1 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V3.1//EN" [
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6 <!entity seealso SYSTEM "seealso.sgml">
7 <!entity buildsource SYSTEM "buildsource.sgml">
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11 <!entity license SYSTEM "license.sgml">
12 <!entity GPLv2 SYSTEM "../../LICENSE">
13 <!entity p-authors SYSTEM "p-authors.sgml">
14 <!entity config SYSTEM "p-config.sgml">
15 <!entity changelog SYSTEM "changelog.sgml">
16 <!entity p-version "3.0.25">
17 <!entity p-status "UNRELEASED">
18 <!entity % p-authors-formal "INCLUDE"> <!-- include additional text, etc -->
19 <!entity % p-not-stable "INCLUDE">
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26 <!entity % p-supp-userman "IGNORE"> <!-- Omit some from supported.sgml -->
27 <!entity my-copy "©"> <!-- kludge for docbook2man -->
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33 File : $Source: /cvsroot/ijbswa/current/doc/source/user-manual.sgml,v $
36 This file belongs into
37 ijbswa.sourceforge.net:/home/groups/i/ij/ijbswa/htdocs/
39 $Id: user-manual.sgml,v 2.202 2016/01/23 13:57:17 diem Exp $
41 Copyright (C) 2001-2014 Privoxy Developers http://www.privoxy.org/
44 ========================================================================
45 NOTE: Please read developer-manual/documentation.html before touching
46 anything in this, or other Privoxy documentation.
47 ========================================================================
54 <title>Privoxy &p-version; User Manual</title>
58 <!-- Completely the wrong markup, but very little is allowed -->
59 <!-- in this part of an article. FIXME -->
60 <link linkend="copyright">Copyright</link> &my-copy; 2001-2014 by
61 <ulink url="http://www.privoxy.org/">Privoxy Developers</ulink>
65 <pubdate>$Id: user-manual.sgml,v 2.202 2016/01/23 13:57:17 diem Exp $</pubdate>
69 Note: the following should generate a separate page, and a live link to it,
70 all nicely done. But it doesn't for some mysterious reason. Please leave
71 commented unless it can be fixed proper. For the time being, the
72 copyright/license declarations will be in their own sgml.
85 This is here to keep vim syntax file from breaking :/
86 If I knew enough to fix it, I would.
87 PLEASE DO NOT REMOVE! HB: hal@foobox.net
93 The <citetitle>Privoxy User Manual</citetitle> gives users information on how to
94 install, configure and use <ulink
95 url="http://www.privoxy.org/">Privoxy</ulink>.
98 <!-- Include privoxy.sgml boilerplate: -->
100 <!-- end privoxy.sgml -->
103 You can find the latest version of the <citetitle>Privoxy User Manual</citetitle> at <ulink
104 url="http://www.privoxy.org/user-manual/">http://www.privoxy.org/user-manual/</ulink>.
105 Please see the <link linkend="contact">Contact section</link> on how to
106 contact the developers.
110 <!-- Feel free to send a note to the developers at <email>ijbswa-developers@lists.sourceforge.net</email>. -->
116 <!-- ~~~~~ New section ~~~~~ -->
117 <sect1 label="1" id="introduction"><title>Introduction</title>
119 This documentation is included with the current &p-status; version of
120 <application>Privoxy</application>, &p-version;<![%p-not-stable;[,
121 and is mostly complete at this point. The most up to date reference for the
122 time being is still the comments in the source files and in the individual
123 configuration files. Development of a new version is currently nearing
124 completion, and includes significant changes and enhancements over
128 <!-- include only in non-stable versions -->
131 Since this is a &p-status; version, not all new features are well tested. This
132 documentation may be slightly out of sync as a result (especially with
133 CVS sources). And there <emphasis>may be</emphasis> bugs, though hopefully
138 <!-- ~~~~~ New section ~~~~~ -->
139 <sect2 id="features"><title>Features</title>
141 In addition to the core
142 features of ad blocking and
143 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookie</ulink> management,
144 <application>Privoxy</application> provides many supplemental
145 features<![%p-not-stable;[, some of them currently under development]]>,
146 that give the end-user more control, more privacy and more freedom:
148 <!-- Include newfeatures.sgml boilerplate here: -->
150 <!-- end boilerplate -->
155 <!-- ~ End section ~ -->
158 <!-- ~~~~~ New section ~~~~~ -->
159 <sect1 id="installation"><title>Installation</title>
162 <application>Privoxy</application> is available both in convenient pre-compiled
163 packages for a wide range of operating systems, and as raw source code.
164 For most users, we recommend using the packages, which can be downloaded from our
165 <ulink url="http://sourceforge.net/projects/ijbswa/">Privoxy Project
171 On some platforms, the installer may remove previously installed versions, if
172 found. (See below for your platform). In any case <emphasis>be sure to backup
173 your old configuration if it is valuable to you.</emphasis> See the <link
174 linkend="upgradersnote">note to upgraders</link> section below.
177 <!-- ~~~~~ New section ~~~~~ -->
178 <sect2 id="installation-packages"><title>Binary Packages</title>
180 How to install the binary packages depends on your operating system:
183 <!-- XXX: The installation sections should be sorted -->
185 <!-- ~~~~~ New section ~~~~~ -->
186 <sect3 id="installation-deb"><title>Debian and Ubuntu</title>
188 DEBs can be installed with <literal>apt-get install privoxy</literal>,
189 and will use <filename>/etc/privoxy</filename> for the location of
194 <!-- ~~~~~ New section ~~~~~ -->
195 <sect3 id="installation-pack-win"><title>Windows</title>
198 Just double-click the installer, which will guide you through
199 the installation process. You will find the configuration files
200 in the same directory as you installed <application>Privoxy</application> in.
203 Version 3.0.5 beta introduced full <application>Windows</application> service
204 functionality. On Windows only, the <application>Privoxy</application>
205 program has two new command line arguments to install and uninstall
206 <application>Privoxy</application> as a <emphasis>service</emphasis>.
210 <term>Arguments:</term>
213 <replaceable class="parameter">--install</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
216 <replaceable class="parameter">--uninstall</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
222 After invoking <application>Privoxy</application> with
223 <command>--install</command>, you will need to bring up the
224 <application>Windows</application> service console to assign the user you
225 want <application>Privoxy</application> to run under, and whether or not you
226 want it to run whenever the system starts. You can start the
227 <application>Windows</application> services console with the following
228 command: <command>services.msc</command>. If you do not take the manual step
229 of modifying <application>Privoxy's</application> service settings, it will
230 not start. Note too that you will need to give Privoxy a user account that
231 actually exists, or it will not be permitted to
232 write to its log and configuration files.
237 <!-- ~~~~~ New section ~~~~~ -->
238 <sect3 id="installation-os2"><title>OS/2</title>
241 First, make sure that no previous installations of
242 <application>Junkbuster</application> and / or
243 <application>Privoxy</application> are left on your
244 system. Check that no <application>Junkbuster</application>
245 or <application>Privoxy</application> objects are in
251 Then, just double-click the WarpIN self-installing archive, which will
252 guide you through the installation process. A shadow of the
253 <application>Privoxy</application> executable will be placed in your
254 startup folder so it will start automatically whenever OS/2 starts.
258 The directory you choose to install <application>Privoxy</application>
259 into will contain all of the configuration files.
263 <!-- ~~~~~ New section ~~~~~ -->
264 <sect3 id="installation-mac"><title>Mac OS X</title>
266 Installation instructions for the OS X platform depend upon whether
267 you downloaded a ready-built installation package (.pkg or .mpkg) or have
268 downloaded the source code.
271 <sect3 renderas="sect4" id="OS-X-install-from-package">
272 <title>Installation from ready-built package</title>
274 The downloaded file will either be a .pkg (for OS X 10.5 upwards) or a bzipped
275 .mpkg file (for OS X 10.4). The former can be double-clicked as is and the
276 installation will start; double-clicking the latter will unzip the .mpkg file
277 which can then be double-clicked to commence the installation.
280 The privoxy service will automatically start after a successful installation
281 (and thereafter every time your computer starts up) however you will need to
282 configure your web browser(s) to use it. To do so, configure them to use a
283 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
286 To prevent the privoxy service from automatically starting when your computer
287 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
288 (on OS X 10.5 and higher) or the folder named
289 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
292 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
293 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
294 administrator account, using sudo.
297 To uninstall, run /Applications/Privoxy/uninstall.command as sudo from an
298 administrator account.
301 <sect3 renderas="sect4" id="OS-X-install-from-source">
302 <title>Installation from source</title>
304 To build and install the Privoxy source code on OS X you will need to obtain
305 the macsetup module from the Privoxy Sourceforge CVS repository (refer to
306 Sourceforge help for details of how to set up a CVS client to have read-only
307 access to the repository). This module contains scripts that leverage the usual
308 open-source tools (available as part of Apple's free of charge Xcode
309 distribution or via the usual open-source software package managers for OS X
310 (MacPorts, Homebrew, Fink etc.) to build and then install the privoxy binary
311 and associated files. The macsetup module's README file contains complete
312 instructions for its use.
315 The privoxy service will automatically start after a successful installation
316 (and thereafter every time your computer starts up) however you will need to
317 configure your web browser(s) to use it. To do so, configure them to use a
318 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
321 To prevent the privoxy service from automatically starting when your computer
322 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
323 (on OS X 10.5 and higher) or the folder named
324 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
327 To manually start or stop the privoxy service, use the Privoxy Utility
328 for Mac OS X (also part of the macsetup module). This application can start
329 and stop the privoxy service and display its log and configuration files.
332 To uninstall, run the macsetup module's uninstall.sh as sudo from an
333 administrator account.
337 <!-- ~~~~~ New section ~~~~~ -->
338 <sect3 id="installation-freebsd"><title>FreeBSD</title>
341 Privoxy is part of FreeBSD's Ports Collection, you can build and install
342 it with <literal>cd /usr/ports/www/privoxy; make install clean</literal>.
348 <!-- ~~~~~ New section ~~~~~ -->
349 <sect2 id="installation-source"><title>Building from Source</title>
352 The most convenient way to obtain the <application>Privoxy</application> sources
353 is to download the source tarball from our
354 <ulink url="http://sourceforge.net/project/showfiles.php?group_id=11118&package_id=10571">project download
359 If you like to live on the bleeding edge and are not afraid of using
360 possibly unstable development versions, you can check out the up-to-the-minute
361 version directly from <ulink url="http://sourceforge.net/cvs/?group_id=11118">the
362 CVS repository</ulink>.
364 deprecated...out of business.
365 or simply download <ulink
366 url="http://cvs.sourceforge.net/cvstarballs/ijbswa-cvsroot.tar.bz2">the nightly CVS
371 <!-- include buildsource.sgml boilerplate: -->
373 <!-- end boilerplate -->
376 <!-- ~~~~~ New section ~~~~~ -->
377 <sect2 id="installation-keepupdated"><title>Keeping your Installation Up-to-Date</title>
380 If you wish to receive an email notification whenever we release updates of
381 <application>Privoxy</application> or the actions file, <ulink
382 url="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce/">subscribe
383 to our announce mailing list</ulink>, ijbswa-announce@lists.sourceforge.net.
387 In order not to lose your personal changes and adjustments when updating
388 to the latest <literal>default.action</literal> file we <emphasis>strongly
389 recommend</emphasis> that you use <literal>user.action</literal> and
390 <literal>user.filter</literal> for your local
391 customizations of <application>Privoxy</application>. See the <link
392 linkend="actions-file">Chapter on actions files</link> for details.
400 <!-- ~ End section ~ -->
402 <!-- ~~~~~ New section ~~~~~ -->
403 <sect1 id="whatsnew">
404 <title>What's New in this Release</title>
408 <!-- ~~~~~ New section ~~~~~ -->
410 <sect2 id="upgradersnote">
411 <title>Note to Upgraders</title>
414 A quick list of things to be aware of before upgrading from earlier
415 versions of <application>Privoxy</application>:
423 The recommended way to upgrade &my-app; is to backup your old
424 configuration files, install the new ones, verify that &my-app;
425 is working correctly and finally merge back your changes using
426 <application>diff</application> and maybe <application>patch</application>.
429 There are a number of new features in each &my-app; release and
430 most of them have to be explicitly enabled in the configuration
431 files. Old configuration files obviously don't do that and due
432 to syntax changes using old configuration files with a new
433 &my-app; isn't always possible anyway.
438 Note that some installers remove earlier versions completely,
439 including configuration files, therefore you should really save
440 any important configuration files!
445 On the other hand, other installers don't overwrite existing configuration
446 files, thinking you will want to do that yourself.
451 In the default configuration only fatal errors are logged now.
452 You can change that in the <link linkend="DEBUG">debug section</link>
453 of the configuration file. You may also want to enable more verbose
454 logging until you verified that the new &my-app; version is working
461 Three other config file settings are now off by default:
462 <link linkend="enable-remote-toggle">enable-remote-toggle</link>,
463 <link linkend="enable-remote-http-toggle">enable-remote-http-toggle</link>,
464 and <link linkend="enable-edit-actions">enable-edit-actions</link>.
465 If you use or want these, you will need to explicitly enable them, and
466 be aware of the security issues involved.
473 What constitutes a <quote>default</quote> configuration has changed,
474 and you may want to review which actions are <quote>on</quote> by
475 default. This is primarily a matter of emphasis, but some features
476 you may have been used to, may now be <quote>off</quote> by default.
477 There are also a number of new actions and filters you may want to
478 consider, most of which are not fully incorporated into the default
479 settings as yet (see above).
486 The default actions setting is now <literal>Cautious</literal>. Previous
487 releases had a default setting of <literal>Medium</literal>. Experienced
488 users may want to adjust this, as it is fairly conservative by &my-app;
489 standards and past practices. See <ulink
490 url="http://config.privoxy.org/edit-actions-list?f=default">
491 http://config.privoxy.org/edit-actions-list?f=default</ulink>. New users
492 should try the default settings for a while before turning up the volume.
498 The default setting has filtering turned <emphasis>off</emphasis>, which
499 subsequently means that compression is <emphasis>on</emphasis>. Remember
500 that filtering does not work on compressed pages, so if you use, or want to
501 use, filtering, you will need to force compression off. Example:
505 { +<link linkend="filter">filter</link>{google} +<link linkend="prevent-compression">prevent-compression</link> }
509 Or if you use a number of filters, or filter many sites, you may just want
510 to turn off compression for all sites in
511 <filename>default.action</filename> (or
512 <filename>user.action</filename>).
519 Also, <link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> is
520 off by default now. If you've liked this feature in the past, you may want
521 to turn it back on in <filename>user.action</filename> now.
528 Some installers may not automatically start
529 <application>Privoxy</application> after installation.
540 <!-- ~~~~~ New section ~~~~~ -->
541 <sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
547 Install <application>Privoxy</application>. See the <link
548 linkend="installation">Installation Section</link> below for platform specific
555 Advanced users and those who want to offer <application>Privoxy</application>
556 service to more than just their local machine should check the <link
557 linkend="config">main config file</link>, especially the <link
558 linkend="access-control">security-relevant</link> options. These are
565 Start <application>Privoxy</application>, if the installation program has
566 not done this already (may vary according to platform). See the section
567 <link linkend="startup">Starting <application>Privoxy</application></link>.
573 Set your browser to use <application>Privoxy</application> as HTTP and
574 HTTPS (SSL) <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
575 by setting the proxy configuration for address of
576 <literal>127.0.0.1</literal> and port <literal>8118</literal>.
577 <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
578 any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
579 browser from using these protocols.
585 Flush your browser's disk and memory caches, to remove any cached ad images.
586 If using <application>Privoxy</application> to manage
587 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
588 you should remove any currently stored cookies too.
594 A default installation should provide a reasonable starting point for
595 most. There will undoubtedly be occasions where you will want to adjust the
596 configuration, but that can be dealt with as the need arises. Little
597 to no initial configuration is required in most cases, you may want
599 <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
600 Be sure to read the warnings first.
603 See the <link linkend="configuration">Configuration section</link> for more
604 configuration options, and how to customize your installation.
605 You might also want to look at the <link
606 linkend="quickstart-ad-blocking">next section</link> for a quick
607 introduction to how <application>Privoxy</application> blocks ads and
614 If you experience ads that slip through, innocent images that are
615 blocked, or otherwise feel the need to fine-tune
616 <application>Privoxy's</application> behavior, take a look at the <link
617 linkend="actions-file">actions files</link>. As a quick start, you might
618 find the <link linkend="act-examples">richly commented examples</link>
619 helpful. You can also view and edit the actions files through the <ulink
620 url="http://config.privoxy.org">web-based user interface</ulink>. The
621 Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
622 Action</link></quote> has hints on how to understand and debug actions that
623 <quote>misbehave</quote>.
629 Please see the section <link linkend="contact">Contacting the
630 Developers</link> on how to report bugs, problems with websites or to get
637 Now enjoy surfing with enhanced control, comfort and privacy!
645 <!-- ~~~~~ New section ~~~~~ -->
647 <sect2 id="quickstart-ad-blocking">
648 <title>Quickstart to Ad Blocking</title>
650 NOTE: This section is deliberately redundant for those that don't
651 want to read the whole thing (which is getting lengthy).
654 Ad blocking is but one of <application>Privoxy's</application>
655 array of features. Many of these features are for the technically minded advanced
656 user. But, ad and banner blocking is surely common ground for everybody.
659 This section will provide a quick summary of ad blocking so
660 you can get up to speed quickly without having to read the more extensive
661 information provided below, though this is highly recommended.
664 First a bit of a warning ... blocking ads is much like blocking SPAM: the
665 more aggressive you are about it, the more likely you are to block
666 things that were not intended. And the more likely that some things
667 may not work as intended. So there is a trade off here. If you want
668 extreme ad free browsing, be prepared to deal with more
669 <quote>problem</quote> sites, and to spend more time adjusting the
670 configuration to solve these unintended consequences. In short, there is
671 not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
672 the easy way and settle for <emphasis>most</emphasis> ads blocked with the
673 default configuration, or jump in and tweak it for your personal surfing
674 habits and preferences.
677 Secondly, a brief explanation of <application>Privoxy's </application>
678 <quote>actions</quote>. <quote>Actions</quote> in this context, are
679 the directives we use to tell <application>Privoxy</application> to perform
680 some task relating to HTTP transactions (i.e. web browsing). We tell
681 <application>Privoxy</application> to take some <quote>action</quote>. Each
682 action has a unique name and function. While there are many potential
683 <application>actions</application> in <application>Privoxy's</application>
684 arsenal, only a few are used for ad blocking. <link
685 linkend="actions">Actions</link>, and <link linkend="actions-file">action
686 configuration files</link>, are explained in depth below.
689 Actions are specified in <application>Privoxy's</application> configuration,
690 followed by one or more URLs to which the action should apply. URLs
691 can actually be URL type <link linkend="af-patterns">patterns</link> that use
692 wildcards so they can apply potentially to a range of similar URLs. The
693 actions, together with the URL patterns are called a section.
696 When you connect to a website, the full URL will either match one or more
697 of the sections as defined in <application>Privoxy's</application> configuration,
698 or not. If so, then <application>Privoxy</application> will perform the
699 respective actions. If not, then nothing special happens. Furthermore, web
700 pages may contain embedded, secondary URLs that your web browser will
701 use to load additional components of the page, as it parses the
702 original page's HTML content. An ad image for instance, is just an URL
703 embedded in the page somewhere. The image itself may be on the same server,
704 or a server somewhere else on the Internet. Complex web pages will have many
705 such embedded URLs. &my-app; can deal with each URL individually, so, for
706 instance, the main page text is not touched, but images from such-and-such
711 The most important actions for basic ad blocking are: <literal><link
712 linkend="block">block</link></literal>, <literal><link
713 linkend="handle-as-image">handle-as-image</link></literal>,
715 linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
716 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
724 <literal><link linkend="block">block</link></literal> - this is perhaps
725 the single most used action, and is particularly important for ad blocking.
726 This action stops any contact between your browser and any URL patterns
727 that match this action's configuration. It can be used for blocking ads,
728 but also anything that is determined to be unwanted. By itself, it simply
729 stops any communication with the remote server and sends
730 <application>Privoxy</application>'s own built-in BLOCKED page instead to
731 let you now what has happened (with some exceptions, see below).
737 <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
738 tells <application>Privoxy</application> to treat this URL as an image.
739 <application>Privoxy</application>'s default configuration already does this
740 for all common image types (e.g. GIF), but there are many situations where this
741 is not so easy to determine. So we'll force it in these cases. This is particularly
742 important for ad blocking, since only if we know that it's an image of
743 some kind, can we replace it with an image of our choosing, instead of the
744 <application>Privoxy</application> BLOCKED page (which would only result in
745 a <quote>broken image</quote> icon). There are some limitations to this
746 though. For instance, you can't just brute-force an image substitution for
747 an entire HTML page in most situations.
753 <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
754 sends an empty document instead of <application>Privoxy's</application>
755 normal BLOCKED HTML page. This is useful for file types that are neither
756 HTML nor images, such as blocking JavaScript files.
763 linkend="set-image-blocker">set-image-blocker</link></literal> - tells
764 <application>Privoxy</application> what to display in place of an ad image that
765 has hit a block rule. For this to come into play, the URL must match a
766 <literal><link linkend="block">block</link></literal> action somewhere in the
767 configuration, <emphasis>and</emphasis>, it must also match an
768 <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
771 The configuration options on what to display instead of the ad are:
775 <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
776 replacement is obvious. This is the default.
781 <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
782 This is the so-called <quote>invisible</quote> configuration option.
787 <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
788 of the user's choosing (advanced usage).
797 Advanced users will eventually want to explore &my-app;
798 <literal><link linkend="filter">filters</link></literal> as well. Filters
799 are very different from <literal><link
800 linkend="block">blocks</link></literal>.
801 A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
802 are a way of filtering or modifying what is actually on the page. An example
803 filter usage: a text replacement of <quote>no-no</quote> for
804 <quote>nasty-word</quote>. That is a very simple example. This process can be
805 used for ad blocking, but it is more in the realm of advanced usage and has
806 some pitfalls to be wary off.
810 The quickest way to adjust any of these settings is with your browser through
811 the special <application>Privoxy</application> editor at <ulink
812 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
813 (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
814 is an internal page, and does not require Internet access.
818 Note that as of <application>Privoxy</application> 3.0.7 beta the
819 action editor is disabled by default. Check the
820 <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
821 section in the configuration file</ulink> to learn why and in which
822 cases it's safe to enable again.
826 If you decided to enable the action editor, select the appropriate
827 <quote>actions</quote> file, and click
828 <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
829 local preferences in <filename>user.action</filename> since this is not
830 meant to be overwritten during upgrades, and will over-ride the settings in
831 other files. Here you can insert new <quote>actions</quote>, and URLs for ad
832 blocking or other purposes, and make other adjustments to the configuration.
833 <application>Privoxy</application> will detect these changes automatically.
837 A quick and simple step by step example:
845 Right click on the ad image to be blocked, then select
846 <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
854 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
859 Find <filename>user.action</filename> in the top section, and click
860 on <quote><guibutton>Edit</guibutton></quote>:
863 <!-- image of editor and actions files selections -->
865 <figure pgwide="0" float="0"><title>Actions Files in Use</title>
868 <imagedata fileref="files-in-use.jpg" format="jpg">
871 <phrase>[ Screenshot of Actions Files in Use ]</phrase>
880 You should have a section with only
881 <literal><link linkend="block">block</link></literal> listed under
882 <quote>Actions:</quote>.
883 If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
884 button, and in the new section that just appeared, click the
885 <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
886 This will bring up a list of all actions. Find
887 <literal><link linkend="block">block</link></literal> near the top, and click
888 in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
894 Now, in the <literal><link linkend="block">block</link></literal> actions section,
895 click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
896 browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
897 Remove the <literal>http://</literal> at the beginning of the URL. Then, click
898 <quote><guibutton>Submit</guibutton></quote> (or
899 <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
904 Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
905 (or flush all browser caches). The image should be gone now.
913 This is a very crude and simple example. There might be good reasons to use a
914 wildcard pattern match to include potentially similar images from the same
915 site. For a more extensive explanation of <quote>patterns</quote>, and
916 the entire actions concept, see <link linkend="actions-file">the Actions
921 For advanced users who want to hand edit their config files, you might want
922 to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
923 The ideas explained therein also apply to the web-based editor.
926 There are also various
927 <link linkend="filter">filters</link> that can be used for ad blocking
928 (filters are a special subset of actions). These
929 fall into the <quote>advanced</quote> usage category, and are explained in
930 depth in later sections.
