1 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V3.1//EN" [
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13 <!entity p-authors SYSTEM "p-authors.sgml">
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16 <!entity p-version "3.0.21">
17 <!entity p-status "UNRELEASED">
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19 <!entity % p-not-stable "INCLUDE">
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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 2.168 2013/02/26 15:09:35 fabiankeil Exp $
41 Copyright (C) 2001-2013 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; 2001-2013 by
61 <ulink url="http://www.privoxy.org/">Privoxy Developers</ulink>
65 <pubdate>$Id: user-manual.sgml,v 2.168 2013/02/26 15:09:35 fabiankeil 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>, v.&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-tbz"><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>.
345 If you don't use the ports, you can fetch and install
346 the package with <literal>pkg_add -r privoxy</literal>.
349 The port skeleton and the package can also be downloaded from the
350 <ulink url="https://sourceforge.net/project/showfiles.php?group_id=11118">File Release
351 Page</ulink>, but there's no reason to use them unless you're interested in the
352 beta releases which are only available there.
358 <!-- ~~~~~ New section ~~~~~ -->
359 <sect2 id="installation-source"><title>Building from Source</title>
362 The most convenient way to obtain the <application>Privoxy</application> sources
363 is to download the source tarball from our
364 <ulink url="http://sourceforge.net/project/showfiles.php?group_id=11118&package_id=10571">project download
369 If you like to live on the bleeding edge and are not afraid of using
370 possibly unstable development versions, you can check out the up-to-the-minute
371 version directly from <ulink url="http://sourceforge.net/cvs/?group_id=11118">the
372 CVS repository</ulink>.
374 deprecated...out of business.
375 or simply download <ulink
376 url="http://cvs.sourceforge.net/cvstarballs/ijbswa-cvsroot.tar.bz2">the nightly CVS
381 <!-- include buildsource.sgml boilerplate: -->
383 <!-- end boilerplate -->
386 <!-- ~~~~~ New section ~~~~~ -->
387 <sect2 id="installation-keepupdated"><title>Keeping your Installation Up-to-Date</title>
390 If you wish to receive an email notification whenever we release updates of
391 <application>Privoxy</application> or the actions file, <ulink
392 url="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce/">subscribe
393 to our announce mailing list</ulink>, ijbswa-announce@lists.sourceforge.net.
397 In order not to lose your personal changes and adjustments when updating
398 to the latest <literal>default.action</literal> file we <emphasis>strongly
399 recommend</emphasis> that you use <literal>user.action</literal> and
400 <literal>user.filter</literal> for your local
401 customizations of <application>Privoxy</application>. See the <link
402 linkend="actions-file">Chapter on actions files</link> for details.
410 <!-- ~ End section ~ -->
412 <!-- ~~~~~ New section ~~~~~ -->
413 <sect1 id="whatsnew">
414 <title>What's New in this Release</title>
418 <!-- ~~~~~ New section ~~~~~ -->
420 <sect2 id="upgradersnote">
421 <title>Note to Upgraders</title>
424 A quick list of things to be aware of before upgrading from earlier
425 versions of <application>Privoxy</application>:
433 The recommended way to upgrade &my-app; is to backup your old
434 configuration files, install the new ones, verify that &my-app;
435 is working correctly and finally merge back your changes using
436 <application>diff</application> and maybe <application>patch</application>.
439 There are a number of new features in each &my-app; release and
440 most of them have to be explicitly enabled in the configuration
441 files. Old configuration files obviously don't do that and due
442 to syntax changes using old configuration files with a new
443 &my-app; isn't always possible anyway.
448 Note that some installers remove earlier versions completely,
449 including configuration files, therefore you should really save
450 any important configuration files!
455 On the other hand, other installers don't overwrite existing configuration
456 files, thinking you will want to do that yourself.
461 In the default configuration only fatal errors are logged now.
462 You can change that in the <link linkend="DEBUG">debug section</link>
463 of the configuration file. You may also want to enable more verbose
464 logging until you verified that the new &my-app; version is working
471 Three other config file settings are now off by default:
472 <link linkend="enable-remote-toggle">enable-remote-toggle</link>,
473 <link linkend="enable-remote-http-toggle">enable-remote-http-toggle</link>,
474 and <link linkend="enable-edit-actions">enable-edit-actions</link>.
475 If you use or want these, you will need to explicitly enable them, and
476 be aware of the security issues involved.
483 What constitutes a <quote>default</quote> configuration has changed,
484 and you may want to review which actions are <quote>on</quote> by
485 default. This is primarily a matter of emphasis, but some features
486 you may have been used to, may now be <quote>off</quote> by default.
487 There are also a number of new actions and filters you may want to
488 consider, most of which are not fully incorporated into the default
489 settings as yet (see above).
496 The default actions setting is now <literal>Cautious</literal>. Previous
497 releases had a default setting of <literal>Medium</literal>. Experienced
498 users may want to adjust this, as it is fairly conservative by &my-app;
499 standards and past practices. See <ulink
500 url="http://config.privoxy.org/edit-actions-list?f=default">
501 http://config.privoxy.org/edit-actions-list?f=default</ulink>. New users
502 should try the default settings for a while before turning up the volume.
508 The default setting has filtering turned <emphasis>off</emphasis>, which
509 subsequently means that compression is <emphasis>on</emphasis>. Remember
510 that filtering does not work on compressed pages, so if you use, or want to
511 use, filtering, you will need to force compression off. Example:
515 { +<link linkend="filter">filter</link>{google} +<link linkend="prevent-compression">prevent-compression</link> }
519 Or if you use a number of filters, or filter many sites, you may just want
520 to turn off compression for all sites in
521 <filename>default.action</filename> (or
522 <filename>user.action</filename>).
529 Also, <link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> is
530 off by default now. If you've liked this feature in the past, you may want
531 to turn it back on in <filename>user.action</filename> now.
538 Some installers may not automatically start
539 <application>Privoxy</application> after installation.
550 <!-- ~~~~~ New section ~~~~~ -->
551 <sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
557 Install <application>Privoxy</application>. See the <link
558 linkend="installation">Installation Section</link> below for platform specific
565 Advanced users and those who want to offer <application>Privoxy</application>
566 service to more than just their local machine should check the <link
567 linkend="config">main config file</link>, especially the <link
568 linkend="access-control">security-relevant</link> options. These are
575 Start <application>Privoxy</application>, if the installation program has
576 not done this already (may vary according to platform). See the section
577 <link linkend="startup">Starting <application>Privoxy</application></link>.
583 Set your browser to use <application>Privoxy</application> as HTTP and
584 HTTPS (SSL) <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
585 by setting the proxy configuration for address of
586 <literal>127.0.0.1</literal> and port <literal>8118</literal>.
587 <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
588 any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
589 browser from using these protocols.
595 Flush your browser's disk and memory caches, to remove any cached ad images.
596 If using <application>Privoxy</application> to manage
597 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
598 you should remove any currently stored cookies too.
604 A default installation should provide a reasonable starting point for
605 most. There will undoubtedly be occasions where you will want to adjust the
606 configuration, but that can be dealt with as the need arises. Little
607 to no initial configuration is required in most cases, you may want
609 <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
610 Be sure to read the warnings first.
613 See the <link linkend="configuration">Configuration section</link> for more
614 configuration options, and how to customize your installation.
615 You might also want to look at the <link
616 linkend="quickstart-ad-blocking">next section</link> for a quick
617 introduction to how <application>Privoxy</application> blocks ads and
624 If you experience ads that slip through, innocent images that are
625 blocked, or otherwise feel the need to fine-tune
626 <application>Privoxy's</application> behavior, take a look at the <link
627 linkend="actions-file">actions files</link>. As a quick start, you might
628 find the <link linkend="act-examples">richly commented examples</link>
629 helpful. You can also view and edit the actions files through the <ulink
630 url="http://config.privoxy.org">web-based user interface</ulink>. The
631 Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
632 Action</link></quote> has hints on how to understand and debug actions that
633 <quote>misbehave</quote>.
638 Did anyone test these lately?
642 For easy access to &my-app;'s most important controls, drag the provided
643 <link linkend="bookmarklets">Bookmarklets</link> into your browser's
651 Please see the section <link linkend="contact">Contacting the
652 Developers</link> on how to report bugs, problems with websites or to get
659 Now enjoy surfing with enhanced control, comfort and privacy!
667 <!-- ~~~~~ New section ~~~~~ -->
669 <sect2 id="quickstart-ad-blocking">
670 <title>Quickstart to Ad Blocking</title>
672 NOTE: This section is deliberately redundant for those that don't
673 want to read the whole thing (which is getting lengthy).
676 Ad blocking is but one of <application>Privoxy's</application>
677 array of features. Many of these features are for the technically minded advanced
678 user. But, ad and banner blocking is surely common ground for everybody.
681 This section will provide a quick summary of ad blocking so
682 you can get up to speed quickly without having to read the more extensive
683 information provided below, though this is highly recommended.
686 First a bit of a warning ... blocking ads is much like blocking SPAM: the
687 more aggressive you are about it, the more likely you are to block
688 things that were not intended. And the more likely that some things
689 may not work as intended. So there is a trade off here. If you want
690 extreme ad free browsing, be prepared to deal with more
691 <quote>problem</quote> sites, and to spend more time adjusting the
692 configuration to solve these unintended consequences. In short, there is
693 not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
694 the easy way and settle for <emphasis>most</emphasis> ads blocked with the
695 default configuration, or jump in and tweak it for your personal surfing
696 habits and preferences.
699 Secondly, a brief explanation of <application>Privoxy's </application>
700 <quote>actions</quote>. <quote>Actions</quote> in this context, are
701 the directives we use to tell <application>Privoxy</application> to perform
702 some task relating to HTTP transactions (i.e. web browsing). We tell
703 <application>Privoxy</application> to take some <quote>action</quote>. Each
704 action has a unique name and function. While there are many potential
705 <application>actions</application> in <application>Privoxy's</application>
706 arsenal, only a few are used for ad blocking. <link
707 linkend="actions">Actions</link>, and <link linkend="actions-file">action
708 configuration files</link>, are explained in depth below.
711 Actions are specified in <application>Privoxy's</application> configuration,
712 followed by one or more URLs to which the action should apply. URLs
713 can actually be URL type <link linkend="af-patterns">patterns</link> that use
714 wildcards so they can apply potentially to a range of similar URLs. The
715 actions, together with the URL patterns are called a section.
718 When you connect to a website, the full URL will either match one or more
719 of the sections as defined in <application>Privoxy's</application> configuration,
720 or not. If so, then <application>Privoxy</application> will perform the
721 respective actions. If not, then nothing special happens. Furthermore, web
722 pages may contain embedded, secondary URLs that your web browser will
723 use to load additional components of the page, as it parses the
724 original page's HTML content. An ad image for instance, is just an URL
725 embedded in the page somewhere. The image itself may be on the same server,
726 or a server somewhere else on the Internet. Complex web pages will have many
727 such embedded URLs. &my-app; can deal with each URL individually, so, for
728 instance, the main page text is not touched, but images from such-and-such
733 The most important actions for basic ad blocking are: <literal><link
734 linkend="block">block</link></literal>, <literal><link
735 linkend="handle-as-image">handle-as-image</link></literal>,
737 linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
738 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
746 <literal><link linkend="block">block</link></literal> - this is perhaps
747 the single most used action, and is particularly important for ad blocking.
748 This action stops any contact between your browser and any URL patterns
749 that match this action's configuration. It can be used for blocking ads,
750 but also anything that is determined to be unwanted. By itself, it simply
751 stops any communication with the remote server and sends
752 <application>Privoxy</application>'s own built-in BLOCKED page instead to
753 let you now what has happened (with some exceptions, see below).
759 <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
760 tells <application>Privoxy</application> to treat this URL as an image.
761 <application>Privoxy</application>'s default configuration already does this
762 for all common image types (e.g. GIF), but there are many situations where this
763 is not so easy to determine. So we'll force it in these cases. This is particularly
764 important for ad blocking, since only if we know that it's an image of
765 some kind, can we replace it with an image of our choosing, instead of the
766 <application>Privoxy</application> BLOCKED page (which would only result in
767 a <quote>broken image</quote> icon). There are some limitations to this
768 though. For instance, you can't just brute-force an image substitution for
769 an entire HTML page in most situations.
775 <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
776 sends an empty document instead of <application>Privoxy's</application>
777 normal BLOCKED HTML page. This is useful for file types that are neither
778 HTML nor images, such as blocking JavaScript files.
785 linkend="set-image-blocker">set-image-blocker</link></literal> - tells
786 <application>Privoxy</application> what to display in place of an ad image that
787 has hit a block rule. For this to come into play, the URL must match a
788 <literal><link linkend="block">block</link></literal> action somewhere in the
789 configuration, <emphasis>and</emphasis>, it must also match an
790 <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
793 The configuration options on what to display instead of the ad are:
797 <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
798 replacement is obvious. This is the default.
803 <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
804 This is the so-called <quote>invisible</quote> configuration option.
809 <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
810 of the user's choosing (advanced usage).
819 Advanced users will eventually want to explore &my-app;
820 <literal><link linkend="filter">filters</link></literal> as well. Filters
821 are very different from <literal><link
822 linkend="block">blocks</link></literal>.
823 A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
824 are a way of filtering or modifying what is actually on the page. An example
825 filter usage: a text replacement of <quote>no-no</quote> for
826 <quote>nasty-word</quote>. That is a very simple example. This process can be
827 used for ad blocking, but it is more in the realm of advanced usage and has
828 some pitfalls to be wary off.
832 The quickest way to adjust any of these settings is with your browser through
833 the special <application>Privoxy</application> editor at <ulink
834 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
835 (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
836 is an internal page, and does not require Internet access.
840 Note that as of <application>Privoxy</application> 3.0.7 beta the
841 action editor is disabled by default. Check the
842 <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
843 section in the configuration file</ulink> to learn why and in which
844 cases it's safe to enable again.
848 If you decided to enable the action editor, select the appropriate
849 <quote>actions</quote> file, and click
850 <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
851 local preferences in <filename>user.action</filename> since this is not
852 meant to be overwritten during upgrades, and will over-ride the settings in
853 other files. Here you can insert new <quote>actions</quote>, and URLs for ad
854 blocking or other purposes, and make other adjustments to the configuration.
855 <application>Privoxy</application> will detect these changes automatically.
859 A quick and simple step by step example:
867 Right click on the ad image to be blocked, then select
868 <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
876 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
881 Find <filename>user.action</filename> in the top section, and click
882 on <quote><guibutton>Edit</guibutton></quote>:
885 <!-- image of editor and actions files selections -->
887 <figure pgwide="0" float="0"><title>Actions Files in Use</title>
890 <imagedata fileref="files-in-use.jpg" format="jpg">
893 <phrase>[ Screenshot of Actions Files in Use ]</phrase>
902 You should have a section with only
903 <literal><link linkend="block">block</link></literal> listed under
904 <quote>Actions:</quote>.
905 If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
906 button, and in the new section that just appeared, click the
907 <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
908 This will bring up a list of all actions. Find
909 <literal><link linkend="block">block</link></literal> near the top, and click
910 in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
916 Now, in the <literal><link linkend="block">block</link></literal> actions section,
917 click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
918 browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
919 Remove the <literal>http://</literal> at the beginning of the URL. Then, click
920 <quote><guibutton>Submit</guibutton></quote> (or
921 <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
926 Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
927 (or flush all browser caches). The image should be gone now.
935 This is a very crude and simple example. There might be good reasons to use a
936 wildcard pattern match to include potentially similar images from the same
937 site. For a more extensive explanation of <quote>patterns</quote>, and
938 the entire actions concept, see <link linkend="actions-file">the Actions
943 For advanced users who want to hand edit their config files, you might want
944 to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
945 The ideas explained therein also apply to the web-based editor.
948 There are also various
949 <link linkend="filter">filters</link> that can be used for ad blocking
950 (filters are a special subset of actions). These
951 fall into the <quote>advanced</quote> usage category, and are explained in
952 depth in later sections.
959 <!-- ~ End section ~ -->
962 <!-- ~~~~~ New section ~~~~~ -->
964 <title>Starting Privoxy</title>
966 Before launching <application>Privoxy</application> for the first time, you
967 will want to configure your browser(s) to use
968 <application>Privoxy</application> as a HTTP and HTTPS (SSL)
969 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
970 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
971 used port 8000). This is the one configuration step <emphasis>that must be done
975 Please note that <application>Privoxy</application> can only proxy HTTP and
976 HTTPS traffic. It will not work with FTP or other protocols.
979 <!-- image of Mozilla Proxy configuration -->
981 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
982 Mozilla/Netscape HTTP and HTTPS (SSL) Settings</title>
985 <imagedata fileref="proxy_setup.jpg" format="jpg">
988 <phrase>[ Screenshot of Mozilla Proxy Configuration ]</phrase>
996 With <application>Firefox</application>, this is typically set under:
1000 <guibutton>Tools</guibutton> -> <guibutton>Options</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Network</guibutton> -><guibutton>Connection</guibutton> -> <guibutton>Settings</guibutton>
1005 Or optionally on some platforms:
1009 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
1015 With <application>Netscape</application> (and
1016 <application>Mozilla</application>), this can be set under:
1021 <!-- Mix ascii and gui art, something for everybody -->
1022 <!-- spacing on this is tricky -->
1023 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
1028 For <application>Internet Explorer v.5-7</application>:
1032 <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
1036 Then, check <quote>Use Proxy</quote> and fill in the appropriate info
1037 (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
1038 proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
1039 checkboxes like <quote>Use the same proxy server for all protocols</quote> is
1040 <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
1043 <!-- image of IE Proxy configuration -->
1045 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1046 Internet Explorer HTTP and HTTPS (Secure) Settings</title>
1049 <imagedata fileref="proxy2.jpg" format="jpg">
1052 <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
1060 After doing this, flush your browser's disk and memory caches to force a
1061 re-reading of all pages and to get rid of any ads that may be cached. Remove
1062 any <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1063 if you want <application>Privoxy</application> to manage that. You are now
1064 ready to start enjoying the benefits of using
1065 <application>Privoxy</application>!
1069 <application>Privoxy</application> itself is typically started by specifying the
1070 main configuration file to be used on the command line. If no configuration
1071 file is specified on the command line, <application>Privoxy</application>
1072 will look for a file named <filename>config</filename> in the current
1073 directory. Except on Win32 where it will try <filename>config.txt</filename>.
1076 <sect2 id="start-debian">
1077 <title>Debian</title>
1079 We use a script. Note that Debian typically starts &my-app; upon booting per
1080 default. It will use the file
1081 <filename>/etc/privoxy/config</filename> as its main configuration
1086 # /etc/init.d/privoxy start
1091 <sect2 id="start-windows">
1092 <title>Windows</title>
1094 Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
1095 specified on the command line, <application>Privoxy</application> will look
1096 for a file named <filename>config.txt</filename>. Note that Windows will
1097 automatically start &my-app; when the system starts if you chose that option
1101 <application>Privoxy</application> can run with full Windows service functionality.
1102 On Windows only, the &my-app; program has two new command line arguments
1103 to install and uninstall &my-app; as a service. See the
1104 <link linkend="installation-pack-win">Windows Installation
1105 instructions</link> for details.
1109 <sect2 id="start-unices">
1110 <title>Solaris, NetBSD, FreeBSD, HP-UX and others</title>
1112 Example Unix startup command:
1116 # /usr/sbin/privoxy /etc/privoxy/config
1121 <sect2 id="start-os2">
1124 During installation, <application>Privoxy</application> is configured to
1125 start automatically when the system restarts. You can start it manually by
1126 double-clicking on the <application>Privoxy</application> icon in the
1127 <application>Privoxy</application> folder.
