
8423 If this still does not work, you will have to go through the remaining
8424 actions one by one to find which one(s) is causing the problem.
8433 This program is free software; you can redistribute it
8434 and/or modify it under the terms of the GNU General
8435 Public License as published by the Free Software
8436 Foundation; either version 2 of the License, or (at
8437 your option) any later version.
8439 This program is distributed in the hope that it will
8440 be useful, but WITHOUT ANY WARRANTY; without even the
8441 implied warranty of MERCHANTABILITY or FITNESS FOR A
8442 PARTICULAR PURPOSE. See the GNU General Public
8443 License for more details.
8445 The GNU General Public License should be included with
8446 this file. If not, you can view it at
8447 http://www.gnu.org/copyleft/gpl.html
8448 or write to the Free Software Foundation, Inc.,
8449 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
projects / privoxy.git / blob