937 <!-- ~ End section ~ -->
940 <!-- ~~~~~ New section ~~~~~ -->
942 <title>Starting Privoxy</title>
944 Before launching <application>Privoxy</application> for the first time, you
945 will want to configure your browser(s) to use
946 <application>Privoxy</application> as a HTTP and HTTPS (SSL)
947 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
948 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
949 used port 8000). This is the one configuration step <emphasis>that must be done
953 Please note that <application>Privoxy</application> can only proxy HTTP and
954 HTTPS traffic. It will not work with FTP or other protocols.
957 <!-- image of Mozilla Proxy configuration -->
959 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
960 Mozilla/Netscape HTTP and HTTPS (SSL) Settings</title>
963 <imagedata fileref="proxy_setup.jpg" format="jpg">
966 <phrase>[ Screenshot of Mozilla Proxy Configuration ]</phrase>
974 With <application>Firefox</application>, this is typically set under:
978 <guibutton>Tools</guibutton> -> <guibutton>Options</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Network</guibutton> -><guibutton>Connection</guibutton> -> <guibutton>Settings</guibutton>
983 Or optionally on some platforms:
987 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
993 With <application>Netscape</application> (and
994 <application>Mozilla</application>), this can be set under:
999 <!-- Mix ascii and gui art, something for everybody -->
1000 <!-- spacing on this is tricky -->
1001 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
1006 For <application>Internet Explorer v.5-7</application>:
1010 <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
1014 Then, check <quote>Use Proxy</quote> and fill in the appropriate info
1015 (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
1016 proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
1017 checkboxes like <quote>Use the same proxy server for all protocols</quote> is
1018 <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
1021 <!-- image of IE Proxy configuration -->
1023 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1024 Internet Explorer HTTP and HTTPS (Secure) Settings</title>
1027 <imagedata fileref="proxy2.jpg" format="jpg">
1030 <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
1038 After doing this, flush your browser's disk and memory caches to force a
1039 re-reading of all pages and to get rid of any ads that may be cached. Remove
1040 any <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1041 if you want <application>Privoxy</application> to manage that. You are now
1042 ready to start enjoying the benefits of using
1043 <application>Privoxy</application>!
1047 <application>Privoxy</application> itself is typically started by specifying the
1048 main configuration file to be used on the command line. If no configuration
1049 file is specified on the command line, <application>Privoxy</application>
1050 will look for a file named <filename>config</filename> in the current
1051 directory. Except on Win32 where it will try <filename>config.txt</filename>.
1054 <sect2 id="start-debian">
1055 <title>Debian</title>
1057 We use a script. Note that Debian typically starts &my-app; upon booting per
1058 default. It will use the file
1059 <filename>/etc/privoxy/config</filename> as its main configuration
1064 # /etc/init.d/privoxy start
1069 <sect2 id="start-freebsd">
1070 <title>FreeBSD and ElectroBSD</title>
1072 To start <application>Privoxy</application> upon booting, add
1073 "privoxy_enable='YES'" to <filename>/etc/rc.conf</filename>.
1074 <application>Privoxy</application> will use
1075 <filename>/usr/local/etc/privoxy/config</filename> as its main
1079 If you installed <application>Privoxy</application> into a jail, the
1080 paths above are relative to the jail root.
1083 To start <application>Privoxy</application> manually, run:
1087 # service privoxy onestart
1092 <sect2 id="start-windows">
1093 <title>Windows</title>
1095 Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
1096 specified on the command line, <application>Privoxy</application> will look
1097 for a file named <filename>config.txt</filename>. Note that Windows will
1098 automatically start &my-app; when the system starts if you chose that option
1102 <application>Privoxy</application> can run with full Windows service functionality.
1103 On Windows only, the &my-app; program has two new command line arguments
1104 to install and uninstall &my-app; as a service. See the
1105 <link linkend="installation-pack-win">Windows Installation
1106 instructions</link> for details.
1110 <sect2 id="start-unices">
1111 <title>Generic instructions for Unix derivates (Solaris, NetBSD, HP-UX etc.)</title>
1113 Example Unix startup command:
1117 # /usr/sbin/privoxy --user privoxy /etc/privoxy/config
1121 Note that if you installed <application>Privoxy</application> through
1122 a package manager, the package will probably contain a platform-specific
1123 script or configuration file to start <application>Privoxy</application>
1128 <sect2 id="start-os2">
1131 During installation, <application>Privoxy</application> is configured to
1132 start automatically when the system restarts. You can start it manually by
1133 double-clicking on the <application>Privoxy</application> icon in the
1134 <application>Privoxy</application> folder.
1138 <sect2 id="start-macosx">
1139 <title>Mac OS X</title>
1141 The privoxy service will automatically start after a successful installation
1142 (and thereafter every time your computer starts up) however you will need to
1143 configure your web browser(s) to use it. To do so, configure them to use a
1144 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
1147 To prevent the privoxy service from automatically starting when your computer
1148 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
1149 (on OS X 10.5 and higher) or the folder named
1150 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
1153 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
1154 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
1155 administrator account, using sudo.
1163 See the section <link linkend="cmdoptions">Command line options</link> for
1167 must find a better place for this paragraph
1170 The included default configuration files should give a reasonable starting
1171 point. Most of the per site configuration is done in the
1172 <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
1173 where various cookie actions are defined, ad and banner blocking, and other
1174 aspects of <application>Privoxy</application> configuration. There are several
1175 such files included, with varying levels of aggressiveness.
1179 You will probably want to keep an eye out for sites for which you may prefer
1180 persistent cookies, and add these to your actions configuration as needed. By
1181 default, most of these will be accepted only during the current browser
1182 session (aka <quote>session cookies</quote>), unless you add them to the
1183 configuration. If you want the browser to handle this instead, you will need
1184 to edit <filename>user.action</filename> (or through the web based interface)
1185 and disable this feature. If you use more than one browser, it would make
1186 more sense to let <application>Privoxy</application> handle this. In which
1187 case, the browser(s) should be set to accept all cookies.
1191 Another feature where you will probably want to define exceptions for trusted
1192 sites is the popup-killing (through <ulink
1193 url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
1194 because your favorite shopping, banking, or leisure site may need
1195 popups (explained below).
1199 <application>Privoxy</application> does not support all of the optional HTTP/1.1
1200 features yet. In the unlikely event that you experience inexplicable problems
1201 with browsers that use HTTP/1.1 per default
1202 (like <application>Mozilla</application> or recent versions of I.E.), you might
1203 try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
1204 Preferences -> Debug -> Networking</literal>.
1205 Alternatively, set the <quote>+downgrade-http-version</quote> config option in
1206 <filename>default.action</filename> which will downgrade your browser's HTTP
1207 requests from HTTP/1.1 to HTTP/1.0 before processing them.
1211 After running <application>Privoxy</application> for a while, you can
1212 start to fine tune the configuration to suit your personal, or site,
1213 preferences and requirements. There are many, many aspects that can
1214 be customized. <quote>Actions</quote>
1215 can be adjusted by pointing your browser to
1216 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1217 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1218 and then follow the link to <quote>View & Change the Current Configuration</quote>.
1219 (This is an internal page and does not require Internet access.)
1223 In fact, various aspects of <application>Privoxy</application>
1224 configuration can be viewed from this page, including
1225 current configuration parameters, source code version numbers,
1226 the browser's request headers, and <quote>actions</quote> that apply
1227 to a given URL. In addition to the actions file
1228 editor mentioned above, <application>Privoxy</application> can also
1229 be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
1233 If you encounter problems, try loading the page without
1234 <application>Privoxy</application>. If that helps, enter the URL where
1235 you have the problems into <ulink url="http://p.p/show-url-info">the browser
1236 based rule tracing utility</ulink>. See which rules apply and why, and
1237 then try turning them off for that site one after the other, until the problem
1238 is gone. When you have found the culprit, you might want to turn the rest on
1243 If the above paragraph sounds gibberish to you, you might want to <link
1244 linkend="actions-file">read more about the actions concept</link>
1245 or even dive deep into the <link linkend="actionsanat">Appendix
1250 If you can't get rid of the problem at all, think you've found a bug in
1251 Privoxy, want to propose a new feature or smarter rules, please see the
1252 section <link linkend="contact"><quote>Contacting the
1253 Developers</quote></link> below.
1258 <!-- ~~~~~ New section ~~~~~ -->
1259 <sect2 id="cmdoptions">
1260 <title>Command Line Options</title>
1262 <application>Privoxy</application> may be invoked with the following
1263 command-line options:
1271 <emphasis>--config-test</emphasis>
1274 Exit after loading the configuration files before binding to
1275 the listen address. The exit code signals whether or not the
1276 configuration files have been successfully loaded.
1279 If the exit code is 1, at least one of the configuration files
1280 is invalid, if it is 0, all the configuration files have been
1281 successfully loaded (but may still contain errors that can
1282 currently only be detected at run time).
1285 This option doesn't affect the log setting, combination with
1286 <emphasis>--no-daemon</emphasis> is recommended if a configured
1287 log file shouldn't be used.
1292 <emphasis>--version</emphasis>
1295 Print version info and exit. Unix only.
1300 <emphasis>--help</emphasis>
1303 Print short usage info and exit. Unix only.
1308 <emphasis>--no-daemon</emphasis>
1311 Don't become a daemon, i.e. don't fork and become process group
1312 leader, and don't detach from controlling tty. Unix only.
1317 <emphasis>--pidfile FILE</emphasis>
1320 On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
1321 <emphasis>FILE</emphasis> on exit. Failure to create or delete the
1322 <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
1323 option is given, no PID file will be used. Unix only.
1328 <emphasis>--user USER[.GROUP]</emphasis>
1331 After (optionally) writing the PID file, assume the user ID of
1332 <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
1333 privileges are not sufficient to do so. Unix only.
1338 <emphasis>--chroot</emphasis>
1341 Before changing to the user ID given in the <emphasis>--user</emphasis> option,
1342 chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
1343 process that the directory tree starts there. If set up carefully, this can limit
1344 the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
1350 <emphasis>--pre-chroot-nslookup hostname</emphasis>
1353 Specifies a hostname (for example www.privoxy.org) to look up before doing a chroot.
1354 On some systems, initializing the resolver library involves reading config files from
1355 /etc and/or loading additional shared libraries from /lib.
1356 On these systems, doing a hostname lookup before the chroot reduces
1357 the number of files that must be copied into the chroot tree.
1360 For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
1361 your local name server (listed in /etc/resolv.conf) can resolve without recursion
1362 (that is, without having to ask any other name servers). The hostname need not exist,
1363 but if it doesn't, an error message (which can be ignored) will be output.
1369 <emphasis>configfile</emphasis>
1372 If no <emphasis>configfile</emphasis> is included on the command line,
1373 <application>Privoxy</application> will look for a file named
1374 <quote>config</quote> in the current directory (except on Win32
1375 where it will look for <quote>config.txt</quote> instead). Specify
1376 full path to avoid confusion. If no config file is found,
1377 <application>Privoxy</application> will fail to start.
1385 On <application>MS Windows</application> only there are two additional
1386 command-line options to allow <application>Privoxy</application> to install and
1387 run as a <emphasis>service</emphasis>. See the
1388 <link linkend="installation-pack-win">Window Installation section</link>
1396 <!-- ~ End section ~ -->
1399 <!-- ~~~~~ New section ~~~~~ -->
1400 <sect1 id="configuration"><title>Privoxy Configuration</title>
1402 All <application>Privoxy</application> configuration is stored
1403 in text files. These files can be edited with a text editor.
1404 Many important aspects of <application>Privoxy</application> can
1405 also be controlled easily with a web browser.
1409 <!-- ~~~~~ New section ~~~~~ -->
1412 <title>Controlling Privoxy with Your Web Browser</title>
1414 <application>Privoxy</application>'s user interface can be reached through the special
1415 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1416 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1417 which is a built-in page and works without Internet access.
1418 You will see the following section:
1422 <!-- Needs to be put in a table and colorized -->
1425 <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
1429 ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
1432 ▪ <ulink url="http://config.privoxy.org/show-version">View the source code version numbers</ulink>
1435 ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
1438 ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
1441 ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
1444 ▪ <ulink
1445 url="http://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
1453 This should be self-explanatory. Note the first item leads to an editor for the
1454 <link linkend="actions-file">actions files</link>, which is where the ad, banner,
1455 cookie, and URL blocking magic is configured as well as other advanced features of
1456 <application>Privoxy</application>. This is an easy way to adjust various
1457 aspects of <application>Privoxy</application> configuration. The actions
1458 file, and other configuration files, are explained in detail below.
1462 <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
1463 have problems with your current actions and filters. You can in fact use
1464 it as a test to see whether it is <application>Privoxy</application>
1465 causing the problem or not. <application>Privoxy</application> continues
1466 to run as a proxy in this case, but all manipulation is disabled, i.e.
1467 <application>Privoxy</application> acts like a normal forwarding proxy.
1471 Note that several of the features described above are disabled by default
1472 in <application>Privoxy</application> 3.0.7 beta and later.
1474 <ulink url="config.html">configuration file</ulink> to learn why
1475 and in which cases it's safe to enable them again.
1480 <!-- ~ End section ~ -->
1485 <!-- ~~~~~ New section ~~~~~ -->
1487 <sect2 id="confoverview">
1488 <title>Configuration Files Overview</title>
1490 For Unix, *BSD and Linux, all configuration files are located in
1491 <filename>/etc/privoxy/</filename> by default. For MS Windows, OS/2, and
1492 AmigaOS these are all in the same directory as the
1493 <application>Privoxy</application> executable. <![%p-not-stable;[ The name
1494 and number of configuration files has changed from previous versions, and is
1495 subject to change as development progresses.]]>
1499 The installed defaults provide a reasonable starting point, though
1500 some settings may be aggressive by some standards. For the time being, the
1501 principle configuration files are:
1509 The <link linkend="config">main configuration file</link> is named <filename>config</filename>
1510 on Linux, Unix, BSD, OS/2, and AmigaOS and <filename>config.txt</filename>
1511 on Windows. This is a required file.
1517 <filename>match-all.action</filename> is used to define which <quote>actions</quote>
1518 relating to banner-blocking, images, pop-ups, content modification, cookie handling
1519 etc should be applied by default. It should be the first actions file loaded.
1522 <filename>default.action</filename> defines many exceptions (both positive and negative)
1523 from the default set of actions that's configured in <filename>match-all.action</filename>.
1524 It should be the second actions file loaded and shouldn't be edited by the user.
1527 Multiple actions files may be defined in <filename>config</filename>. These
1528 are processed in the order they are defined. Local customizations and locally
1529 preferred exceptions to the default policies as defined in
1530 <filename>match-all.action</filename> (which you will most probably want
1531 to define sooner or later) are best applied in <filename>user.action</filename>,
1532 where you can preserve them across upgrades. The file isn't installed by all
1533 installers, but you can easily create it yourself with a text editor.
1536 There is also a web based editor that can be accessed from
1538 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1540 url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
1541 various actions files.
1547 <quote>Filter files</quote> (the <link linkend="filter-file">filter
1548 file</link>) can be used to re-write the raw page content, including
1549 viewable text as well as embedded HTML and JavaScript, and whatever else
1550 lurks on any given web page. The filtering jobs are only pre-defined here;
1551 whether to apply them or not is up to the actions files.
1552 <filename>default.filter</filename> includes various filters made
1553 available for use by the developers. Some are much more intrusive than
1554 others, and all should be used with caution. You may define additional
1555 filter files in <filename>config</filename> as you can with
1556 actions files. We suggest <filename>user.filter</filename> for any
1557 locally defined filters or customizations.
1565 The syntax of the configuration and filter files may change between different
1566 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
1567 <!-- Add link to documentation-->
1571 All files use the <quote><literal>#</literal></quote> character to denote a
1572 comment (the rest of the line will be ignored) and understand line continuation
1573 through placing a backslash ("<literal>\</literal>") as the very last character
1574 in a line. If the <literal>#</literal> is preceded by a backslash, it looses
1575 its special function. Placing a <literal>#</literal> in front of an otherwise
1576 valid configuration line to prevent it from being interpreted is called "commenting
1577 out" that line. Blank lines are ignored.
1581 The actions files and filter files
1582 can use Perl style <link linkend="regex">regular expressions</link> for
1583 maximum flexibility.
1587 After making any changes, there is no need to restart
1588 <application>Privoxy</application> in order for the changes to take
1589 effect. <application>Privoxy</application> detects such changes
1590 automatically. Note, however, that it may take one or two additional
1591 requests for the change to take effect. When changing the listening address
1592 of <application>Privoxy</application>, these <quote>wake up</quote> requests
1593 must obviously be sent to the <emphasis>old</emphasis> listening address.
1598 While under development, the configuration content is subject to change.
1599 The below documentation may not be accurate by the time you read this.
1600 Also, what constitutes a <quote>default</quote> setting, may change, so
1601 please check all your configuration files on important issues.
1607 <!-- ~ End section ~ -->
1610 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1612 <!-- **************************************************** -->
1613 <!-- Include config.sgml here -->
1614 <!-- This is where the entire config file is detailed. -->
1616 <!-- end include -->
1619 <!-- ~ End section ~ -->
1623 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1625 <sect1 id="actions-file"><title>Actions Files</title>
1629 XXX: similar descriptions are in the Configuration Files sections.
1630 We should only describe them at one place.
1633 The actions files are used to define what <emphasis>actions</emphasis>
1634 <application>Privoxy</application> takes for which URLs, and thus determines
1635 how ad images, cookies and various other aspects of HTTP content and
1636 transactions are handled, and on which sites (or even parts thereof).
1637 There are a number of such actions, with a wide range of functionality.
1638 Each action does something a little different.
1639 These actions give us a veritable arsenal of tools with which to exert
1640 our control, preferences and independence. Actions can be combined so that
1641 their effects are aggregated when applied against a given set of URLs.
1645 are three action files included with <application>Privoxy</application> with
1652 <filename>match-all.action</filename> - is used to define which
1653 <quote>actions</quote> relating to banner-blocking, images, pop-ups,
1654 content modification, cookie handling etc should be applied by default.
1655 It should be the first actions file loaded
1660 <filename>default.action</filename> - defines many exceptions (both
1661 positive and negative) from the default set of actions that's configured
1662 in <filename>match-all.action</filename>. It is a set of rules that should
1663 work reasonably well as-is for most users. This file is only supposed to
1664 be edited by the developers. It should be the second actions file loaded.
1669 <filename>user.action</filename> - is intended to be for local site
1670 preferences and exceptions. As an example, if your ISP or your bank
1671 has specific requirements, and need special handling, this kind of
1672 thing should go here. This file will not be upgraded.
1677 <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
1680 These have increasing levels of aggressiveness <emphasis>and have no
1681 influence on your browsing unless you select them explicitly in the
1682 editor</emphasis>. A default installation should be pre-set to
1683 <literal>Cautious</literal>. New users should try this for a while before
1684 adjusting the settings to more aggressive levels. The more aggressive
1685 the settings, then the more likelihood there is of problems such as sites
1686 not working as they should.
1689 The <guibutton>Edit</guibutton> button allows you to turn each
1690 action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
1691 button changes the actions list to low/safe settings which will activate
1692 ad blocking and a minimal set of &my-app;'s features, and subsequently
1693 there will be less of a chance for accidental problems. The
1694 <guibutton>Medium</guibutton> button sets the list to a medium level of
1695 other features and a low level set of privacy features. The
1696 <guibutton>Advanced</guibutton> button sets the list to a high level of
1697 ad blocking and medium level of privacy. See the chart below. The latter
1698 three buttons over-ride any changes via with the
1699 <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
1700 lower sections of this internal page.
1703 While the actions file editor allows to enable these settings in all
1704 actions files, they are only supposed to be enabled in the first one
1705 to make sure you don't unintentionally overrule earlier rules.
1708 The default profiles, and their associated actions, as pre-defined in
1709 <filename>default.action</filename> are:
1712 <table frame=all><title>Default Configurations</title>
1713 <tgroup cols=4 align=left colsep=1 rowsep=1>
1714 <colspec colname=c1>
1715 <colspec colname=c2>
1716 <colspec colname=c3>
1717 <colspec colname=c4>
1720 <entry>Feature</entry>
1721 <entry>Cautious</entry>
1722 <entry>Medium</entry>
1723 <entry>Advanced</entry>
1728 <!-- <entry>f1</entry> -->
1729 <!-- <entry>f2</entry> -->
1730 <!-- <entry>f3</entry> -->
1731 <!-- <entry>f4</entry> -->
1737 <entry>Ad-blocking Aggressiveness</entry>
1738 <entry>medium</entry>
1744 <entry>Ad-filtering by size</entry>
1751 <entry>Ad-filtering by link</entry>
1757 <entry>Pop-up killing</entry>
1758 <entry>blocks only</entry>
1759 <entry>blocks only</entry>
1760 <entry>blocks only</entry>
1764 <entry>Privacy Features</entry>
1766 <entry>medium</entry>
1767 <entry>medium/high</entry>
1771 <entry>Cookie handling</entry>
1773 <entry>session-only</entry>
1778 <entry>Referer forging</entry>
1785 <entry>GIF de-animation</entry>
1792 <entry>Fast redirects</entry>
1799 <entry>HTML taming</entry>
1806 <entry>JavaScript taming</entry>
1813 <entry>Web-bug killing</entry>
1820 <entry>Image tag reordering</entry>
1836 The list of actions files to be used are defined in the main configuration
1837 file, and are processed in the order they are defined (e.g.
1838 <filename>default.action</filename> is typically processed before
1839 <filename>user.action</filename>). The content of these can all be viewed and
1841 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1842 The over-riding principle when applying actions, is that the last action that
1843 matches a given URL wins. The broadest, most general rules go first
1844 (defined in <filename>default.action</filename>),
1845 followed by any exceptions (typically also in
1846 <filename>default.action</filename>), which are then followed lastly by any
1847 local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
1848 Generally, <filename>user.action</filename> has the last word.
1852 An actions file typically has multiple sections. If you want to use
1853 <quote>aliases</quote> in an actions file, you have to place the (optional)
1854 <link linkend="aliases">alias section</link> at the top of that file.
1855 Then comes the default set of rules which will apply universally to all
1856 sites and pages (be <emphasis>very careful</emphasis> with using such a
1857 universal set in <filename>user.action</filename> or any other actions file after
1858 <filename>default.action</filename>, because it will override the result
1859 from consulting any previous file). And then below that,
1860 exceptions to the defined universal policies. You can regard
1861 <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
1862 with the advantage that it is a separate file, which makes preserving your
1863 personal settings across <application>Privoxy</application> upgrades easier.
1867 Actions can be used to block anything you want, including ads, banners, or
1868 just some obnoxious URL whose content you would rather not see. Cookies can be accepted
1869 or rejected, or accepted only during the current browser session (i.e. not
1870 written to disk), content can be modified, some JavaScripts tamed, user-tracking
1871 fooled, and much more. See below for a <link linkend="actions">complete list
1875 <!-- ~~~~~ New section ~~~~~ -->
1877 <title>Finding the Right Mix</title>
1879 Note that some <link linkend="actions">actions</link>, like cookie suppression
1880 or script disabling, may render some sites unusable that rely on these
1881 techniques to work properly. Finding the right mix of actions is not always easy and
1882 certainly a matter of personal taste. And, things can always change, requiring
1883 refinements in the configuration. In general, it can be said that the more
1884 <quote>aggressive</quote> your default settings (in the top section of the
1885 actions file) are, the more exceptions for <quote>trusted</quote> sites you
1886 will have to make later. If, for example, you want to crunch all cookies per
1887 default, you'll have to make exceptions from that rule for sites that you
1888 regularly use and that require cookies for actually useful purposes, like maybe
1889 your bank, favorite shop, or newspaper.
1893 We have tried to provide you with reasonable rules to start from in the
1894 distribution actions files. But there is no general rule of thumb on these
1895 things. There just are too many variables, and sites are constantly changing.
1896 Sooner or later you will want to change the rules (and read this chapter again :).
1900 <!-- ~~~~~ New section ~~~~~ -->
1902 <title>How to Edit</title>
1904 The easiest way to edit the actions files is with a browser by
1905 using our browser-based editor, which can be reached from <ulink
1906 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1907 Note: the config file option <link
1908 linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
1909 this to work. The editor allows both fine-grained control over every single
1910 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
1911 like <quote>Cautious</quote>, <quote>Medium</quote> or
1912 <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
1913 aggressive, and will be more likely to cause problems for some sites.
1914 Experienced users only!
1918 If you prefer plain text editing to GUIs, you can of course also directly edit the
1919 the actions files with your favorite text editor. Look at
1920 <filename>default.action</filename> which is richly commented with many
1926 <sect2 id="actions-apply">
1927 <title>How Actions are Applied to Requests</title>
1929 Actions files are divided into sections. There are special sections,
1930 like the <quote><link linkend="aliases">alias</link></quote> sections which will
1931 be discussed later. For now let's concentrate on regular sections: They have a
1932 heading line (often split up to multiple lines for readability) which consist
1933 of a list of actions, separated by whitespace and enclosed in curly braces.
1934 Below that, there is a list of URL and tag patterns, each on a separate line.
1938 To determine which actions apply to a request, the URL of the request is
1939 compared to all URL patterns in each <quote>action file</quote>.
1940 Every time it matches, the list of applicable actions for the request is
1941 incrementally updated, using the heading of the section in which the
1942 pattern is located. The same is done again for tags and tag patterns later on.
1946 If multiple applying sections set the same action differently,
1947 the last match wins. If not, the effects are aggregated.
1948 E.g. a URL might match a regular section with a heading line of <literal>{
1949 +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
1950 then later another one with just <literal>{
1951 +<link linkend="block">block</link> }</literal>, resulting
1952 in <emphasis>both</emphasis> actions to apply. And there may well be
1953 cases where you will want to combine actions together. Such a section then
1959 { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
1960 # Block these as if they were images. Send no block page.