1131 <sect2 id="start-macosx">
1132 <title>Mac OS X</title>
1134 After downloading the privoxy software, unzip the downloaded file by
1135 double-clicking on the zip file icon. Then, double-click on the
1136 installer package icon and follow the installation process.
1139 The privoxy service will automatically start after a successful
1140 installation. In addition, the privoxy service will automatically
1141 start every time your computer starts up.
1144 To prevent the privoxy service from automatically starting when your
1145 computer starts up, remove or rename the folder named
1146 /Library/StartupItems/Privoxy.
1149 A simple application named Privoxy Utility has been created which
1150 enables administrators to easily start and stop the privoxy service.
1153 In addition, the Privoxy Utility presents a simple way for
1154 administrators to edit the various privoxy config files. A method
1155 to uninstall the software is also available.
1158 An administrator username and password must be supplied in order for
1159 the Privoxy Utility to perform any of the tasks.
1167 See the section <link linkend="cmdoptions">Command line options</link> for
1171 must find a better place for this paragraph
1174 The included default configuration files should give a reasonable starting
1175 point. Most of the per site configuration is done in the
1176 <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
1177 where various cookie actions are defined, ad and banner blocking, and other
1178 aspects of <application>Privoxy</application> configuration. There are several
1179 such files included, with varying levels of aggressiveness.
1183 You will probably want to keep an eye out for sites for which you may prefer
1184 persistent cookies, and add these to your actions configuration as needed. By
1185 default, most of these will be accepted only during the current browser
1186 session (aka <quote>session cookies</quote>), unless you add them to the
1187 configuration. If you want the browser to handle this instead, you will need
1188 to edit <filename>user.action</filename> (or through the web based interface)
1189 and disable this feature. If you use more than one browser, it would make
1190 more sense to let <application>Privoxy</application> handle this. In which
1191 case, the browser(s) should be set to accept all cookies.
1195 Another feature where you will probably want to define exceptions for trusted
1196 sites is the popup-killing (through <ulink
1197 url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
1198 because your favorite shopping, banking, or leisure site may need
1199 popups (explained below).
1203 <application>Privoxy</application> does not support all of the optional HTTP/1.1
1204 features yet. In the unlikely event that you experience inexplicable problems
1205 with browsers that use HTTP/1.1 per default
1206 (like <application>Mozilla</application> or recent versions of I.E.), you might
1207 try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
1208 Preferences -> Debug -> Networking</literal>.
1209 Alternatively, set the <quote>+downgrade-http-version</quote> config option in
1210 <filename>default.action</filename> which will downgrade your browser's HTTP
1211 requests from HTTP/1.1 to HTTP/1.0 before processing them.
1215 After running <application>Privoxy</application> for a while, you can
1216 start to fine tune the configuration to suit your personal, or site,
1217 preferences and requirements. There are many, many aspects that can
1218 be customized. <quote>Actions</quote>
1219 can be adjusted by pointing your browser to
1220 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1221 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1222 and then follow the link to <quote>View & Change the Current Configuration</quote>.
1223 (This is an internal page and does not require Internet access.)
1227 In fact, various aspects of <application>Privoxy</application>
1228 configuration can be viewed from this page, including
1229 current configuration parameters, source code version numbers,
1230 the browser's request headers, and <quote>actions</quote> that apply
1231 to a given URL. In addition to the actions file
1232 editor mentioned above, <application>Privoxy</application> can also
1233 be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
1237 If you encounter problems, try loading the page without
1238 <application>Privoxy</application>. If that helps, enter the URL where
1239 you have the problems into <ulink url="http://p.p/show-url-info">the browser
1240 based rule tracing utility</ulink>. See which rules apply and why, and
1241 then try turning them off for that site one after the other, until the problem
1242 is gone. When you have found the culprit, you might want to turn the rest on
1247 If the above paragraph sounds gibberish to you, you might want to <link
1248 linkend="actions-file">read more about the actions concept</link>
1249 or even dive deep into the <link linkend="actionsanat">Appendix
1254 If you can't get rid of the problem at all, think you've found a bug in
1255 Privoxy, want to propose a new feature or smarter rules, please see the
1256 section <link linkend="contact"><quote>Contacting the
1257 Developers</quote></link> below.
1262 <!-- ~~~~~ New section ~~~~~ -->
1263 <sect2 id="cmdoptions">
1264 <title>Command Line Options</title>
1266 <application>Privoxy</application> may be invoked with the following
1267 command-line options:
1275 <emphasis>--config-test</emphasis>
1278 Exit after loading the configuration files before binding to
1279 the listen address. The exit code signals whether or not the
1280 configuration files have been successfully loaded.
1283 If the exit code is 1, at least one of the configuration files
1284 is invalid, if it is 0, all the configuration files have been
1285 successfully loaded (but may still contain errors that can
1286 currently only be detected at run time).
1289 This option doesn't affect the log setting, combination with
1290 <emphasis>--no-daemon</emphasis> is recommended if a configured
1291 log file shouldn't be used.
1296 <emphasis>--version</emphasis>
1299 Print version info and exit. Unix only.
1304 <emphasis>--help</emphasis>
1307 Print short usage info and exit. Unix only.
1312 <emphasis>--no-daemon</emphasis>
1315 Don't become a daemon, i.e. don't fork and become process group
1316 leader, and don't detach from controlling tty. Unix only.
1321 <emphasis>--pidfile FILE</emphasis>
1324 On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
1325 <emphasis>FILE</emphasis> on exit. Failure to create or delete the
1326 <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
1327 option is given, no PID file will be used. Unix only.
1332 <emphasis>--user USER[.GROUP]</emphasis>
1335 After (optionally) writing the PID file, assume the user ID of
1336 <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
1337 privileges are not sufficient to do so. Unix only.
1342 <emphasis>--chroot</emphasis>
1345 Before changing to the user ID given in the <emphasis>--user</emphasis> option,
1346 chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
1347 process that the directory tree starts there. If set up carefully, this can limit
1348 the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
1354 <emphasis>--pre-chroot-nslookup hostname</emphasis>
1357 Specifies a hostname to look up before doing a chroot. On some systems, initializing the
1358 resolver library involves reading config files from /etc and/or loading additional shared
1359 libraries from /lib. On these systems, doing a hostname lookup before the chroot reduces
1360 the number of files that must be copied into the chroot tree.
1363 For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
1364 your local name server (listed in /etc/resolv.conf) can resolve without recursion
1365 (that is, without having to ask any other name servers). The hostname need not exist,
1366 but if it doesn't, an error message (which can be ignored) will be output.
1372 <emphasis>configfile</emphasis>
1375 If no <emphasis>configfile</emphasis> is included on the command line,
1376 <application>Privoxy</application> will look for a file named
1377 <quote>config</quote> in the current directory (except on Win32
1378 where it will look for <quote>config.txt</quote> instead). Specify
1379 full path to avoid confusion. If no config file is found,
1380 <application>Privoxy</application> will fail to start.
1388 On <application>MS Windows</application> only there are two additional
1389 command-line options to allow <application>Privoxy</application> to install and
1390 run as a <emphasis>service</emphasis>. See the
1391 <link linkend="installation-pack-win">Window Installation section</link>
1399 <!-- ~ End section ~ -->
1402 <!-- ~~~~~ New section ~~~~~ -->
1403 <sect1 id="configuration"><title>Privoxy Configuration</title>
1405 All <application>Privoxy</application> configuration is stored
1406 in text files. These files can be edited with a text editor.
1407 Many important aspects of <application>Privoxy</application> can
1408 also be controlled easily with a web browser.
1412 <!-- ~~~~~ New section ~~~~~ -->
1415 <title>Controlling Privoxy with Your Web Browser</title>
1417 <application>Privoxy</application>'s user interface can be reached through the special
1418 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1419 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1420 which is a built-in page and works without Internet access.
1421 You will see the following section:
1425 <!-- Needs to be put in a table and colorized -->
1428 <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
1432 ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
1435 ▪ <ulink url="http://config.privoxy.org/show-version">View the source code version numbers</ulink>
1438 ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
1441 ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
1444 ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
1447 ▪ <ulink
1448 url="http://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
1456 This should be self-explanatory. Note the first item leads to an editor for the
1457 <link linkend="actions-file">actions files</link>, which is where the ad, banner,
1458 cookie, and URL blocking magic is configured as well as other advanced features of
1459 <application>Privoxy</application>. This is an easy way to adjust various
1460 aspects of <application>Privoxy</application> configuration. The actions
1461 file, and other configuration files, are explained in detail below.
1465 <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
1466 have problems with your current actions and filters. You can in fact use
1467 it as a test to see whether it is <application>Privoxy</application>
1468 causing the problem or not. <application>Privoxy</application> continues
1469 to run as a proxy in this case, but all manipulation is disabled, i.e.
1470 <application>Privoxy</application> acts like a normal forwarding proxy. There
1471 is even a toggle <link linkend="bookmarklets">Bookmarklet</link> offered, so
1472 that you can toggle <application>Privoxy</application> with one click from
1477 Note that several of the features described above are disabled by default
1478 in <application>Privoxy</application> 3.0.7 beta and later.
1480 <ulink url="config.html">configuration file</ulink> to learn why
1481 and in which cases it's safe to enable them again.
1486 <!-- ~ End section ~ -->
1491 <!-- ~~~~~ New section ~~~~~ -->
1493 <sect2 id="confoverview">
1494 <title>Configuration Files Overview</title>
1496 For Unix, *BSD and Linux, all configuration files are located in
1497 <filename>/etc/privoxy/</filename> by default. For MS Windows, OS/2, and
1498 AmigaOS these are all in the same directory as the
1499 <application>Privoxy</application> executable. <![%p-not-stable;[ The name
1500 and number of configuration files has changed from previous versions, and is
1501 subject to change as development progresses.]]>
1505 The installed defaults provide a reasonable starting point, though
1506 some settings may be aggressive by some standards. For the time being, the
1507 principle configuration files are:
1515 The <link linkend="config">main configuration file</link> is named <filename>config</filename>
1516 on Linux, Unix, BSD, OS/2, and AmigaOS and <filename>config.txt</filename>
1517 on Windows. This is a required file.
1523 <filename>match-all.action</filename> is used to define which <quote>actions</quote>
1524 relating to banner-blocking, images, pop-ups, content modification, cookie handling
1525 etc should be applied by default. It should be the first actions file loaded.
1528 <filename>default.action</filename> defines many exceptions (both positive and negative)
1529 from the default set of actions that's configured in <filename>match-all.action</filename>.
1530 It should be the second actions file loaded and shouldn't be edited by the user.
1533 Multiple actions files may be defined in <filename>config</filename>. These
1534 are processed in the order they are defined. Local customizations and locally
1535 preferred exceptions to the default policies as defined in
1536 <filename>match-all.action</filename> (which you will most probably want
1537 to define sooner or later) are best applied in <filename>user.action</filename>,
1538 where you can preserve them across upgrades. The file isn't installed by all
1539 installers, but you can easily create it yourself with a text editor.
1542 There is also a web based editor that can be accessed from
1544 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1546 url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
1547 various actions files.
1553 <quote>Filter files</quote> (the <link linkend="filter-file">filter
1554 file</link>) can be used to re-write the raw page content, including
1555 viewable text as well as embedded HTML and JavaScript, and whatever else
1556 lurks on any given web page. The filtering jobs are only pre-defined here;
1557 whether to apply them or not is up to the actions files.
1558 <filename>default.filter</filename> includes various filters made
1559 available for use by the developers. Some are much more intrusive than
1560 others, and all should be used with caution. You may define additional
1561 filter files in <filename>config</filename> as you can with
1562 actions files. We suggest <filename>user.filter</filename> for any
1563 locally defined filters or customizations.
1571 The syntax of the configuration and filter files may change between different
1572 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
1573 <!-- Add link to documentation-->
1577 All files use the <quote><literal>#</literal></quote> character to denote a
1578 comment (the rest of the line will be ignored) and understand line continuation
1579 through placing a backslash ("<literal>\</literal>") as the very last character
1580 in a line. If the <literal>#</literal> is preceded by a backslash, it looses
1581 its special function. Placing a <literal>#</literal> in front of an otherwise
1582 valid configuration line to prevent it from being interpreted is called "commenting
1583 out" that line. Blank lines are ignored.
1587 The actions files and filter files
1588 can use Perl style <link linkend="regex">regular expressions</link> for
1589 maximum flexibility.
1593 After making any changes, there is no need to restart
1594 <application>Privoxy</application> in order for the changes to take
1595 effect. <application>Privoxy</application> detects such changes
1596 automatically. Note, however, that it may take one or two additional
1597 requests for the change to take effect. When changing the listening address
1598 of <application>Privoxy</application>, these <quote>wake up</quote> requests
1599 must obviously be sent to the <emphasis>old</emphasis> listening address.
1604 While under development, the configuration content is subject to change.
1605 The below documentation may not be accurate by the time you read this.
1606 Also, what constitutes a <quote>default</quote> setting, may change, so
1607 please check all your configuration files on important issues.
1613 <!-- ~ End section ~ -->
1616 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1618 <!-- **************************************************** -->
1619 <!-- Include config.sgml here -->
1620 <!-- This is where the entire config file is detailed. -->
1622 <!-- end include -->
1625 <!-- ~ End section ~ -->
1629 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1631 <sect1 id="actions-file"><title>Actions Files</title>
1635 XXX: similar descriptions are in the Configuration Files sections.
1636 We should only describe them at one place.
1639 The actions files are used to define what <emphasis>actions</emphasis>
1640 <application>Privoxy</application> takes for which URLs, and thus determines
1641 how ad images, cookies and various other aspects of HTTP content and
1642 transactions are handled, and on which sites (or even parts thereof).
1643 There are a number of such actions, with a wide range of functionality.
1644 Each action does something a little different.
1645 These actions give us a veritable arsenal of tools with which to exert
1646 our control, preferences and independence. Actions can be combined so that
1647 their effects are aggregated when applied against a given set of URLs.
1651 are three action files included with <application>Privoxy</application> with
1658 <filename>match-all.action</filename> - is used to define which
1659 <quote>actions</quote> relating to banner-blocking, images, pop-ups,
1660 content modification, cookie handling etc should be applied by default.
1661 It should be the first actions file loaded
1666 <filename>default.action</filename> - defines many exceptions (both
1667 positive and negative) from the default set of actions that's configured
1668 in <filename>match-all.action</filename>. It is a set of rules that should
1669 work reasonably well as-is for most users. This file is only supposed to
1670 be edited by the developers. It should be the second actions file loaded.
1675 <filename>user.action</filename> - is intended to be for local site
1676 preferences and exceptions. As an example, if your ISP or your bank
1677 has specific requirements, and need special handling, this kind of
1678 thing should go here. This file will not be upgraded.
1683 <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
1686 These have increasing levels of aggressiveness <emphasis>and have no
1687 influence on your browsing unless you select them explicitly in the
1688 editor</emphasis>. A default installation should be pre-set to
1689 <literal>Cautious</literal>. New users should try this for a while before
1690 adjusting the settings to more aggressive levels. The more aggressive
1691 the settings, then the more likelihood there is of problems such as sites
1692 not working as they should.
1695 The <guibutton>Edit</guibutton> button allows you to turn each
1696 action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
1697 button changes the actions list to low/safe settings which will activate
1698 ad blocking and a minimal set of &my-app;'s features, and subsequently
1699 there will be less of a chance for accidental problems. The
1700 <guibutton>Medium</guibutton> button sets the list to a medium level of
1701 other features and a low level set of privacy features. The
1702 <guibutton>Advanced</guibutton> button sets the list to a high level of
1703 ad blocking and medium level of privacy. See the chart below. The latter
1704 three buttons over-ride any changes via with the
1705 <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
1706 lower sections of this internal page.
1709 While the actions file editor allows to enable these settings in all
1710 actions files, they are only supposed to be enabled in the first one
1711 to make sure you don't unintentionally overrule earlier rules.
1714 The default profiles, and their associated actions, as pre-defined in
1715 <filename>default.action</filename> are:
1718 <table frame=all><title>Default Configurations</title>
1719 <tgroup cols=4 align=left colsep=1 rowsep=1>
1720 <colspec colname=c1>
1721 <colspec colname=c2>
1722 <colspec colname=c3>
1723 <colspec colname=c4>
1726 <entry>Feature</entry>
1727 <entry>Cautious</entry>
1728 <entry>Medium</entry>
1729 <entry>Advanced</entry>
1734 <!-- <entry>f1</entry> -->
1735 <!-- <entry>f2</entry> -->
1736 <!-- <entry>f3</entry> -->
1737 <!-- <entry>f4</entry> -->
1743 <entry>Ad-blocking Aggressiveness</entry>
1744 <entry>medium</entry>
1750 <entry>Ad-filtering by size</entry>
1757 <entry>Ad-filtering by link</entry>
1763 <entry>Pop-up killing</entry>
1764 <entry>blocks only</entry>
1765 <entry>blocks only</entry>
1766 <entry>blocks only</entry>
1770 <entry>Privacy Features</entry>
1772 <entry>medium</entry>
1773 <entry>medium/high</entry>
1777 <entry>Cookie handling</entry>
1779 <entry>session-only</entry>
1784 <entry>Referer forging</entry>
1791 <entry>GIF de-animation</entry>
1798 <entry>Fast redirects</entry>
1805 <entry>HTML taming</entry>
1812 <entry>JavaScript taming</entry>
1819 <entry>Web-bug killing</entry>
1826 <entry>Image tag reordering</entry>
1842 The list of actions files to be used are defined in the main configuration
1843 file, and are processed in the order they are defined (e.g.
1844 <filename>default.action</filename> is typically processed before
1845 <filename>user.action</filename>). The content of these can all be viewed and
1847 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1848 The over-riding principle when applying actions, is that the last action that
1849 matches a given URL wins. The broadest, most general rules go first
1850 (defined in <filename>default.action</filename>),
1851 followed by any exceptions (typically also in
1852 <filename>default.action</filename>), which are then followed lastly by any
1853 local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
1854 Generally, <filename>user.action</filename> has the last word.
1858 An actions file typically has multiple sections. If you want to use
1859 <quote>aliases</quote> in an actions file, you have to place the (optional)
1860 <link linkend="aliases">alias section</link> at the top of that file.
1861 Then comes the default set of rules which will apply universally to all
1862 sites and pages (be <emphasis>very careful</emphasis> with using such a
1863 universal set in <filename>user.action</filename> or any other actions file after
1864 <filename>default.action</filename>, because it will override the result
1865 from consulting any previous file). And then below that,
1866 exceptions to the defined universal policies. You can regard
1867 <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
1868 with the advantage that it is a separate file, which makes preserving your
1869 personal settings across <application>Privoxy</application> upgrades easier.