1962 media.example.com/.*banners
1963 .example.com/images/ads/</screen>
1967 You can trace this process for URL patterns and any given URL by visiting <ulink
1968 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
1972 Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
1973 Troubleshooting: Anatomy of an Action</link> section.
1977 <!-- ~~~~~ New section ~~~~~ -->
1978 <sect2 id="af-patterns">
1979 <title>Patterns</title>
1981 As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
1982 to determine what <emphasis>actions</emphasis> might apply to which sites and
1983 pages your browser attempts to access. These <quote>patterns</quote> use wild
1984 card type <emphasis>pattern</emphasis> matching to achieve a high degree of
1985 flexibility. This allows one expression to be expanded and potentially match
1986 against many similar patterns.
1990 Generally, an URL pattern has the form
1991 <literal><host><port>/<path></literal>, where the
1992 <literal><host></literal>, the <literal><port></literal>
1993 and the <literal><path></literal> are optional. (This is why the special
1994 <literal>/</literal> pattern matches all URLs). Note that the protocol
1995 portion of the URL pattern (e.g. <literal>http://</literal>) should
1996 <emphasis>not</emphasis> be included in the pattern. This is assumed already!
1999 The pattern matching syntax is different for the host and path parts of
2000 the URL. The host part uses a simple globbing type matching technique,
2001 while the path part uses more flexible
2002 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2003 Expressions</quote></ulink> (POSIX 1003.2).
2006 The port part of a pattern is a decimal port number preceded by a colon
2007 (<literal>:</literal>). If the host part contains a numerical IPv6 address,
2008 it has to be put into angle brackets
2009 (<literal><</literal>, <literal>></literal>).
2014 <term><literal>www.example.com/</literal></term>
2017 is a host-only pattern and will match any request to <literal>www.example.com</literal>,
2018 regardless of which document on that server is requested. So ALL pages in
2019 this domain would be covered by the scope of this action. Note that a
2020 simple <literal>example.com</literal> is different and would NOT match.
2025 <term><literal>www.example.com</literal></term>
2028 means exactly the same. For host-only patterns, the trailing <literal>/</literal> may
2034 <term><literal>www.example.com/index.html</literal></term>
2037 matches all the documents on <literal>www.example.com</literal>
2038 whose name starts with <literal>/index.html</literal>.
2043 <term><literal>www.example.com/index.html$</literal></term>
2046 matches only the single document <literal>/index.html</literal>
2047 on <literal>www.example.com</literal>.
2052 <term><literal>/index.html$</literal></term>
2055 matches the document <literal>/index.html</literal>, regardless of the domain,
2056 i.e. on <emphasis>any</emphasis> web server anywhere.
2061 <term><literal>/</literal></term>
2064 Matches any URL because there's no requirement for either the
2065 domain or the path to match anything.
2070 <term><literal>:8000/</literal></term>
2073 Matches any URL pointing to TCP port 8000.
2078 <term><literal>10.0.0.1/</literal></term>
2081 Matches any URL with the host address <literal>10.0.0.1</literal>.
2082 (Note that the real URL uses plain brackets, not angle brackets.)
2087 <term><literal><2001:db8::1>/</literal></term>
2090 Matches any URL with the host address <literal>2001:db8::1</literal>.
2091 (Note that the real URL uses plain brackets, not angle brackets.)
2096 <term><literal>index.html</literal></term>
2099 matches nothing, since it would be interpreted as a domain name and
2100 there is no top-level domain called <literal>.html</literal>. So its
2108 <!-- ~~~~~ New section ~~~~~ -->
2109 <sect3 id="host-pattern"><title>The Host Pattern</title>
2112 The matching of the host part offers some flexible options: if the
2113 host pattern starts or ends with a dot, it becomes unanchored at that end.
2114 The host pattern is often referred to as domain pattern as it is usually
2115 used to match domain names and not IP addresses.
2121 <term><literal>.example.com</literal></term>
2124 matches any domain with first-level domain <literal>com</literal>
2125 and second-level domain <literal>example</literal>.
2126 For example <literal>www.example.com</literal>,
2127 <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
2128 Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
2133 <term><literal>www.</literal></term>
2136 matches any domain that <emphasis>STARTS</emphasis> with
2137 <literal>www.</literal> (It also matches the domain
2138 <literal>www</literal> but most of the time that doesn't matter.)
2143 <term><literal>.example.</literal></term>
2146 matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
2147 And, by the way, also included would be any files or documents that exist
2148 within that domain since no path limitations are specified. (Correctly
2149 speaking: It matches any FQDN that contains <literal>example</literal> as
2150 a domain.) This might be <literal>www.example.com</literal>,
2151 <literal>news.example.de</literal>, or
2152 <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
2160 Additionally, there are wild-cards that you can use in the domain names
2161 themselves. These work similarly to shell globbing type wild-cards:
2162 <quote>*</quote> represents zero or more arbitrary characters (this is
2164 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2165 Expression</quote></ulink> based syntax of <quote>.*</quote>),
2166 <quote>?</quote> represents any single character (this is equivalent to the
2167 regular expression syntax of a simple <quote>.</quote>), and you can define
2168 <quote>character classes</quote> in square brackets which is similar to
2169 the same regular expression technique. All of this can be freely mixed:
2174 <term><literal>ad*.example.com</literal></term>
2177 matches <quote>adserver.example.com</quote>,
2178 <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
2183 <term><literal>*ad*.example.com</literal></term>
2186 matches all of the above, and then some.
2191 <term><literal>.?pix.com</literal></term>
2194 matches <literal>www.ipix.com</literal>,
2195 <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
2200 <term><literal>www[1-9a-ez].example.c*</literal></term>
2203 matches <literal>www1.example.com</literal>,
2204 <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
2205 <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
2206 <literal>wwww.example.com</literal>.
2213 While flexible, this is not the sophistication of full regular expression based syntax.
2218 <!-- ~ End section ~ -->
2221 <!-- ~~~~~ New section ~~~~~ -->
2222 <sect3><title>The Path Pattern</title>
2225 <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
2226 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2227 Expressions</quote></ulink> for matching the path portion (after the slash),
2228 and is thus more flexible.
2232 There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
2233 expressions, you also might want to have a look at your operating system's documentation
2234 on regular expressions (try <literal>man re_format</literal>).
2238 Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
2239 i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
2240 for the beginning of a line).
2244 Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
2245 by default, but you can switch to case sensitive at any point in the pattern by using the
2246 <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
2247 only documents whose path starts with <literal>PaTtErN</literal> in
2248 <emphasis>exactly</emphasis> this capitalization.
2253 <term><literal>.example.com/.*</literal></term>
2256 Is equivalent to just <quote>.example.com</quote>, since any documents
2257 within that domain are matched with or without the <quote>.*</quote>
2258 regular expression. This is redundant
2263 <term><literal>.example.com/.*/index.html$</literal></term>
2266 Will match any page in the domain of <quote>example.com</quote> that is
2267 named <quote>index.html</quote>, and that is part of some path. For
2268 example, it matches <quote>www.example.com/testing/index.html</quote> but
2269 NOT <quote>www.example.com/index.html</quote> because the regular
2270 expression called for at least two <quote>/'s</quote>, thus the path
2271 requirement. It also would match
2272 <quote>www.example.com/testing/index_html</quote>, because of the
2273 special meta-character <quote>.</quote>.
2278 <term><literal>.example.com/(.*/)?index\.html$</literal></term>
2281 This regular expression is conditional so it will match any page
2282 named <quote>index.html</quote> regardless of path which in this case can
2283 have one or more <quote>/'s</quote>. And this one must contain exactly
2284 <quote>.html</quote> (but does not have to end with that!).
2289 <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
2292 This regular expression will match any path of <quote>example.com</quote>
2293 that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
2294 <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
2295 The path does not have to end in these words, just contain them.
2300 <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
2303 This is very much the same as above, except now it must end in either
2304 <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
2305 one is limited to common image formats.
2312 There are many, many good examples to be found in <filename>default.action</filename>,
2313 and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
2318 <!-- ~ End section ~ -->
2321 <!-- ~~~~~ New section ~~~~~ -->
2322 <sect3 id="tag-pattern"><title>The Tag Pattern</title>
2325 Tag patterns are used to change the applying actions based on the
2326 request's tags. Tags can be created with either the
2327 <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
2328 or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
2332 Tag patterns have to start with <quote>TAG:</quote>, so &my-app;
2333 can tell them apart from URL patterns. Everything after the colon
2334 including white space, is interpreted as a regular expression with
2335 path pattern syntax, except that tag patterns aren't left-anchored
2336 automatically (&my-app; doesn't silently add a <quote>^</quote>,
2337 you have to do it yourself if you need it).
2341 To match all requests that are tagged with <quote>foo</quote>
2342 your pattern line should be <quote>TAG:^foo$</quote>,
2343 <quote>TAG:foo</quote> would work as well, but it would also
2344 match requests whose tags contain <quote>foo</quote> somewhere.
2345 <quote>TAG: foo</quote> wouldn't work as it requires white space.
2349 Sections can contain URL and tag patterns at the same time,
2350 but tag patterns are checked after the URL patterns and thus
2351 always overrule them, even if they are located before the URL patterns.
2355 Once a new tag is added, Privoxy checks right away if it's matched by one
2356 of the tag patterns and updates the action settings accordingly. As a result
2357 tags can be used to activate other tagger actions, as long as these other
2358 taggers look for headers that haven't already be parsed.
2362 For example you could tag client requests which use the
2363 <literal>POST</literal> method,
2364 then use this tag to activate another tagger that adds a tag if cookies
2365 are sent, and then use a block action based on the cookie tag. This allows
2366 the outcome of one action, to be input into a subsequent action. However if
2367 you'd reverse the position of the described taggers, and activated the
2368 method tagger based on the cookie tagger, no method tags would be created.
2369 The method tagger would look for the request line, but at the time
2370 the cookie tag is created, the request line has already been parsed.
2374 While this is a limitation you should be aware of, this kind of
2375 indirection is seldom needed anyway and even the example doesn't
2376 make too much sense.
2381 <!-- ~~~~~ New section ~~~~~ -->
2382 <sect3 id="negative-tag-patterns"><title>The Negative Tag Patterns</title>
2385 To match requests that do not have a certain tag, specify a negative tag pattern
2386 by prefixing the tag pattern line with either <quote>NO-REQUEST-TAG:</quote>
2387 or <quote>NO-RESPONSE-TAG:</quote> instead of <quote>TAG:</quote>.
2391 Negative tag patterns created with <quote>NO-REQUEST-TAG:</quote> are checked
2392 after all client headers are scanned, the ones created with <quote>NO-RESPONSE-TAG:</quote>
2393 are checked after all server headers are scanned. In both cases all the created
2394 tags are considered.
2400 <!-- ~ End section ~ -->
2403 <!-- ~~~~~ New section ~~~~~ -->
2405 <sect2 id="actions">
2406 <title>Actions</title>
2408 All actions are disabled by default, until they are explicitly enabled
2409 somewhere in an actions file. Actions are turned on if preceded with a
2410 <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
2411 <literal>+action</literal> means <quote>do that action</quote>, e.g.
2412 <literal>+block</literal> means <quote>please block URLs that match the
2413 following patterns</quote>, and <literal>-block</literal> means <quote>don't
2414 block URLs that match the following patterns, even if <literal>+block</literal>
2415 previously applied.</quote>
2420 Again, actions are invoked by placing them on a line, enclosed in curly braces and
2421 separated by whitespace, like in
2422 <literal>{+some-action -some-other-action{some-parameter}}</literal>,
2423 followed by a list of URL patterns, one per line, to which they apply.
2424 Together, the actions line and the following pattern lines make up a section
2425 of the actions file.
2429 Actions fall into three categories:
2436 Boolean, i.e the action can only be <quote>enabled</quote> or
2437 <quote>disabled</quote>. Syntax:
2441 +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
2442 -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable></screen>
2445 Example: <literal>+handle-as-image</literal>
2452 Parameterized, where some value is required in order to enable this type of action.
2457 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
2458 # overwriting parameter from previous match if necessary
2459 -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted</screen>
2462 Note that if the URL matches multiple positive forms of a parameterized action,
2463 the last match wins, i.e. the params from earlier matches are simply ignored.
2466 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>
2472 Multi-value. These look exactly like parameterized actions,
2473 but they behave differently: If the action applies multiple times to the
2474 same URL, but with different parameters, <emphasis>all</emphasis> the parameters
2475 from <emphasis>all</emphasis> matches are remembered. This is used for actions
2476 that can be executed for the same request repeatedly, like adding multiple
2477 headers, or filtering through multiple filters. Syntax:
2481 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
2482 -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
2483 # If it was the last one left, disable the action.
2484 <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list</screen>
2487 Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
2488 <literal>+filter{html-annoyances}</literal>
2496 If nothing is specified in any actions file, no <quote>actions</quote> are
2497 taken. So in this case <application>Privoxy</application> would just be a
2498 normal, non-blocking, non-filtering proxy. You must specifically enable the
2499 privacy and blocking features you need (although the provided default actions
2500 files will give a good starting point).
2504 Later defined action sections always over-ride earlier ones of the same type.
2505 So exceptions to any rules you make, should come in the latter part of the file (or
2506 in a file that is processed later when using multiple actions files such
2507 as <filename>user.action</filename>). For multi-valued actions, the actions
2508 are applied in the order they are specified. Actions files are processed in
2509 the order they are defined in <filename>config</filename> (the default
2510 installation has three actions files). It also quite possible for any given
2511 URL to match more than one <quote>pattern</quote> (because of wildcards and
2512 regular expressions), and thus to trigger more than one set of actions! Last
2516 <!-- start actions listing -->
2518 The list of valid <application>Privoxy</application> actions are:
2522 <!-- ********************************************************** -->
2523 <!-- Please note the below defined actions use id's that are -->
2524 <!-- probably linked from other places, so please don't change. -->
2526 <!-- ********************************************************** -->
2529 <!-- ~~~~~ New section ~~~~~ -->
2531 <sect3 renderas="sect4" id="add-header">
2532 <title>add-header</title>
2536 <term>Typical use:</term>
2538 <para>Confuse log analysis, custom applications</para>
2543 <term>Effect:</term>
2546 Sends a user defined HTTP header to the web server.
2553 <!-- boolean, parameterized, Multi-value -->
2555 <para>Multi-value.</para>
2560 <term>Parameter:</term>
2563 Any string value is possible. Validity of the defined HTTP headers is not checked.
2564 It is recommended that you use the <quote><literal>X-</literal></quote> prefix
2574 This action may be specified multiple times, in order to define multiple
2575 headers. This is rarely needed for the typical user. If you don't know what
2576 <quote>HTTP headers</quote> are, you definitely don't need to worry about this
2580 Headers added by this action are not modified by other actions.
2586 <term>Example usage:</term>
2589 <screen>+add-header{X-User-Tracking: sucks}</screen>
2597 <!-- ~~~~~ New section ~~~~~ -->
2598 <sect3 renderas="sect4" id="block">
2599 <title>block</title>
2603 <term>Typical use:</term>
2605 <para>Block ads or other unwanted content</para>
2610 <term>Effect:</term>
2613 Requests for URLs to which this action applies are blocked, i.e. the
2614 requests are trapped by &my-app; and the requested URL is never retrieved,
2615 but is answered locally with a substitute page or image, as determined by
2617 linkend="handle-as-image">handle-as-image</link></literal>,
2619 linkend="set-image-blocker">set-image-blocker</link></literal>, and
2621 linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
2629 <!-- boolean, parameterized, Multi-value -->
2631 <para>Parameterized.</para>
2636 <term>Parameter:</term>
2638 <para>A block reason that should be given to the user.</para>
2646 <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
2647 for requests to blocked pages. This page contains the block reason given as
2648 parameter, a link to find out why the block action applies, and a click-through
2649 to the blocked content (the latter only if the force feature is available and
2653 A very important exception occurs if <emphasis>both</emphasis>
2654 <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
2655 apply to the same request: it will then be replaced by an image. If
2656 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
2657 (see below) also applies, the type of image will be determined by its parameter,
2658 if not, the standard checkerboard pattern is sent.
2661 It is important to understand this process, in order
2662 to understand how <application>Privoxy</application> deals with
2663 ads and other unwanted content. Blocking is a core feature, and one
2664 upon which various other features depend.
2667 The <literal><link linkend="filter">filter</link></literal>
2668 action can perform a very similar task, by <quote>blocking</quote>
2669 banner images and other content through rewriting the relevant URLs in the
2670 document's HTML source, so they don't get requested in the first place.
2671 Note that this is a totally different technique, and it's easy to confuse the two.
2677 <term>Example usage (section):</term>
2680 <screen>{+block{No nasty stuff for you.}}
2681 # Block and replace with "blocked" page
2682 .nasty-stuff.example.com
2684 {+block{Doubleclick banners.} +handle-as-image}
2685 # Block and replace with image
2689 {+block{Layered ads.} +handle-as-empty-document}
2690 # Block and then ignore
2691 adserver.example.net/.*\.js$</screen>
2701 <!-- ~~~~~ New section ~~~~~ -->
2702 <sect3 renderas="sect4" id="change-x-forwarded-for">
2703 <title>change-x-forwarded-for</title>
2707 <term>Typical use:</term>
2709 <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
2714 <term>Effect:</term>
2717 Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
2725 <!-- Boolean, Parameterized, Multi-value -->
2727 <para>Parameterized.</para>
2732 <term>Parameter:</term>
2736 <para><quote>block</quote> to delete the header.</para>
2740 <quote>add</quote> to create the header (or append
2741 the client's IP address to an already existing one).
2752 It is safe and recommended to use <literal>block</literal>.
2755 Forwarding the source address of the request may make
2756 sense in some multi-user setups but is also a privacy risk.
2761 <term>Example usage:</term>
2764 <screen>+change-x-forwarded-for{block}</screen>
2771 <!-- ~~~~~ New section ~~~~~ -->
2772 <sect3 renderas="sect4" id="client-header-filter">
2773 <title>client-header-filter</title>
2777 <term>Typical use:</term>
2780 Rewrite or remove single client headers.
2786 <term>Effect:</term>
2789 All client headers to which this action applies are filtered on-the-fly through
2790 the specified regular expression based substitutions.
2797 <!-- boolean, parameterized, Multi-value -->
2799 <para>Multi-value.</para>
2804 <term>Parameter:</term>
2807 The name of a client-header filter, as defined in one of the
2808 <link linkend="filter-file">filter files</link>.
2817 Client-header filters are applied to each header on its own, not to
2818 all at once. This makes it easier to diagnose problems, but on the downside
2819 you can't write filters that only change header x if header y's value is z.
2820 You can do that by using tags though.
2823 Client-header filters are executed after the other header actions have finished
2824 and use their output as input.
2827 If the request URI gets changed, &my-app; will detect that and use the new
2828 one. This can be used to rewrite the request destination behind the client's
2829 back, for example to specify a Tor exit relay for certain requests.
2832 Please refer to the <link linkend="filter-file">filter file chapter</link>
2833 to learn which client-header filters are available by default, and how to
2841 <term>Example usage (section):</term>
2845 # Hide Tor exit notation in Host and Referer Headers
2846 {+client-header-filter{hide-tor-exit-notation}}
2857 <!-- ~~~~~ New section ~~~~~ -->
2858 <sect3 renderas="sect4" id="client-header-tagger">
2859 <title>client-header-tagger</title>
2863 <term>Typical use:</term>
2866 Block requests based on their headers.
2872 <term>Effect:</term>
2875 Client headers to which this action applies are filtered on-the-fly through
2876 the specified regular expression based substitutions, the result is used as
2884 <!-- boolean, parameterized, Multi-value -->
2886 <para>Multi-value.</para>
2891 <term>Parameter:</term>
2894 The name of a client-header tagger, as defined in one of the
2895 <link linkend="filter-file">filter files</link>.
2904 Client-header taggers are applied to each header on its own,
2905 and as the header isn't modified, each tagger <quote>sees</quote>
2909 Client-header taggers are the first actions that are executed
2910 and their tags can be used to control every other action.
2916 <term>Example usage (section):</term>
2920 # Tag every request with the User-Agent header
2921 {+client-header-tagger{user-agent}}
2924 # Tagging itself doesn't change the action
2925 # settings, sections with TAG patterns do:
2927 # If it's a download agent, use a different forwarding proxy,
2928 # show the real User-Agent and make sure resume works.
2929 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
2930 -hide-if-modified-since \
2931 -overwrite-last-modified \
2936 TAG:^User-Agent: NetBSD-ftp/
2937 TAG:^User-Agent: Novell ZYPP Installer
2938 TAG:^User-Agent: RPM APT-HTTP/
2939 TAG:^User-Agent: fetch libfetch/
2940 TAG:^User-Agent: Ubuntu APT-HTTP/
2941 TAG:^User-Agent: MPlayer/
2946 # Tag all requests with the Range header set
2947 {+client-header-tagger{range-requests}}
2950 # Disable filtering for the tagged requests.
2952 # With filtering enabled Privoxy would remove the Range headers
2953 # to be able to filter the whole response. The downside is that
2954 # it prevents clients from resuming downloads or skipping over
2955 # parts of multimedia files.
2956 {-filter -deanimate-gifs}
2967 <!-- ~~~~~ New section ~~~~~ -->
2968 <sect3 renderas="sect4" id="content-type-overwrite">
2969 <title>content-type-overwrite</title>
2973 <term>Typical use:</term>
2975 <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
2980 <term>Effect:</term>
2983 Replaces the <quote>Content-Type:</quote> HTTP server header.
2990 <!-- Boolean, Parameterized, Multi-value -->
2992 <para>Parameterized.</para>
2997 <term>Parameter:</term>
3009 The <quote>Content-Type:</quote> HTTP server header is used by the
3010 browser to decide what to do with the document. The value of this
3011 header can cause the browser to open a download menu instead of
3012 displaying the document by itself, even if the document's format is
3013 supported by the browser.
3016 The declared content type can also affect which rendering mode
3017 the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
3018 many browsers treat it as yet another broken HTML document.
3019 If it is send as <quote>application/xml</quote>, browsers with
3020 XHTML support will only display it, if the syntax is correct.
3023 If you see a web site that proudly uses XHTML buttons, but sets
3024 <quote>Content-Type: text/html</quote>, you can use &my-app;
3025 to overwrite it with <quote>application/xml</quote> and validate
3026 the web master's claim inside your XHTML-supporting browser.
3027 If the syntax is incorrect, the browser will complain loudly.
3030 You can also go the opposite direction: if your browser prints
3031 error messages instead of rendering a document falsely declared
3032 as XHTML, you can overwrite the content type with
3033 <quote>text/html</quote> and have it rendered as broken HTML document.
3036 By default <literal>content-type-overwrite</literal> only replaces
3037 <quote>Content-Type:</quote> headers that look like some kind of text.
3038 If you want to overwrite it unconditionally, you have to combine it with
3039 <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
3040 This limitation exists for a reason, think twice before circumventing it.
3043 Most of the time it's easier to replace this action with a custom
3044 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3045 It allows you to activate it for every document of a certain site and it will still
3046 only replace the content types you aimed at.
3049 Of course you can apply <literal>content-type-overwrite</literal>
3050 to a whole site and then make URL based exceptions, but it's a lot
3051 more work to get the same precision.
3057 <term>Example usage (sections):</term>
3060 <screen># Check if www.example.net/ really uses valid XHTML
3061 { +content-type-overwrite{application/xml} }
3064 # but leave the content type unmodified if the URL looks like a style sheet
3065 {-content-type-overwrite}
3066 www.example.net/.*\.css$
3067 www.example.net/.*style
3076 <!-- ~~~~~ New section ~~~~~ -->
3077 <sect3 renderas="sect4" id="crunch-client-header">
3081 <title>crunch-client-header</title>
3085 <term>Typical use:</term>
3087 <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
3092 <term>Effect:</term>
3095 Deletes every header sent by the client that contains the string the user supplied as parameter.
3102 <!-- Boolean, Parameterized, Multi-value -->
3104 <para>Parameterized.</para>
3109 <term>Parameter:</term>
3121 This action allows you to block client headers for which no dedicated
3122 <application>Privoxy</application> action exists.
3123 <application>Privoxy</application> will remove every client header that
3124 contains the string you supplied as parameter.
3127 Regular expressions are <emphasis>not supported</emphasis> and you can't
3128 use this action to block different headers in the same request, unless
3129 they contain the same string.
3132 <literal>crunch-client-header</literal> is only meant for quick tests.
3133 If you have to block several different headers, or only want to modify
3134 parts of them, you should use a
3135 <literal><link linkend="client-header-filter">client-header filter</link></literal>.
3139 Don't block any header without understanding the consequences.
3146 <term>Example usage (section):</term>
3149 <screen># Block the non-existent "Privacy-Violation:" client header
3150 { +crunch-client-header{Privacy-Violation:} }
3160 <!-- ~~~~~ New section ~~~~~ -->
3161 <sect3 renderas="sect4" id="crunch-if-none-match">
3162 <title>crunch-if-none-match</title>
3168 <term>Typical use:</term>
3170 <para>Prevent yet another way to track the user's steps between sessions.</para>
3175 <term>Effect:</term>
3178 Deletes the <quote>If-None-Match:</quote> HTTP client header.
3185 <!-- Boolean, Parameterized, Multi-value -->
3187 <para>Boolean.</para>
3192 <term>Parameter:</term>
3204 Removing the <quote>If-None-Match:</quote> HTTP client header
3205 is useful for filter testing, where you want to force a real
3206 reload instead of getting status code <quote>304</quote> which
3207 would cause the browser to use a cached copy of the page.
3210 It is also useful to make sure the header isn't used as a cookie
3211 replacement (unlikely but possible).
3214 Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
3215 caching problems, as long as the <quote>If-Modified-Since:</quote> header
3216 isn't blocked or missing as well.
3219 It is recommended to use this action together with
3220 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
3222 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
3228 <term>Example usage (section):</term>
3231 <screen># Let the browser revalidate cached documents but don't
3232 # allow the server to use the revalidation headers for user tracking.
3233 {+hide-if-modified-since{-60} \
3234 +overwrite-last-modified{randomize} \
3235 +crunch-if-none-match}
3244 <!-- ~~~~~ New section ~~~~~ -->
3245 <sect3 renderas="sect4" id="crunch-incoming-cookies">
3246 <title>crunch-incoming-cookies</title>
3250 <term>Typical use:</term>
3253 Prevent the web server from setting HTTP cookies on your system
3259 <term>Effect:</term>
3262 Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
3269 <!-- Boolean, Parameterized, Multi-value -->
3271 <para>Boolean.</para>
3276 <term>Parameter:</term>
3288 This action is only concerned with <emphasis>incoming</emphasis> HTTP cookies. For
3289 <emphasis>outgoing</emphasis> HTTP cookies, use
3290 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
3291 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3294 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3295 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3296 since it would prevent the session cookies from being set. See also
3297 <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
3303 <term>Example usage:</term>
3306 <screen>+crunch-incoming-cookies</screen>
3314 <!-- ~~~~~ New section ~~~~~ -->
3315 <sect3 renderas="sect4" id="crunch-server-header">
3316 <title>crunch-server-header</title>
3322 <term>Typical use:</term>
3324 <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
3329 <term>Effect:</term>
3332 Deletes every header sent by the server that contains the string the user supplied as parameter.
3339 <!-- Boolean, Parameterized, Multi-value -->
3341 <para>Parameterized.</para>
3346 <term>Parameter:</term>
3358 This action allows you to block server headers for which no dedicated
3359 <application>Privoxy</application> action exists. <application>Privoxy</application>
3360 will remove every server header that contains the string you supplied as parameter.
3363 Regular expressions are <emphasis>not supported</emphasis> and you can't
3364 use this action to block different headers in the same request, unless
3365 they contain the same string.
3368 <literal>crunch-server-header</literal> is only meant for quick tests.
3369 If you have to block several different headers, or only want to modify
3370 parts of them, you should use a custom
3371 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3375 Don't block any header without understanding the consequences.
3382 <term>Example usage (section):</term>
3385 <screen># Crunch server headers that try to prevent caching
3386 { +crunch-server-header{no-cache} }
3395 <!-- ~~~~~ New section ~~~~~ -->
3396 <sect3 renderas="sect4" id="crunch-outgoing-cookies">
3397 <title>crunch-outgoing-cookies</title>
3401 <term>Typical use:</term>
3404 Prevent the web server from reading any HTTP cookies from your system
3410 <term>Effect:</term>
3413 Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
3420 <!-- Boolean, Parameterized, Multi-value -->
3422 <para>Boolean.</para>
3427 <term>Parameter:</term>
3439 This action is only concerned with <emphasis>outgoing</emphasis> HTTP cookies. For
3440 <emphasis>incoming</emphasis> HTTP cookies, use
3441 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
3442 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3445 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3446 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3447 since it would prevent the session cookies from being read.
3453 <term>Example usage:</term>
3456 <screen>+crunch-outgoing-cookies</screen>
3465 <!-- ~~~~~ New section ~~~~~ -->
3466 <sect3 renderas="sect4" id="deanimate-gifs">
3467 <title>deanimate-gifs</title>
3471 <term>Typical use:</term>
3473 <para>Stop those annoying, distracting animated GIF images.</para>
3478 <term>Effect:</term>
3481 De-animate GIF animations, i.e. reduce them to their first or last image.
3488 <!-- boolean, parameterized, Multi-value -->
3490 <para>Parameterized.</para>
3495 <term>Parameter:</term>
3498 <quote>last</quote> or <quote>first</quote>
3507 This will also shrink the images considerably (in bytes, not pixels!). If
3508 the option <quote>first</quote> is given, the first frame of the animation
3509 is used as the replacement. If <quote>last</quote> is given, the last
3510 frame of the animation is used instead, which probably makes more sense for
3511 most banner animations, but also has the risk of not showing the entire
3512 last frame (if it is only a delta to an earlier frame).
3515 You can safely use this action with patterns that will also match non-GIF
3516 objects, because no attempt will be made at anything that doesn't look like
3523 <term>Example usage:</term>
3526 <screen>+deanimate-gifs{last}</screen>
3533 <!-- ~~~~~ New section ~~~~~ -->
3534 <sect3 renderas="sect4" id="downgrade-http-version">
3535 <title>downgrade-http-version</title>
3539 <term>Typical use:</term>
3541 <para>Work around (very rare) problems with HTTP/1.1</para>
3546 <term>Effect:</term>
3549 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
3556 <!-- boolean, parameterized, Multi-value -->
3558 <para>Boolean.</para>
3563 <term>Parameter:</term>
3575 This is a left-over from the time when <application>Privoxy</application>
3576 didn't support important HTTP/1.1 features well. It is left here for the
3577 unlikely case that you experience HTTP/1.1-related problems with some server
3581 Note that enabling this action is only a workaround. It should not
3582 be enabled for sites that work without it. While it shouldn't break
3583 any pages, it has an (usually negative) performance impact.
3586 If you come across a site where enabling this action helps, please report it,
3587 so the cause of the problem can be analyzed. If the problem turns out to be
3588 caused by a bug in <application>Privoxy</application> it should be
3589 fixed so the following release works without the work around.
3595 <term>Example usage (section):</term>
3598 <screen>{+downgrade-http-version}
3599 problem-host.example.com</screen>
3607 <!-- ~~~~~ New section ~~~~~ -->
3608 <sect3 renderas="sect4" id="external-filter">
3609 <title>external-filter</title>
3613 <term>Typical use:</term>
3615 <para>Modify content using a programming language of your choice.</para>
3620 <term>Effect:</term>
3623 All instances of text-based type, most notably HTML and JavaScript, to which
3624 this action applies, can be filtered on-the-fly through the specified external
3626 By default plain text documents are exempted from filtering, because web
3627 servers often use the <literal>text/plain</literal> MIME type for all files
3628 whose type they don't know.)
3635 <!-- boolean, parameterized, Multi-value -->
3637 <para>Multi-value.</para>
3642 <term>Parameter:</term>
3645 The name of an external content filter, as defined in the
3646 <link linkend="filter-file">filter file</link>.
3647 External filters can be defined in one or more files as defined by the
3648 <literal><link linkend="filterfile">filterfile</link></literal>
3649 option in the <link linkend="config">config file</link>.
3652 When used in its negative form,
3653 and without parameters, <emphasis>all</emphasis> filtering with external
3654 filters is completely disabled.
3663 External filters are scripts or programs that can modify the content in
3664 case common <literal><link linkend="filter">filters</link></literal>
3665 aren't powerful enough. With the exception that this action doesn't
3666 use pcrs-based filters, the notes in the
3667 <literal><link linkend="filter">filter</link></literal> section apply.
3671 Currently external filters are executed with &my-app;'s privileges.
3672 Only use external filters you understand and trust.
3676 This feature is experimental, the <literal><link
3677 linkend="external-filter-syntax">syntax</link></literal>
3678 may change in the future.
3685 <term>Example usage:</term>
3688 <screen>+external-filter{fancy-filter}</screen>
3695 <!-- ~~~~~ New section ~~~~~ -->
3696 <sect3 renderas="sect4" id="fast-redirects">
3697 <title>fast-redirects</title>
3701 <term>Typical use:</term>
3703 <para>Fool some click-tracking scripts and speed up indirect links.</para>
3708 <term>Effect:</term>
3711 Detects redirection URLs and redirects the browser without contacting
3712 the redirection server first.
3719 <!-- boolean, parameterized, Multi-value -->
3721 <para>Parameterized.</para>
3726 <term>Parameter:</term>
3731 <quote>simple-check</quote> to just search for the string <quote>http://</quote>
3732 to detect redirection URLs.
3737 <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
3738 for redirection URLs.
3749 Many sites, like yahoo.com, don't just link to other sites. Instead, they
3750 will link to some script on their own servers, giving the destination as a
3751 parameter, which will then redirect you to the final target. URLs
3752 resulting from this scheme typically look like:
3753 <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
3756 Sometimes, there are even multiple consecutive redirects encoded in the
3757 URL. These redirections via scripts make your web browsing more traceable,
3758 since the server from which you follow such a link can see where you go
3759 to. Apart from that, valuable bandwidth and time is wasted, while your
3760 browser asks the server for one redirect after the other. Plus, it feeds
3764 This feature is currently not very smart and is scheduled for improvement.
3765 If it is enabled by default, you will have to create some exceptions to
3766 this action. It can lead to failures in several ways:
3769 Not every URLs with other URLs as parameters is evil.
3770 Some sites offer a real service that requires this information to work.
3771 For example a validation service needs to know, which document to validate.
3772 <literal>fast-redirects</literal> assumes that every URL parameter that
3773 looks like another URL is a redirection target, and will always redirect to
3774 the last one. Most of the time the assumption is correct, but if it isn't,
3775 the user gets redirected anyway.
3778 Another failure occurs if the URL contains other parameters after the URL parameter.
3780 <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
3781 contains the redirection URL <quote>http://www.example.net/</quote>,
3782 followed by another parameter. <literal>fast-redirects</literal> doesn't know that
3783 and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
3784 Depending on the target server configuration, the parameter will be silently ignored
3785 or lead to a <quote>page not found</quote> error. You can prevent this problem by
3786 first using the <literal><link linkend="redirect">redirect</link></literal> action
3787 to remove the last part of the URL, but it requires a little effort.
3790 To detect a redirection URL, <literal>fast-redirects</literal> only
3791 looks for the string <quote>http://</quote>, either in plain text
3792 (invalid but often used) or encoded as <quote>http%3a//</quote>.
3793 Some sites use their own URL encoding scheme, encrypt the address
3794 of the target server or replace it with a database id. In theses cases
3795 <literal>fast-redirects</literal> is fooled and the request reaches the
3796 redirection server where it probably gets logged.
3802 <term>Example usage:</term>
3806 { +fast-redirects{simple-check} }
3809 { +fast-redirects{check-decoded-url} }
3810 another.example.com/testing</screen>
3819 <!-- ~~~~~ New section ~~~~~ -->
3820 <sect3 renderas="sect4" id="filter">
3821 <title>filter</title>
3825 <term>Typical use:</term>
3827 <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
3828 do fun text replacements, add personalized effects, etc.</para>
3833 <term>Effect:</term>
3836 All instances of text-based type, most notably HTML and JavaScript, to which
3837 this action applies, can be filtered on-the-fly through the specified regular
3838 expression based substitutions. (Note: as of version 3.0.3 plain text documents
3839 are exempted from filtering, because web servers often use the
3840 <literal>text/plain</literal> MIME type for all files whose type they don't know.)
3847 <!-- boolean, parameterized, Multi-value -->
3849 <para>Multi-value.</para>
3854 <term>Parameter:</term>
3857 The name of a content filter, as defined in the <link linkend="filter-file">filter file</link>.
3858 Filters can be defined in one or more files as defined by the
3859 <literal><link linkend="filterfile">filterfile</link></literal>
3860 option in the <link linkend="config">config file</link>.
3861 <filename>default.filter</filename> is the collection of filters
3862 supplied by the developers. Locally defined filters should go
3863 in their own file, such as <filename>user.filter</filename>.
3866 When used in its negative form,
3867 and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
3876 For your convenience, there are a number of pre-defined filters available
3877 in the distribution filter file that you can use. See the examples below for
3881 Filtering requires buffering the page content, which may appear to
3882 slow down page rendering since nothing is displayed until all content has
3883 passed the filters. (The total time until the page is completely rendered
3884 doesn't change much, but it may be perceived as slower since the page is
3885 not incrementally displayed.)
3886 This effect will be more noticeable on slower connections.
3889 <quote>Rolling your own</quote>
3890 filters requires a knowledge of
3891 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3892 Expressions</quote></ulink> and
3893 <ulink url="http://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
3894 This is very powerful feature, and potentially very intrusive.
3895 Filters should be used with caution, and where an equivalent
3896 <quote>action</quote> is not available.
3899 The amount of data that can be filtered is limited to the
3900 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
3901 option in the main <link linkend="config">config file</link>. The
3902 default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
3903 data, and all pending data, is passed through unfiltered.
3906 Inappropriate MIME types, such as zipped files, are not filtered at all.
3907 (Again, only text-based types except plain text). Encrypted SSL data
3908 (from HTTPS servers) cannot be filtered either, since this would violate
3909 the integrity of the secure transaction. In some situations it might
3910 be necessary to protect certain text, like source code, from filtering
3911 by defining appropriate <literal>-filter</literal> exceptions.
3914 Compressed content can't be filtered either, but if &my-app;
3915 is compiled with zlib support and a supported compression algorithm
3916 is used (gzip or deflate), &my-app; can first decompress the content
3920 If you use a &my-app; version without zlib support, but want filtering to work on
3921 as much documents as possible, even those that would normally be sent compressed,
3922 you must use the <literal><link linkend="prevent-compression">prevent-compression</link></literal>
3923 action in conjunction with <literal>filter</literal>.
3926 Content filtering can achieve some of the same effects as the
3927 <literal><link linkend="block">block</link></literal>
3928 action, i.e. it can be used to block ads and banners. But the mechanism
3929 works quite differently. One effective use, is to block ad banners
3930 based on their size (see below), since many of these seem to be somewhat
3934 <link linkend="contact">Feedback</link> with suggestions for new or
3935 improved filters is particularly welcome!
3938 The below list has only the names and a one-line description of each
3939 predefined filter. There are <link linkend="predefined-filters">more
3940 verbose explanations</link> of what these filters do in the <link
3941 linkend="filter-file">filter file chapter</link>.
3947 <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
3948 See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
3949 more explanation on each:</term>
3952 <anchor id="filter-js-annoyances">
3953 <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse.</screen>
3956 <anchor id="filter-js-events">
3957 <screen>+filter{js-events} # Kill JavaScript event bindings and timers (Radically destructive! Only for extra nasty sites).</screen>
3960 <anchor id="filter-html-annoyances">
3961 <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse.</screen>
3964 <anchor id="filter-content-cookies">
3965 <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content.</screen>
3968 <anchor id="filter-refresh-tags">
3969 <screen>+filter{refresh-tags} # Kill automatic refresh tags if refresh time is larger than 9 seconds.</screen>
3972 <anchor id="filter-unsolicited-popups">
3973 <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows.</screen>
3976 <anchor id="filter-all-popups">
3977 <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML.</screen>
3980 <anchor id="filter-img-reorder">
3981 <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective.</screen>
3984 <anchor id="filter-banners-by-size">
3985 <screen>+filter{banners-by-size} # Kill banners by size.</screen>
3988 <anchor id="filter-banners-by-link">
3989 <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers.</screen>
3992 <anchor id="filter-webbugs">
3993 <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking).</screen>
3996 <anchor id="filter-tiny-textforms">
3997 <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap.</screen>
4000 <anchor id="filter-jumping-windows">
4001 <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves.</screen>
4004 <anchor id="filter-frameset-borders">
4005 <screen>+filter{frameset-borders} # Give frames a border and make them resizable.</screen>
4008 <anchor id="filter-iframes">
4009 <screen>+filter{iframes} # Removes all detected iframes. Should only be enabled for individual sites.</screen>
4012 <anchor id="filter-demoronizer">
4013 <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets.</screen>
4016 <anchor id="filter-shockwave-flash">
4017 <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects.</screen>
4020 <anchor id="filter-quicktime-kioskmode">
4021 <screen>+filter{quicktime-kioskmode} # Make Quicktime movies saveable.</screen>
4024 <anchor id="filter-fun">
4025 <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
4028 <anchor id="filter-crude-parental">
4029 <screen>+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably.</screen>
4032 <anchor id="filter-ie-exploits">
4033 <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits.</screen>
4036 <anchor id="filter-site-specifics">
4037 <screen>+filter{site-specifics} # Cure for site-specific problems. Don't apply generally!</screen>
4040 <anchor id="filter-no-ping">
4041 <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
4044 <anchor id="filter-google">
4045 <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
4048 <anchor id="filter-yahoo">
4049 <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
4052 <anchor id="filter-msn">
4053 <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
4056 <anchor id="filter-blogspot">
4057 <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</screen>
4065 <!-- ~~~~~ New section ~~~~~ -->
4066 <sect3 renderas="sect4" id="force-text-mode">
4067 <title>force-text-mode</title>
4073 <term>Typical use:</term>
4075 <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
4080 <term>Effect:</term>
4083 Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
4090 <!-- Boolean, Parameterized, Multi-value -->
4092 <para>Boolean.</para>
4097 <term>Parameter:</term>
4109 As explained <literal><link linkend="filter">above</link></literal>,
4110 <application>Privoxy</application> tries to only filter files that are
4111 in some kind of text format. The same restrictions apply to
4112 <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
4113 <literal>force-text-mode</literal> declares a document as text,
4114 without looking at the <quote>Content-Type:</quote> first.
4118 Think twice before activating this action. Filtering binary data
4119 with regular expressions can cause file damage.
4126 <term>Example usage:</term>
4139 <!-- ~~~~~ New section ~~~~~ -->
4140 <sect3 renderas="sect4" id="forward-override">
4141 <title>forward-override</title>
4147 <term>Typical use:</term>
4149 <para>Change the forwarding settings based on User-Agent or request origin</para>
4154 <term>Effect:</term>
4157 Overrules the forward directives in the configuration file.
4164 <!-- Boolean, Parameterized, Multi-value -->
4166 <para>Parameterized.</para>
4171 <term>Parameter:</term>
4175 <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
4179 <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
4184 <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
4185 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
4186 to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4187 for socks5 connections (with remote DNS resolution).
4192 <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
4193 listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
4194 Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
4195 (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4196 for socks5 connections (with remote DNS resolution).
4201 <quote>forward-webserver 127.0.0.1:80</quote> to use the HTTP
4202 server listening at 127.0.0.1 port 80 without adjusting the
4206 This makes it more convenient to use Privoxy to make
4207 existing websites available as onion services as well.
4210 Many websites serve content with hardcoded URLs and
4211 can't be easily adjusted to change the domain based
4212 on the one used by the client.
4215 Putting Privoxy between Tor and the webserver (or an stunnel
4216 that forwards to the webserver) allows to rewrite headers and
4217 content to make client and server happy at the same time.
4220 Using Privoxy for webservers that are only reachable through
4221 onion addresses and whose location is supposed to be secret
4222 is not recommended and should not be necessary anyway.
4233 This action takes parameters similar to the
4234 <link linkend="forwarding">forward</link> directives in the configuration
4235 file, but without the URL pattern. It can be used as replacement, but normally it's only
4236 used in cases where matching based on the request URL isn't sufficient.
4240 Please read the description for the <link linkend="forwarding">forward</link> directives before
4241 using this action. Forwarding to the wrong people will reduce your privacy and increase the
4242 chances of man-in-the-middle attacks.
4245 If the ports are missing or invalid, default values will be used. This might change
4246 in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
4247 to exit. Due to design limitations, invalid parameter syntax isn't detected until the
4248 action is used the first time.
4251 Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
4252 to verify that your forward settings do what you thought the do.
4259 <term>Example usage:</term>
4263 # Use an ssh tunnel for requests previously tagged as
4264 # <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
4265 # resuming downloads continues to work.
4267 # This way you can continue to use Tor for your normal browsing,
4268 # without overloading the Tor network with your FreeBSD ports updates
4269 # or downloads of bigger files like ISOs.
4271 # Note that HTTP headers are easy to fake and therefore their
4272 # values are as (un)trustworthy as your clients and users.
4273 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
4274 -hide-if-modified-since \
4275 -overwrite-last-modified \
4277 TAG:^User-Agent: fetch libfetch/2\.0$
4286 <!-- ~~~~~ New section ~~~~~ -->
4287 <sect3 renderas="sect4" id="handle-as-empty-document">
4288 <title>handle-as-empty-document</title>
4294 <term>Typical use:</term>
4296 <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
4301 <term>Effect:</term>
4304 This action alone doesn't do anything noticeable. It just marks URLs.
4305 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4306 the presence or absence of this mark decides whether an HTML <quote>BLOCKED</quote>
4307 page, or an empty document will be sent to the client as a substitute for the blocked content.
4308 The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
4315 <!-- Boolean, Parameterized, Multi-value -->
4317 <para>Boolean.</para>
4322 <term>Parameter:</term>
4334 Some browsers complain about syntax errors if JavaScript documents
4335 are blocked with <application>Privoxy's</application>
4336 default HTML page; this option can be used to silence them.
4337 And of course this action can also be used to eliminate the &my-app;
4338 BLOCKED message in frames.
4341 The content type for the empty document can be specified with
4342 <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
4343 but usually this isn't necessary.
4349 <term>Example usage:</term>
4352 <screen># Block all documents on example.org that end with ".js",
4353 # but send an empty document instead of the usual HTML message.
4354 {+block{Blocked JavaScript} +handle-as-empty-document}
4364 <!-- ~~~~~ New section ~~~~~ -->
4365 <sect3 renderas="sect4" id="handle-as-image">
4366 <title>handle-as-image</title>
4370 <term>Typical use:</term>
4372 <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>
4377 <term>Effect:</term>
4380 This action alone doesn't do anything noticeable. It just marks URLs as images.
4381 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4382 the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
4383 page, or a replacement image (as determined by the <literal><link
4384 linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
4385 client as a substitute for the blocked content.
4392 <!-- Boolean, Parameterized, Multi-value -->
4394 <para>Boolean.</para>
4399 <term>Parameter:</term>
4411 The below generic example section is actually part of <filename>default.action</filename>.
4412 It marks all URLs with well-known image file name extensions as images and should
4416 Users will probably only want to use the handle-as-image action in conjunction with
4417 <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
4418 reflect the file type, like in the second example section.
4421 Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
4422 frames require an HTML page to be sent, or they won't display properly.
4423 Forcing <literal>handle-as-image</literal> in this situation will not replace the
4424 ad frame with an image, but lead to error messages.
4430 <term>Example usage (sections):</term>
4433 <screen># Generic image extensions:
4436 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
4438 # These don't look like images, but they're banners and should be
4439 # blocked as images:
4441 {+block{Nasty banners.} +handle-as-image}
4442 nasty-banner-server.example.com/junk.cgi\?output=trash
4451 <!-- ~~~~~ New section ~~~~~ -->
4452 <sect3 renderas="sect4" id="hide-accept-language">
4453 <title>hide-accept-language</title>
4459 <term>Typical use:</term>
4461 <para>Pretend to use different language settings.</para>
4466 <term>Effect:</term>
4469 Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
4476 <!-- Boolean, Parameterized, Multi-value -->
4478 <para>Parameterized.</para>
4483 <term>Parameter:</term>
4486 Keyword: <quote>block</quote>, or any user defined value.
4495 Faking the browser's language settings can be useful to make a
4496 foreign User-Agent set with
4497 <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
4501 However some sites with content in different languages check the
4502 <quote>Accept-Language:</quote> to decide which one to take by default.
4503 Sometimes it isn't possible to later switch to another language without
4504 changing the <quote>Accept-Language:</quote> header first.
4507 Therefore it's a good idea to either only change the
4508 <quote>Accept-Language:</quote> header to languages you understand,
4509 or to languages that aren't wide spread.
4512 Before setting the <quote>Accept-Language:</quote> header
4513 to a rare language, you should consider that it helps to
4514 make your requests unique and thus easier to trace.
4515 If you don't plan to change this header frequently,
4516 you should stick to a common language.
4522 <term>Example usage (section):</term>
4525 <screen># Pretend to use Canadian language settings.
4526 {+hide-accept-language{en-ca} \
4527 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
4537 <!-- ~~~~~ New section ~~~~~ -->
4538 <sect3 renderas="sect4" id="hide-content-disposition">
4539 <title>hide-content-disposition</title>
4545 <term>Typical use:</term>
4547 <para>Prevent download menus for content you prefer to view inside the browser.</para>
4552 <term>Effect:</term>
4555 Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
4562 <!-- Boolean, Parameterized, Multi-value -->
4564 <para>Parameterized.</para>
4569 <term>Parameter:</term>
4572 Keyword: <quote>block</quote>, or any user defined value.
4581 Some servers set the <quote>Content-Disposition:</quote> HTTP header for
4582 documents they assume you want to save locally before viewing them.
4583 The <quote>Content-Disposition:</quote> header contains the file name
4584 the browser is supposed to use by default.
4587 In most browsers that understand this header, it makes it impossible to
4588 <emphasis>just view</emphasis> the document, without downloading it first,
4589 even if it's just a simple text file or an image.
4592 Removing the <quote>Content-Disposition:</quote> header helps
4593 to prevent this annoyance, but some browsers additionally check the
4594 <quote>Content-Type:</quote> header, before they decide if they can
4595 display a document without saving it first. In these cases, you have
4596 to change this header as well, before the browser stops displaying
4600 It is also possible to change the server's file name suggestion
4601 to another one, but in most cases it isn't worth the time to set
4605 This action will probably be removed in the future,
4606 use server-header filters instead.