1873 Actions can be used to block anything you want, including ads, banners, or
1874 just some obnoxious URL whose content you would rather not see. Cookies can be accepted
1875 or rejected, or accepted only during the current browser session (i.e. not
1876 written to disk), content can be modified, some JavaScripts tamed, user-tracking
1877 fooled, and much more. See below for a <link linkend="actions">complete list
1881 <!-- ~~~~~ New section ~~~~~ -->
1883 <title>Finding the Right Mix</title>
1885 Note that some <link linkend="actions">actions</link>, like cookie suppression
1886 or script disabling, may render some sites unusable that rely on these
1887 techniques to work properly. Finding the right mix of actions is not always easy and
1888 certainly a matter of personal taste. And, things can always change, requiring
1889 refinements in the configuration. In general, it can be said that the more
1890 <quote>aggressive</quote> your default settings (in the top section of the
1891 actions file) are, the more exceptions for <quote>trusted</quote> sites you
1892 will have to make later. If, for example, you want to crunch all cookies per
1893 default, you'll have to make exceptions from that rule for sites that you
1894 regularly use and that require cookies for actually useful purposes, like maybe
1895 your bank, favorite shop, or newspaper.
1899 We have tried to provide you with reasonable rules to start from in the
1900 distribution actions files. But there is no general rule of thumb on these
1901 things. There just are too many variables, and sites are constantly changing.
1902 Sooner or later you will want to change the rules (and read this chapter again :).
1906 <!-- ~~~~~ New section ~~~~~ -->
1908 <title>How to Edit</title>
1910 The easiest way to edit the actions files is with a browser by
1911 using our browser-based editor, which can be reached from <ulink
1912 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1913 Note: the config file option <link
1914 linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
1915 this to work. The editor allows both fine-grained control over every single
1916 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
1917 like <quote>Cautious</quote>, <quote>Medium</quote> or
1918 <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
1919 aggressive, and will be more likely to cause problems for some sites.
1920 Experienced users only!
1924 If you prefer plain text editing to GUIs, you can of course also directly edit the
1925 the actions files with your favorite text editor. Look at
1926 <filename>default.action</filename> which is richly commented with many
1932 <sect2 id="actions-apply">
1933 <title>How Actions are Applied to Requests</title>
1935 Actions files are divided into sections. There are special sections,
1936 like the <quote><link linkend="aliases">alias</link></quote> sections which will
1937 be discussed later. For now let's concentrate on regular sections: They have a
1938 heading line (often split up to multiple lines for readability) which consist
1939 of a list of actions, separated by whitespace and enclosed in curly braces.
1940 Below that, there is a list of URL and tag patterns, each on a separate line.
1944 To determine which actions apply to a request, the URL of the request is
1945 compared to all URL patterns in each <quote>action file</quote>.
1946 Every time it matches, the list of applicable actions for the request is
1947 incrementally updated, using the heading of the section in which the
1948 pattern is located. The same is done again for tags and tag patterns later on.
1952 If multiple applying sections set the same action differently,
1953 the last match wins. If not, the effects are aggregated.
1954 E.g. a URL might match a regular section with a heading line of <literal>{
1955 +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
1956 then later another one with just <literal>{
1957 +<link linkend="block">block</link> }</literal>, resulting
1958 in <emphasis>both</emphasis> actions to apply. And there may well be
1959 cases where you will want to combine actions together. Such a section then
1965 { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
1966 # Block these as if they were images. Send no block page.
1968 media.example.com/.*banners
1969 .example.com/images/ads/</screen>
1973 You can trace this process for URL patterns and any given URL by visiting <ulink
1974 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
1978 Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
1979 Troubleshooting: Anatomy of an Action</link> section.
1983 <!-- ~~~~~ New section ~~~~~ -->
1984 <sect2 id="af-patterns">
1985 <title>Patterns</title>
1987 As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
1988 to determine what <emphasis>actions</emphasis> might apply to which sites and
1989 pages your browser attempts to access. These <quote>patterns</quote> use wild
1990 card type <emphasis>pattern</emphasis> matching to achieve a high degree of
1991 flexibility. This allows one expression to be expanded and potentially match
1992 against many similar patterns.
1996 Generally, an URL pattern has the form
1997 <literal><domain><port>/<path></literal>, where the
1998 <literal><domain></literal>, the <literal><port></literal>
1999 and the <literal><path></literal> are optional. (This is why the special
2000 <literal>/</literal> pattern matches all URLs). Note that the protocol
2001 portion of the URL pattern (e.g. <literal>http://</literal>) should
2002 <emphasis>not</emphasis> be included in the pattern. This is assumed already!
2005 The pattern matching syntax is different for the domain and path parts of
2006 the URL. The domain part uses a simple globbing type matching technique,
2007 while the path part uses more flexible
2008 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2009 Expressions</quote></ulink> (POSIX 1003.2).
2012 The port part of a pattern is a decimal port number preceded by a colon
2013 (<literal>:</literal>). If the domain part contains a numerical IPv6 address,
2014 it has to be put into angle brackets
2015 (<literal><</literal>, <literal>></literal>).
2020 <term><literal>www.example.com/</literal></term>
2023 is a domain-only pattern and will match any request to <literal>www.example.com</literal>,
2024 regardless of which document on that server is requested. So ALL pages in
2025 this domain would be covered by the scope of this action. Note that a
2026 simple <literal>example.com</literal> is different and would NOT match.
2031 <term><literal>www.example.com</literal></term>
2034 means exactly the same. For domain-only patterns, the trailing <literal>/</literal> may
2040 <term><literal>www.example.com/index.html</literal></term>
2043 matches all the documents on <literal>www.example.com</literal>
2044 whose name starts with <literal>/index.html</literal>.
2049 <term><literal>www.example.com/index.html$</literal></term>
2052 matches only the single document <literal>/index.html</literal>
2053 on <literal>www.example.com</literal>.
2058 <term><literal>/index.html$</literal></term>
2061 matches the document <literal>/index.html</literal>, regardless of the domain,
2062 i.e. on <emphasis>any</emphasis> web server anywhere.
2067 <term><literal>/</literal></term>
2070 Matches any URL because there's no requirement for either the
2071 domain or the path to match anything.
2076 <term><literal>:8000/</literal></term>
2079 Matches any URL pointing to TCP port 8000.
2084 <term><literal><2001:db8::1>/</literal></term>
2087 Matches any URL with the host address <literal>2001:db8::1</literal>.
2088 (Note that the real URL uses plain brackets, not angle brackets.)
2093 <term><literal>index.html</literal></term>
2096 matches nothing, since it would be interpreted as a domain name and
2097 there is no top-level domain called <literal>.html</literal>. So its
2105 <!-- ~~~~~ New section ~~~~~ -->
2106 <sect3><title>The Domain Pattern</title>
2109 The matching of the domain part offers some flexible options: if the
2110 domain starts or ends with a dot, it becomes unanchored at that end.
2116 <term><literal>.example.com</literal></term>
2119 matches any domain with first-level domain <literal>com</literal>
2120 and second-level domain <literal>example</literal>.
2121 For example <literal>www.example.com</literal>,
2122 <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
2123 Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
2128 <term><literal>www.</literal></term>
2131 matches any domain that <emphasis>STARTS</emphasis> with
2132 <literal>www.</literal> (It also matches the domain
2133 <literal>www</literal> but most of the time that doesn't matter.)
2138 <term><literal>.example.</literal></term>
2141 matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
2142 And, by the way, also included would be any files or documents that exist
2143 within that domain since no path limitations are specified. (Correctly
2144 speaking: It matches any FQDN that contains <literal>example</literal> as
2145 a domain.) This might be <literal>www.example.com</literal>,
2146 <literal>news.example.de</literal>, or
2147 <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
2155 Additionally, there are wild-cards that you can use in the domain names
2156 themselves. These work similarly to shell globbing type wild-cards:
2157 <quote>*</quote> represents zero or more arbitrary characters (this is
2159 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2160 Expression</quote></ulink> based syntax of <quote>.*</quote>),
2161 <quote>?</quote> represents any single character (this is equivalent to the
2162 regular expression syntax of a simple <quote>.</quote>), and you can define
2163 <quote>character classes</quote> in square brackets which is similar to
2164 the same regular expression technique. All of this can be freely mixed:
2169 <term><literal>ad*.example.com</literal></term>
2172 matches <quote>adserver.example.com</quote>,
2173 <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
2178 <term><literal>*ad*.example.com</literal></term>
2181 matches all of the above, and then some.
2186 <term><literal>.?pix.com</literal></term>
2189 matches <literal>www.ipix.com</literal>,
2190 <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
2195 <term><literal>www[1-9a-ez].example.c*</literal></term>
2198 matches <literal>www1.example.com</literal>,
2199 <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
2200 <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
2201 <literal>wwww.example.com</literal>.
2208 While flexible, this is not the sophistication of full regular expression based syntax.
2213 <!-- ~ End section ~ -->
2216 <!-- ~~~~~ New section ~~~~~ -->
2217 <sect3><title>The Path Pattern</title>
2220 <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
2221 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2222 Expressions</quote></ulink> for matching the path portion (after the slash),
2223 and is thus more flexible.
2227 There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
2228 expressions, you also might want to have a look at your operating system's documentation
2229 on regular expressions (try <literal>man re_format</literal>).
2233 Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
2234 i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
2235 for the beginning of a line).
2239 Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
2240 by default, but you can switch to case sensitive at any point in the pattern by using the
2241 <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
2242 only documents whose path starts with <literal>PaTtErN</literal> in
2243 <emphasis>exactly</emphasis> this capitalization.
2248 <term><literal>.example.com/.*</literal></term>
2251 Is equivalent to just <quote>.example.com</quote>, since any documents
2252 within that domain are matched with or without the <quote>.*</quote>
2253 regular expression. This is redundant
2258 <term><literal>.example.com/.*/index.html$</literal></term>
2261 Will match any page in the domain of <quote>example.com</quote> that is
2262 named <quote>index.html</quote>, and that is part of some path. For
2263 example, it matches <quote>www.example.com/testing/index.html</quote> but
2264 NOT <quote>www.example.com/index.html</quote> because the regular
2265 expression called for at least two <quote>/'s</quote>, thus the path
2266 requirement. It also would match
2267 <quote>www.example.com/testing/index_html</quote>, because of the
2268 special meta-character <quote>.</quote>.
2273 <term><literal>.example.com/(.*/)?index\.html$</literal></term>
2276 This regular expression is conditional so it will match any page
2277 named <quote>index.html</quote> regardless of path which in this case can
2278 have one or more <quote>/'s</quote>. And this one must contain exactly
2279 <quote>.html</quote> (but does not have to end with that!).
2284 <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
2287 This regular expression will match any path of <quote>example.com</quote>
2288 that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
2289 <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
2290 The path does not have to end in these words, just contain them.
2295 <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
2298 This is very much the same as above, except now it must end in either
2299 <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
2300 one is limited to common image formats.
2307 There are many, many good examples to be found in <filename>default.action</filename>,
2308 and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
2313 <!-- ~ End section ~ -->
2316 <!-- ~~~~~ New section ~~~~~ -->
2317 <sect3 id="tag-pattern"><title>The Tag Pattern</title>
2320 Tag patterns are used to change the applying actions based on the
2321 request's tags. Tags can be created with either the
2322 <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
2323 or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
2327 Tag patterns have to start with <quote>TAG:</quote>, so &my-app;
2328 can tell them apart from URL patterns. Everything after the colon
2329 including white space, is interpreted as a regular expression with
2330 path pattern syntax, except that tag patterns aren't left-anchored
2331 automatically (&my-app; doesn't silently add a <quote>^</quote>,
2332 you have to do it yourself if you need it).
2336 To match all requests that are tagged with <quote>foo</quote>
2337 your pattern line should be <quote>TAG:^foo$</quote>,
2338 <quote>TAG:foo</quote> would work as well, but it would also
2339 match requests whose tags contain <quote>foo</quote> somewhere.
2340 <quote>TAG: foo</quote> wouldn't work as it requires white space.
2344 Sections can contain URL and tag patterns at the same time,
2345 but tag patterns are checked after the URL patterns and thus
2346 always overrule them, even if they are located before the URL patterns.
2350 Once a new tag is added, Privoxy checks right away if it's matched by one
2351 of the tag patterns and updates the action settings accordingly. As a result
2352 tags can be used to activate other tagger actions, as long as these other
2353 taggers look for headers that haven't already be parsed.
2357 For example you could tag client requests which use the
2358 <literal>POST</literal> method,
2359 then use this tag to activate another tagger that adds a tag if cookies
2360 are sent, and then use a block action based on the cookie tag. This allows
2361 the outcome of one action, to be input into a subsequent action. However if
2362 you'd reverse the position of the described taggers, and activated the
2363 method tagger based on the cookie tagger, no method tags would be created.
2364 The method tagger would look for the request line, but at the time
2365 the cookie tag is created, the request line has already been parsed.
2369 While this is a limitation you should be aware of, this kind of
2370 indirection is seldom needed anyway and even the example doesn't
2371 make too much sense.
2378 <!-- ~ End section ~ -->
2381 <!-- ~~~~~ New section ~~~~~ -->
2383 <sect2 id="actions">
2384 <title>Actions</title>
2386 All actions are disabled by default, until they are explicitly enabled
2387 somewhere in an actions file. Actions are turned on if preceded with a
2388 <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
2389 <literal>+action</literal> means <quote>do that action</quote>, e.g.
2390 <literal>+block</literal> means <quote>please block URLs that match the
2391 following patterns</quote>, and <literal>-block</literal> means <quote>don't
2392 block URLs that match the following patterns, even if <literal>+block</literal>
2393 previously applied.</quote>
2398 Again, actions are invoked by placing them on a line, enclosed in curly braces and
2399 separated by whitespace, like in
2400 <literal>{+some-action -some-other-action{some-parameter}}</literal>,
2401 followed by a list of URL patterns, one per line, to which they apply.
2402 Together, the actions line and the following pattern lines make up a section
2403 of the actions file.
2407 Actions fall into three categories:
2414 Boolean, i.e the action can only be <quote>enabled</quote> or
2415 <quote>disabled</quote>. Syntax:
2419 +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
2420 -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable></screen>
2423 Example: <literal>+handle-as-image</literal>
2430 Parameterized, where some value is required in order to enable this type of action.
2435 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
2436 # overwriting parameter from previous match if necessary
2437 -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted</screen>
2440 Note that if the URL matches multiple positive forms of a parameterized action,
2441 the last match wins, i.e. the params from earlier matches are simply ignored.
2444 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>
2450 Multi-value. These look exactly like parameterized actions,
2451 but they behave differently: If the action applies multiple times to the
2452 same URL, but with different parameters, <emphasis>all</emphasis> the parameters
2453 from <emphasis>all</emphasis> matches are remembered. This is used for actions
2454 that can be executed for the same request repeatedly, like adding multiple
2455 headers, or filtering through multiple filters. Syntax:
2459 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
2460 -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
2461 # If it was the last one left, disable the action.
2462 <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list</screen>
2465 Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
2466 <literal>+filter{html-annoyances}</literal>
2474 If nothing is specified in any actions file, no <quote>actions</quote> are
2475 taken. So in this case <application>Privoxy</application> would just be a
2476 normal, non-blocking, non-filtering proxy. You must specifically enable the
2477 privacy and blocking features you need (although the provided default actions
2478 files will give a good starting point).
2482 Later defined action sections always over-ride earlier ones of the same type.
2483 So exceptions to any rules you make, should come in the latter part of the file (or
2484 in a file that is processed later when using multiple actions files such
2485 as <filename>user.action</filename>). For multi-valued actions, the actions
2486 are applied in the order they are specified. Actions files are processed in
2487 the order they are defined in <filename>config</filename> (the default
2488 installation has three actions files). It also quite possible for any given
2489 URL to match more than one <quote>pattern</quote> (because of wildcards and
2490 regular expressions), and thus to trigger more than one set of actions! Last
2494 <!-- start actions listing -->
2496 The list of valid <application>Privoxy</application> actions are:
2500 <!-- ********************************************************** -->
2501 <!-- Please note the below defined actions use id's that are -->
2502 <!-- probably linked from other places, so please don't change. -->
2504 <!-- ********************************************************** -->
2507 <!-- ~~~~~ New section ~~~~~ -->
2509 <sect3 renderas="sect4" id="add-header">
2510 <title>add-header</title>
2514 <term>Typical use:</term>
2516 <para>Confuse log analysis, custom applications</para>
2521 <term>Effect:</term>
2524 Sends a user defined HTTP header to the web server.
2531 <!-- boolean, parameterized, Multi-value -->
2533 <para>Multi-value.</para>
2538 <term>Parameter:</term>
2541 Any string value is possible. Validity of the defined HTTP headers is not checked.
2542 It is recommended that you use the <quote><literal>X-</literal></quote> prefix
2552 This action may be specified multiple times, in order to define multiple
2553 headers. This is rarely needed for the typical user. If you don't know what
2554 <quote>HTTP headers</quote> are, you definitely don't need to worry about this
2558 Headers added by this action are not modified by other actions.
2564 <term>Example usage:</term>
2567 <screen>+add-header{X-User-Tracking: sucks}</screen>
2575 <!-- ~~~~~ New section ~~~~~ -->
2576 <sect3 renderas="sect4" id="block">
2577 <title>block</title>
2581 <term>Typical use:</term>
2583 <para>Block ads or other unwanted content</para>
2588 <term>Effect:</term>
2591 Requests for URLs to which this action applies are blocked, i.e. the
2592 requests are trapped by &my-app; and the requested URL is never retrieved,
2593 but is answered locally with a substitute page or image, as determined by
2595 linkend="handle-as-image">handle-as-image</link></literal>,
2597 linkend="set-image-blocker">set-image-blocker</link></literal>, and
2599 linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
2607 <!-- boolean, parameterized, Multi-value -->
2609 <para>Parameterized.</para>
2614 <term>Parameter:</term>
2616 <para>A block reason that should be given to the user.</para>
2624 <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
2625 for requests to blocked pages. This page contains the block reason given as
2626 parameter, a link to find out why the block action applies, and a click-through
2627 to the blocked content (the latter only if the force feature is available and
2631 A very important exception occurs if <emphasis>both</emphasis>
2632 <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
2633 apply to the same request: it will then be replaced by an image. If
2634 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
2635 (see below) also applies, the type of image will be determined by its parameter,
2636 if not, the standard checkerboard pattern is sent.
2639 It is important to understand this process, in order
2640 to understand how <application>Privoxy</application> deals with
2641 ads and other unwanted content. Blocking is a core feature, and one
2642 upon which various other features depend.
2645 The <literal><link linkend="filter">filter</link></literal>
2646 action can perform a very similar task, by <quote>blocking</quote>
2647 banner images and other content through rewriting the relevant URLs in the
2648 document's HTML source, so they don't get requested in the first place.
2649 Note that this is a totally different technique, and it's easy to confuse the two.
2655 <term>Example usage (section):</term>
2658 <screen>{+block{No nasty stuff for you.}}
2659 # Block and replace with "blocked" page
2660 .nasty-stuff.example.com
2662 {+block{Doubleclick banners.} +handle-as-image}
2663 # Block and replace with image
2667 {+block{Layered ads.} +handle-as-empty-document}
2668 # Block and then ignore
2669 adserver.example.net/.*\.js$</screen>
2679 <!-- ~~~~~ New section ~~~~~ -->
2680 <sect3 renderas="sect4" id="change-x-forwarded-for">
2681 <title>change-x-forwarded-for</title>
2685 <term>Typical use:</term>
2687 <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
2692 <term>Effect:</term>
2695 Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
2703 <!-- Boolean, Parameterized, Multi-value -->
2705 <para>Parameterized.</para>
2710 <term>Parameter:</term>
2714 <para><quote>block</quote> to delete the header.</para>
2718 <quote>add</quote> to create the header (or append
2719 the client's IP address to an already existing one).
2730 It is safe and recommended to use <literal>block</literal>.
2733 Forwarding the source address of the request may make
2734 sense in some multi-user setups but is also a privacy risk.