4612 <term>Example usage:</term>
4615 <screen># Disarm the download link in Sourceforge's patch tracker
4617 +content-type-overwrite{text/plain}\
4618 +hide-content-disposition{block} }
4619 .sourceforge.net/tracker/download\.php</screen>
4627 <!-- ~~~~~ New section ~~~~~ -->
4628 <sect3 renderas="sect4" id="hide-if-modified-since">
4629 <title>hide-if-modified-since</title>
4635 <term>Typical use:</term>
4637 <para>Prevent yet another way to track the user's steps between sessions.</para>
4642 <term>Effect:</term>
4645 Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
4652 <!-- Boolean, Parameterized, Multi-value -->
4654 <para>Parameterized.</para>
4659 <term>Parameter:</term>
4662 Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
4671 Removing this header is useful for filter testing, where you want to force a real
4672 reload instead of getting status code <quote>304</quote>, which would cause the
4673 browser to use a cached copy of the page.
4676 Instead of removing the header, <literal>hide-if-modified-since</literal> can
4677 also add or subtract a random amount of time to/from the header's value.
4678 You specify a range of minutes where the random factor should be chosen from and
4679 <application>Privoxy</application> does the rest. A negative value means
4680 subtracting, a positive value adding.
4683 Randomizing the value of the <quote>If-Modified-Since:</quote> makes
4684 it less likely that the server can use the time as a cookie replacement,
4685 but you will run into caching problems if the random range is too high.
4688 It is a good idea to only use a small negative value and let
4689 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
4690 handle the greater changes.
4693 It is also recommended to use this action together with
4694 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>,
4695 otherwise it's more or less pointless.
4701 <term>Example usage (section):</term>
4704 <screen># Let the browser revalidate but make tracking based on the time less likely.
4705 {+hide-if-modified-since{-60} \
4706 +overwrite-last-modified{randomize} \
4707 +crunch-if-none-match}
4716 <!-- ~~~~~ New section ~~~~~ -->
4717 <sect3 renderas="sect4" id="hide-from-header">
4718 <title>hide-from-header</title>
4722 <term>Typical use:</term>
4724 <para>Keep your (old and ill) browser from telling web servers your email address</para>
4729 <term>Effect:</term>
4732 Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
4740 <!-- Boolean, Parameterized, Multi-value -->
4742 <para>Parameterized.</para>
4747 <term>Parameter:</term>
4750 Keyword: <quote>block</quote>, or any user defined value.
4759 The keyword <quote>block</quote> will completely remove the header
4760 (not to be confused with the <literal><link linkend="block">block</link></literal>
4764 Alternately, you can specify any value you prefer to be sent to the web
4765 server. If you do, it is a matter of fairness not to use any address that
4766 is actually used by a real person.
4769 This action is rarely needed, as modern web browsers don't send
4770 <quote>From:</quote> headers anymore.
4776 <term>Example usage:</term>
4779 <screen>+hide-from-header{block}</screen> or
4780 <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
4788 <!-- ~~~~~ New section ~~~~~ -->
4789 <sect3 renderas="sect4" id="hide-referrer">
4790 <title>hide-referrer</title>
4791 <anchor id="hide-referer">
4794 <term>Typical use:</term>
4796 <para>Conceal which link you followed to get to a particular site</para>
4801 <term>Effect:</term>
4804 Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
4805 or replaces it with a forged one.
4812 <!-- Boolean, Parameterized, Multi-value -->
4814 <para>Parameterized.</para>
4819 <term>Parameter:</term>
4823 <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
4826 <para><quote>conditional-forge</quote> to forge the header if the host has changed.</para>
4829 <para><quote>block</quote> to delete the header unconditionally.</para>
4832 <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
4835 <para>Any other string to set a user defined referrer.</para>
4845 <literal>conditional-block</literal> is the only parameter,
4846 that isn't easily detected in the server's log file. If it blocks the
4847 referrer, the request will look like the visitor used a bookmark or
4848 typed in the address directly.
4851 Leaving the referrer unmodified for requests on the same host
4852 allows the server owner to see the visitor's <quote>click path</quote>,
4853 but in most cases she could also get that information by comparing
4854 other parts of the log file: for example the User-Agent if it isn't
4855 a very common one, or the user's IP address if it doesn't change between
4859 Always blocking the referrer, or using a custom one, can lead to
4860 failures on servers that check the referrer before they answer any
4861 requests, in an attempt to prevent their content from being
4862 embedded or linked to elsewhere.
4865 Both <literal>conditional-block</literal> and <literal>forge</literal>
4866 will work with referrer checks, as long as content and valid referring page
4867 are on the same host. Most of the time that's the case.
4870 <literal>hide-referer</literal> is an alternate spelling of
4871 <literal>hide-referrer</literal> and the two can be can be freely
4872 substituted with each other. (<quote>referrer</quote> is the
4873 correct English spelling, however the HTTP specification has a bug - it
4874 requires it to be spelled as <quote>referer</quote>.)
4880 <term>Example usage:</term>
4883 <screen>+hide-referrer{forge}</screen> or
4884 <screen>+hide-referrer{http://www.yahoo.com/}</screen>
4892 <!-- ~~~~~ New section ~~~~~ -->
4893 <sect3 renderas="sect4" id="hide-user-agent">
4894 <title>hide-user-agent</title>
4898 <term>Typical use:</term>
4900 <para>Try to conceal your type of browser and client operating system</para>
4905 <term>Effect:</term>
4908 Replaces the value of the <quote>User-Agent:</quote> HTTP header
4909 in client requests with the specified value.
4916 <!-- Boolean, Parameterized, Multi-value -->
4918 <para>Parameterized.</para>
4923 <term>Parameter:</term>
4926 Any user-defined string.
4936 This can lead to problems on web sites that depend on looking at this header in
4937 order to customize their content for different browsers (which, by the
4938 way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
4939 work browser-independently).
4943 Using this action in multi-user setups or wherever different types of
4944 browsers will access the same <application>Privoxy</application> is
4945 <emphasis>not recommended</emphasis>. In single-user, single-browser
4946 setups, you might use it to delete your OS version information from
4947 the headers, because it is an invitation to exploit known bugs for your
4948 OS. It is also occasionally useful to forge this in order to access
4949 sites that won't let you in otherwise (though there may be a good
4950 reason in some cases).
4953 More information on known user-agent strings can be found at
4954 <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
4956 <ulink url="http://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
4962 <term>Example usage:</term>
4965 <screen>+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}</screen>
4973 <!-- ~~~~~ New section ~~~~~ -->
4974 <sect3 renderas="sect4" id="limit-connect">
4975 <title>limit-connect</title>
4979 <term>Typical use:</term>
4981 <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
4986 <term>Effect:</term>
4989 Specifies to which ports HTTP CONNECT requests are allowable.
4996 <!-- Boolean, Parameterized, Multi-value -->
4998 <para>Parameterized.</para>
5003 <term>Parameter:</term>
5006 A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
5007 defaulting to 0 and the maximum to 65K).
5016 By default, i.e. if no <literal>limit-connect</literal> action applies,
5017 <application>Privoxy</application> allows HTTP CONNECT requests to all
5018 ports. Use <literal>limit-connect</literal> if fine-grained control
5019 is desired for some or all destinations.
5022 The CONNECT methods exists in HTTP to allow access to secure websites
5023 (<quote>https://</quote> URLs) through proxies. It works very simply:
5024 the proxy connects to the server on the specified port, and then
5025 short-circuits its connections to the client and to the remote server.
5026 This means CONNECT-enabled proxies can be used as TCP relays very easily.
5029 <application>Privoxy</application> relays HTTPS traffic without seeing
5030 the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
5031 filters. By specifying an invalid port range you can disable HTTPS entirely.
5037 <term>Example usages:</term>
5039 <!-- I had trouble getting the spacing to look right in my browser -->
5040 <!-- I probably have the wrong font setup, bollocks. -->
5041 <!-- Apparently the emphasis tag uses a proportional font no matter what -->
5043 <screen>+limit-connect{443} # Port 443 is OK.
5044 +limit-connect{80,443} # Ports 80 and 443 are OK.
5045 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
5046 +limit-connect{-} # All ports are OK
5047 +limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
5055 <!-- ~~~~~ New section ~~~~~ -->
5056 <sect3 renderas="sect4" id="limit-cookie-lifetime">
5057 <title>limit-cookie-lifetime</title>
5061 <term>Typical use:</term>
5063 <para>Limit the lifetime of HTTP cookies to a couple of minutes or hours.</para>
5068 <term>Effect:</term>
5071 Overwrites the expires field in Set-Cookie server headers if it's above the specified limit.
5078 <!-- Boolean, Parameterized, Multi-value -->
5080 <para>Parameterized.</para>
5085 <term>Parameter:</term>
5088 The lifetime limit in minutes, or 0.
5097 This action reduces the lifetime of HTTP cookies coming from the
5098 server to the specified number of minutes, starting from the time
5099 the cookie passes Privoxy.
5102 Cookies with a lifetime below the limit are not modified.
5103 The lifetime of session cookies is set to the specified limit.
5106 The effect of this action depends on the server.
5109 In case of servers which refresh their cookies with each response
5110 (or at least frequently), the lifetime limit set by this action
5112 Thus, a session associated with the cookie continues to work with
5113 this action enabled, as long as a new request is made before the
5114 last limit set is reached.
5117 However, some servers send their cookies once, with a lifetime of several
5118 years (the year 2037 is a popular choice), and do not refresh them
5119 until a certain event in the future, for example the user logging out.
5120 In this case this action may limit the absolute lifetime of the session,
5121 even if requests are made frequently.
5124 If the parameter is <quote>0</quote>, this action behaves like
5125 <literal><link linkend="session-cookies-only">session-cookies-only</link></literal>.
5131 <term>Example usages:</term>
5134 <screen>+limit-cookie-lifetime{60}
5142 <!-- ~~~~~ New section ~~~~~ -->
5143 <sect3 renderas="sect4" id="prevent-compression">
5144 <title>prevent-compression</title>
5148 <term>Typical use:</term>
5151 Ensure that servers send the content uncompressed, so it can be
5152 passed through <literal><link linkend="filter">filter</link></literal>s.
5158 <term>Effect:</term>
5161 Removes the Accept-Encoding header which can be used to ask for compressed transfer.
5168 <!-- Boolean, Parameterized, Multi-value -->
5170 <para>Boolean.</para>
5175 <term>Parameter:</term>
5187 More and more websites send their content compressed by default, which
5188 is generally a good idea and saves bandwidth. But the <literal><link
5189 linkend="filter">filter</link></literal> and
5190 <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
5191 actions need access to the uncompressed data.
5194 When compiled with zlib support (available since &my-app; 3.0.7), content that should be
5195 filtered is decompressed on-the-fly and you don't have to worry about this action.
5196 If you are using an older &my-app; version, or one that hasn't been compiled with zlib
5197 support, this action can be used to convince the server to send the content uncompressed.
5200 Most text-based instances compress very well, the size is seldom decreased by less than 50%,
5201 for markup-heavy instances like news feeds saving more than 90% of the original size isn't
5205 Not using compression will therefore slow down the transfer, and you should only
5206 enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
5207 predefined action settings.
5210 Note that some (rare) ill-configured sites don't handle requests for uncompressed
5211 documents correctly. Broken PHP applications tend to send an empty document body,
5212 some IIS versions only send the beginning of the content. If you enable
5213 <literal>prevent-compression</literal> per default, you might want to add
5214 exceptions for those sites. See the example for how to do that.
5220 <term>Example usage (sections):</term>
5224 # Selectively turn off compression, and enable a filter
5226 { +filter{tiny-textforms} +prevent-compression }
5227 # Match only these sites
5232 # Or instead, we could set a universal default:
5234 { +prevent-compression }
5237 # Then maybe make exceptions for broken sites:
5239 { -prevent-compression }
5240 .compusa.com/</screen>
5249 <!-- ~~~~~ New section ~~~~~ -->
5250 <sect3 renderas="sect4" id="overwrite-last-modified">
5251 <title>overwrite-last-modified</title>
5257 <term>Typical use:</term>
5259 <para>Prevent yet another way to track the user's steps between sessions.</para>
5264 <term>Effect:</term>
5267 Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
5274 <!-- Boolean, Parameterized, Multi-value -->
5276 <para>Parameterized.</para>
5281 <term>Parameter:</term>
5284 One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
5285 and <quote>randomize</quote>
5294 Removing the <quote>Last-Modified:</quote> header is useful for filter
5295 testing, where you want to force a real reload instead of getting status
5296 code <quote>304</quote>, which would cause the browser to reuse the old
5297 version of the page.
5300 The <quote>randomize</quote> option overwrites the value of the
5301 <quote>Last-Modified:</quote> header with a randomly chosen time
5302 between the original value and the current time. In theory the server
5303 could send each document with a different <quote>Last-Modified:</quote>
5304 header to track visits without using cookies. <quote>Randomize</quote>
5305 makes it impossible and the browser can still revalidate cached documents.
5308 <quote>reset-to-request-time</quote> overwrites the value of the
5309 <quote>Last-Modified:</quote> header with the current time. You could use
5310 this option together with
5311 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
5312 to further customize your random range.
5315 The preferred parameter here is <quote>randomize</quote>. It is safe
5316 to use, as long as the time settings are more or less correct.
5317 If the server sets the <quote>Last-Modified:</quote> header to the time
5318 of the request, the random range becomes zero and the value stays the same.
5319 Therefore you should later randomize it a second time with
5320 <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
5324 It is also recommended to use this action together with
5325 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
5331 <term>Example usage:</term>
5334 <screen># Let the browser revalidate without being tracked across sessions
5335 { +hide-if-modified-since{-60} \
5336 +overwrite-last-modified{randomize} \
5337 +crunch-if-none-match}
5346 <!-- ~~~~~ New section ~~~~~ -->
5347 <sect3 renderas="sect4" id="redirect">
5348 <title>redirect</title>
5354 <term>Typical use:</term>
5357 Redirect requests to other sites.
5363 <term>Effect:</term>
5366 Convinces the browser that the requested document has been moved
5367 to another location and the browser should get it from there.
5374 <!-- Boolean, Parameterized, Multi-value -->
5376 <para>Parameterized</para>
5381 <term>Parameter:</term>
5384 An absolute URL or a single pcrs command.
5393 Requests to which this action applies are answered with a
5394 HTTP redirect to URLs of your choosing. The new URL is
5395 either provided as parameter, or derived by applying a
5396 single pcrs command to the original URL.
5399 The syntax for pcrs commands is documented in the
5400 <link linkend="filter-file">filter file</link> section.
5403 Requests can't be blocked and redirected at the same time,
5404 applying this action together with
5405 <literal><link linkend="block">block</link></literal>
5406 is a configuration error. Currently the request is blocked
5407 and an error message logged, the behavior may change in the
5408 future and result in Privoxy rejecting the action file.
5411 This action can be combined with
5412 <literal><link linkend="fast-redirects">fast-redirects{check-decoded-url}</link></literal>
5413 to redirect to a decoded version of a rewritten URL.
5416 Use this action carefully, make sure not to create redirection loops
5417 and be aware that using your own redirects might make it
5418 possible to fingerprint your requests.
5421 In case of problems with your redirects, or simply to watch
5422 them working, enable <link linkend="DEBUG">debug 128</link>.
5428 <term>Example usages:</term>
5431 <screen># Replace example.com's style sheet with another one
5432 { +redirect{http://localhost/css-replacements/example.com.css} }
5433 example.com/stylesheet\.css
5435 # Create a short, easy to remember nickname for a favorite site
5436 # (relies on the browser to accept and forward invalid URLs to &my-app;)
5437 { +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
5440 # Always use the expanded view for Undeadly.org articles
5441 # (Note the $ at the end of the URL pattern to make sure
5442 # the request for the rewritten URL isn't redirected as well)
5443 {+redirect{s@$@&mode=expanded@}}
5444 undeadly.org/cgi\?action=article&sid=\d*$
5446 # Redirect Google search requests to MSN
5447 {+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}}
5450 # Redirect MSN search requests to Yahoo
5451 {+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}}
5452 search.msn.com//results\.aspx\?q=
5454 # Redirect http://example.com/&bla=fasel&toChange=foo (and any other value but "bar")
5455 # to http://example.com/&bla=fasel&toChange=bar
5457 # The URL pattern makes sure that the following request isn't redirected again.
5458 {+redirect{s@toChange=[^&]+@toChange=bar@}}
5459 example.com/.*toChange=(?!bar)
5461 # Add a shortcut to look up illumos bugs
5462 {+redirect{s@^http://i([0-9]+)/.*@https://www.illumos.org/issues/$1@}}
5463 # Redirected URL = http://i4974/
5464 # Redirect Destination = https://www.illumos.org/issues/4974
5465 i[0-9][0-9][0-9][0-9]*/
5467 # Redirect remote requests for this manual
5468 # to the local version delivered by Privoxy
5469 {+redirect{s@^http://www@http://config@}}
5470 www.privoxy.org/user-manual/</screen>
5479 <!-- ~~~~~ New section ~~~~~ -->
5480 <sect3 renderas="sect4" id="server-header-filter">
5481 <title>server-header-filter</title>
5485 <term>Typical use:</term>
5488 Rewrite or remove single server headers.
5494 <term>Effect:</term>
5497 All server headers to which this action applies are filtered on-the-fly
5498 through the specified regular expression based substitutions.
5505 <!-- boolean, parameterized, Multi-value -->
5507 <para>Multi-value.</para>
5512 <term>Parameter:</term>
5515 The name of a server-header filter, as defined in one of the
5516 <link linkend="filter-file">filter files</link>.
5525 Server-header filters are applied to each header on its own, not to
5526 all at once. This makes it easier to diagnose problems, but on the downside
5527 you can't write filters that only change header x if header y's value is z.
5528 You can do that by using tags though.
5531 Server-header filters are executed after the other header actions have finished
5532 and use their output as input.
5535 Please refer to the <link linkend="filter-file">filter file chapter</link>
5536 to learn which server-header filters are available by default, and how to
5543 <term>Example usage (section):</term>
5547 {+server-header-filter{html-to-xml}}
5548 example.org/xml-instance-that-is-delivered-as-html
5550 {+server-header-filter{xml-to-html}}
5551 example.org/instance-that-is-delivered-as-xml-but-is-not
5561 <!-- ~~~~~ New section ~~~~~ -->
5562 <sect3 renderas="sect4" id="server-header-tagger">
5563 <title>server-header-tagger</title>
5567 <term>Typical use:</term>
5570 Enable or disable filters based on the Content-Type header.
5576 <term>Effect:</term>
5579 Server headers to which this action applies are filtered on-the-fly through
5580 the specified regular expression based substitutions, the result is used as
5588 <!-- boolean, parameterized, Multi-value -->
5590 <para>Multi-value.</para>
5595 <term>Parameter:</term>
5598 The name of a server-header tagger, as defined in one of the
5599 <link linkend="filter-file">filter files</link>.
5608 Server-header taggers are applied to each header on its own,
5609 and as the header isn't modified, each tagger <quote>sees</quote>
5613 Server-header taggers are executed before all other header actions
5614 that modify server headers. Their tags can be used to control
5615 all of the other server-header actions, the content filters
5616 and the crunch actions (<link linkend="redirect">redirect</link>
5617 and <link linkend="block">block</link>).
5620 Obviously crunching based on tags created by server-header taggers
5621 doesn't prevent the request from showing up in the server's log file.
5628 <term>Example usage (section):</term>
5632 # Tag every request with the content type declared by the server
5633 {+server-header-tagger{content-type}}
5636 # If the response has a tag starting with 'image/' enable an external
5637 # filter that only applies to images.
5639 # Note that the filter is not available by default, it's just a
5640 # <literal><link linkend="external-filter-syntax">silly example</link></literal>.
5641 {+external-filter{rotate-image} +force-text-mode}
5652 <!-- ~~~~~ New section ~~~~~ -->
5653 <sect3 renderas="sect4" id="session-cookies-only">
5654 <title>session-cookies-only</title>
5658 <term>Typical use:</term>
5661 Allow only temporary <quote>session</quote> cookies (for the current
5662 browser session <emphasis>only</emphasis>).
5668 <term>Effect:</term>
5671 Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
5672 server headers. Most browsers will not store such cookies permanently and
5673 forget them in between sessions.
5680 <!-- Boolean, Parameterized, Multi-value -->
5682 <para>Boolean.</para>
5687 <term>Parameter:</term>
5699 This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
5700 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
5701 websites that insist or rely on setting cookies, without compromising your privacy too badly.
5704 Most browsers will not permanently store cookies that have been processed by
5705 <literal>session-cookies-only</literal> and will forget about them between sessions.
5706 This makes profiling cookies useless, but won't break sites which require cookies so
5707 that you can log in for transactions. This is generally turned on for all
5708 sites, and is the recommended setting.
5711 It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
5712 together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
5713 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
5714 will be plainly killed.
5717 Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
5718 field. If you use an exotic browser, you might want to try it out to be sure.
5721 This setting also has no effect on cookies that may have been stored
5722 previously by the browser before starting <application>Privoxy</application>.
5723 These would have to be removed manually.
5726 <application>Privoxy</application> also uses
5727 the <link linkend="filter-content-cookies">content-cookies filter</link>
5728 to block some types of cookies. Content cookies are not effected by
5729 <literal>session-cookies-only</literal>.
5735 <term>Example usage:</term>
5738 <screen>+session-cookies-only</screen>
5746 <!-- ~~~~~ New section ~~~~~ -->
5747 <sect3 renderas="sect4" id="set-image-blocker">
5748 <title>set-image-blocker</title>
5752 <term>Typical use:</term>
5754 <para>Choose the replacement for blocked images</para>
5759 <term>Effect:</term>
5762 This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
5763 <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
5764 linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
5765 apply, i.e. if the request is to be blocked as an image,
5766 <emphasis>then</emphasis> the parameter of this action decides what will be
5767 sent as a replacement.
5774 <!-- Boolean, Parameterized, Multi-value -->
5776 <para>Parameterized.</para>
5781 <term>Parameter:</term>
5786 <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
5787 decent, scales very well, and makes it obvious where banners were busted.
5792 <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
5793 completely, but makes it hard to detect where <application>Privoxy</application> has blocked
5794 images on a given page and complicates troubleshooting if <application>Privoxy</application>
5795 has blocked innocent images, like navigation icons.
5800 <quote><replaceable class="parameter">target-url</replaceable></quote> to
5801 send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
5802 to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
5803 (But note that not all browsers support redirecting to a local file system).
5806 A good application of redirects is to use special <application>Privoxy</application>-built-in
5807 URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
5808 This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
5809 the first place, but enables your browser to cache the replacement image, instead of requesting
5810 it over and over again.
5821 The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
5822 class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
5823 either <quote>blank</quote> or <quote>pattern</quote>.
5826 There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
5827 used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
5828 Auto will select the type of image that would have applied to the referring page, had it been an image.
5834 <term>Example usage:</term>
5840 <screen>+set-image-blocker{pattern}</screen>
5843 Redirect to the BSD daemon:
5846 <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
5849 Redirect to the built-in pattern for better caching:
5852 <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
5860 <!-- ~~~~~ New section ~~~~~ -->
5862 <title>Summary</title>
5864 Note that many of these actions have the potential to cause a page to
5865 misbehave, possibly even not to display at all. There are many ways
5866 a site designer may choose to design his site, and what HTTP header
5867 content, and other criteria, he may depend on. There is no way to have hard
5868 and fast rules for all sites. See the <link
5869 linkend="ACTIONSANAT">Appendix</link> for a brief example on troubleshooting
5875 <!-- ~~~~~ New section ~~~~~ -->
5876 <sect2 id="aliases">
5877 <title>Aliases</title>
5879 Custom <quote>actions</quote>, known to <application>Privoxy</application>
5880 as <quote>aliases</quote>, can be defined by combining other actions.
5881 These can in turn be invoked just like the built-in actions.
5882 Currently, an alias name can contain any character except space, tab,
5884 <quote>{</quote> and <quote>}</quote>, but we <emphasis>strongly
5885 recommend</emphasis> that you only use <quote>a</quote> to <quote>z</quote>,
5886 <quote>0</quote> to <quote>9</quote>, <quote>+</quote>, and <quote>-</quote>.
5887 Alias names are not case sensitive, and are not required to start with a
5888 <quote>+</quote> or <quote>-</quote> sign, since they are merely textually
5892 Aliases can be used throughout the actions file, but they <emphasis>must be
5893 defined in a special section at the top of the file!</emphasis>
5894 And there can only be one such section per actions file. Each actions file may
5895 have its own alias section, and the aliases defined in it are only visible
5899 There are two main reasons to use aliases: One is to save typing for frequently
5900 used combinations of actions, the other one is a gain in flexibility: If you
5901 decide once how you want to handle shops by defining an alias called
5902 <quote>shop</quote>, you can later change your policy on shops in
5903 <emphasis>one</emphasis> place, and your changes will take effect everywhere
5904 in the actions file where the <quote>shop</quote> alias is used. Calling aliases
5905 by their purpose also makes your actions files more readable.
5908 Currently, there is one big drawback to using aliases, though:
5909 <application>Privoxy</application>'s built-in web-based action file
5910 editor honors aliases when reading the actions files, but it expands
5911 them before writing. So the effects of your aliases are of course preserved,
5912 but the aliases themselves are lost when you edit sections that use aliases
5917 Now let's define some aliases...
5922 # Useful custom aliases we can use later.
5924 # Note the (required!) section header line and that this section
5925 # must be at the top of the actions file!
5929 # These aliases just save typing later:
5930 # (Note that some already use other aliases!)
5932 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5933 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5934 +block-as-image = +block{Blocked image.} +handle-as-image
5935 allow-all-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
5937 # These aliases define combinations of actions
5938 # that are useful for certain types of sites:
5940 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>
5942 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link>
5944 # Short names for other aliases, for really lazy people ;-)
5946 c0 = +crunch-all-cookies
5947 c1 = -crunch-all-cookies</screen>
5951 ...and put them to use. These sections would appear in the lower part of an
5952 actions file and define exceptions to the default actions (as specified further
5953 up for the <quote>/</quote> pattern):
5958 # These sites are either very complex or very keen on
5959 # user data and require minimal interference to work:
5962 .office.microsoft.com
5963 .windowsupdate.microsoft.com
5964 # Gmail is really mail.google.com, not gmail.com
5968 # Allow cookies (for setting and retrieving your customer data)
5972 .worldpay.com # for quietpc.com
5975 # These shops require pop-ups:
5977 {-filter{all-popups} -filter{unsolicited-popups}}
5979 .overclockers.co.uk</screen>
5983 Aliases like <quote>shop</quote> and <quote>fragile</quote> are typically used for
5984 <quote>problem</quote> sites that require more than one action to be disabled
5985 in order to function properly.
5991 <!-- ~~~~~ New section ~~~~~ -->
5992 <sect2 id="act-examples">
5993 <title>Actions Files Tutorial</title>
5995 The above chapters have shown <link linkend="actions-file">which actions files
5996 there are and how they are organized</link>, how actions are <link
5997 linkend="actions">specified</link> and <link linkend="actions-apply">applied
5998 to URLs</link>, how <link linkend="af-patterns">patterns</link> work, and how to
5999 define and use <link linkend="aliases">aliases</link>. Now, let's look at an
6000 example <filename>match-all.action</filename>, <filename>default.action</filename>
6001 and <filename>user.action</filename> file and see how all these pieces come together:
6005 <title>match-all.action</title>
6007 Remember <emphasis>all actions are disabled when matching starts</emphasis>,
6008 so we have to explicitly enable the ones we want.
6012 While the <filename>match-all.action</filename> file only contains a
6013 single section, it is probably the most important one. It has only one
6014 pattern, <quote><literal>/</literal></quote>, but this pattern
6015 <link linkend="af-patterns">matches all URLs</link>. Therefore, the set of
6016 actions used in this <quote>default</quote> section <emphasis>will
6017 be applied to all requests as a start</emphasis>. It can be partly or
6018 wholly overridden by other actions files like <filename>default.action</filename>
6019 and <filename>user.action</filename>, but it will still be largely responsible
6020 for your overall browsing experience.
6024 Again, at the start of matching, all actions are disabled, so there is
6025 no need to disable any actions here. (Remember: a <quote>+</quote>
6026 preceding the action name enables the action, a <quote>-</quote> disables!).
6027 Also note how this long line has been made more readable by splitting it into
6028 multiple lines with line continuation.
6034 +<link linkend="CHANGE-X-FORWARDED-FOR">change-x-forwarded-for{block}</link> \
6035 +<link linkend="HIDE-FROM-HEADER">hide-from-header{block}</link> \
6036 +<link linkend="SET-IMAGE-BLOCKER">set-image-blocker{pattern}</link> \
6043 The default behavior is now set.
6048 <title>default.action</title>
6051 If you aren't a developer, there's no need for you to edit the
6052 <filename>default.action</filename> file. It is maintained by
6053 the &my-app; developers and if you disagree with some of the
6054 sections, you should overrule them in your <filename>user.action</filename>.
6058 Understanding the <filename>default.action</filename> file can
6059 help you with your <filename>user.action</filename>, though.
6063 The first section in this file is a special section for internal use
6064 that prevents older &my-app; versions from reading the file:
6069 ##########################################################################
6070 # Settings -- Don't change! For internal Privoxy use ONLY.
6071 ##########################################################################
6073 for-privoxy-version=3.0.11</screen>
6077 After that comes the (optional) alias section. We'll use the example
6078 section from the above <link linkend="aliases">chapter on aliases</link>,
6079 that also explains why and how aliases are used:
6084 ##########################################################################
6086 ##########################################################################
6089 # These aliases just save typing later:
6090 # (Note that some already use other aliases!)
6092 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6093 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6094 +block-as-image = +block{Blocked image.} +handle-as-image
6095 mercy-for-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
6097 # These aliases define combinations of actions
6098 # that are useful for certain types of sites:
6100 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>
6101 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link></screen>
6105 The first of our specialized sections is concerned with <quote>fragile</quote>
6106 sites, i.e. sites that require minimum interference, because they are either
6107 very complex or very keen on tracking you (and have mechanisms in place that
6108 make them unusable for people who avoid being tracked). We will simply use
6109 our pre-defined <literal>fragile</literal> alias instead of stating the list
6110 of actions explicitly:
6115 ##########################################################################
6116 # Exceptions for sites that'll break under the default action set:
6117 ##########################################################################
6119 # "Fragile" Use a minimum set of actions for these sites (see alias above):
6122 .office.microsoft.com # surprise, surprise!
6123 .windowsupdate.microsoft.com
6124 mail.google.com</screen>
6128 Shopping sites are not as fragile, but they typically
6129 require cookies to log in, and pop-up windows for shopping
6130 carts or item details. Again, we'll use a pre-defined alias:
6139 .worldpay.com # for quietpc.com
6141 .scan.co.uk</screen>
6145 The <literal><link linkend="FAST-REDIRECTS">fast-redirects</link></literal>
6146 action, which may have been enabled in <filename>match-all.action</filename>,
6147 breaks some sites. So disable it for popular sites where we know it misbehaves:
6152 { -<link linkend="FAST-REDIRECTS">fast-redirects</link> }
6156 .altavista.com/.*(like|url|link):http
6157 .altavista.com/trans.*urltext=http
6158 .nytimes.com</screen>
6162 It is important that <application>Privoxy</application> knows which
6163 URLs belong to images, so that <emphasis>if</emphasis> they are to
6164 be blocked, a substitute image can be sent, rather than an HTML page.
6165 Contacting the remote site to find out is not an option, since it
6166 would destroy the loading time advantage of banner blocking, and it
6167 would feed the advertisers information about you. We can mark any
6168 URL as an image with the <literal><link
6169 linkend="handle-as-image">handle-as-image</link></literal> action,
6170 and marking all URLs that end in a known image file extension is a
6176 ##########################################################################
6178 ##########################################################################
6180 # Define which file types will be treated as images, in case they get
6181 # blocked further down this file:
6183 { +<link linkend="HANDLE-AS-IMAGE">handle-as-image</link> }
6184 /.*\.(gif|jpe?g|png|bmp|ico)$</screen>
6188 And then there are known banner sources. They often use scripts to
6189 generate the banners, so it won't be visible from the URL that the
6190 request is for an image. Hence we block them <emphasis>and</emphasis>
6191 mark them as images in one go, with the help of our
6192 <literal>+block-as-image</literal> alias defined above. (We could of
6193 course just as well use <literal>+<link linkend="block">block</link>
6194 +<link linkend="handle-as-image">handle-as-image</link></literal> here.)
6195 Remember that the type of the replacement image is chosen by the
6196 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
6197 action. Since all URLs have matched the default section with its
6198 <literal>+<link linkend="set-image-blocker">set-image-blocker</link>{pattern}</literal>
6199 action before, it still applies and needn't be repeated:
6204 # Known ad generators:
6209 .ad.*.doubleclick.net
6210 .a.yimg.com/(?:(?!/i/).)*$
6211 .a[0-9].yimg.com/(?:(?!/i/).)*$
6217 One of the most important jobs of <application>Privoxy</application>
6218 is to block banners. Many of these can be <quote>blocked</quote>
6219 by the <literal><link linkend="filter">filter</link>{banners-by-size}</literal>
6220 action, which we enabled above, and which deletes the references to banner
6221 images from the pages while they are loaded, so the browser doesn't request
6222 them anymore, and hence they don't need to be blocked here. But this naturally
6223 doesn't catch all banners, and some people choose not to use filters, so we
6224 need a comprehensive list of patterns for banner URLs here, and apply the
6225 <literal><link linkend="block">block</link></literal> action to them.
6228 First comes many generic patterns, which do most of the work, by
6229 matching typical domain and path name components of banners. Then comes
6230 a list of individual patterns for specific sites, which is omitted here
6231 to keep the example short:
6236 ##########################################################################
6237 # Block these fine banners:
6238 ##########################################################################
6239 { <link linkend="BLOCK">+block{Banner ads.}</link> }
6247 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
6248 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
6250 # Site-specific patterns (abbreviated):
6252 .hitbox.com</screen>
6256 It's quite remarkable how many advertisers actually call their banner
6257 servers ads.<replaceable>company</replaceable>.com, or call the directory
6258 in which the banners are stored simply <quote>banners</quote>. So the above
6259 generic patterns are surprisingly effective.
6262 But being very generic, they necessarily also catch URLs that we don't want
6263 to block. The pattern <literal>.*ads.</literal> e.g. catches
6264 <quote>nasty-<emphasis>ads</emphasis>.nasty-corp.com</quote> as intended,
6265 but also <quote>downlo<emphasis>ads</emphasis>.sourcefroge.net</quote> or
6266 <quote><emphasis>ads</emphasis>l.some-provider.net.</quote> So here come some
6267 well-known exceptions to the <literal>+<link linkend="BLOCK">block</link></literal>
6271 Note that these are exceptions to exceptions from the default! Consider the URL
6272 <quote>downloads.sourcefroge.net</quote>: Initially, all actions are deactivated,
6273 so it wouldn't get blocked. Then comes the defaults section, which matches the
6274 URL, but just deactivates the <literal><link linkend="BLOCK">block</link></literal>
6275 action once again. Then it matches <literal>.*ads.</literal>, an exception to the
6276 general non-blocking policy, and suddenly
6277 <literal><link linkend="BLOCK">+block</link></literal> applies. And now, it'll match
6278 <literal>.*loads.</literal>, where <literal><link linkend="BLOCK">-block</link></literal>
6279 applies, so (unless it matches <emphasis>again</emphasis> further down) it ends up
6280 with no <literal><link linkend="BLOCK">block</link></literal> action applying.
6285 ##########################################################################
6286 # Save some innocent victims of the above generic block patterns:
6287 ##########################################################################
6291 { -<link linkend="BLOCK">block</link> }
6292 adv[io]*. # (for advogato.org and advice.*)
6293 adsl. # (has nothing to do with ads)
6294 adobe. # (has nothing to do with ads either)
6295 ad[ud]*. # (adult.* and add.*)
6296 .edu # (universities don't host banners (yet!))
6297 .*loads. # (downloads, uploads etc)
6305 www.globalintersec.com/adv # (adv = advanced)
6306 www.ugu.com/sui/ugu/adv</screen>
6310 Filtering source code can have nasty side effects,
6311 so make an exception for our friends at sourceforge.net,
6312 and all paths with <quote>cvs</quote> in them. Note that
6313 <literal>-<link linkend="FILTER">filter</link></literal>
6314 disables <emphasis>all</emphasis> filters in one fell swoop!
6319 # Don't filter code!
6321 { -<link linkend="FILTER">filter</link> }
6326 .sourceforge.net</screen>
6330 The actual <filename>default.action</filename> is of course much more
6331 comprehensive, but we hope this example made clear how it works.
6336 <sect3><title>user.action</title>
6339 So far we are painting with a broad brush by setting general policies,
6340 which would be a reasonable starting point for many people. Now,
6341 you might want to be more specific and have customized rules that
6342 are more suitable to your personal habits and preferences. These would
6343 be for narrowly defined situations like your ISP or your bank, and should
6344 be placed in <filename>user.action</filename>, which is parsed after all other
6345 actions files and hence has the last word, over-riding any previously
6346 defined actions. <filename>user.action</filename> is also a
6347 <emphasis>safe</emphasis> place for your personal settings, since
6348 <filename>default.action</filename> is actively maintained by the
6349 <application>Privoxy</application> developers and you'll probably want
6350 to install updated versions from time to time.
6354 So let's look at a few examples of things that one might typically do in
6355 <filename>user.action</filename>:
6359 <!-- brief sample user.action here -->
6363 # My user.action file. <fred@example.com></screen>
6367 As <link linkend="aliases">aliases</link> are local to the actions
6368 file that they are defined in, you can't use the ones from
6369 <filename>default.action</filename>, unless you repeat them here:
6374 # Aliases are local to the file they are defined in.
6375 # (Re-)define aliases for this file:
6379 # These aliases just save typing later, and the alias names should
6380 # be self explanatory.
6382 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
6383 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
6384 allow-all-cookies = -crunch-all-cookies -session-cookies-only
6385 allow-popups = -filter{all-popups}
6386 +block-as-image = +block{Blocked as image.} +handle-as-image
6387 -block-as-image = -block
6389 # These aliases define combinations of actions that are useful for
6390 # certain types of sites:
6392 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer
6393 shop = -crunch-all-cookies allow-popups
6395 # Allow ads for selected useful free sites:
6397 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
6399 # Alias for specific file types that are text, but might have conflicting
6400 # MIME types. We want the browser to force these to be text documents.
6401 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>
6406 Say you have accounts on some sites that you visit regularly, and
6407 you don't want to have to log in manually each time. So you'd like
6408 to allow persistent cookies for these sites. The
6409 <literal>allow-all-cookies</literal> alias defined above does exactly
6410 that, i.e. it disables crunching of cookies in any direction, and the
6411 processing of cookies to make them only temporary.
6416 { allow-all-cookies }
6420 .redhat.com</screen>
6424 Your bank is allergic to some filter, but you don't know which, so you disable them all:
6429 { -<link linkend="FILTER">filter</link> }
6430 .your-home-banking-site.com</screen>
6434 Some file types you may not want to filter for various reasons:
6439 # Technical documentation is likely to contain strings that might
6440 # erroneously get altered by the JavaScript-oriented filters:
6445 # And this stupid host sends streaming video with a wrong MIME type,
6446 # so that Privoxy thinks it is getting HTML and starts filtering:
6448 stupid-server.example.com/</screen>
6452 Example of a simple <link linkend="BLOCK">block</link> action. Say you've
6453 seen an ad on your favourite page on example.com that you want to get rid of.
6454 You have right-clicked the image, selected <quote>copy image location</quote>
6455 and pasted the URL below while removing the leading http://, into a
6456 <literal>{ +block{} }</literal> section. Note that <literal>{ +handle-as-image
6457 }</literal> need not be specified, since all URLs ending in
6458 <literal>.gif</literal> will be tagged as images by the general rules as set
6459 in default.action anyway:
6464 { +<link linkend="BLOCK">block</link>{Nasty ads.} }
6465 www.example.com/nasty-ads/sponsor\.gif
6466 another.example.net/more/junk/here/</screen>
6470 The URLs of dynamically generated banners, especially from large banner
6471 farms, often don't use the well-known image file name extensions, which
6472 makes it impossible for <application>Privoxy</application> to guess
6473 the file type just by looking at the URL.
6474 You can use the <literal>+block-as-image</literal> alias defined above for
6476 Note that objects which match this rule but then turn out NOT to be an
6477 image are typically rendered as a <quote>broken image</quote> icon by the
6478 browser. Use cautiously.
6487 ar.atwola.com/</screen>
6491 Now you noticed that the default configuration breaks Forbes Magazine,
6492 but you were too lazy to find out which action is the culprit, and you
6493 were again too lazy to give <link linkend="contact">feedback</link>, so
6494 you just used the <literal>fragile</literal> alias on the site, and
6495 -- <emphasis>whoa!</emphasis> -- it worked. The <literal>fragile</literal>
6496 aliases disables those actions that are most likely to break a site. Also,
6497 good for testing purposes to see if it is <application>Privoxy</application>
6498 that is causing the problem or not. We later find other regular sites
6499 that misbehave, and add those to our personalized list of troublemakers:
6507 .mybank.com</screen>
6511 You like the <quote>fun</quote> text replacements in <filename>default.filter</filename>,
6512 but it is disabled in the distributed actions file.
6513 So you'd like to turn it on in your private,
6514 update-safe config, once and for all:
6519 { +<link linkend="filter-fun">filter{fun}</link> }
6520 / # For ALL sites!</screen>
6524 Note that the above is not really a good idea: There are exceptions
6525 to the filters in <filename>default.action</filename> for things that
6526 really shouldn't be filtered, like code on CVS->Web interfaces. Since
6527 <filename>user.action</filename> has the last word, these exceptions
6528 won't be valid for the <quote>fun</quote> filtering specified here.
6532 You might also worry about how your favourite free websites are
6533 funded, and find that they rely on displaying banner advertisements
6534 to survive. So you might want to specifically allow banners for those
6535 sites that you feel provide value to you:
6547 Note that <literal>allow-ads</literal> has been aliased to
6548 <literal>-<link linkend="block">block</link></literal>,
6549 <literal>-<link linkend="filter-banners-by-size">filter{banners-by-size}</link></literal>, and
6550 <literal>-<link linkend="filter-banners-by-link">filter{banners-by-link}</link></literal> above.
6554 Invoke another alias here to force an over-ride of the MIME type <literal>
6555 application/x-sh</literal> which typically would open a download type
6556 dialog. In my case, I want to look at the shell script, and then I can save
6557 it should I choose to.
6567 <filename>user.action</filename> is generally the best place to define
6568 exceptions and additions to the default policies of
6569 <filename>default.action</filename>. Some actions are safe to have their
6570 default policies set here though. So let's set a default policy to have a
6571 <quote>blank</quote> image as opposed to the checkerboard pattern for
6572 <emphasis>ALL</emphasis> sites. <quote>/</quote> of course matches all URL
6578 { +<link linkend="set-image-blocker">set-image-blocker{blank}</link> }
6579 / # ALL sites</screen>
6585 <!-- ~ End section ~ -->
6589 <!-- ~ End section ~ -->
6591 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6593 <sect1 id="filter-file">
6594 <title>Filter Files</title>
6597 On-the-fly text substitutions need
6598 to be defined in a <quote>filter file</quote>. Once defined, they
6599 can then be invoked as an <quote>action</quote>.
6603 &my-app; supports three different pcrs-based filter actions:
6604 <literal><link linkend="filter">filter</link></literal> to
6605 rewrite the content that is send to the client,
6606 <literal><link linkend="client-header-filter">client-header-filter</link></literal>
6607 to rewrite headers that are send by the client, and
6608 <literal><link linkend="server-header-filter">server-header-filter</link></literal>
6609 to rewrite headers that are send by the server.
6613 &my-app; also supports two tagger actions:
6614 <literal><link linkend="client-header-tagger">client-header-tagger</link></literal>
6616 <literal><link linkend="server-header-tagger">server-header-tagger</link></literal>.
6617 Taggers and filters use the same syntax in the filter files, the difference
6618 is that taggers don't modify the text they are filtering, but use a rewritten
6619 version of the filtered text as tag. The tags can then be used to change the
6620 applying actions through sections with <link linkend="tag-pattern">tag-patterns</link>.
6624 Finally &my-app; supports the
6625 <literal><link linkend="external-filter">external-filter</link></literal> action
6626 to enable <literal><link linkend="external-filter-syntax">external filters</link></literal>
6627 written in proper programming languages.
6632 Multiple filter files can be defined through the <literal> <link
6633 linkend="filterfile">filterfile</link></literal> config directive. The filters
6634 as supplied by the developers are located in
6635 <filename>default.filter</filename>. It is recommended that any locally
6636 defined or modified filters go in a separately defined file such as
6637 <filename>user.filter</filename>.
6641 Common tasks for content filters are to eliminate common annoyances in
6642 HTML and JavaScript, such as pop-up windows,
6643 exit consoles, crippled windows without navigation tools, the
6644 infamous <BLINK> tag etc, to suppress images with certain
6645 width and height attributes (standard banner sizes or web-bugs),
6646 or just to have fun.
6650 Enabled content filters are applied to any content whose
6651 <quote>Content Type</quote> header is recognised as a sign
6652 of text-based content, with the exception of <literal>text/plain</literal>.
6653 Use the <link linkend="FORCE-TEXT-MODE">force-text-mode</link> action
6654 to also filter other content.
6658 Substitutions are made at the source level, so if you want to <quote>roll
6659 your own</quote> filters, you should first be familiar with HTML syntax,
6660 and, of course, regular expressions.
6664 Just like the <link linkend="actions-file">actions files</link>, the
6665 filter file is organized in sections, which are called <emphasis>filters</emphasis>
6666 here. Each filter consists of a heading line, that starts with one of the
6667 <emphasis>keywords</emphasis> <literal>FILTER:</literal>,
6668 <literal>CLIENT-HEADER-FILTER:</literal> or <literal>SERVER-HEADER-FILTER:</literal>
6669 followed by the filter's <emphasis>name</emphasis>, and a short (one line)
6670 <emphasis>description</emphasis> of what it does. Below that line
6671 come the <emphasis>jobs</emphasis>, i.e. lines that define the actual
6672 text substitutions. By convention, the name of a filter
6673 should describe what the filter <emphasis>eliminates</emphasis>. The
6674 comment is used in the <ulink url="http://config.privoxy.org/">web-based
6675 user interface</ulink>.
6679 Once a filter called <replaceable>name</replaceable> has been defined
6680 in the filter file, it can be invoked by using an action of the form
6681 +<literal><link linkend="filter">filter</link>{<replaceable>name</replaceable>}</literal>
6682 in any <link linkend="actions-file">actions file</link>.
6686 Filter definitions start with a header line that contains the filter
6687 type, the filter name and the filter description.
6688 A content filter header line for a filter called <quote>foo</quote> could look
6693 <screen>FILTER: foo Replace all "foo" with "bar"</screen>
6697 Below that line, and up to the next header line, come the jobs that
6698 define what text replacements the filter executes. They are specified
6699 in a syntax that imitates <ulink url="http://www.perl.org/">Perl</ulink>'s
6700 <literal>s///</literal> operator. If you are familiar with Perl, you
6701 will find this to be quite intuitive, and may want to look at the
6702 PCRS documentation for the subtle differences to Perl behaviour.
6706 Most notably, the non-standard option letter <literal>U</literal> is supported,
6707 which turns the default to ungreedy matching (add <literal>?</literal> to
6708 quantifiers to turn them greedy again).
6712 The non-standard option letter <literal>D</literal> (dynamic) allows
6713 to use the variables $host, $origin (the IP address the request came from),
6714 $path and $url. They will be replaced with the value they refer to before
6715 the filter is executed.
6719 Note that '$' is a bad choice for a delimiter in a dynamic filter as you
6720 might end up with unintended variables if you use a variable name
6721 directly after the delimiter. Variables will be resolved without
6722 escaping anything, therefore you also have to be careful not to chose
6723 delimiters that appear in the replacement text. For example '<' should
6724 be save, while '?' will sooner or later cause conflicts with $url.
6728 The non-standard option letter <literal>T</literal> (trivial) prevents
6729 parsing for backreferences in the substitute. Use it if you want to include
6730 text like '$&' in your substitute without quoting.
6735 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
6736 Expressions</quote></ulink>, you might want to take a look at
6737 the <link linkend="regex">Appendix on regular expressions</link>, and
6738 see the <ulink url="http://perldoc.perl.org/perlre.html">Perl
6740 <ulink url="http://perldoc.perl.org/perlop.html">the
6741 <literal>s///</literal> operator's syntax</ulink> and <ulink
6742 url="http://perldoc.perl.org/perlre.html">Perl-style regular
6743 expressions</ulink> in general.
6744 The below examples might also help to get you started.
6748 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6750 <sect2><title>Filter File Tutorial</title>
6752 Now, let's complete our <quote>foo</quote> content filter. We have already defined
6753 the heading, but the jobs are still missing. Since all it does is to replace
6754 <quote>foo</quote> with <quote>bar</quote>, there is only one (trivial) job
6759 <screen>s/foo/bar/</screen>
6763 But wait! Didn't the comment say that <emphasis>all</emphasis> occurrences
6764 of <quote>foo</quote> should be replaced? Our current job will only take
6765 care of the first <quote>foo</quote> on each page. For global substitution,
6766 we'll need to add the <literal>g</literal> option:
6770 <screen>s/foo/bar/g</screen>
6774 Our complete filter now looks like this:
6777 <screen>FILTER: foo Replace all "foo" with "bar"
6778 s/foo/bar/g</screen>
6782 Let's look at some real filters for more interesting examples. Here you see
6783 a filter that protects against some common annoyances that arise from JavaScript
6784 abuse. Let's look at its jobs one after the other:
6790 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
6792 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
6794 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg</screen>
6798 Following the header line and a comment, you see the job. Note that it uses
6799 <literal>|</literal> as the delimiter instead of <literal>/</literal>, because
6800 the pattern contains a forward slash, which would otherwise have to be escaped
6801 by a backslash (<literal>\</literal>).