2739 <term>Example usage:</term>
2742 <screen>+change-x-forwarded-for{block}</screen>
2749 <!-- ~~~~~ New section ~~~~~ -->
2750 <sect3 renderas="sect4" id="client-header-filter">
2751 <title>client-header-filter</title>
2755 <term>Typical use:</term>
2758 Rewrite or remove single client headers.
2764 <term>Effect:</term>
2767 All client headers to which this action applies are filtered on-the-fly through
2768 the specified regular expression based substitutions.
2775 <!-- boolean, parameterized, Multi-value -->
2777 <para>Parameterized.</para>
2782 <term>Parameter:</term>
2785 The name of a client-header filter, as defined in one of the
2786 <link linkend="filter-file">filter files</link>.
2795 Client-header filters are applied to each header on its own, not to
2796 all at once. This makes it easier to diagnose problems, but on the downside
2797 you can't write filters that only change header x if header y's value is z.
2798 You can do that by using tags though.
2801 Client-header filters are executed after the other header actions have finished
2802 and use their output as input.
2805 If the request URI gets changed, &my-app; will detect that and use the new
2806 one. This can be used to rewrite the request destination behind the client's
2807 back, for example to specify a Tor exit relay for certain requests.
2810 Please refer to the <link linkend="filter-file">filter file chapter</link>
2811 to learn which client-header filters are available by default, and how to
2819 <term>Example usage (section):</term>
2823 # Hide Tor exit notation in Host and Referer Headers
2824 {+client-header-filter{hide-tor-exit-notation}}
2835 <!-- ~~~~~ New section ~~~~~ -->
2836 <sect3 renderas="sect4" id="client-header-tagger">
2837 <title>client-header-tagger</title>
2841 <term>Typical use:</term>
2844 Block requests based on their headers.
2850 <term>Effect:</term>
2853 Client headers to which this action applies are filtered on-the-fly through
2854 the specified regular expression based substitutions, the result is used as
2862 <!-- boolean, parameterized, Multi-value -->
2864 <para>Parameterized.</para>
2869 <term>Parameter:</term>
2872 The name of a client-header tagger, as defined in one of the
2873 <link linkend="filter-file">filter files</link>.
2882 Client-header taggers are applied to each header on its own,
2883 and as the header isn't modified, each tagger <quote>sees</quote>
2887 Client-header taggers are the first actions that are executed
2888 and their tags can be used to control every other action.
2894 <term>Example usage (section):</term>
2898 # Tag every request with the User-Agent header
2899 {+client-header-tagger{user-agent}}
2902 # Tagging itself doesn't change the action
2903 # settings, sections with TAG patterns do:
2905 # If it's a download agent, use a different forwarding proxy,
2906 # show the real User-Agent and make sure resume works.
2907 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
2908 -hide-if-modified-since \
2909 -overwrite-last-modified \
2914 TAG:^User-Agent: NetBSD-ftp/
2915 TAG:^User-Agent: Novell ZYPP Installer
2916 TAG:^User-Agent: RPM APT-HTTP/
2917 TAG:^User-Agent: fetch libfetch/
2918 TAG:^User-Agent: Ubuntu APT-HTTP/
2919 TAG:^User-Agent: MPlayer/
2924 # Tag all requests with the Range header set
2925 {+client-header-tagger{range-requests}}
2928 # Disable filtering for the tagged requests.
2930 # With filtering enabled Privoxy would remove the Range headers
2931 # to be able to filter the whole response. The downside is that
2932 # it prevents clients from resuming downloads or skipping over
2933 # parts of multimedia files.
2934 {-filter -deanimate-gifs}
2945 <!-- ~~~~~ New section ~~~~~ -->
2946 <sect3 renderas="sect4" id="content-type-overwrite">
2947 <title>content-type-overwrite</title>
2951 <term>Typical use:</term>
2953 <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
2958 <term>Effect:</term>
2961 Replaces the <quote>Content-Type:</quote> HTTP server header.
2968 <!-- Boolean, Parameterized, Multi-value -->
2970 <para>Parameterized.</para>
2975 <term>Parameter:</term>
2987 The <quote>Content-Type:</quote> HTTP server header is used by the
2988 browser to decide what to do with the document. The value of this
2989 header can cause the browser to open a download menu instead of
2990 displaying the document by itself, even if the document's format is
2991 supported by the browser.
2994 The declared content type can also affect which rendering mode
2995 the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
2996 many browsers treat it as yet another broken HTML document.
2997 If it is send as <quote>application/xml</quote>, browsers with
2998 XHTML support will only display it, if the syntax is correct.
3001 If you see a web site that proudly uses XHTML buttons, but sets
3002 <quote>Content-Type: text/html</quote>, you can use &my-app;
3003 to overwrite it with <quote>application/xml</quote> and validate
3004 the web master's claim inside your XHTML-supporting browser.
3005 If the syntax is incorrect, the browser will complain loudly.
3008 You can also go the opposite direction: if your browser prints
3009 error messages instead of rendering a document falsely declared
3010 as XHTML, you can overwrite the content type with
3011 <quote>text/html</quote> and have it rendered as broken HTML document.
3014 By default <literal>content-type-overwrite</literal> only replaces
3015 <quote>Content-Type:</quote> headers that look like some kind of text.
3016 If you want to overwrite it unconditionally, you have to combine it with
3017 <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
3018 This limitation exists for a reason, think twice before circumventing it.
3021 Most of the time it's easier to replace this action with a custom
3022 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3023 It allows you to activate it for every document of a certain site and it will still
3024 only replace the content types you aimed at.
3027 Of course you can apply <literal>content-type-overwrite</literal>
3028 to a whole site and then make URL based exceptions, but it's a lot
3029 more work to get the same precision.
3035 <term>Example usage (sections):</term>
3038 <screen># Check if www.example.net/ really uses valid XHTML
3039 { +content-type-overwrite{application/xml} }
3042 # but leave the content type unmodified if the URL looks like a style sheet
3043 {-content-type-overwrite}
3044 www.example.net/.*\.css$
3045 www.example.net/.*style
3054 <!-- ~~~~~ New section ~~~~~ -->
3055 <sect3 renderas="sect4" id="crunch-client-header">
3059 <title>crunch-client-header</title>
3063 <term>Typical use:</term>
3065 <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
3070 <term>Effect:</term>
3073 Deletes every header sent by the client that contains the string the user supplied as parameter.
3080 <!-- Boolean, Parameterized, Multi-value -->
3082 <para>Parameterized.</para>
3087 <term>Parameter:</term>
3099 This action allows you to block client headers for which no dedicated
3100 <application>Privoxy</application> action exists.
3101 <application>Privoxy</application> will remove every client header that
3102 contains the string you supplied as parameter.
3105 Regular expressions are <emphasis>not supported</emphasis> and you can't
3106 use this action to block different headers in the same request, unless
3107 they contain the same string.
3110 <literal>crunch-client-header</literal> is only meant for quick tests.
3111 If you have to block several different headers, or only want to modify
3112 parts of them, you should use a
3113 <literal><link linkend="client-header-filter">client-header filter</link></literal>.
3117 Don't block any header without understanding the consequences.
3124 <term>Example usage (section):</term>
3127 <screen># Block the non-existent "Privacy-Violation:" client header
3128 { +crunch-client-header{Privacy-Violation:} }
3138 <!-- ~~~~~ New section ~~~~~ -->
3139 <sect3 renderas="sect4" id="crunch-if-none-match">
3140 <title>crunch-if-none-match</title>
3146 <term>Typical use:</term>
3148 <para>Prevent yet another way to track the user's steps between sessions.</para>
3153 <term>Effect:</term>
3156 Deletes the <quote>If-None-Match:</quote> HTTP client header.
3163 <!-- Boolean, Parameterized, Multi-value -->
3165 <para>Boolean.</para>
3170 <term>Parameter:</term>
3182 Removing the <quote>If-None-Match:</quote> HTTP client header
3183 is useful for filter testing, where you want to force a real
3184 reload instead of getting status code <quote>304</quote> which
3185 would cause the browser to use a cached copy of the page.
3188 It is also useful to make sure the header isn't used as a cookie
3189 replacement (unlikely but possible).
3192 Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
3193 caching problems, as long as the <quote>If-Modified-Since:</quote> header
3194 isn't blocked or missing as well.
3197 It is recommended to use this action together with
3198 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
3200 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
3206 <term>Example usage (section):</term>
3209 <screen># Let the browser revalidate cached documents but don't
3210 # allow the server to use the revalidation headers for user tracking.
3211 {+hide-if-modified-since{-60} \
3212 +overwrite-last-modified{randomize} \
3213 +crunch-if-none-match}
3222 <!-- ~~~~~ New section ~~~~~ -->
3223 <sect3 renderas="sect4" id="crunch-incoming-cookies">
3224 <title>crunch-incoming-cookies</title>
3228 <term>Typical use:</term>
3231 Prevent the web server from setting HTTP cookies on your system
3237 <term>Effect:</term>
3240 Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
3247 <!-- Boolean, Parameterized, Multi-value -->
3249 <para>Boolean.</para>
3254 <term>Parameter:</term>
3266 This action is only concerned with <emphasis>incoming</emphasis> HTTP cookies. For
3267 <emphasis>outgoing</emphasis> HTTP cookies, use
3268 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
3269 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3272 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3273 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3274 since it would prevent the session cookies from being set. See also
3275 <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
3281 <term>Example usage:</term>
3284 <screen>+crunch-incoming-cookies</screen>
3292 <!-- ~~~~~ New section ~~~~~ -->
3293 <sect3 renderas="sect4" id="crunch-server-header">
3294 <title>crunch-server-header</title>
3300 <term>Typical use:</term>
3302 <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
3307 <term>Effect:</term>
3310 Deletes every header sent by the server that contains the string the user supplied as parameter.
3317 <!-- Boolean, Parameterized, Multi-value -->
3319 <para>Parameterized.</para>
3324 <term>Parameter:</term>
3336 This action allows you to block server headers for which no dedicated
3337 <application>Privoxy</application> action exists. <application>Privoxy</application>
3338 will remove every server header that contains the string you supplied as parameter.
3341 Regular expressions are <emphasis>not supported</emphasis> and you can't
3342 use this action to block different headers in the same request, unless
3343 they contain the same string.
3346 <literal>crunch-server-header</literal> is only meant for quick tests.
3347 If you have to block several different headers, or only want to modify
3348 parts of them, you should use a custom
3349 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3353 Don't block any header without understanding the consequences.
3360 <term>Example usage (section):</term>
3363 <screen># Crunch server headers that try to prevent caching
3364 { +crunch-server-header{no-cache} }
3373 <!-- ~~~~~ New section ~~~~~ -->
3374 <sect3 renderas="sect4" id="crunch-outgoing-cookies">
3375 <title>crunch-outgoing-cookies</title>
3379 <term>Typical use:</term>
3382 Prevent the web server from reading any HTTP cookies from your system
3388 <term>Effect:</term>
3391 Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
3398 <!-- Boolean, Parameterized, Multi-value -->
3400 <para>Boolean.</para>
3405 <term>Parameter:</term>
3417 This action is only concerned with <emphasis>outgoing</emphasis> HTTP cookies. For
3418 <emphasis>incoming</emphasis> HTTP cookies, use
3419 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
3420 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3423 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3424 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3425 since it would prevent the session cookies from being read.
3431 <term>Example usage:</term>
3434 <screen>+crunch-outgoing-cookies</screen>
3443 <!-- ~~~~~ New section ~~~~~ -->
3444 <sect3 renderas="sect4" id="deanimate-gifs">
3445 <title>deanimate-gifs</title>
3449 <term>Typical use:</term>
3451 <para>Stop those annoying, distracting animated GIF images.</para>
3456 <term>Effect:</term>
3459 De-animate GIF animations, i.e. reduce them to their first or last image.
3466 <!-- boolean, parameterized, Multi-value -->
3468 <para>Parameterized.</para>
3473 <term>Parameter:</term>
3476 <quote>last</quote> or <quote>first</quote>
3485 This will also shrink the images considerably (in bytes, not pixels!). If
3486 the option <quote>first</quote> is given, the first frame of the animation
3487 is used as the replacement. If <quote>last</quote> is given, the last
3488 frame of the animation is used instead, which probably makes more sense for
3489 most banner animations, but also has the risk of not showing the entire
3490 last frame (if it is only a delta to an earlier frame).
3493 You can safely use this action with patterns that will also match non-GIF
3494 objects, because no attempt will be made at anything that doesn't look like
3501 <term>Example usage:</term>
3504 <screen>+deanimate-gifs{last}</screen>
3511 <!-- ~~~~~ New section ~~~~~ -->
3512 <sect3 renderas="sect4" id="downgrade-http-version">
3513 <title>downgrade-http-version</title>
3517 <term>Typical use:</term>
3519 <para>Work around (very rare) problems with HTTP/1.1</para>
3524 <term>Effect:</term>
3527 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
3534 <!-- boolean, parameterized, Multi-value -->
3536 <para>Boolean.</para>
3541 <term>Parameter:</term>
3553 This is a left-over from the time when <application>Privoxy</application>
3554 didn't support important HTTP/1.1 features well. It is left here for the
3555 unlikely case that you experience HTTP/1.1-related problems with some server
3559 Note that enabling this action is only a workaround. It should not
3560 be enabled for sites that work without it. While it shouldn't break
3561 any pages, it has an (usually negative) performance impact.
3564 If you come across a site where enabling this action helps, please report it,
3565 so the cause of the problem can be analyzed. If the problem turns out to be
3566 caused by a bug in <application>Privoxy</application> it should be
3567 fixed so the following release works without the work around.
3573 <term>Example usage (section):</term>
3576 <screen>{+downgrade-http-version}
3577 problem-host.example.com</screen>
3585 <!-- ~~~~~ New section ~~~~~ -->
3586 <sect3 renderas="sect4" id="fast-redirects">
3587 <title>fast-redirects</title>
3591 <term>Typical use:</term>
3593 <para>Fool some click-tracking scripts and speed up indirect links.</para>
3598 <term>Effect:</term>
3601 Detects redirection URLs and redirects the browser without contacting
3602 the redirection server first.
3609 <!-- boolean, parameterized, Multi-value -->
3611 <para>Parameterized.</para>
3616 <term>Parameter:</term>
3621 <quote>simple-check</quote> to just search for the string <quote>http://</quote>
3622 to detect redirection URLs.
3627 <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
3628 for redirection URLs.
3639 Many sites, like yahoo.com, don't just link to other sites. Instead, they
3640 will link to some script on their own servers, giving the destination as a
3641 parameter, which will then redirect you to the final target. URLs
3642 resulting from this scheme typically look like:
3643 <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
3646 Sometimes, there are even multiple consecutive redirects encoded in the
3647 URL. These redirections via scripts make your web browsing more traceable,
3648 since the server from which you follow such a link can see where you go
3649 to. Apart from that, valuable bandwidth and time is wasted, while your
3650 browser asks the server for one redirect after the other. Plus, it feeds
3654 This feature is currently not very smart and is scheduled for improvement.
3655 If it is enabled by default, you will have to create some exceptions to
3656 this action. It can lead to failures in several ways:
3659 Not every URLs with other URLs as parameters is evil.
3660 Some sites offer a real service that requires this information to work.
3661 For example a validation service needs to know, which document to validate.
3662 <literal>fast-redirects</literal> assumes that every URL parameter that
3663 looks like another URL is a redirection target, and will always redirect to
3664 the last one. Most of the time the assumption is correct, but if it isn't,
3665 the user gets redirected anyway.
3668 Another failure occurs if the URL contains other parameters after the URL parameter.
3670 <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
3671 contains the redirection URL <quote>http://www.example.net/</quote>,
3672 followed by another parameter. <literal>fast-redirects</literal> doesn't know that
3673 and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
3674 Depending on the target server configuration, the parameter will be silently ignored
3675 or lead to a <quote>page not found</quote> error. You can prevent this problem by
3676 first using the <literal><link linkend="redirect">redirect</link></literal> action
3677 to remove the last part of the URL, but it requires a little effort.
3680 To detect a redirection URL, <literal>fast-redirects</literal> only
3681 looks for the string <quote>http://</quote>, either in plain text
3682 (invalid but often used) or encoded as <quote>http%3a//</quote>.
3683 Some sites use their own URL encoding scheme, encrypt the address
3684 of the target server or replace it with a database id. In theses cases
3685 <literal>fast-redirects</literal> is fooled and the request reaches the
3686 redirection server where it probably gets logged.
3692 <term>Example usage:</term>
3696 { +fast-redirects{simple-check} }
3699 { +fast-redirects{check-decoded-url} }
3700 another.example.com/testing</screen>
3709 <!-- ~~~~~ New section ~~~~~ -->
3710 <sect3 renderas="sect4" id="filter">
3711 <title>filter</title>
3715 <term>Typical use:</term>
3717 <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
3718 do fun text replacements, add personalized effects, etc.</para>
3723 <term>Effect:</term>
3726 All instances of text-based type, most notably HTML and JavaScript, to which
3727 this action applies, can be filtered on-the-fly through the specified regular
3728 expression based substitutions. (Note: as of version 3.0.3 plain text documents
3729 are exempted from filtering, because web servers often use the
3730 <literal>text/plain</literal> MIME type for all files whose type they don't know.)
3737 <!-- boolean, parameterized, Multi-value -->
3739 <para>Parameterized.</para>
3744 <term>Parameter:</term>
3747 The name of a content filter, as defined in the <link linkend="filter-file">filter file</link>.
3748 Filters can be defined in one or more files as defined by the
3749 <literal><link linkend="filterfile">filterfile</link></literal>
3750 option in the <link linkend="config">config file</link>.
3751 <filename>default.filter</filename> is the collection of filters
3752 supplied by the developers. Locally defined filters should go
3753 in their own file, such as <filename>user.filter</filename>.
3756 When used in its negative form,
3757 and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
3766 For your convenience, there are a number of pre-defined filters available
3767 in the distribution filter file that you can use. See the examples below for
3771 Filtering requires buffering the page content, which may appear to
3772 slow down page rendering since nothing is displayed until all content has
3773 passed the filters. (The total time until the page is completely rendered
3774 doesn't change much, but it may be perceived as slower since the page is
3775 not incrementally displayed.)
3776 This effect will be more noticeable on slower connections.
3779 <quote>Rolling your own</quote>
3780 filters requires a knowledge of
3781 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3782 Expressions</quote></ulink> and
3783 <ulink url="http://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
3784 This is very powerful feature, and potentially very intrusive.
3785 Filters should be used with caution, and where an equivalent
3786 <quote>action</quote> is not available.
3789 The amount of data that can be filtered is limited to the
3790 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
3791 option in the main <link linkend="config">config file</link>. The
3792 default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
3793 data, and all pending data, is passed through unfiltered.
3796 Inappropriate MIME types, such as zipped files, are not filtered at all.
3797 (Again, only text-based types except plain text). Encrypted SSL data
3798 (from HTTPS servers) cannot be filtered either, since this would violate
3799 the integrity of the secure transaction. In some situations it might
3800 be necessary to protect certain text, like source code, from filtering
3801 by defining appropriate <literal>-filter</literal> exceptions.
3804 Compressed content can't be filtered either, but if &my-app;
3805 is compiled with zlib support and a supported compression algorithm
3806 is used (gzip or deflate), &my-app; can first decompress the content
3810 If you use a &my-app; version without zlib support, but want filtering to work on
3811 as much documents as possible, even those that would normally be sent compressed,
3812 you must use the <literal><link linkend="prevent-compression">prevent-compression</link></literal>
3813 action in conjunction with <literal>filter</literal>.
3816 Content filtering can achieve some of the same effects as the
3817 <literal><link linkend="block">block</link></literal>
3818 action, i.e. it can be used to block ads and banners. But the mechanism
3819 works quite differently. One effective use, is to block ad banners
3820 based on their size (see below), since many of these seem to be somewhat
3824 <link linkend="contact">Feedback</link> with suggestions for new or
3825 improved filters is particularly welcome!
3828 The below list has only the names and a one-line description of each
3829 predefined filter. There are <link linkend="predefined-filters">more
3830 verbose explanations</link> of what these filters do in the <link
3831 linkend="filter-file">filter file chapter</link>.
3837 <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
3838 See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
3839 more explanation on each:</term>
3842 <anchor id="filter-js-annoyances">
3843 <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse.</screen>
3846 <anchor id="filter-js-events">
3847 <screen>+filter{js-events} # Kill all JS event bindings and timers (Radically destructive! Only for extra nasty sites).</screen>
3850 <anchor id="filter-html-annoyances">
3851 <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse.</screen>
3854 <anchor id="filter-content-cookies">
3855 <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content.</screen>
3858 <anchor id="filter-refresh-tags">
3859 <screen>+filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups).</screen>
3862 <anchor id="filter-unsolicited-popups">
3863 <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability.</screen>
3866 <anchor id="filter-all-popups">
3867 <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability.</screen>
3870 <anchor id="filter-img-reorder">
3871 <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective.</screen>
3874 <anchor id="filter-banners-by-size">
3875 <screen>+filter{banners-by-size} # Kill banners by size.</screen>
3878 <anchor id="filter-banners-by-link">
3879 <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers.</screen>
3882 <anchor id="filter-webbugs">
3883 <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking).</screen>
3886 <anchor id="filter-tiny-textforms">
3887 <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap.</screen>
3890 <anchor id="filter-jumping-windows">
3891 <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves.</screen>
3894 <anchor id="filter-frameset-borders">
3895 <screen>+filter{frameset-borders} # Give frames a border and make them resizable.</screen>
3898 <anchor id="filter-demoronizer">
3899 <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets.</screen>
3902 <anchor id="filter-shockwave-flash">
3903 <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects.</screen>
3906 <anchor id="filter-quicktime-kioskmode">
3907 <screen>+filter{quicktime-kioskmode} # Make Quicktime movies saveable.</screen>
3910 <anchor id="filter-fun">
3911 <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
3914 <anchor id="filter-crude-parental">
3915 <screen>+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably.</screen>
3918 <anchor id="filter-ie-exploits">
3919 <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits.</screen>
3922 <anchor id="filter-site-specifics">
3923 <screen>+filter{site-specifics} # Cure for site-specific problems. Don't apply generally!</screen>
3926 <anchor id="filter-no-ping">
3927 <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
3930 <anchor id="filter-google">
3931 <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
3934 <anchor id="filter-yahoo">
3935 <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
3938 <anchor id="filter-msn">
3939 <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
3942 <anchor id="filter-blogspot">
3943 <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</screen>
3951 <!-- ~~~~~ New section ~~~~~ -->
3952 <sect3 renderas="sect4" id="force-text-mode">
3953 <title>force-text-mode</title>
3959 <term>Typical use:</term>
3961 <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
3966 <term>Effect:</term>
3969 Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
3976 <!-- Boolean, Parameterized, Multi-value -->
3978 <para>Boolean.</para>
3983 <term>Parameter:</term>
3995 As explained <literal><link linkend="filter">above</link></literal>,
3996 <application>Privoxy</application> tries to only filter files that are
3997 in some kind of text format. The same restrictions apply to
3998 <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
3999 <literal>force-text-mode</literal> declares a document as text,
4000 without looking at the <quote>Content-Type:</quote> first.
4004 Think twice before activating this action. Filtering binary data
4005 with regular expressions can cause file damage.
4012 <term>Example usage:</term>
4025 <!-- ~~~~~ New section ~~~~~ -->
4026 <sect3 renderas="sect4" id="forward-override">
4027 <title>forward-override</title>
4033 <term>Typical use:</term>
4035 <para>Change the forwarding settings based on User-Agent or request origin</para>
4040 <term>Effect:</term>
4043 Overrules the forward directives in the configuration file.
4050 <!-- Boolean, Parameterized, Multi-value -->
4052 <para>Multi-value.</para>
4057 <term>Parameter:</term>
4061 <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
4065 <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
4070 <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
4071 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
4072 to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4073 for socks5 connections (with remote DNS resolution).
4078 <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
4079 listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
4080 Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
4081 (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4082 for socks5 connections (with remote DNS resolution).
4093 This action takes parameters similar to the
4094 <link linkend="forwarding">forward</link> directives in the configuration
4095 file, but without the URL pattern. It can be used as replacement, but normally it's only
4096 used in cases where matching based on the request URL isn't sufficient.
4100 Please read the description for the <link linkend="forwarding">forward</link> directives before
4101 using this action. Forwarding to the wrong people will reduce your privacy and increase the
4102 chances of man-in-the-middle attacks.
4105 If the ports are missing or invalid, default values will be used. This might change
4106 in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
4110 Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
4111 to verify that your forward settings do what you thought the do.
4118 <term>Example usage:</term>
4122 # Always use direct connections for requests previously tagged as
4123 # <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
4124 # resuming downloads continues to work.
4125 # This way you can continue to use Tor for your normal browsing,
4126 # without overloading the Tor network with your FreeBSD ports updates
4127 # or downloads of bigger files like ISOs.
4128 # Note that HTTP headers are easy to fake and therefore their
4129 # values are as (un)trustworthy as your clients and users.
4130 {+forward-override{forward .} \
4131 -hide-if-modified-since \
4132 -overwrite-last-modified \
4134 TAG:^User-Agent: fetch libfetch/2\.0$
4143 <!-- ~~~~~ New section ~~~~~ -->
4144 <sect3 renderas="sect4" id="handle-as-empty-document">
4145 <title>handle-as-empty-document</title>
4151 <term>Typical use:</term>
4153 <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
4158 <term>Effect:</term>
4161 This action alone doesn't do anything noticeable. It just marks URLs.
4162 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4163 the presence or absence of this mark decides whether an HTML <quote>BLOCKED</quote>
4164 page, or an empty document will be sent to the client as a substitute for the blocked content.
4165 The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
4172 <!-- Boolean, Parameterized, Multi-value -->
4174 <para>Boolean.</para>
4179 <term>Parameter:</term>
4191 Some browsers complain about syntax errors if JavaScript documents
4192 are blocked with <application>Privoxy's</application>
4193 default HTML page; this option can be used to silence them.
4194 And of course this action can also be used to eliminate the &my-app;
4195 BLOCKED message in frames.
4198 The content type for the empty document can be specified with
4199 <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
4200 but usually this isn't necessary.
4206 <term>Example usage:</term>
4209 <screen># Block all documents on example.org that end with ".js",
4210 # but send an empty document instead of the usual HTML message.
4211 {+block{Blocked JavaScript} +handle-as-empty-document}
4221 <!-- ~~~~~ New section ~~~~~ -->
4222 <sect3 renderas="sect4" id="handle-as-image">
4223 <title>handle-as-image</title>
4227 <term>Typical use:</term>
4229 <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>
4234 <term>Effect:</term>
4237 This action alone doesn't do anything noticeable. It just marks URLs as images.
4238 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4239 the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
4240 page, or a replacement image (as determined by the <literal><link
4241 linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
4242 client as a substitute for the blocked content.
4249 <!-- Boolean, Parameterized, Multi-value -->
4251 <para>Boolean.</para>
4256 <term>Parameter:</term>
4268 The below generic example section is actually part of <filename>default.action</filename>.
4269 It marks all URLs with well-known image file name extensions as images and should
4273 Users will probably only want to use the handle-as-image action in conjunction with
4274 <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
4275 reflect the file type, like in the second example section.
4278 Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
4279 frames require an HTML page to be sent, or they won't display properly.
4280 Forcing <literal>handle-as-image</literal> in this situation will not replace the
4281 ad frame with an image, but lead to error messages.
4287 <term>Example usage (sections):</term>
4290 <screen># Generic image extensions:
4293 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
4295 # These don't look like images, but they're banners and should be
4296 # blocked as images:
4298 {+block{Nasty banners.} +handle-as-image}
4299 nasty-banner-server.example.com/junk.cgi\?output=trash
4308 <!-- ~~~~~ New section ~~~~~ -->
4309 <sect3 renderas="sect4" id="hide-accept-language">
4310 <title>hide-accept-language</title>
4316 <term>Typical use:</term>
4318 <para>Pretend to use different language settings.</para>
4323 <term>Effect:</term>
4326 Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
4333 <!-- Boolean, Parameterized, Multi-value -->
4335 <para>Parameterized.</para>
4340 <term>Parameter:</term>
4343 Keyword: <quote>block</quote>, or any user defined value.
4352 Faking the browser's language settings can be useful to make a
4353 foreign User-Agent set with
4354 <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
4358 However some sites with content in different languages check the
4359 <quote>Accept-Language:</quote> to decide which one to take by default.
4360 Sometimes it isn't possible to later switch to another language without
4361 changing the <quote>Accept-Language:</quote> header first.
4364 Therefore it's a good idea to either only change the
4365 <quote>Accept-Language:</quote> header to languages you understand,
4366 or to languages that aren't wide spread.
4369 Before setting the <quote>Accept-Language:</quote> header
4370 to a rare language, you should consider that it helps to
4371 make your requests unique and thus easier to trace.
4372 If you don't plan to change this header frequently,
4373 you should stick to a common language.
4379 <term>Example usage (section):</term>
4382 <screen># Pretend to use Canadian language settings.
4383 {+hide-accept-language{en-ca} \
4384 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
4394 <!-- ~~~~~ New section ~~~~~ -->
4395 <sect3 renderas="sect4" id="hide-content-disposition">
4396 <title>hide-content-disposition</title>
4402 <term>Typical use:</term>
4404 <para>Prevent download menus for content you prefer to view inside the browser.</para>
4409 <term>Effect:</term>
4412 Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
4419 <!-- Boolean, Parameterized, Multi-value -->
4421 <para>Parameterized.</para>
4426 <term>Parameter:</term>
4429 Keyword: <quote>block</quote>, or any user defined value.
4438 Some servers set the <quote>Content-Disposition:</quote> HTTP header for
4439 documents they assume you want to save locally before viewing them.
4440 The <quote>Content-Disposition:</quote> header contains the file name
4441 the browser is supposed to use by default.
4444 In most browsers that understand this header, it makes it impossible to
4445 <emphasis>just view</emphasis> the document, without downloading it first,
4446 even if it's just a simple text file or an image.
4449 Removing the <quote>Content-Disposition:</quote> header helps
4450 to prevent this annoyance, but some browsers additionally check the
4451 <quote>Content-Type:</quote> header, before they decide if they can
4452 display a document without saving it first. In these cases, you have
4453 to change this header as well, before the browser stops displaying
4457 It is also possible to change the server's file name suggestion
4458 to another one, but in most cases it isn't worth the time to set
4462 This action will probably be removed in the future,
4463 use server-header filters instead.
4469 <term>Example usage:</term>
4472 <screen># Disarm the download link in Sourceforge's patch tracker
4474 +content-type-overwrite{text/plain}\
4475 +hide-content-disposition{block} }
4476 .sourceforge.net/tracker/download\.php</screen>
4484 <!-- ~~~~~ New section ~~~~~ -->
4485 <sect3 renderas="sect4" id="hide-if-modified-since">
4486 <title>hide-if-modified-since</title>
4492 <term>Typical use:</term>
4494 <para>Prevent yet another way to track the user's steps between sessions.</para>
4499 <term>Effect:</term>
4502 Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
4509 <!-- Boolean, Parameterized, Multi-value -->
4511 <para>Parameterized.</para>
4516 <term>Parameter:</term>
4519 Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
4528 Removing this header is useful for filter testing, where you want to force a real
4529 reload instead of getting status code <quote>304</quote>, which would cause the
4530 browser to use a cached copy of the page.
4533 Instead of removing the header, <literal>hide-if-modified-since</literal> can
4534 also add or subtract a random amount of time to/from the header's value.
4535 You specify a range of minutes where the random factor should be chosen from and
4536 <application>Privoxy</application> does the rest. A negative value means
4537 subtracting, a positive value adding.
4540 Randomizing the value of the <quote>If-Modified-Since:</quote> makes
4541 it less likely that the server can use the time as a cookie replacement,
4542 but you will run into caching problems if the random range is too high.
4545 It is a good idea to only use a small negative value and let
4546 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
4547 handle the greater changes.
4550 It is also recommended to use this action together with
4551 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>,
4552 otherwise it's more or less pointless.
4558 <term>Example usage (section):</term>
4561 <screen># Let the browser revalidate but make tracking based on the time less likely.
4562 {+hide-if-modified-since{-60} \
4563 +overwrite-last-modified{randomize} \
4564 +crunch-if-none-match}
4573 <!-- ~~~~~ New section ~~~~~ -->
4574 <sect3 renderas="sect4" id="hide-from-header">
4575 <title>hide-from-header</title>
4579 <term>Typical use:</term>
4581 <para>Keep your (old and ill) browser from telling web servers your email address</para>
4586 <term>Effect:</term>
4589 Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
4597 <!-- Boolean, Parameterized, Multi-value -->
4599 <para>Parameterized.</para>
4604 <term>Parameter:</term>
4607 Keyword: <quote>block</quote>, or any user defined value.
4616 The keyword <quote>block</quote> will completely remove the header
4617 (not to be confused with the <literal><link linkend="block">block</link></literal>
4621 Alternately, you can specify any value you prefer to be sent to the web
4622 server. If you do, it is a matter of fairness not to use any address that
4623 is actually used by a real person.
4626 This action is rarely needed, as modern web browsers don't send
4627 <quote>From:</quote> headers anymore.
4633 <term>Example usage:</term>
4636 <screen>+hide-from-header{block}</screen> or
4637 <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
4645 <!-- ~~~~~ New section ~~~~~ -->
4646 <sect3 renderas="sect4" id="hide-referrer">
4647 <title>hide-referrer</title>
4648 <anchor id="hide-referer">
4651 <term>Typical use:</term>
4653 <para>Conceal which link you followed to get to a particular site</para>
4658 <term>Effect:</term>
4661 Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
4662 or replaces it with a forged one.
4669 <!-- Boolean, Parameterized, Multi-value -->
4671 <para>Parameterized.</para>
4676 <term>Parameter:</term>
4680 <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
4683 <para><quote>conditional-forge</quote> to forge the header if the host has changed.</para>
4686 <para><quote>block</quote> to delete the header unconditionally.</para>
4689 <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
4692 <para>Any other string to set a user defined referrer.</para>
4702 <literal>conditional-block</literal> is the only parameter,
4703 that isn't easily detected in the server's log file. If it blocks the
4704 referrer, the request will look like the visitor used a bookmark or
4705 typed in the address directly.
4708 Leaving the referrer unmodified for requests on the same host
4709 allows the server owner to see the visitor's <quote>click path</quote>,
4710 but in most cases she could also get that information by comparing
4711 other parts of the log file: for example the User-Agent if it isn't
4712 a very common one, or the user's IP address if it doesn't change between
4716 Always blocking the referrer, or using a custom one, can lead to
4717 failures on servers that check the referrer before they answer any
4718 requests, in an attempt to prevent their content from being
4719 embedded or linked to elsewhere.
4722 Both <literal>conditional-block</literal> and <literal>forge</literal>
4723 will work with referrer checks, as long as content and valid referring page
4724 are on the same host. Most of the time that's the case.
4727 <literal>hide-referer</literal> is an alternate spelling of
4728 <literal>hide-referrer</literal> and the two can be can be freely
4729 substituted with each other. (<quote>referrer</quote> is the
4730 correct English spelling, however the HTTP specification has a bug - it
4731 requires it to be spelled as <quote>referer</quote>.)
4737 <term>Example usage:</term>
4740 <screen>+hide-referrer{forge}</screen> or
4741 <screen>+hide-referrer{http://www.yahoo.com/}</screen>
4749 <!-- ~~~~~ New section ~~~~~ -->
4750 <sect3 renderas="sect4" id="hide-user-agent">
4751 <title>hide-user-agent</title>
4755 <term>Typical use:</term>
4757 <para>Try to conceal your type of browser and client operating system</para>
4762 <term>Effect:</term>
4765 Replaces the value of the <quote>User-Agent:</quote> HTTP header
4766 in client requests with the specified value.
4773 <!-- Boolean, Parameterized, Multi-value -->
4775 <para>Parameterized.</para>
4780 <term>Parameter:</term>
4783 Any user-defined string.
4793 This can lead to problems on web sites that depend on looking at this header in
4794 order to customize their content for different browsers (which, by the
4795 way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
4796 work browser-independently).
4800 Using this action in multi-user setups or wherever different types of
4801 browsers will access the same <application>Privoxy</application> is
4802 <emphasis>not recommended</emphasis>. In single-user, single-browser
4803 setups, you might use it to delete your OS version information from
4804 the headers, because it is an invitation to exploit known bugs for your
4805 OS. It is also occasionally useful to forge this in order to access
4806 sites that won't let you in otherwise (though there may be a good
4807 reason in some cases).
4810 More information on known user-agent strings can be found at
4811 <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
4813 <ulink url="http://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
4819 <term>Example usage:</term>
4822 <screen>+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}</screen>
4830 <!-- ~~~~~ New section ~~~~~ -->
4831 <sect3 renderas="sect4" id="limit-connect">
4832 <title>limit-connect</title>
4836 <term>Typical use:</term>
4838 <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
4843 <term>Effect:</term>
4846 Specifies to which ports HTTP CONNECT requests are allowable.
4853 <!-- Boolean, Parameterized, Multi-value -->
4855 <para>Parameterized.</para>
4860 <term>Parameter:</term>
4863 A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
4864 defaulting to 0 and the maximum to 65K).
4873 By default, i.e. if no <literal>limit-connect</literal> action applies,
4874 <application>Privoxy</application> allows HTTP CONNECT requests to all
4875 ports. Use <literal>limit-connect</literal> if fine-grained control
4876 is desired for some or all destinations.
4879 The CONNECT methods exists in HTTP to allow access to secure websites
4880 (<quote>https://</quote> URLs) through proxies. It works very simply:
4881 the proxy connects to the server on the specified port, and then
4882 short-circuits its connections to the client and to the remote server.
4883 This means CONNECT-enabled proxies can be used as TCP relays very easily.
4886 <application>Privoxy</application> relays HTTPS traffic without seeing
4887 the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
4888 filters. By specifying an invalid port range you can disable HTTPS entirely.
4894 <term>Example usages:</term>
4896 <!-- I had trouble getting the spacing to look right in my browser -->
4897 <!-- I probably have the wrong font setup, bollocks. -->
4898 <!-- Apparently the emphasis tag uses a proportional font no matter what -->
4900 <screen>+limit-connect{443} # Port 443 is OK.
4901 +limit-connect{80,443} # Ports 80 and 443 are OK.