6805 Now, let's examine the pattern: it starts with the text <literal><script.*</literal>
6806 enclosed in parentheses. Since the dot matches any character, and <literal>*</literal>
6807 means: <quote>Match an arbitrary number of the element left of myself</quote>, this
6808 matches <quote><script</quote>, followed by <emphasis>any</emphasis> text, i.e.
6809 it matches the whole page, from the start of the first <script> tag.
6813 That's more than we want, but the pattern continues: <literal>document\.referrer</literal>
6814 matches only the exact string <quote>document.referrer</quote>. The dot needed to
6815 be <emphasis>escaped</emphasis>, i.e. preceded by a backslash, to take away its
6816 special meaning as a joker, and make it just a regular dot. So far, the meaning is:
6817 Match from the start of the first <script> tag in a the page, up to, and including,
6818 the text <quote>document.referrer</quote>, if <emphasis>both</emphasis> are present
6819 in the page (and appear in that order).
6823 But there's still more pattern to go. The next element, again enclosed in parentheses,
6824 is <literal>.*</script></literal>. You already know what <literal>.*</literal>
6825 means, so the whole pattern translates to: Match from the start of the first <script>
6826 tag in a page to the end of the last <script> tag, provided that the text
6827 <quote>document.referrer</quote> appears somewhere in between.
6831 This is still not the whole story, since we have ignored the options and the parentheses:
6832 The portions of the page matched by sub-patterns that are enclosed in parentheses, will be
6833 remembered and be available through the variables <literal>$1, $2, ...</literal> in
6834 the substitute. The <literal>U</literal> option switches to ungreedy matching, which means
6835 that the first <literal>.*</literal> in the pattern will only <quote>eat up</quote> all
6836 text in between <quote><script</quote> and the <emphasis>first</emphasis> occurrence
6837 of <quote>document.referrer</quote>, and that the second <literal>.*</literal> will
6838 only span the text up to the <emphasis>first</emphasis> <quote></script></quote>
6839 tag. Furthermore, the <literal>s</literal> option says that the match may span
6840 multiple lines in the page, and the <literal>g</literal> option again means that the
6841 substitution is global.
6845 So, to summarize, the pattern means: Match all scripts that contain the text
6846 <quote>document.referrer</quote>. Remember the parts of the script from
6847 (and including) the start tag up to (and excluding) the string
6848 <quote>document.referrer</quote> as <literal>$1</literal>, and the part following
6849 that string, up to and including the closing tag, as <literal>$2</literal>.
6853 Now the pattern is deciphered, but wasn't this about substituting things? So
6854 lets look at the substitute: <literal>$1"Not Your Business!"$2</literal> is
6855 easy to read: The text remembered as <literal>$1</literal>, followed by
6856 <literal>"Not Your Business!"</literal> (<emphasis>including</emphasis>
6857 the quotation marks!), followed by the text remembered as <literal>$2</literal>.
6858 This produces an exact copy of the original string, with the middle part
6859 (the <quote>document.referrer</quote>) replaced by <literal>"Not Your
6860 Business!"</literal>.
6864 The whole job now reads: Replace <quote>document.referrer</quote> by
6865 <literal>"Not Your Business!"</literal> wherever it appears inside a
6866 <script> tag. Note that this job won't break JavaScript syntax,
6867 since both the original and the replacement are syntactically valid
6868 string objects. The script just won't have access to the referrer
6869 information anymore.
6873 We'll show you two other jobs from the JavaScript taming department, but
6874 this time only point out the constructs of special interest:
6879 # The status bar is for displaying link targets, not pointless blahblah
6881 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig</screen>
6885 <literal>\s</literal> stands for whitespace characters (space, tab, newline,
6886 carriage return, form feed), so that <literal>\s*</literal> means: <quote>zero
6887 or more whitespace</quote>. The <literal>?</literal> in <literal>.*?</literal>
6888 makes this matching of arbitrary text ungreedy. (Note that the <literal>U</literal>
6889 option is not set). The <literal>['"]</literal> construct means: <quote>a single
6890 <emphasis>or</emphasis> a double quote</quote>. Finally, <literal>\1</literal> is
6891 a back-reference to the first parenthesis just like <literal>$1</literal> above,
6892 with the difference that in the <emphasis>pattern</emphasis>, a backslash indicates
6893 a back-reference, whereas in the <emphasis>substitute</emphasis>, it's the dollar.
6897 So what does this job do? It replaces assignments of single- or double-quoted
6898 strings to the <quote>window.status</quote> object with a dummy assignment
6899 (using a variable name that is hopefully odd enough not to conflict with
6900 real variables in scripts). Thus, it catches many cases where e.g. pointless
6901 descriptions are displayed in the status bar instead of the link target when
6902 you move your mouse over links.
6907 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
6909 s/(<body [^>]*)onunload(.*>)/$1never$2/iU</screen>
6914 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">OnUnload
6915 event binding</ulink> in the HTML DOM was a <emphasis>CRIME</emphasis>.
6916 When I close a browser window, I want it to close and die. Basta.
6917 This job replaces the <quote>onunload</quote> attribute in
6918 <quote><body></quote> tags with the dummy word <literal>never</literal>.
6919 Note that the <literal>i</literal> option makes the pattern matching
6920 case-insensitive. Also note that ungreedy matching alone doesn't always guarantee
6921 a minimal match: In the first parenthesis, we had to use <literal>[^>]*</literal>
6922 instead of <literal>.*</literal> to prevent the match from exceeding the
6923 <body> tag if it doesn't contain <quote>OnUnload</quote>, but the page's
6928 The last example is from the fun department:
6933 FILTER: fun Fun text replacements
6935 # Spice the daily news:
6937 s/microsoft(?!\.com)/MicroSuck/ig</screen>
6941 Note the <literal>(?!\.com)</literal> part (a so-called negative lookahead)
6942 in the job's pattern, which means: Don't match, if the string
6943 <quote>.com</quote> appears directly following <quote>microsoft</quote>
6944 in the page. This prevents links to microsoft.com from being trashed, while
6945 still replacing the word everywhere else.
6950 # Buzzword Bingo (example for extended regex syntax)
6952 s* industry[ -]leading \
6954 | customer[ -]focused \
6955 | market[ -]driven \
6956 | award[ -]winning # Comments are OK, too! \
6957 | high[ -]performance \
6958 | solutions[ -]based \
6962 *<font color="red"><b>BINGO!</b></font> \
6967 The <literal>x</literal> option in this job turns on extended syntax, and allows for
6968 e.g. the liberal use of (non-interpreted!) whitespace for nicer formatting.
6976 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6978 <sect2 id="predefined-filters"><title>The Pre-defined Filters</title>
6982 Note each filter is also listed in the +filter action section above. Please
6983 keep these listings in sync.
6988 The distribution <filename>default.filter</filename> file contains a selection of
6989 pre-defined filters for your convenience:
6994 <term><emphasis>js-annoyances</emphasis></term>
6997 The purpose of this filter is to get rid of particularly annoying JavaScript abuse.
7002 replaces JavaScript references to the browser's referrer information
7003 with the string "Not Your Business!". This compliments the <literal><link
7004 linkend="hide-referrer">hide-referrer</link></literal> action on the content level.
7009 removes the bindings to the DOM's
7010 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">unload
7011 event</ulink> which we feel has no right to exist and is responsible for most <quote>exit consoles</quote>, i.e.
7012 nasty windows that pop up when you close another one.
7017 removes code that causes new windows to be opened with undesired properties, such as being
7018 full-screen, non-resizeable, without location, status or menu bar etc.
7024 Use with caution. This is an aggressive filter, and can break sites that
7025 rely heavily on JavaScript.
7031 <term><emphasis>js-events</emphasis></term>
7034 This is a very radical measure. It removes virtually all JavaScript event bindings, which
7035 means that scripts can not react to user actions such as mouse movements or clicks, window
7036 resizing etc, anymore. Use with caution!
7039 We <emphasis>strongly discourage</emphasis> using this filter as a default since it breaks
7040 many legitimate scripts. It is meant for use only on extra-nasty sites (should you really
7047 <term><emphasis>html-annoyances</emphasis></term>
7050 This filter will undo many common instances of HTML based abuse.
7053 The <literal>BLINK</literal> and <literal>MARQUEE</literal> tags
7054 are neutralized (yeah baby!), and browser windows will be created as
7055 resizeable (as of course they should be!), and will have location,
7056 scroll and menu bars -- even if specified otherwise.
7062 <term><emphasis>content-cookies</emphasis></term>
7065 Most cookies are set in the HTTP dialog, where they can be intercepted
7067 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>
7068 and <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>
7069 actions. But web sites increasingly make use of HTML meta tags and JavaScript
7070 to sneak cookies to the browser on the content level.
7073 This filter disables most HTML and JavaScript code that reads or sets
7074 cookies. It cannot detect all clever uses of these types of code, so it
7075 should not be relied on as an absolute fix. Use it wherever you would also
7076 use the cookie crunch actions.
7082 <term><emphasis>refresh-tags</emphasis></term>
7085 Disable any refresh tags if the interval is greater than nine seconds (so
7086 that redirections done via refresh tags are not destroyed). This is useful
7087 for dial-on-demand setups, or for those who find this HTML feature
7094 <term><emphasis>unsolicited-popups</emphasis></term>
7097 This filter attempts to prevent only <quote>unsolicited</quote> pop-up
7098 windows from opening, yet still allow pop-up windows that the user
7099 has explicitly chosen to open. It was added in version 3.0.1,
7100 as an improvement over earlier such filters.
7103 Technical note: The filter works by redefining the window.open JavaScript
7104 function to a dummy function, <literal>PrivoxyWindowOpen()</literal>,
7105 during the loading and rendering phase of each HTML page access, and
7106 restoring the function afterward.
7109 This is recommended only for browsers that cannot perform this function
7110 reliably themselves. And be aware that some sites require such windows
7111 in order to function normally. Use with caution.
7117 <term><emphasis>all-popups</emphasis></term>
7120 Attempt to prevent <emphasis>all</emphasis> pop-up windows from opening.
7121 Note this should be used with even more discretion than the above, since
7122 it is more likely to break some sites that require pop-ups for normal
7123 usage. Use with caution.
7129 <term><emphasis>img-reorder</emphasis></term>
7132 This is a helper filter that has no value if used alone. It makes the
7133 <literal>banners-by-size</literal> and <literal>banners-by-link</literal>
7134 (see below) filters more effective and should be enabled together with them.
7140 <term><emphasis>banners-by-size</emphasis></term>
7143 This filter removes image tags purely based on what size they are. Fortunately
7144 for us, many ads and banner images tend to conform to certain standardized
7145 sizes, which makes this filter quite effective for ad stripping purposes.
7148 Occasionally this filter will cause false positives on images that are not ads,
7149 but just happen to be of one of the standard banner sizes.
7152 Recommended only for those who require extreme ad blocking. The default
7153 block rules should catch 95+% of all ads <emphasis>without</emphasis> this filter enabled.
7159 <term><emphasis>banners-by-link</emphasis></term>
7162 This is an experimental filter that attempts to kill any banners if
7163 their URLs seem to point to known or suspected click trackers. It is currently
7164 not of much value and is not recommended for use by default.
7170 <term><emphasis>webbugs</emphasis></term>
7173 Webbugs are small, invisible images (technically 1X1 GIF images), that
7174 are used to track users across websites, and collect information on them.
7175 As an HTML page is loaded by the browser, an embedded image tag causes the
7176 browser to contact a third-party site, disclosing the tracking information
7177 through the requested URL and/or cookies for that third-party domain, without
7178 the user ever becoming aware of the interaction with the third-party site.
7179 HTML-ized spam also uses a similar technique to verify email addresses.
7182 This filter removes the HTML code that loads such <quote>webbugs</quote>.
7188 <term><emphasis>tiny-textforms</emphasis></term>
7191 A rather special-purpose filter that can be used to enlarge textareas (those
7192 multi-line text boxes in web forms) and turn off hard word wrap in them.
7193 It was written for the sourceforge.net tracker system where such boxes are
7194 a nuisance, but it can be handy on other sites, too.
7197 It is not recommended to use this filter as a default.
7203 <term><emphasis>jumping-windows</emphasis></term>
7206 Many consider windows that move, or resize themselves to be abusive. This filter
7207 neutralizes the related JavaScript code. Note that some sites might not display
7208 or behave as intended when using this filter. Use with caution.
7214 <term><emphasis>frameset-borders</emphasis></term>
7217 Some web designers seem to assume that everyone in the world will view their
7218 web sites using the same browser brand and version, screen resolution etc,
7219 because only that assumption could explain why they'd use static frame sizes,
7220 yet prevent their frames from being resized by the user, should they be too
7221 small to show their whole content.
7224 This filter removes the related HTML code. It should only be applied to sites
7231 <term><emphasis>demoronizer</emphasis></term>
7234 Many Microsoft products that generate HTML use non-standard extensions (read:
7235 violations) of the ISO 8859-1 aka Latin-1 character set. This can cause those
7236 HTML documents to display with errors on standard-compliant platforms.
7239 This filter translates the MS-only characters into Latin-1 equivalents.
7240 It is not necessary when using MS products, and will cause corruption of
7241 all documents that use 8-bit character sets other than Latin-1. It's mostly
7242 worthwhile for Europeans on non-MS platforms, if weird garbage characters
7243 sometimes appear on some pages, or user agents that don't correct for this on
7246 My version of Mozilla (ancient) shows litte square boxes for quote
7247 characters, and apostrophes on moronized pages. So many pages have this, I
7248 can read them fine now. HB 08/27/06
7255 <term><emphasis>shockwave-flash</emphasis></term>
7258 A filter for shockwave haters. As the name suggests, this filter strips code
7259 out of web pages that is used to embed shockwave flash objects.
7267 <term><emphasis>quicktime-kioskmode</emphasis></term>
7270 Change HTML code that embeds Quicktime objects so that kioskmode, which
7271 prevents saving, is disabled.
7277 <term><emphasis>fun</emphasis></term>
7280 Text replacements for subversive browsing fun. Make fun of your favorite
7281 Monopolist or play buzzword bingo.
7287 <term><emphasis>crude-parental</emphasis></term>
7290 A demonstration-only filter that shows how <application>Privoxy</application>
7291 can be used to delete web content on a keyword basis.
7297 <term><emphasis>ie-exploits</emphasis></term>
7300 An experimental collection of text replacements to disable malicious HTML and JavaScript
7301 code that exploits known security holes in Internet Explorer.
7304 Presently, it only protects against Nimda and a cross-site scripting bug, and
7305 would need active maintenance to provide more substantial protection.
7311 <term><emphasis>site-specifics</emphasis></term>
7314 Some web sites have very specific problems, the cure for which doesn't apply
7315 anywhere else, or could even cause damage on other sites.
7318 This is a collection of such site-specific cures which should only be applied
7319 to the sites they were intended for, which is what the supplied
7320 <filename>default.action</filename> file does. Users shouldn't need to change
7321 anything regarding this filter.
7327 <term><emphasis>google</emphasis></term>
7330 A CSS based block for Google text ads. Also removes a width limitation
7331 and the toolbar advertisement.
7337 <term><emphasis>yahoo</emphasis></term>
7340 Another CSS based block, this time for Yahoo text ads. And removes
7341 a width limitation as well.
7347 <term><emphasis>msn</emphasis></term>
7350 Another CSS based block, this time for MSN text ads. And removes
7351 tracking URLs, as well as a width limitation.
7357 <term><emphasis>blogspot</emphasis></term>
7360 Cleans up some Blogspot blogs. Read the fine print before using this one!
7363 This filter also intentionally removes some navigation stuff and sets the
7364 page width to 100%. As a result, some rounded <quote>corners</quote> would
7365 appear to early or not at all and as fixing this would require a browser
7366 that understands background-size (CSS3), they are removed instead.
7372 <term><emphasis>xml-to-html</emphasis></term>
7375 Server-header filter to change the Content-Type from xml to html.
7381 <term><emphasis>html-to-xml</emphasis></term>
7384 Server-header filter to change the Content-Type from html to xml.
7390 <term><emphasis>no-ping</emphasis></term>
7393 Removes the non-standard <literal>ping</literal> attribute from
7394 anchor and area HTML tags.
7400 <term><emphasis>hide-tor-exit-notation</emphasis></term>
7403 Client-header filter to remove the <command>Tor</command> exit node notation
7404 found in Host and Referer headers.
7407 If &my-app; and <command>Tor</command> are chained and &my-app;
7408 is configured to use socks4a, one can use <quote>http://www.example.org.foobar.exit/</quote>
7409 to access the host <quote>www.example.org</quote> through the
7410 <command>Tor</command> exit node <quote>foobar</quote>.
7413 As the HTTP client isn't aware of this notation, it treats the
7414 whole string <quote>www.example.org.foobar.exit</quote> as host and uses it
7415 for the <quote>Host</quote> and <quote>Referer</quote> headers. From the
7416 server's point of view the resulting headers are invalid and can cause problems.
7419 An invalid <quote>Referer</quote> header can trigger <quote>hot-linking</quote>
7420 protections, an invalid <quote>Host</quote> header will make it impossible for
7421 the server to find the right vhost (several domains hosted on the same IP address).
7424 This client-header filter removes the <quote>foo.exit</quote> part in those headers
7425 to prevent the mentioned problems. Note that it only modifies
7426 the HTTP headers, it doesn't make it impossible for the server
7427 to detect your <command>Tor</command> exit node based on the IP address
7428 the request is coming from.
7435 <term><emphasis> </emphasis></term>
7448 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7449 <sect2 id="external-filter-syntax"><title>External filter syntax</title>
7451 External filters are scripts or programs that can modify the content in
7452 case common <literal><link linkend="filter">filters</link></literal>
7453 aren't powerful enough.
7456 External filters can be written in any language the platform &my-app; runs
7460 They are controlled with the
7461 <literal><link linkend="external-filter">external-filter</link></literal> action
7462 and have to be defined in the <literal><link linkend="filterfile">filterfile</link></literal>
7466 The header looks like any other filter, but instead of pcrs jobs, external
7467 filters contain a single job which can be a program or a shell script (which
7468 may call other scripts or programs).
7471 External filters read the content from STDIN and write the rewritten
7472 content to STDOUT. The environment variables PRIVOXY_URL, PRIVOXY_PATH,
7473 PRIVOXY_HOST, PRIVOXY_ORIGIN can be used to get some details about the
7477 &my-app; will temporary store the content to filter in the
7478 <literal><link linkend="temporary-directory">temporary-directory</link></literal>.
7482 EXTERNAL-FILTER: cat Pointless example filter that doesn't actually modify the content
7485 # Incorrect reimplementation of the filter above in POSIX shell.
7487 # Note that it's a single job that spans multiple lines, the line
7488 # breaks are not passed to the shell, thus the semicolons are required.
7490 # If the script isn't trivial, it is recommended to put it into an external file.
7492 # In general, writing external filters entirely in POSIX shell is not
7493 # considered a good idea.
7494 EXTERNAL-FILTER: cat2 Pointless example filter that despite its name may actually modify the content
7500 EXTERNAL-FILTER: rotate-image Rotate an image by 180 degree. Test filter with limited value.
7501 /usr/local/bin/convert - -rotate 180 -
7503 EXTERNAL-FILTER: citation-needed Adds a "[citation needed]" tag to an image. The coordinates may need adjustment.
7504 /usr/local/bin/convert - -pointsize 16 -fill white -annotate +17+418 "[citation needed]" -
7510 Currently external filters are executed with &my-app;'s privileges!
7511 Only use external filters you understand and trust.
7515 External filters are experimental and the syntax may change in the future.
7521 <!-- ~ End section ~ -->
7525 <!-- ~~~~~ New section ~~~~~ -->
7527 <sect1 id="templates">
7528 <title>Privoxy's Template Files</title>
7530 All <application>Privoxy</application> built-in pages, i.e. error pages such as the
7531 <ulink url="http://show-the-404-error.page"><quote>404 - No Such Domain</quote>
7532 error page</ulink>, the <ulink
7533 url="http://ads.bannerserver.example.com/nasty-ads/sponsor.html"><quote>BLOCKED</quote>
7535 and all pages of its <ulink url="http://config.privoxy.org/">web-based
7536 user interface</ulink>, are generated from <emphasis>templates</emphasis>.
7537 (<application>Privoxy</application> must be running for the above links to work as
7542 These templates are stored in a subdirectory of the <link linkend="confdir">configuration
7543 directory</link> called <filename>templates</filename>. On Unixish platforms,
7545 <ulink url="file:///etc/privoxy/templates/"><filename>/etc/privoxy/templates/</filename></ulink>.
7549 The templates are basically normal HTML files, but with place-holders (called symbols
7550 or exports), which <application>Privoxy</application> fills at run time. It
7551 is possible to edit the templates with a normal text editor, should you want
7552 to customize them. (<emphasis>Not recommended for the casual
7553 user</emphasis>). Should you create your own custom templates, you should use
7554 the <filename>config</filename> setting <link linkend="templdir">templdir</link>
7555 to specify an alternate location, so your templates do not get overwritten
7559 Note that just like in configuration files, lines starting
7560 with <literal>#</literal> are ignored when the templates are filled in.
7564 The place-holders are of the form <literal>@name@</literal>, and you will
7565 find a list of available symbols, which vary from template to template,
7566 in the comments at the start of each file. Note that these comments are not
7567 always accurate, and that it's probably best to look at the existing HTML
7568 code to find out which symbols are supported and what they are filled in with.
7572 A special application of this substitution mechanism is to make whole
7573 blocks of HTML code disappear when a specific symbol is set. We use this
7574 for many purposes, one of them being to include the beta warning in all
7575 our user interface (CGI) pages when <application>Privoxy</application>
7576 is in an alpha or beta development stage:
7581 <!-- @if-unstable-start -->
7583 ... beta warning HTML code goes here ...
7585 <!-- if-unstable-end@ --></screen>
7589 If the "unstable" symbol is set, everything in between and including
7590 <literal>@if-unstable-start</literal> and <literal>if-unstable-end@</literal>
7591 will disappear, leaving nothing but an empty comment:
7595 <screen><!-- --></screen>
7599 There's also an if-then-else construct and an <literal>#include</literal>
7600 mechanism, but you'll sure find out if you are inclined to edit the
7605 All templates refer to a style located at
7606 <ulink url="http://config.privoxy.org/send-stylesheet"><literal>http://config.privoxy.org/send-stylesheet</literal></ulink>.
7607 This is, of course, locally served by <application>Privoxy</application>
7608 and the source for it can be found and edited in the
7609 <filename>cgi-style.css</filename> template.
7614 <!-- ~ End section ~ -->
7618 <!-- ~~~~~ New section ~~~~~ -->
7620 <sect1 id="contact"><title>Contacting the Developers, Bug Reporting and Feature
7623 <!-- Include contacting.sgml boilerplate: -->
7625 <!-- end boilerplate -->
7629 <!-- ~ End section ~ -->
7632 <!-- ~~~~~ New section ~~~~~ -->
7633 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
7635 <!-- Include copyright.sgml: -->
7637 <!-- end copyright -->
7640 <application>Privoxy</application> is free software; you can
7641 redistribute it and/or modify it under the terms of the
7642 <citetitle>GNU General Public License</citetitle>, version 2,
7643 as published by the Free Software Foundation and included in
7647 <!-- ~~~~~ New section ~~~~~ -->
7648 <sect2 id="license"><title>License</title>
7650 <screen><![ RCDATA [ &GPLv2; ]]></screen>
7654 <!-- ~ End section ~ -->
7657 <!-- ~~~~~ New section ~~~~~ -->
7659 <sect2 id="history"><title>History</title>
7660 <!-- Include history.sgml: -->
7662 <!-- end history -->
7665 <sect2 id="authors"><title>Authors</title>
7666 <!-- Include p-authors.sgml: -->
7668 <!-- end authors -->
7673 <!-- ~ End section ~ -->
7676 <!-- ~~~~~ New section ~~~~~ -->
7677 <sect1 id="seealso"><title>See Also</title>
7678 <!-- Include seealso.sgml: -->
7680 <!-- end seealso -->
7685 <!-- ~~~~~ New section ~~~~~ -->
7686 <sect1 id="appendix"><title>Appendix</title>
7689 <!-- ~~~~~ New section ~~~~~ -->
7691 <title>Regular Expressions</title>
7693 <application>Privoxy</application> uses Perl-style <quote>regular
7694 expressions</quote> in its <link linkend="actions-file">actions
7695 files</link> and <link linkend="filter-file">filter file</link>,
7696 through the <ulink url="http://www.pcre.org/">PCRE</ulink> and
7699 <ulink url="http://www.oesterhelt.org/pcrs/">PCRS</ulink> libraries.
7701 <application>PCRS</application> libraries.
7705 If you are reading this, you probably don't understand what <quote>regular
7706 expressions</quote> are, or what they can do. So this will be a very brief
7707 introduction only. A full explanation would require a <ulink
7708 url="http://www.oreilly.com/catalog/regex/">book</ulink> ;-)
7712 Regular expressions provide a language to describe patterns that can be
7713 run against strings of characters (letter, numbers, etc), to see if they
7714 match the string or not. The patterns are themselves (sometimes complex)
7715 strings of literal characters, combined with wild-cards, and other special
7716 characters, called meta-characters. The <quote>meta-characters</quote> have
7717 special meanings and are used to build complex patterns to be matched against.