4902 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
4903 +limit-connect{-} # All ports are OK
4904 +limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
4912 <!-- ~~~~~ New section ~~~~~ -->
4913 <sect3 renderas="sect4" id="limit-cookie-lifetime">
4914 <title>limit-cookie-lifetime</title>
4918 <term>Typical use:</term>
4920 <para>Limit the lifetime of HTTP cookies to a couple of minutes or hours.</para>
4925 <term>Effect:</term>
4928 Overwrites the expires field in Set-Cookie server headers if it's above the specified limit.
4935 <!-- Boolean, Parameterized, Multi-value -->
4937 <para>Parameterized.</para>
4942 <term>Parameter:</term>
4945 The lifetime limit in minutes, or 0.
4954 This action reduces the lifetime of HTTP cookies coming from the
4955 server to the specified number of minutes, starting from the time
4956 the cookie passes Privoxy.
4959 Cookies with a lifetime below the limit are not modified.
4960 The lifetime of session cookies is set to the specified limit.
4963 The effect of this action depends on the server.
4966 In case of servers which refresh their cookies with each response
4967 (or at least frequently), the lifetime limit set by this action
4969 Thus, a session associated with the cookie continues to work with
4970 this action enabled, as long as a new request is made before the
4971 last limit set is reached.
4974 However, some servers send their cookies once, with a lifetime of several
4975 years (the year 2037 is a popular choice), and do not refresh them
4976 until a certain event in the future, for example the user logging out.
4977 In this case this action may limit the absolute lifetime of the session,
4978 even if requests are made frequently.
4981 If the parameter is <quote>0</quote>, this action behaves like
4982 <literal><link linkend="session-cookies-only">session-cookies-only</link></literal>.
4988 <term>Example usages:</term>
4991 <screen>+limit-cookie-lifetime{60}
4999 <!-- ~~~~~ New section ~~~~~ -->
5000 <sect3 renderas="sect4" id="prevent-compression">
5001 <title>prevent-compression</title>
5005 <term>Typical use:</term>
5008 Ensure that servers send the content uncompressed, so it can be
5009 passed through <literal><link linkend="filter">filter</link></literal>s.
5015 <term>Effect:</term>
5018 Removes the Accept-Encoding header which can be used to ask for compressed transfer.
5025 <!-- Boolean, Parameterized, Multi-value -->
5027 <para>Boolean.</para>
5032 <term>Parameter:</term>
5044 More and more websites send their content compressed by default, which
5045 is generally a good idea and saves bandwidth. But the <literal><link
5046 linkend="filter">filter</link></literal> and
5047 <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
5048 actions need access to the uncompressed data.
5051 When compiled with zlib support (available since &my-app; 3.0.7), content that should be
5052 filtered is decompressed on-the-fly and you don't have to worry about this action.
5053 If you are using an older &my-app; version, or one that hasn't been compiled with zlib
5054 support, this action can be used to convince the server to send the content uncompressed.
5057 Most text-based instances compress very well, the size is seldom decreased by less than 50%,
5058 for markup-heavy instances like news feeds saving more than 90% of the original size isn't
5062 Not using compression will therefore slow down the transfer, and you should only
5063 enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
5064 predefined action settings.
5067 Note that some (rare) ill-configured sites don't handle requests for uncompressed
5068 documents correctly. Broken PHP applications tend to send an empty document body,
5069 some IIS versions only send the beginning of the content. If you enable
5070 <literal>prevent-compression</literal> per default, you might want to add
5071 exceptions for those sites. See the example for how to do that.
5077 <term>Example usage (sections):</term>
5081 # Selectively turn off compression, and enable a filter
5083 { +filter{tiny-textforms} +prevent-compression }
5084 # Match only these sites
5089 # Or instead, we could set a universal default:
5091 { +prevent-compression }
5094 # Then maybe make exceptions for broken sites:
5096 { -prevent-compression }
5097 .compusa.com/</screen>
5106 <!-- ~~~~~ New section ~~~~~ -->
5107 <sect3 renderas="sect4" id="overwrite-last-modified">
5108 <title>overwrite-last-modified</title>
5114 <term>Typical use:</term>
5116 <para>Prevent yet another way to track the user's steps between sessions.</para>
5121 <term>Effect:</term>
5124 Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
5131 <!-- Boolean, Parameterized, Multi-value -->
5133 <para>Parameterized.</para>
5138 <term>Parameter:</term>
5141 One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
5142 and <quote>randomize</quote>
5151 Removing the <quote>Last-Modified:</quote> header is useful for filter
5152 testing, where you want to force a real reload instead of getting status
5153 code <quote>304</quote>, which would cause the browser to reuse the old
5154 version of the page.
5157 The <quote>randomize</quote> option overwrites the value of the
5158 <quote>Last-Modified:</quote> header with a randomly chosen time
5159 between the original value and the current time. In theory the server
5160 could send each document with a different <quote>Last-Modified:</quote>
5161 header to track visits without using cookies. <quote>Randomize</quote>
5162 makes it impossible and the browser can still revalidate cached documents.
5165 <quote>reset-to-request-time</quote> overwrites the value of the
5166 <quote>Last-Modified:</quote> header with the current time. You could use
5167 this option together with
5168 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
5169 to further customize your random range.
5172 The preferred parameter here is <quote>randomize</quote>. It is safe
5173 to use, as long as the time settings are more or less correct.
5174 If the server sets the <quote>Last-Modified:</quote> header to the time
5175 of the request, the random range becomes zero and the value stays the same.
5176 Therefore you should later randomize it a second time with
5177 <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
5181 It is also recommended to use this action together with
5182 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
5188 <term>Example usage:</term>
5191 <screen># Let the browser revalidate without being tracked across sessions
5192 { +hide-if-modified-since{-60} \
5193 +overwrite-last-modified{randomize} \
5194 +crunch-if-none-match}
5203 <!-- ~~~~~ New section ~~~~~ -->
5204 <sect3 renderas="sect4" id="redirect">
5205 <title>redirect</title>
5211 <term>Typical use:</term>
5214 Redirect requests to other sites.
5220 <term>Effect:</term>
5223 Convinces the browser that the requested document has been moved
5224 to another location and the browser should get it from there.
5231 <!-- Boolean, Parameterized, Multi-value -->
5233 <para>Parameterized</para>
5238 <term>Parameter:</term>
5241 An absolute URL or a single pcrs command.
5250 Requests to which this action applies are answered with a
5251 HTTP redirect to URLs of your choosing. The new URL is
5252 either provided as parameter, or derived by applying a
5253 single pcrs command to the original URL.
5256 The syntax for pcrs commands is documented in the
5257 <link linkend="filter-file">filter file</link> section.
5260 This action will be ignored if you use it together with
5261 <literal><link linkend="block">block</link></literal>.
5262 It can be combined with
5263 <literal><link linkend="fast-redirects">fast-redirects{check-decoded-url}</link></literal>
5264 to redirect to a decoded version of a rewritten URL.
5267 Use this action carefully, make sure not to create redirection loops
5268 and be aware that using your own redirects might make it
5269 possible to fingerprint your requests.
5272 In case of problems with your redirects, or simply to watch
5273 them working, enable <link linkend="DEBUG">debug 128</link>.
5279 <term>Example usages:</term>
5282 <screen># Replace example.com's style sheet with another one
5283 { +redirect{http://localhost/css-replacements/example.com.css} }
5284 example.com/stylesheet\.css
5286 # Create a short, easy to remember nickname for a favorite site
5287 # (relies on the browser accept and forward invalid URLs to &my-app;)
5288 { +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
5291 # Always use the expanded view for Undeadly.org articles
5292 # (Note the $ at the end of the URL pattern to make sure
5293 # the request for the rewritten URL isn't redirected as well)
5294 {+redirect{s@$@&mode=expanded@}}
5295 undeadly.org/cgi\?action=article&sid=\d*$
5297 # Redirect Google search requests to MSN
5298 {+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}}
5301 # Redirect MSN search requests to Yahoo
5302 {+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}}
5303 search.msn.com//results\.aspx\?q=
5305 # Redirect remote requests for this manual
5306 # to the local version delivered by Privoxy
5307 {+redirect{s@^http://www@http://config@}}
5308 www.privoxy.org/user-manual/</screen>
5317 <!-- ~~~~~ New section ~~~~~ -->
5318 <sect3 renderas="sect4" id="server-header-filter">
5319 <title>server-header-filter</title>
5323 <term>Typical use:</term>
5326 Rewrite or remove single server headers.
5332 <term>Effect:</term>
5335 All server headers to which this action applies are filtered on-the-fly
5336 through the specified regular expression based substitutions.
5343 <!-- boolean, parameterized, Multi-value -->
5345 <para>Parameterized.</para>
5350 <term>Parameter:</term>
5353 The name of a server-header filter, as defined in one of the
5354 <link linkend="filter-file">filter files</link>.
5363 Server-header filters are applied to each header on its own, not to
5364 all at once. This makes it easier to diagnose problems, but on the downside
5365 you can't write filters that only change header x if header y's value is z.
5366 You can do that by using tags though.
5369 Server-header filters are executed after the other header actions have finished
5370 and use their output as input.
5373 Please refer to the <link linkend="filter-file">filter file chapter</link>
5374 to learn which server-header filters are available by default, and how to
5381 <term>Example usage (section):</term>
5385 {+server-header-filter{html-to-xml}}
5386 example.org/xml-instance-that-is-delivered-as-html
5388 {+server-header-filter{xml-to-html}}
5389 example.org/instance-that-is-delivered-as-xml-but-is-not
5399 <!-- ~~~~~ New section ~~~~~ -->
5400 <sect3 renderas="sect4" id="server-header-tagger">
5401 <title>server-header-tagger</title>
5405 <term>Typical use:</term>
5408 Enable or disable filters based on the Content-Type header.
5414 <term>Effect:</term>
5417 Server headers to which this action applies are filtered on-the-fly through
5418 the specified regular expression based substitutions, the result is used as
5426 <!-- boolean, parameterized, Multi-value -->
5428 <para>Parameterized.</para>
5433 <term>Parameter:</term>
5436 The name of a server-header tagger, as defined in one of the
5437 <link linkend="filter-file">filter files</link>.
5446 Server-header taggers are applied to each header on its own,
5447 and as the header isn't modified, each tagger <quote>sees</quote>
5451 Server-header taggers are executed before all other header actions
5452 that modify server headers. Their tags can be used to control
5453 all of the other server-header actions, the content filters
5454 and the crunch actions (<link linkend="redirect">redirect</link>
5455 and <link linkend="block">block</link>).
5458 Obviously crunching based on tags created by server-header taggers
5459 doesn't prevent the request from showing up in the server's log file.
5466 <term>Example usage (section):</term>
5470 # Tag every request with the content type declared by the server
5471 {+server-header-tagger{content-type}}
5482 <!-- ~~~~~ New section ~~~~~ -->
5483 <sect3 renderas="sect4" id="session-cookies-only">
5484 <title>session-cookies-only</title>
5488 <term>Typical use:</term>
5491 Allow only temporary <quote>session</quote> cookies (for the current
5492 browser session <emphasis>only</emphasis>).
5498 <term>Effect:</term>
5501 Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
5502 server headers. Most browsers will not store such cookies permanently and
5503 forget them in between sessions.
5510 <!-- Boolean, Parameterized, Multi-value -->
5512 <para>Boolean.</para>
5517 <term>Parameter:</term>
5529 This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
5530 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
5531 websites that insist or rely on setting cookies, without compromising your privacy too badly.
5534 Most browsers will not permanently store cookies that have been processed by
5535 <literal>session-cookies-only</literal> and will forget about them between sessions.
5536 This makes profiling cookies useless, but won't break sites which require cookies so
5537 that you can log in for transactions. This is generally turned on for all
5538 sites, and is the recommended setting.
5541 It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
5542 together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
5543 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
5544 will be plainly killed.
5547 Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
5548 field. If you use an exotic browser, you might want to try it out to be sure.
5551 This setting also has no effect on cookies that may have been stored
5552 previously by the browser before starting <application>Privoxy</application>.
5553 These would have to be removed manually.
5556 <application>Privoxy</application> also uses
5557 the <link linkend="filter-content-cookies">content-cookies filter</link>
5558 to block some types of cookies. Content cookies are not effected by
5559 <literal>session-cookies-only</literal>.
5565 <term>Example usage:</term>
5568 <screen>+session-cookies-only</screen>
5576 <!-- ~~~~~ New section ~~~~~ -->
5577 <sect3 renderas="sect4" id="set-image-blocker">
5578 <title>set-image-blocker</title>
5582 <term>Typical use:</term>
5584 <para>Choose the replacement for blocked images</para>
5589 <term>Effect:</term>
5592 This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
5593 <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
5594 linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
5595 apply, i.e. if the request is to be blocked as an image,
5596 <emphasis>then</emphasis> the parameter of this action decides what will be
5597 sent as a replacement.
5604 <!-- Boolean, Parameterized, Multi-value -->
5606 <para>Parameterized.</para>
5611 <term>Parameter:</term>
5616 <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
5617 decent, scales very well, and makes it obvious where banners were busted.
5622 <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
5623 completely, but makes it hard to detect where <application>Privoxy</application> has blocked
5624 images on a given page and complicates troubleshooting if <application>Privoxy</application>
5625 has blocked innocent images, like navigation icons.
5630 <quote><replaceable class="parameter">target-url</replaceable></quote> to
5631 send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
5632 to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
5633 (But note that not all browsers support redirecting to a local file system).
5636 A good application of redirects is to use special <application>Privoxy</application>-built-in
5637 URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
5638 This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
5639 the first place, but enables your browser to cache the replacement image, instead of requesting
5640 it over and over again.
5651 The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
5652 class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
5653 either <quote>blank</quote> or <quote>pattern</quote>.
5656 There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
5657 used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
5658 Auto will select the type of image that would have applied to the referring page, had it been an image.
5664 <term>Example usage:</term>
5670 <screen>+set-image-blocker{pattern}</screen>
5673 Redirect to the BSD daemon:
5676 <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
5679 Redirect to the built-in pattern for better caching:
5682 <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
5690 <!-- ~~~~~ New section ~~~~~ -->
5692 <title>Summary</title>
5694 Note that many of these actions have the potential to cause a page to
5695 misbehave, possibly even not to display at all. There are many ways
5696 a site designer may choose to design his site, and what HTTP header
5697 content, and other criteria, he may depend on. There is no way to have hard
5698 and fast rules for all sites. See the <link
5699 linkend="ACTIONSANAT">Appendix</link> for a brief example on troubleshooting
5705 <!-- ~~~~~ New section ~~~~~ -->
5706 <sect2 id="aliases">
5707 <title>Aliases</title>
5709 Custom <quote>actions</quote>, known to <application>Privoxy</application>
5710 as <quote>aliases</quote>, can be defined by combining other actions.
5711 These can in turn be invoked just like the built-in actions.
5712 Currently, an alias name can contain any character except space, tab,
5714 <quote>{</quote> and <quote>}</quote>, but we <emphasis>strongly
5715 recommend</emphasis> that you only use <quote>a</quote> to <quote>z</quote>,
5716 <quote>0</quote> to <quote>9</quote>, <quote>+</quote>, and <quote>-</quote>.
5717 Alias names are not case sensitive, and are not required to start with a
5718 <quote>+</quote> or <quote>-</quote> sign, since they are merely textually
5722 Aliases can be used throughout the actions file, but they <emphasis>must be
5723 defined in a special section at the top of the file!</emphasis>
5724 And there can only be one such section per actions file. Each actions file may
5725 have its own alias section, and the aliases defined in it are only visible
5729 There are two main reasons to use aliases: One is to save typing for frequently
5730 used combinations of actions, the other one is a gain in flexibility: If you
5731 decide once how you want to handle shops by defining an alias called
5732 <quote>shop</quote>, you can later change your policy on shops in
5733 <emphasis>one</emphasis> place, and your changes will take effect everywhere
5734 in the actions file where the <quote>shop</quote> alias is used. Calling aliases
5735 by their purpose also makes your actions files more readable.
5738 Currently, there is one big drawback to using aliases, though:
5739 <application>Privoxy</application>'s built-in web-based action file
5740 editor honors aliases when reading the actions files, but it expands
5741 them before writing. So the effects of your aliases are of course preserved,
5742 but the aliases themselves are lost when you edit sections that use aliases
5747 Now let's define some aliases...
5752 # Useful custom aliases we can use later.
5754 # Note the (required!) section header line and that this section
5755 # must be at the top of the actions file!
5759 # These aliases just save typing later:
5760 # (Note that some already use other aliases!)
5762 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5763 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5764 +block-as-image = +block{Blocked image.} +handle-as-image
5765 allow-all-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
5767 # These aliases define combinations of actions
5768 # that are useful for certain types of sites:
5770 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>
5772 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link>
5774 # Short names for other aliases, for really lazy people ;-)
5776 c0 = +crunch-all-cookies
5777 c1 = -crunch-all-cookies</screen>
5781 ...and put them to use. These sections would appear in the lower part of an
5782 actions file and define exceptions to the default actions (as specified further
5783 up for the <quote>/</quote> pattern):
5788 # These sites are either very complex or very keen on
5789 # user data and require minimal interference to work:
5792 .office.microsoft.com
5793 .windowsupdate.microsoft.com
5794 # Gmail is really mail.google.com, not gmail.com
5798 # Allow cookies (for setting and retrieving your customer data)
5802 .worldpay.com # for quietpc.com
5805 # These shops require pop-ups:
5807 {-filter{all-popups} -filter{unsolicited-popups}}
5809 .overclockers.co.uk</screen>
5813 Aliases like <quote>shop</quote> and <quote>fragile</quote> are typically used for
5814 <quote>problem</quote> sites that require more than one action to be disabled
5815 in order to function properly.
5821 <!-- ~~~~~ New section ~~~~~ -->
5822 <sect2 id="act-examples">
5823 <title>Actions Files Tutorial</title>
5825 The above chapters have shown <link linkend="actions-file">which actions files
5826 there are and how they are organized</link>, how actions are <link
5827 linkend="actions">specified</link> and <link linkend="actions-apply">applied
5828 to URLs</link>, how <link linkend="af-patterns">patterns</link> work, and how to
5829 define and use <link linkend="aliases">aliases</link>. Now, let's look at an
5830 example <filename>match-all.action</filename>, <filename>default.action</filename>
5831 and <filename>user.action</filename> file and see how all these pieces come together:
5835 <title>match-all.action</title>
5837 Remember <emphasis>all actions are disabled when matching starts</emphasis>,
5838 so we have to explicitly enable the ones we want.
5842 While the <filename>match-all.action</filename> file only contains a
5843 single section, it is probably the most important one. It has only one
5844 pattern, <quote><literal>/</literal></quote>, but this pattern
5845 <link linkend="af-patterns">matches all URLs</link>. Therefore, the set of
5846 actions used in this <quote>default</quote> section <emphasis>will
5847 be applied to all requests as a start</emphasis>. It can be partly or
5848 wholly overridden by other actions files like <filename>default.action</filename>
5849 and <filename>user.action</filename>, but it will still be largely responsible
5850 for your overall browsing experience.
5854 Again, at the start of matching, all actions are disabled, so there is
5855 no need to disable any actions here. (Remember: a <quote>+</quote>
5856 preceding the action name enables the action, a <quote>-</quote> disables!).
5857 Also note how this long line has been made more readable by splitting it into
5858 multiple lines with line continuation.
5864 +<link linkend="CHANGE-X-FORWARDED-FOR">change-x-forwarded-for{block}</link> \
5865 +<link linkend="HIDE-FROM-HEADER">hide-from-header{block}</link> \
5866 +<link linkend="SET-IMAGE-BLOCKER">set-image-blocker{pattern}</link> \
5873 The default behavior is now set.
5878 <title>default.action</title>
5881 If you aren't a developer, there's no need for you to edit the
5882 <filename>default.action</filename> file. It is maintained by
5883 the &my-app; developers and if you disagree with some of the
5884 sections, you should overrule them in your <filename>user.action</filename>.
5888 Understanding the <filename>default.action</filename> file can
5889 help you with your <filename>user.action</filename>, though.
5893 The first section in this file is a special section for internal use
5894 that prevents older &my-app; versions from reading the file:
5899 ##########################################################################
5900 # Settings -- Don't change! For internal Privoxy use ONLY.
5901 ##########################################################################
5903 for-privoxy-version=3.0.11</screen>
5907 After that comes the (optional) alias section. We'll use the example
5908 section from the above <link linkend="aliases">chapter on aliases</link>,
5909 that also explains why and how aliases are used:
5914 ##########################################################################
5916 ##########################################################################
5919 # These aliases just save typing later:
5920 # (Note that some already use other aliases!)
5922 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5923 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5924 +block-as-image = +block{Blocked image.} +handle-as-image
5925 mercy-for-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
5927 # These aliases define combinations of actions
5928 # that are useful for certain types of sites:
5930 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>
5931 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link></screen>
5935 The first of our specialized sections is concerned with <quote>fragile</quote>
5936 sites, i.e. sites that require minimum interference, because they are either
5937 very complex or very keen on tracking you (and have mechanisms in place that
5938 make them unusable for people who avoid being tracked). We will simply use
5939 our pre-defined <literal>fragile</literal> alias instead of stating the list
5940 of actions explicitly:
5945 ##########################################################################
5946 # Exceptions for sites that'll break under the default action set:
5947 ##########################################################################
5949 # "Fragile" Use a minimum set of actions for these sites (see alias above):
5952 .office.microsoft.com # surprise, surprise!
5953 .windowsupdate.microsoft.com
5954 mail.google.com</screen>
5958 Shopping sites are not as fragile, but they typically
5959 require cookies to log in, and pop-up windows for shopping
5960 carts or item details. Again, we'll use a pre-defined alias:
5969 .worldpay.com # for quietpc.com
5971 .scan.co.uk</screen>
5975 The <literal><link linkend="FAST-REDIRECTS">fast-redirects</link></literal>
5976 action, which may have been enabled in <filename>match-all.action</filename>,
5977 breaks some sites. So disable it for popular sites where we know it misbehaves:
5982 { -<link linkend="FAST-REDIRECTS">fast-redirects</link> }
5986 .altavista.com/.*(like|url|link):http
5987 .altavista.com/trans.*urltext=http
5988 .nytimes.com</screen>
5992 It is important that <application>Privoxy</application> knows which
5993 URLs belong to images, so that <emphasis>if</emphasis> they are to
5994 be blocked, a substitute image can be sent, rather than an HTML page.
5995 Contacting the remote site to find out is not an option, since it
5996 would destroy the loading time advantage of banner blocking, and it
5997 would feed the advertisers information about you. We can mark any
5998 URL as an image with the <literal><link
5999 linkend="handle-as-image">handle-as-image</link></literal> action,
6000 and marking all URLs that end in a known image file extension is a
6006 ##########################################################################
6008 ##########################################################################
6010 # Define which file types will be treated as images, in case they get
6011 # blocked further down this file:
6013 { +<link linkend="HANDLE-AS-IMAGE">handle-as-image</link> }
6014 /.*\.(gif|jpe?g|png|bmp|ico)$</screen>
6018 And then there are known banner sources. They often use scripts to
6019 generate the banners, so it won't be visible from the URL that the
6020 request is for an image. Hence we block them <emphasis>and</emphasis>
6021 mark them as images in one go, with the help of our
6022 <literal>+block-as-image</literal> alias defined above. (We could of
6023 course just as well use <literal>+<link linkend="block">block</link>
6024 +<link linkend="handle-as-image">handle-as-image</link></literal> here.)
6025 Remember that the type of the replacement image is chosen by the
6026 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
6027 action. Since all URLs have matched the default section with its
6028 <literal>+<link linkend="set-image-blocker">set-image-blocker</link>{pattern}</literal>
6029 action before, it still applies and needn't be repeated:
6034 # Known ad generators:
6039 .ad.*.doubleclick.net
6040 .a.yimg.com/(?:(?!/i/).)*$
6041 .a[0-9].yimg.com/(?:(?!/i/).)*$
6047 One of the most important jobs of <application>Privoxy</application>
6048 is to block banners. Many of these can be <quote>blocked</quote>
6049 by the <literal><link linkend="filter">filter</link>{banners-by-size}</literal>
6050 action, which we enabled above, and which deletes the references to banner
6051 images from the pages while they are loaded, so the browser doesn't request
6052 them anymore, and hence they don't need to be blocked here. But this naturally
6053 doesn't catch all banners, and some people choose not to use filters, so we
6054 need a comprehensive list of patterns for banner URLs here, and apply the
6055 <literal><link linkend="block">block</link></literal> action to them.
6058 First comes many generic patterns, which do most of the work, by
6059 matching typical domain and path name components of banners. Then comes
6060 a list of individual patterns for specific sites, which is omitted here
6061 to keep the example short:
6066 ##########################################################################
6067 # Block these fine banners:
6068 ##########################################################################
6069 { <link linkend="BLOCK">+block{Banner ads.}</link> }
6077 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
6078 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
6080 # Site-specific patterns (abbreviated):
6082 .hitbox.com</screen>
6086 It's quite remarkable how many advertisers actually call their banner
6087 servers ads.<replaceable>company</replaceable>.com, or call the directory
6088 in which the banners are stored simply <quote>banners</quote>. So the above
6089 generic patterns are surprisingly effective.
6092 But being very generic, they necessarily also catch URLs that we don't want
6093 to block. The pattern <literal>.*ads.</literal> e.g. catches
6094 <quote>nasty-<emphasis>ads</emphasis>.nasty-corp.com</quote> as intended,
6095 but also <quote>downlo<emphasis>ads</emphasis>.sourcefroge.net</quote> or
6096 <quote><emphasis>ads</emphasis>l.some-provider.net.</quote> So here come some
6097 well-known exceptions to the <literal>+<link linkend="BLOCK">block</link></literal>
6101 Note that these are exceptions to exceptions from the default! Consider the URL
6102 <quote>downloads.sourcefroge.net</quote>: Initially, all actions are deactivated,
6103 so it wouldn't get blocked. Then comes the defaults section, which matches the
6104 URL, but just deactivates the <literal><link linkend="BLOCK">block</link></literal>
6105 action once again. Then it matches <literal>.*ads.</literal>, an exception to the
6106 general non-blocking policy, and suddenly
6107 <literal><link linkend="BLOCK">+block</link></literal> applies. And now, it'll match
6108 <literal>.*loads.</literal>, where <literal><link linkend="BLOCK">-block</link></literal>
6109 applies, so (unless it matches <emphasis>again</emphasis> further down) it ends up
6110 with no <literal><link linkend="BLOCK">block</link></literal> action applying.
6115 ##########################################################################
6116 # Save some innocent victims of the above generic block patterns:
6117 ##########################################################################
6121 { -<link linkend="BLOCK">block</link> }
6122 adv[io]*. # (for advogato.org and advice.*)
6123 adsl. # (has nothing to do with ads)
6124 adobe. # (has nothing to do with ads either)
6125 ad[ud]*. # (adult.* and add.*)
6126 .edu # (universities don't host banners (yet!))
6127 .*loads. # (downloads, uploads etc)
6135 www.globalintersec.com/adv # (adv = advanced)
6136 www.ugu.com/sui/ugu/adv</screen>
6140 Filtering source code can have nasty side effects,
6141 so make an exception for our friends at sourceforge.net,
6142 and all paths with <quote>cvs</quote> in them. Note that
6143 <literal>-<link linkend="FILTER">filter</link></literal>
6144 disables <emphasis>all</emphasis> filters in one fell swoop!
6149 # Don't filter code!
6151 { -<link linkend="FILTER">filter</link> }
6156 .sourceforge.net</screen>
6160 The actual <filename>default.action</filename> is of course much more
6161 comprehensive, but we hope this example made clear how it works.
6166 <sect3><title>user.action</title>
6169 So far we are painting with a broad brush by setting general policies,
6170 which would be a reasonable starting point for many people. Now,
6171 you might want to be more specific and have customized rules that
6172 are more suitable to your personal habits and preferences. These would
6173 be for narrowly defined situations like your ISP or your bank, and should
6174 be placed in <filename>user.action</filename>, which is parsed after all other
6175 actions files and hence has the last word, over-riding any previously
6176 defined actions. <filename>user.action</filename> is also a
6177 <emphasis>safe</emphasis> place for your personal settings, since
6178 <filename>default.action</filename> is actively maintained by the
6179 <application>Privoxy</application> developers and you'll probably want
6180 to install updated versions from time to time.
6184 So let's look at a few examples of things that one might typically do in
6185 <filename>user.action</filename>:
6189 <!-- brief sample user.action here -->
6193 # My user.action file. <fred@example.com></screen>
6197 As <link linkend="aliases">aliases</link> are local to the actions
6198 file that they are defined in, you can't use the ones from
6199 <filename>default.action</filename>, unless you repeat them here:
6204 # Aliases are local to the file they are defined in.
6205 # (Re-)define aliases for this file:
6209 # These aliases just save typing later, and the alias names should
6210 # be self explanatory.
6212 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
6213 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
6214 allow-all-cookies = -crunch-all-cookies -session-cookies-only
6215 allow-popups = -filter{all-popups}
6216 +block-as-image = +block{Blocked as image.} +handle-as-image
6217 -block-as-image = -block
6219 # These aliases define combinations of actions that are useful for
6220 # certain types of sites:
6222 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer
6223 shop = -crunch-all-cookies allow-popups
6225 # Allow ads for selected useful free sites:
6227 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
6229 # Alias for specific file types that are text, but might have conflicting
6230 # MIME types. We want the browser to force these to be text documents.
6231 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>
6236 Say you have accounts on some sites that you visit regularly, and
6237 you don't want to have to log in manually each time. So you'd like
6238 to allow persistent cookies for these sites. The
6239 <literal>allow-all-cookies</literal> alias defined above does exactly
6240 that, i.e. it disables crunching of cookies in any direction, and the
6241 processing of cookies to make them only temporary.
6246 { allow-all-cookies }
6250 .redhat.com</screen>
6254 Your bank is allergic to some filter, but you don't know which, so you disable them all:
6259 { -<link linkend="FILTER">filter</link> }
6260 .your-home-banking-site.com</screen>
6264 Some file types you may not want to filter for various reasons:
6269 # Technical documentation is likely to contain strings that might
6270 # erroneously get altered by the JavaScript-oriented filters:
6275 # And this stupid host sends streaming video with a wrong MIME type,
6276 # so that Privoxy thinks it is getting HTML and starts filtering:
6278 stupid-server.example.com/</screen>
6282 Example of a simple <link linkend="BLOCK">block</link> action. Say you've
6283 seen an ad on your favourite page on example.com that you want to get rid of.
6284 You have right-clicked the image, selected <quote>copy image location</quote>
6285 and pasted the URL below while removing the leading http://, into a
6286 <literal>{ +block{} }</literal> section. Note that <literal>{ +handle-as-image
6287 }</literal> need not be specified, since all URLs ending in
6288 <literal>.gif</literal> will be tagged as images by the general rules as set
6289 in default.action anyway:
6294 { +<link linkend="BLOCK">block</link>{Nasty ads.} }
6295 www.example.com/nasty-ads/sponsor\.gif
6296 another.example.net/more/junk/here/</screen>
6300 The URLs of dynamically generated banners, especially from large banner
6301 farms, often don't use the well-known image file name extensions, which
6302 makes it impossible for <application>Privoxy</application> to guess
6303 the file type just by looking at the URL.
6304 You can use the <literal>+block-as-image</literal> alias defined above for
6306 Note that objects which match this rule but then turn out NOT to be an
6307 image are typically rendered as a <quote>broken image</quote> icon by the
6308 browser. Use cautiously.
6317 ar.atwola.com/</screen>
6321 Now you noticed that the default configuration breaks Forbes Magazine,
6322 but you were too lazy to find out which action is the culprit, and you
6323 were again too lazy to give <link linkend="contact">feedback</link>, so
6324 you just used the <literal>fragile</literal> alias on the site, and
6325 -- <emphasis>whoa!</emphasis> -- it worked. The <literal>fragile</literal>
6326 aliases disables those actions that are most likely to break a site. Also,
6327 good for testing purposes to see if it is <application>Privoxy</application>
6328 that is causing the problem or not. We later find other regular sites
6329 that misbehave, and add those to our personalized list of troublemakers:
6337 .mybank.com</screen>
6341 You like the <quote>fun</quote> text replacements in <filename>default.filter</filename>,
6342 but it is disabled in the distributed actions file.
6343 So you'd like to turn it on in your private,
6344 update-safe config, once and for all:
6349 { +<link linkend="filter-fun">filter{fun}</link> }
6350 / # For ALL sites!</screen>
6354 Note that the above is not really a good idea: There are exceptions
6355 to the filters in <filename>default.action</filename> for things that
6356 really shouldn't be filtered, like code on CVS->Web interfaces. Since
6357 <filename>user.action</filename> has the last word, these exceptions
6358 won't be valid for the <quote>fun</quote> filtering specified here.
6362 You might also worry about how your favourite free websites are
6363 funded, and find that they rely on displaying banner advertisements
6364 to survive. So you might want to specifically allow banners for those
6365 sites that you feel provide value to you:
6377 Note that <literal>allow-ads</literal> has been aliased to
6378 <literal>-<link linkend="block">block</link></literal>,
6379 <literal>-<link linkend="filter-banners-by-size">filter{banners-by-size}</link></literal>, and
6380 <literal>-<link linkend="filter-banners-by-link">filter{banners-by-link}</link></literal> above.
6384 Invoke another alias here to force an over-ride of the MIME type <literal>
6385 application/x-sh</literal> which typically would open a download type
6386 dialog. In my case, I want to look at the shell script, and then I can save
6387 it should I choose to.
6397 <filename>user.action</filename> is generally the best place to define
6398 exceptions and additions to the default policies of
6399 <filename>default.action</filename>. Some actions are safe to have their
6400 default policies set here though. So let's set a default policy to have a
6401 <quote>blank</quote> image as opposed to the checkerboard pattern for
6402 <emphasis>ALL</emphasis> sites. <quote>/</quote> of course matches all URL
6408 { +<link linkend="set-image-blocker">set-image-blocker{blank}</link> }
6409 / # ALL sites</screen>
6415 <!-- ~ End section ~ -->
6419 <!-- ~ End section ~ -->
6421 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6423 <sect1 id="filter-file">
6424 <title>Filter Files</title>
6427 On-the-fly text substitutions need
6428 to be defined in a <quote>filter file</quote>. Once defined, they
6429 can then be invoked as an <quote>action</quote>.
6433 &my-app; supports three different filter actions:
6434 <literal><link linkend="filter">filter</link></literal> to
6435 rewrite the content that is send to the client,
6436 <literal><link linkend="client-header-filter">client-header-filter</link></literal>
6437 to rewrite headers that are send by the client, and
6438 <literal><link linkend="server-header-filter">server-header-filter</link></literal>
6439 to rewrite headers that are send by the server.
6443 &my-app; also supports two tagger actions:
6444 <literal><link linkend="client-header-tagger">client-header-tagger</link></literal>
6446 <literal><link linkend="server-header-tagger">server-header-tagger</link></literal>.
6447 Taggers and filters use the same syntax in the filter files, the difference
6448 is that taggers don't modify the text they are filtering, but use a rewritten
6449 version of the filtered text as tag. The tags can then be used to change the
6450 applying actions through sections with <link linkend="tag-pattern">tag-patterns</link>.
6455 Multiple filter files can be defined through the <literal> <link
6456 linkend="filterfile">filterfile</link></literal> config directive. The filters
6457 as supplied by the developers are located in
6458 <filename>default.filter</filename>. It is recommended that any locally
6459 defined or modified filters go in a separately defined file such as
6460 <filename>user.filter</filename>.
6464 Common tasks for content filters are to eliminate common annoyances in
6465 HTML and JavaScript, such as pop-up windows,
6466 exit consoles, crippled windows without navigation tools, the
6467 infamous <BLINK> tag etc, to suppress images with certain
6468 width and height attributes (standard banner sizes or web-bugs),
6469 or just to have fun.
6473 Enabled content filters are applied to any content whose
6474 <quote>Content Type</quote> header is recognised as a sign
6475 of text-based content, with the exception of <literal>text/plain</literal>.
6476 Use the <link linkend="FORCE-TEXT-MODE">force-text-mode</link> action
6477 to also filter other content.
6481 Substitutions are made at the source level, so if you want to <quote>roll
6482 your own</quote> filters, you should first be familiar with HTML syntax,
6483 and, of course, regular expressions.
6487 Just like the <link linkend="actions-file">actions files</link>, the
6488 filter file is organized in sections, which are called <emphasis>filters</emphasis>
6489 here. Each filter consists of a heading line, that starts with one of the
6490 <emphasis>keywords</emphasis> <literal>FILTER:</literal>,
6491 <literal>CLIENT-HEADER-FILTER:</literal> or <literal>SERVER-HEADER-FILTER:</literal>
6492 followed by the filter's <emphasis>name</emphasis>, and a short (one line)
6493 <emphasis>description</emphasis> of what it does. Below that line
6494 come the <emphasis>jobs</emphasis>, i.e. lines that define the actual
6495 text substitutions. By convention, the name of a filter
6496 should describe what the filter <emphasis>eliminates</emphasis>. The
6497 comment is used in the <ulink url="http://config.privoxy.org/">web-based
6498 user interface</ulink>.
6502 Once a filter called <replaceable>name</replaceable> has been defined
6503 in the filter file, it can be invoked by using an action of the form
6504 +<literal><link linkend="filter">filter</link>{<replaceable>name</replaceable>}</literal>
6505 in any <link linkend="actions-file">actions file</link>.
6509 Filter definitions start with a header line that contains the filter
6510 type, the filter name and the filter description.
6511 A content filter header line for a filter called <quote>foo</quote> could look
6516 <screen>FILTER: foo Replace all "foo" with "bar"</screen>
6520 Below that line, and up to the next header line, come the jobs that
6521 define what text replacements the filter executes. They are specified
6522 in a syntax that imitates <ulink url="http://www.perl.org/">Perl</ulink>'s
6523 <literal>s///</literal> operator. If you are familiar with Perl, you
6524 will find this to be quite intuitive, and may want to look at the
6525 PCRS documentation for the subtle differences to Perl behaviour. Most
6526 notably, the non-standard option letter <literal>U</literal> is supported,
6527 which turns the default to ungreedy matching.
6532 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
6533 Expressions</quote></ulink>, you might want to take a look at
6534 the <link linkend="regex">Appendix on regular expressions</link>, and
6535 see the <ulink url="http://perldoc.perl.org/perlre.html">Perl
6537 <ulink url="http://perldoc.perl.org/perlop.html">the
6538 <literal>s///</literal> operator's syntax</ulink> and <ulink
6539 url="http://perldoc.perl.org/perlre.html">Perl-style regular
6540 expressions</ulink> in general.