7718 Perl Compatible Regular Expressions are an especially convenient
7719 <quote>dialect</quote> of the regular expression language.
7723 To make a simple analogy, we do something similar when we use wild-card
7724 characters when listing files with the <command>dir</command> command in DOS.
7725 <literal>*.*</literal> matches all filenames. The <quote>special</quote>
7726 character here is the asterisk which matches any and all characters. We can be
7727 more specific and use <literal>?</literal> to match just individual
7728 characters. So <quote>dir file?.text</quote> would match
7729 <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
7730 matching, using a similar technique to <quote>regular expressions</quote>!
7734 Regular expressions do essentially the same thing, but are much, much more
7735 powerful. There are many more <quote>special characters</quote> and ways of
7736 building complex patterns however. Let's look at a few of the common ones,
7737 and then some examples:
7742 <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
7743 <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
7745 </simplelist></para>
7749 <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
7752 </simplelist></para>
7756 <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
7759 </simplelist></para>
7763 <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
7766 </simplelist></para>
7770 <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
7771 the following character should be taken literally. This is used where one of the
7772 special characters (e.g. <quote>.</quote>) needs to be taken literally and
7773 not as a special meta-character. Example: <quote>example\.com</quote>, makes
7774 sure the period is recognized only as a period (and not expanded to its
7775 meta-character meaning of any single character).
7777 </simplelist></para>
7781 <emphasis>[ ]</emphasis> - Characters enclosed in brackets will be matched if
7782 any of the enclosed characters are encountered. For instance, <quote>[0-9]</quote>
7783 matches any numeric digit (zero through nine). As an example, we can combine
7784 this with <quote>+</quote> to match any digit one of more times: <quote>[0-9]+</quote>.
7786 </simplelist></para>
7790 <emphasis>( )</emphasis> - parentheses are used to group a sub-expression,
7791 or multiple sub-expressions.
7793 </simplelist></para>
7797 <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
7798 <quote>or</quote> conditional statement. A match is successful if the
7799 sub-expression on either side of <quote>|</quote> matches. As an example:
7800 <quote>/(this|that) example/</quote> uses grouping and the bar character
7801 and would match either <quote>this example</quote> or <quote>that
7802 example</quote>, and nothing else.
7804 </simplelist></para>
7807 These are just some of the ones you are likely to use when matching URLs with
7808 <application>Privoxy</application>, and is a long way from a definitive
7809 list. This is enough to get us started with a few simple examples which may
7810 be more illuminating:
7814 <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
7815 that uses the common combination of <quote>.</quote> and <quote>*</quote> to
7816 denote any character, zero or more times. In other words, any string at all.
7817 So we start with a literal forward slash, then our regular expression pattern
7818 (<quote>.*</quote>) another literal forward slash, the string
7819 <quote>banners</quote>, another forward slash, and lastly another
7820 <quote>.*</quote>. We are building
7821 a directory path here. This will match any file with the path that has a
7822 directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
7823 any characters, and this could conceivably be more forward slashes, so it
7824 might expand into a much longer looking path. For example, this could match:
7825 <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
7826 <quote>/banners/annoying.html</quote>, or almost an infinite number of other
7827 possible combinations, just so it has <quote>banners</quote> in the path
7832 And now something a little more complex:
7836 <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
7837 We have several literal forward slashes again (<quote>/</quote>), so we are
7838 building another expression that is a file path statement. We have another
7839 <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
7840 it matches our expression. The only true literal that <emphasis>must
7841 match</emphasis> our pattern is <application>adv</application>, together with
7842 the forward slashes. What comes after the <quote>adv</quote> string is the
7847 Remember the <quote>?</quote> means the preceding expression (either a
7848 literal character or anything grouped with <quote>(...)</quote> in this case)
7849 can exist or not, since this means either zero or one match. So
7850 <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
7851 individual sub-expressions: <quote>(er)</quote>,
7852 <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
7853 means <quote>or</quote>. We have two of those. For instance,
7854 <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
7855 <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
7856 attempt at matching as many variations of <quote>advertisement</quote>, and
7857 similar, as possible. So this would expand to match just <quote>adv</quote>,
7858 or <quote>advert</quote>, or <quote>adverts</quote>, or
7859 <quote>advertising</quote>, or <quote>advertisement</quote>, or
7860 <quote>advertisements</quote>. You get the idea. But it would not match
7861 <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
7862 changing our regular expression to:
7863 <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
7868 <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
7869 another path statement with forward slashes. Anything in the square brackets
7870 <quote>[ ]</quote> can be matched. This is using <quote>0-9</quote> as a
7871 shorthand expression to mean any digit one through nine. It is the same as
7872 saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
7873 means one or more of the preceding expression must be included. The preceding
7874 expression here is what is in the square brackets -- in this case, any digit
7875 one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
7876 This includes a <quote>|</quote>, so this needs to match the expression on
7877 either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
7878 side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
7879 since the <quote>?</quote> means the letter <quote>e</quote> is optional and
7880 can be matched once or not at all. So we are building an expression here to
7881 match image GIF or JPEG type image file. It must include the literal
7882 string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
7883 (which is now a literal, and not a special character, since it is escaped
7884 with <quote>\</quote>), and lastly either <quote>gif</quote>, or
7885 <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
7886 include: <quote>//advert1.jpg</quote>,
7887 <quote>/nasty/ads/advert1234.gif</quote>,
7888 <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
7889 <quote>advert1.gif</quote> (no leading slash), or
7890 <quote>/adverts232.jpg</quote> (the expression does not include an
7891 <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
7892 in the expression anywhere).
7896 We are barely scratching the surface of regular expressions here so that you
7897 can understand the default <application>Privoxy</application>
7898 configuration files, and maybe use this knowledge to customize your own
7899 installation. There is much, much more that can be done with regular
7900 expressions. Now that you know enough to get started, you can learn more on
7905 More reading on Perl Compatible Regular expressions:
7906 <ulink url="http://perldoc.perl.org/perlre.html">http://perldoc.perl.org/perlre.html</ulink>
7910 For information on regular expression based substitutions and their applications
7911 in filters, please see the <link linkend="filter-file">filter file tutorial</link>
7916 <!-- ~ End section ~ -->
7919 <!-- ~~~~~ New section ~~~~~ -->
7921 <title>Privoxy's Internal Pages</title>
7924 Since <application>Privoxy</application> proxies each requested
7925 web page, it is easy for <application>Privoxy</application> to
7926 trap certain special URLs. In this way, we can talk directly to
7927 <application>Privoxy</application>, and see how it is
7928 configured, see how our rules are being applied, change these
7929 rules and other configuration options, and even turn
7930 <application>Privoxy's</application> filtering off, all with
7936 The URLs listed below are the special ones that allow direct access
7937 to <application>Privoxy</application>. Of course,
7938 <application>Privoxy</application> must be running to access these. If
7939 not, you will get a friendly error message. Internet access is not
7952 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
7956 There is a shortcut: <ulink url="http://p.p/">http://p.p/</ulink> (But it
7957 doesn't provide a fall-back to a real page, in case the request is not
7958 sent through <application>Privoxy</application>)
7964 Show information about the current configuration, including viewing and
7965 editing of actions files:
7969 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
7976 Show the source code version numbers:
7980 <ulink url="http://config.privoxy.org/show-version">http://config.privoxy.org/show-version</ulink>
7987 Show the browser's request headers:
7991 <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
7998 Show which actions apply to a URL and why:
8002 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8009 Toggle Privoxy on or off. This feature can be turned off/on in the main
8010 <filename>config</filename> file. When toggled <quote>off</quote>, <quote>Privoxy</quote>
8011 continues to run, but only as a pass-through proxy, with no actions taking
8016 <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
8020 Short cuts. Turn off, then on:
8024 <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
8029 <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
8040 <!-- ~~~~~ New section ~~~~~ -->
8042 <title>Chain of Events</title>
8044 Let's take a quick look at how some of <application>Privoxy's</application>
8045 core features are triggered, and the ensuing sequence of events when a web
8046 page is requested by your browser:
8053 First, your web browser requests a web page. The browser knows to send
8054 the request to <application>Privoxy</application>, which will in turn,
8055 relay the request to the remote web server after passing the following
8061 <application>Privoxy</application> traps any request for its own internal CGI
8062 pages (e.g <ulink url="http://p.p/">http://p.p/</ulink>) and sends the CGI page back to the browser.
8067 Next, <application>Privoxy</application> checks to see if the URL
8069 linkend="BLOCK"><quote>+block</quote></link> patterns. If
8070 so, the URL is then blocked, and the remote web server will not be contacted.
8071 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>
8073 <link linkend="HANDLE-AS-EMPTY-DOCUMENT"><quote>+handle-as-empty-document</quote></link>
8074 are then checked, and if there is no match, an
8075 HTML <quote>BLOCKED</quote> page is sent back to the browser. Otherwise, if
8076 it does match, an image is returned for the former, and an empty text
8077 document for the latter. The type of image would depend on the setting of
8078 <link linkend="SET-IMAGE-BLOCKER"><quote>+set-image-blocker</quote></link>
8079 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
8084 Untrusted URLs are blocked. If URLs are being added to the
8085 <filename>trust</filename> file, then that is done.
8090 If the URL pattern matches the <link
8091 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link> action,
8092 it is then processed. Unwanted parts of the requested URL are stripped.
8097 Now the rest of the client browser's request headers are processed. If any
8098 of these match any of the relevant actions (e.g. <link
8099 linkend="HIDE-USER-AGENT"><quote>+hide-user-agent</quote></link>,
8100 etc.), headers are suppressed or forged as determined by these actions and
8106 Now the web server starts sending its response back (i.e. typically a web
8112 First, the server headers are read and processed to determine, among other
8113 things, the MIME type (document type) and encoding. The headers are then
8114 filtered as determined by the
8115 <link linkend="CRUNCH-INCOMING-COOKIES"><quote>+crunch-incoming-cookies</quote></link>,
8116 <link linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>,
8117 and <link linkend="DOWNGRADE-HTTP-VERSION"><quote>+downgrade-http-version</quote></link>
8123 If any <link linkend="FILTER"><quote>+filter</quote></link> action
8125 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
8126 action applies (and the document type fits the action), the rest of the page is
8127 read into memory (up to a configurable limit). Then the filter rules (from
8128 <filename>default.filter</filename> and any other filter files) are
8129 processed against the buffered content. Filters are applied in the order
8130 they are specified in one of the filter files. Animated GIFs, if present,
8131 are reduced to either the first or last frame, depending on the action
8132 setting.The entire page, which is now filtered, is then sent by
8133 <application>Privoxy</application> back to your browser.
8136 If neither a <link linkend="FILTER"><quote>+filter</quote></link> action
8138 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
8139 matches, then <application>Privoxy</application> passes the raw data through
8140 to the client browser as it becomes available.
8145 As the browser receives the now (possibly filtered) page content, it
8146 reads and then requests any URLs that may be embedded within the page
8147 source, e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
8148 frames), sounds, etc. For each of these objects, the browser issues a
8149 separate request (this is easily viewable in <application>Privoxy's</application>
8150 logs). And each such request is in turn processed just as above. Note that a
8151 complex web page will have many, many such embedded URLs. If these
8152 secondary requests are to a different server, then quite possibly a very
8153 differing set of actions is triggered.
8160 NOTE: This is somewhat of a simplistic overview of what happens with each URL
8161 request. For the sake of brevity and simplicity, we have focused on
8162 <application>Privoxy's</application> core features only.
8168 <!-- ~~~~~ New section ~~~~~ -->
8169 <sect2 id="actionsanat">
8170 <title>Troubleshooting: Anatomy of an Action</title>
8173 The way <application>Privoxy</application> applies
8174 <link linkend="ACTIONS">actions</link> and <link linkend="FILTER">filters</link>
8175 to any given URL can be complex, and not always so
8176 easy to understand what is happening. And sometimes we need to be able to
8177 <emphasis>see</emphasis> just what <application>Privoxy</application> is
8178 doing. Especially, if something <application>Privoxy</application> is doing
8179 is causing us a problem inadvertently. It can be a little daunting to look at
8180 the actions and filters files themselves, since they tend to be filled with
8181 <link linkend="regex">regular expressions</link> whose consequences are not
8186 One quick test to see if <application>Privoxy</application> is causing a problem
8187 or not, is to disable it temporarily. This should be the first troubleshooting
8188 step (be sure to flush caches afterward!). Looking at the
8189 logs is a good idea too. (Note that both the toggle feature and logging are
8190 enabled via <filename>config</filename> file settings, and may need to be
8191 turned <quote>on</quote>.)
8194 Another easy troubleshooting step to try is if you have done any
8195 customization of your installation, revert back to the installed
8196 defaults and see if that helps. There are times the developers get complaints
8197 about one thing or another, and the problem is more related to a customized
8198 configuration issue.
8202 <application>Privoxy</application> also provides the
8203 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8204 page that can show us very specifically how <application>actions</application>
8205 are being applied to any given URL. This is a big help for troubleshooting.
8209 First, enter one URL (or partial URL) at the prompt, and then
8210 <application>Privoxy</application> will tell us
8211 how the current configuration will handle it. This will not
8212 help with filtering effects (i.e. the <link
8213 linkend="FILTER"><quote>+filter</quote></link> action) from
8214 one of the filter files since this is handled very
8215 differently and not so easy to trap! It also will not tell you about any other
8216 URLs that may be embedded within the URL you are testing. For instance, images
8217 such as ads are expressed as URLs within the raw page source of HTML pages. So
8218 you will only get info for the actual URL that is pasted into the prompt area
8219 -- not any sub-URLs. If you want to know about embedded URLs like ads, you
8220 will have to dig those out of the HTML source. Use your browser's <quote>View
8221 Page Source</quote> option for this. Or right click on the ad, and grab the
8226 Let's try an example, <ulink url="http://google.com">google.com</ulink>,
8227 and look at it one section at a time in a sample configuration (your real
8228 configuration may vary):
8233 Matches for http://www.google.com:
8235 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8237 {+change-x-forwarded-for{block}
8238 +deanimate-gifs {last}
8239 +fast-redirects {check-decoded-url}
8240 +filter {refresh-tags}
8241 +filter {img-reorder}
8242 +filter {banners-by-size}
8244 +filter {jumping-windows}
8245 +filter {ie-exploits}
8246 +hide-from-header {block}
8247 +hide-referrer {forge}
8248 +session-cookies-only
8249 +set-image-blocker {pattern}
8252 { -session-cookies-only }
8258 In file: user.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8259 (no matches in this file)
8264 This is telling us how we have defined our
8265 <link linkend="ACTIONS"><quote>actions</quote></link>, and
8266 which ones match for our test case, <quote>google.com</quote>.
8267 Displayed is all the actions that are available to us. Remember,
8268 the <literal>+</literal> sign denotes <quote>on</quote>. <literal>-</literal>
8269 denotes <quote>off</quote>. So some are <quote>on</quote> here, but many
8270 are <quote>off</quote>. Each example we try may provide a slightly different
8271 end result, depending on our configuration directives.
8275 is for our <filename>default.action</filename> file. The large, multi-line
8276 listing, is how the actions are set to match for all URLs, i.e. our default
8277 settings. If you look at your <quote>actions</quote> file, this would be the
8278 section just below the <quote>aliases</quote> section near the top. This
8279 will apply to all URLs as signified by the single forward slash at the end
8280 of the listing -- <quote> / </quote>.
8284 But we have defined additional actions that would be exceptions to these general
8285 rules, and then we list specific URLs (or patterns) that these exceptions
8286 would apply to. Last match wins. Just below this then are two explicit
8287 matches for <quote>.google.com</quote>. The first is negating our previous
8288 cookie setting, which was for <link
8289 linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>
8290 (i.e. not persistent). So we will allow persistent cookies for google, at
8291 least that is how it is in this example. The second turns
8292 <emphasis>off</emphasis> any <link
8293 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link>
8294 action, allowing this to take place unmolested. Note that there is a leading
8295 dot here -- <quote>.google.com</quote>. This will match any hosts and
8296 sub-domains, in the google.com domain also, such as
8297 <quote>www.google.com</quote> or <quote>mail.google.com</quote>. But it would not
8298 match <quote>www.google.de</quote>! So, apparently, we have these two actions
8299 defined as exceptions to the general rules at the top somewhere in the lower
8300 part of our <filename>default.action</filename> file, and
8301 <quote>google.com</quote> is referenced somewhere in these latter sections.
8305 Then, for our <filename>user.action</filename> file, we again have no hits.
8306 So there is nothing google-specific that we might have added to our own, local
8307 configuration. If there was, those actions would over-rule any actions from
8308 previously processed files, such as <filename>default.action</filename>.
8309 <filename>user.action</filename> typically has the last word. This is the
8310 best place to put hard and fast exceptions,
8314 And finally we pull it all together in the bottom section and summarize how
8315 <application>Privoxy</application> is applying all its <quote>actions</quote>
8316 to <quote>google.com</quote>:
8327 +change-x-forwarded-for{block}
8328 -client-header-filter{hide-tor-exit-notation}
8329 -content-type-overwrite
8330 -crunch-client-header
8331 -crunch-if-none-match
8332 -crunch-incoming-cookies
8333 -crunch-outgoing-cookies
8334 -crunch-server-header
8335 +deanimate-gifs {last}
8336 -downgrade-http-version
8339 -filter {content-cookies}
8340 -filter {all-popups}
8341 -filter {banners-by-link}
8342 -filter {tiny-textforms}
8343 -filter {frameset-borders}
8344 -filter {demoronizer}
8345 -filter {shockwave-flash}
8346 -filter {quicktime-kioskmode}
8348 -filter {crude-parental}
8349 -filter {site-specifics}
8350 -filter {js-annoyances}
8351 -filter {html-annoyances}
8352 +filter {refresh-tags}
8353 -filter {unsolicited-popups}
8354 +filter {img-reorder}
8355 +filter {banners-by-size}
8357 +filter {jumping-windows}
8358 +filter {ie-exploits}
8365 -handle-as-empty-document
8367 -hide-accept-language
8368 -hide-content-disposition
8369 +hide-from-header {block}
8370 -hide-if-modified-since
8371 +hide-referrer {forge}
8374 -overwrite-last-modified
8375 -prevent-compression
8377 -server-header-filter{xml-to-html}
8378 -server-header-filter{html-to-xml}
8379 -session-cookies-only
8380 +set-image-blocker {pattern} </screen>
8384 Notice the only difference here to the previous listing, is to
8385 <quote>fast-redirects</quote> and <quote>session-cookies-only</quote>,
8386 which are activated specifically for this site in our configuration,
8387 and thus show in the <quote>Final Results</quote>.
8391 Now another example, <quote>ad.doubleclick.net</quote>:
8397 { +block{Domains starts with "ad"} }
8400 { +block{Domain contains "ad"} }
8403 { +block{Doubleclick banner server} +handle-as-image }
8404 .[a-vx-z]*.doubleclick.net
8409 We'll just show the interesting part here - the explicit matches. It is
8410 matched three different times. Two <quote>+block{}</quote> sections,
8411 and a <quote>+block{} +handle-as-image</quote>,
8412 which is the expanded form of one of our aliases that had been defined as:
8413 <quote>+block-as-image</quote>. (<link
8414 linkend="ALIASES"><quote>Aliases</quote></link> are defined in
8415 the first section of the actions file and typically used to combine more
8420 Any one of these would have done the trick and blocked this as an unwanted
8421 image. This is unnecessarily redundant since the last case effectively
8422 would also cover the first. No point in taking chances with these guys
8423 though ;-) Note that if you want an ad or obnoxious
8424 URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
8425 is done here -- as both a <link
8426 linkend="BLOCK"><quote>+block{}</quote></link>
8427 <emphasis>and</emphasis> an
8428 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>.
8429 The custom alias <quote><literal>+block-as-image</literal></quote> just
8430 simplifies the process and make it more readable.
8434 One last example. Let's try <quote>http://www.example.net/adsl/HOWTO/</quote>.
8435 This one is giving us problems. We are getting a blank page. Hmmm ...
8441 Matches for http://www.example.net/adsl/HOWTO/:
8443 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8447 +change-x-forwarded-for{block}
8448 -client-header-filter{hide-tor-exit-notation}
8449 -content-type-overwrite
8450 -crunch-client-header
8451 -crunch-if-none-match
8452 -crunch-incoming-cookies
8453 -crunch-outgoing-cookies
8454 -crunch-server-header
8456 -downgrade-http-version
8457 +fast-redirects {check-decoded-url}
8459 -filter {content-cookies}
8460 -filter {all-popups}
8461 -filter {banners-by-link}
8462 -filter {tiny-textforms}
8463 -filter {frameset-borders}
8464 -filter {demoronizer}
8465 -filter {shockwave-flash}
8466 -filter {quicktime-kioskmode}
8468 -filter {crude-parental}
8469 -filter {site-specifics}
8470 -filter {js-annoyances}
8471 -filter {html-annoyances}
8472 +filter {refresh-tags}
8473 -filter {unsolicited-popups}
8474 +filter {img-reorder}
8475 +filter {banners-by-size}
8477 +filter {jumping-windows}
8478 +filter {ie-exploits}
8485 -handle-as-empty-document
8487 -hide-accept-language
8488 -hide-content-disposition
8489 +hide-from-header{block}
8490 +hide-referer{forge}
8492 -overwrite-last-modified
8493 +prevent-compression
8495 -server-header-filter{xml-to-html}
8496 -server-header-filter{html-to-xml}
8497 +session-cookies-only
8498 +set-image-blocker{blank} }
8501 { +block{Path contains "ads".} +handle-as-image }
8507 Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote> in our
8508 configuration! But we did not want this at all! Now we see why we get the
8509 blank page. It is actually triggering two different actions here, and
8510 the effects are aggregated so that the URL is blocked, and &my-app; is told
8511 to treat the block as if it were an image. But this is, of course, all wrong.
8512 We could now add a new action below this (or better in our own
8513 <filename>user.action</filename> file) that explicitly
8514 <emphasis>un</emphasis> blocks (
8515 <link linkend="BLOCK"><quote>{-block}</quote></link>) paths with
8516 <quote>adsl</quote> in them (remember, last match in the configuration
8517 wins). There are various ways to handle such exceptions. Example:
8529 Now the page displays ;-)
8530 Remember to flush your browser's caches when making these kinds of changes to
8531 your configuration to insure that you get a freshly delivered page! Or, try
8532 using <literal>Shift+Reload</literal>.
8536 But now what about a situation where we get no explicit matches like
8543 { +block{Path starts with "ads".} +handle-as-image }
8549 That actually was very helpful and pointed us quickly to where the problem
8550 was. If you don't get this kind of match, then it means one of the default
8551 rules in the first section of <filename>default.action</filename> is causing
8552 the problem. This would require some guesswork, and maybe a little trial and
8553 error to isolate the offending rule. One likely cause would be one of the
8554 <link linkend="FILTER"><quote>+filter</quote></link> actions.
8555 These tend to be harder to troubleshoot.
8556 Try adding the URL for the site to one of aliases that turn off
8557 <link linkend="FILTER"><quote>+filter</quote></link>:
8565 .worldpay.com # for quietpc.com
8573 <quote><literal>{ shop }</literal></quote> is an <quote>alias</quote> that expands to
8574 <quote><literal>{ -filter -session-cookies-only }</literal></quote>.
8575 Or you could do your own exception to negate filtering:
8583 # Disable ALL filter actions for sites in this section
8591 This would turn off all filtering for these sites. This is best
8592 put in <filename>user.action</filename>, for local site
8593 exceptions. Note that when a simple domain pattern is used by itself (without
8594 the subsequent path portion), all sub-pages within that domain are included
8595 automatically in the scope of the action.
8599 Images that are inexplicably being blocked, may well be hitting the
8600 <link linkend="FILTER-BANNERS-BY-SIZE"><quote>+filter{banners-by-size}</quote></link>
8602 that images of certain sizes are ad banners (works well
8603 <emphasis>most of the time</emphasis> since these tend to be standardized).
8607 <quote><literal>{ fragile }</literal></quote> is an alias that disables most
8608 actions that are the most likely to cause trouble. This can be used as a
8609 last resort for problem sites.
8615 # Handle with care: easy to break
8617 mybank.example.com</screen>
8622 <emphasis>Remember to flush caches!</emphasis> Note that the
8623 <literal>mail.google</literal> reference lacks the TLD portion (e.g.
8624 <quote>.com</quote>). This will effectively match any TLD with
8625 <literal>google</literal> in it, such as <literal>mail.google.de.</literal>,
8629 If this still does not work, you will have to go through the remaining
8630 actions one by one to find which one(s) is causing the problem.
8639 This program is free software; you can redistribute it
8640 and/or modify it under the terms of the GNU General
8641 Public License as published by the Free Software
8642 Foundation; either version 2 of the License, or (at
8643 your option) any later version.
8645 This program is distributed in the hope that it will
8646 be useful, but WITHOUT ANY WARRANTY; without even the
8647 implied warranty of MERCHANTABILITY or FITNESS FOR A
8648 PARTICULAR PURPOSE. See the GNU General Public
8649 License for more details.
8651 The GNU General Public License should be included with
8652 this file. If not, you can view it at
8653 http://www.gnu.org/copyleft/gpl.html
8654 or write to the Free Software Foundation, Inc.,
8655 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
projects / privoxy.git / blob