6541 The below examples might also help to get you started.
6545 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6547 <sect2><title>Filter File Tutorial</title>
6549 Now, let's complete our <quote>foo</quote> content filter. We have already defined
6550 the heading, but the jobs are still missing. Since all it does is to replace
6551 <quote>foo</quote> with <quote>bar</quote>, there is only one (trivial) job
6556 <screen>s/foo/bar/</screen>
6560 But wait! Didn't the comment say that <emphasis>all</emphasis> occurrences
6561 of <quote>foo</quote> should be replaced? Our current job will only take
6562 care of the first <quote>foo</quote> on each page. For global substitution,
6563 we'll need to add the <literal>g</literal> option:
6567 <screen>s/foo/bar/g</screen>
6571 Our complete filter now looks like this:
6574 <screen>FILTER: foo Replace all "foo" with "bar"
6575 s/foo/bar/g</screen>
6579 Let's look at some real filters for more interesting examples. Here you see
6580 a filter that protects against some common annoyances that arise from JavaScript
6581 abuse. Let's look at its jobs one after the other:
6587 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
6589 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
6591 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg</screen>
6595 Following the header line and a comment, you see the job. Note that it uses
6596 <literal>|</literal> as the delimiter instead of <literal>/</literal>, because
6597 the pattern contains a forward slash, which would otherwise have to be escaped
6598 by a backslash (<literal>\</literal>).
6602 Now, let's examine the pattern: it starts with the text <literal><script.*</literal>
6603 enclosed in parentheses. Since the dot matches any character, and <literal>*</literal>
6604 means: <quote>Match an arbitrary number of the element left of myself</quote>, this
6605 matches <quote><script</quote>, followed by <emphasis>any</emphasis> text, i.e.
6606 it matches the whole page, from the start of the first <script> tag.
6610 That's more than we want, but the pattern continues: <literal>document\.referrer</literal>
6611 matches only the exact string <quote>document.referrer</quote>. The dot needed to
6612 be <emphasis>escaped</emphasis>, i.e. preceded by a backslash, to take away its
6613 special meaning as a joker, and make it just a regular dot. So far, the meaning is:
6614 Match from the start of the first <script> tag in a the page, up to, and including,
6615 the text <quote>document.referrer</quote>, if <emphasis>both</emphasis> are present
6616 in the page (and appear in that order).
6620 But there's still more pattern to go. The next element, again enclosed in parentheses,
6621 is <literal>.*</script></literal>. You already know what <literal>.*</literal>
6622 means, so the whole pattern translates to: Match from the start of the first <script>
6623 tag in a page to the end of the last <script> tag, provided that the text
6624 <quote>document.referrer</quote> appears somewhere in between.
6628 This is still not the whole story, since we have ignored the options and the parentheses:
6629 The portions of the page matched by sub-patterns that are enclosed in parentheses, will be
6630 remembered and be available through the variables <literal>$1, $2, ...</literal> in
6631 the substitute. The <literal>U</literal> option switches to ungreedy matching, which means
6632 that the first <literal>.*</literal> in the pattern will only <quote>eat up</quote> all
6633 text in between <quote><script</quote> and the <emphasis>first</emphasis> occurrence
6634 of <quote>document.referrer</quote>, and that the second <literal>.*</literal> will
6635 only span the text up to the <emphasis>first</emphasis> <quote></script></quote>
6636 tag. Furthermore, the <literal>s</literal> option says that the match may span
6637 multiple lines in the page, and the <literal>g</literal> option again means that the
6638 substitution is global.
6642 So, to summarize, the pattern means: Match all scripts that contain the text
6643 <quote>document.referrer</quote>. Remember the parts of the script from
6644 (and including) the start tag up to (and excluding) the string
6645 <quote>document.referrer</quote> as <literal>$1</literal>, and the part following
6646 that string, up to and including the closing tag, as <literal>$2</literal>.
6650 Now the pattern is deciphered, but wasn't this about substituting things? So
6651 lets look at the substitute: <literal>$1"Not Your Business!"$2</literal> is
6652 easy to read: The text remembered as <literal>$1</literal>, followed by
6653 <literal>"Not Your Business!"</literal> (<emphasis>including</emphasis>
6654 the quotation marks!), followed by the text remembered as <literal>$2</literal>.
6655 This produces an exact copy of the original string, with the middle part
6656 (the <quote>document.referrer</quote>) replaced by <literal>"Not Your
6657 Business!"</literal>.
6661 The whole job now reads: Replace <quote>document.referrer</quote> by
6662 <literal>"Not Your Business!"</literal> wherever it appears inside a
6663 <script> tag. Note that this job won't break JavaScript syntax,
6664 since both the original and the replacement are syntactically valid
6665 string objects. The script just won't have access to the referrer
6666 information anymore.
6670 We'll show you two other jobs from the JavaScript taming department, but
6671 this time only point out the constructs of special interest:
6676 # The status bar is for displaying link targets, not pointless blahblah
6678 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig</screen>
6682 <literal>\s</literal> stands for whitespace characters (space, tab, newline,
6683 carriage return, form feed), so that <literal>\s*</literal> means: <quote>zero
6684 or more whitespace</quote>. The <literal>?</literal> in <literal>.*?</literal>
6685 makes this matching of arbitrary text ungreedy. (Note that the <literal>U</literal>
6686 option is not set). The <literal>['"]</literal> construct means: <quote>a single
6687 <emphasis>or</emphasis> a double quote</quote>. Finally, <literal>\1</literal> is
6688 a back-reference to the first parenthesis just like <literal>$1</literal> above,
6689 with the difference that in the <emphasis>pattern</emphasis>, a backslash indicates
6690 a back-reference, whereas in the <emphasis>substitute</emphasis>, it's the dollar.
6694 So what does this job do? It replaces assignments of single- or double-quoted
6695 strings to the <quote>window.status</quote> object with a dummy assignment
6696 (using a variable name that is hopefully odd enough not to conflict with
6697 real variables in scripts). Thus, it catches many cases where e.g. pointless
6698 descriptions are displayed in the status bar instead of the link target when
6699 you move your mouse over links.
6704 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
6706 s/(<body [^>]*)onunload(.*>)/$1never$2/iU</screen>
6711 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">OnUnload
6712 event binding</ulink> in the HTML DOM was a <emphasis>CRIME</emphasis>.
6713 When I close a browser window, I want it to close and die. Basta.
6714 This job replaces the <quote>onunload</quote> attribute in
6715 <quote><body></quote> tags with the dummy word <literal>never</literal>.
6716 Note that the <literal>i</literal> option makes the pattern matching
6717 case-insensitive. Also note that ungreedy matching alone doesn't always guarantee
6718 a minimal match: In the first parenthesis, we had to use <literal>[^>]*</literal>
6719 instead of <literal>.*</literal> to prevent the match from exceeding the
6720 <body> tag if it doesn't contain <quote>OnUnload</quote>, but the page's
6725 The last example is from the fun department:
6730 FILTER: fun Fun text replacements
6732 # Spice the daily news:
6734 s/microsoft(?!\.com)/MicroSuck/ig</screen>
6738 Note the <literal>(?!\.com)</literal> part (a so-called negative lookahead)
6739 in the job's pattern, which means: Don't match, if the string
6740 <quote>.com</quote> appears directly following <quote>microsoft</quote>
6741 in the page. This prevents links to microsoft.com from being trashed, while
6742 still replacing the word everywhere else.
6747 # Buzzword Bingo (example for extended regex syntax)
6749 s* industry[ -]leading \
6751 | customer[ -]focused \
6752 | market[ -]driven \
6753 | award[ -]winning # Comments are OK, too! \
6754 | high[ -]performance \
6755 | solutions[ -]based \
6759 *<font color="red"><b>BINGO!</b></font> \
6764 The <literal>x</literal> option in this job turns on extended syntax, and allows for
6765 e.g. the liberal use of (non-interpreted!) whitespace for nicer formatting.
6773 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6775 <sect2 id="predefined-filters"><title>The Pre-defined Filters</title>
6779 Note each filter is also listed in the +filter action section above. Please
6780 keep these listings in sync.
6785 The distribution <filename>default.filter</filename> file contains a selection of
6786 pre-defined filters for your convenience:
6791 <term><emphasis>js-annoyances</emphasis></term>
6794 The purpose of this filter is to get rid of particularly annoying JavaScript abuse.
6799 replaces JavaScript references to the browser's referrer information
6800 with the string "Not Your Business!". This compliments the <literal><link
6801 linkend="hide-referrer">hide-referrer</link></literal> action on the content level.
6806 removes the bindings to the DOM's
6807 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">unload
6808 event</ulink> which we feel has no right to exist and is responsible for most <quote>exit consoles</quote>, i.e.
6809 nasty windows that pop up when you close another one.
6814 removes code that causes new windows to be opened with undesired properties, such as being
6815 full-screen, non-resizeable, without location, status or menu bar etc.
6821 Use with caution. This is an aggressive filter, and can break sites that
6822 rely heavily on JavaScript.
6828 <term><emphasis>js-events</emphasis></term>
6831 This is a very radical measure. It removes virtually all JavaScript event bindings, which
6832 means that scripts can not react to user actions such as mouse movements or clicks, window
6833 resizing etc, anymore. Use with caution!
6836 We <emphasis>strongly discourage</emphasis> using this filter as a default since it breaks
6837 many legitimate scripts. It is meant for use only on extra-nasty sites (should you really
6844 <term><emphasis>html-annoyances</emphasis></term>
6847 This filter will undo many common instances of HTML based abuse.
6850 The <literal>BLINK</literal> and <literal>MARQUEE</literal> tags
6851 are neutralized (yeah baby!), and browser windows will be created as
6852 resizeable (as of course they should be!), and will have location,
6853 scroll and menu bars -- even if specified otherwise.
6859 <term><emphasis>content-cookies</emphasis></term>
6862 Most cookies are set in the HTTP dialog, where they can be intercepted
6864 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>
6865 and <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>
6866 actions. But web sites increasingly make use of HTML meta tags and JavaScript
6867 to sneak cookies to the browser on the content level.
6870 This filter disables most HTML and JavaScript code that reads or sets
6871 cookies. It cannot detect all clever uses of these types of code, so it
6872 should not be relied on as an absolute fix. Use it wherever you would also
6873 use the cookie crunch actions.
6879 <term><emphasis>refresh-tags</emphasis></term>
6882 Disable any refresh tags if the interval is greater than nine seconds (so
6883 that redirections done via refresh tags are not destroyed). This is useful
6884 for dial-on-demand setups, or for those who find this HTML feature
6891 <term><emphasis>unsolicited-popups</emphasis></term>
6894 This filter attempts to prevent only <quote>unsolicited</quote> pop-up
6895 windows from opening, yet still allow pop-up windows that the user
6896 has explicitly chosen to open. It was added in version 3.0.1,
6897 as an improvement over earlier such filters.
6900 Technical note: The filter works by redefining the window.open JavaScript
6901 function to a dummy function, <literal>PrivoxyWindowOpen()</literal>,
6902 during the loading and rendering phase of each HTML page access, and
6903 restoring the function afterward.
6906 This is recommended only for browsers that cannot perform this function
6907 reliably themselves. And be aware that some sites require such windows
6908 in order to function normally. Use with caution.
6914 <term><emphasis>all-popups</emphasis></term>
6917 Attempt to prevent <emphasis>all</emphasis> pop-up windows from opening.
6918 Note this should be used with even more discretion than the above, since
6919 it is more likely to break some sites that require pop-ups for normal
6920 usage. Use with caution.
6926 <term><emphasis>img-reorder</emphasis></term>
6929 This is a helper filter that has no value if used alone. It makes the
6930 <literal>banners-by-size</literal> and <literal>banners-by-link</literal>
6931 (see below) filters more effective and should be enabled together with them.
6937 <term><emphasis>banners-by-size</emphasis></term>
6940 This filter removes image tags purely based on what size they are. Fortunately
6941 for us, many ads and banner images tend to conform to certain standardized
6942 sizes, which makes this filter quite effective for ad stripping purposes.
6945 Occasionally this filter will cause false positives on images that are not ads,
6946 but just happen to be of one of the standard banner sizes.
6949 Recommended only for those who require extreme ad blocking. The default
6950 block rules should catch 95+% of all ads <emphasis>without</emphasis> this filter enabled.
6956 <term><emphasis>banners-by-link</emphasis></term>
6959 This is an experimental filter that attempts to kill any banners if
6960 their URLs seem to point to known or suspected click trackers. It is currently
6961 not of much value and is not recommended for use by default.
6967 <term><emphasis>webbugs</emphasis></term>
6970 Webbugs are small, invisible images (technically 1X1 GIF images), that
6971 are used to track users across websites, and collect information on them.
6972 As an HTML page is loaded by the browser, an embedded image tag causes the
6973 browser to contact a third-party site, disclosing the tracking information
6974 through the requested URL and/or cookies for that third-party domain, without
6975 the user ever becoming aware of the interaction with the third-party site.
6976 HTML-ized spam also uses a similar technique to verify email addresses.
6979 This filter removes the HTML code that loads such <quote>webbugs</quote>.
6985 <term><emphasis>tiny-textforms</emphasis></term>
6988 A rather special-purpose filter that can be used to enlarge textareas (those
6989 multi-line text boxes in web forms) and turn off hard word wrap in them.
6990 It was written for the sourceforge.net tracker system where such boxes are
6991 a nuisance, but it can be handy on other sites, too.
6994 It is not recommended to use this filter as a default.
7000 <term><emphasis>jumping-windows</emphasis></term>
7003 Many consider windows that move, or resize themselves to be abusive. This filter
7004 neutralizes the related JavaScript code. Note that some sites might not display
7005 or behave as intended when using this filter. Use with caution.
7011 <term><emphasis>frameset-borders</emphasis></term>
7014 Some web designers seem to assume that everyone in the world will view their
7015 web sites using the same browser brand and version, screen resolution etc,
7016 because only that assumption could explain why they'd use static frame sizes,
7017 yet prevent their frames from being resized by the user, should they be too
7018 small to show their whole content.
7021 This filter removes the related HTML code. It should only be applied to sites
7028 <term><emphasis>demoronizer</emphasis></term>
7031 Many Microsoft products that generate HTML use non-standard extensions (read:
7032 violations) of the ISO 8859-1 aka Latin-1 character set. This can cause those
7033 HTML documents to display with errors on standard-compliant platforms.
7036 This filter translates the MS-only characters into Latin-1 equivalents.
7037 It is not necessary when using MS products, and will cause corruption of
7038 all documents that use 8-bit character sets other than Latin-1. It's mostly
7039 worthwhile for Europeans on non-MS platforms, if weird garbage characters
7040 sometimes appear on some pages, or user agents that don't correct for this on
7043 My version of Mozilla (ancient) shows litte square boxes for quote
7044 characters, and apostrophes on moronized pages. So many pages have this, I
7045 can read them fine now. HB 08/27/06
7052 <term><emphasis>shockwave-flash</emphasis></term>
7055 A filter for shockwave haters. As the name suggests, this filter strips code
7056 out of web pages that is used to embed shockwave flash objects.
7064 <term><emphasis>quicktime-kioskmode</emphasis></term>
7067 Change HTML code that embeds Quicktime objects so that kioskmode, which
7068 prevents saving, is disabled.
7074 <term><emphasis>fun</emphasis></term>
7077 Text replacements for subversive browsing fun. Make fun of your favorite
7078 Monopolist or play buzzword bingo.
7084 <term><emphasis>crude-parental</emphasis></term>
7087 A demonstration-only filter that shows how <application>Privoxy</application>
7088 can be used to delete web content on a keyword basis.
7094 <term><emphasis>ie-exploits</emphasis></term>
7097 An experimental collection of text replacements to disable malicious HTML and JavaScript
7098 code that exploits known security holes in Internet Explorer.
7101 Presently, it only protects against Nimda and a cross-site scripting bug, and
7102 would need active maintenance to provide more substantial protection.
7108 <term><emphasis>site-specifics</emphasis></term>
7111 Some web sites have very specific problems, the cure for which doesn't apply
7112 anywhere else, or could even cause damage on other sites.
7115 This is a collection of such site-specific cures which should only be applied
7116 to the sites they were intended for, which is what the supplied
7117 <filename>default.action</filename> file does. Users shouldn't need to change
7118 anything regarding this filter.
7124 <term><emphasis>google</emphasis></term>
7127 A CSS based block for Google text ads. Also removes a width limitation
7128 and the toolbar advertisement.
7134 <term><emphasis>yahoo</emphasis></term>
7137 Another CSS based block, this time for Yahoo text ads. And removes
7138 a width limitation as well.
7144 <term><emphasis>msn</emphasis></term>
7147 Another CSS based block, this time for MSN text ads. And removes
7148 tracking URLs, as well as a width limitation.
7154 <term><emphasis>blogspot</emphasis></term>
7157 Cleans up some Blogspot blogs. Read the fine print before using this one!
7160 This filter also intentionally removes some navigation stuff and sets the
7161 page width to 100%. As a result, some rounded <quote>corners</quote> would
7162 appear to early or not at all and as fixing this would require a browser
7163 that understands background-size (CSS3), they are removed instead.
7169 <term><emphasis>xml-to-html</emphasis></term>
7172 Server-header filter to change the Content-Type from xml to html.
7178 <term><emphasis>html-to-xml</emphasis></term>
7181 Server-header filter to change the Content-Type from html to xml.
7187 <term><emphasis>no-ping</emphasis></term>
7190 Removes the non-standard <literal>ping</literal> attribute from
7191 anchor and area HTML tags.
7197 <term><emphasis>hide-tor-exit-notation</emphasis></term>
7200 Client-header filter to remove the <command>Tor</command> exit node notation
7201 found in Host and Referer headers.
7204 If &my-app; and <command>Tor</command> are chained and &my-app;
7205 is configured to use socks4a, one can use <quote>http://www.example.org.foobar.exit/</quote>
7206 to access the host <quote>www.example.org</quote> through the
7207 <command>Tor</command> exit node <quote>foobar</quote>.
7210 As the HTTP client isn't aware of this notation, it treats the
7211 whole string <quote>www.example.org.foobar.exit</quote> as host and uses it
7212 for the <quote>Host</quote> and <quote>Referer</quote> headers. From the
7213 server's point of view the resulting headers are invalid and can cause problems.
7216 An invalid <quote>Referer</quote> header can trigger <quote>hot-linking</quote>
7217 protections, an invalid <quote>Host</quote> header will make it impossible for
7218 the server to find the right vhost (several domains hosted on the same IP address).
7221 This client-header filter removes the <quote>foo.exit</quote> part in those headers
7222 to prevent the mentioned problems. Note that it only modifies
7223 the HTTP headers, it doesn't make it impossible for the server
7224 to detect your <command>Tor</command> exit node based on the IP address
7225 the request is coming from.
7232 <term><emphasis> </emphasis></term>
7246 <!-- ~ End section ~ -->
7250 <!-- ~~~~~ New section ~~~~~ -->
7252 <sect1 id="templates">
7253 <title>Privoxy's Template Files</title>
7255 All <application>Privoxy</application> built-in pages, i.e. error pages such as the
7256 <ulink url="http://show-the-404-error.page"><quote>404 - No Such Domain</quote>
7257 error page</ulink>, the <ulink
7258 url="http://ads.bannerserver.example.com/nasty-ads/sponsor.html"><quote>BLOCKED</quote>
7260 and all pages of its <ulink url="http://config.privoxy.org/">web-based
7261 user interface</ulink>, are generated from <emphasis>templates</emphasis>.
7262 (<application>Privoxy</application> must be running for the above links to work as
7267 These templates are stored in a subdirectory of the <link linkend="confdir">configuration
7268 directory</link> called <filename>templates</filename>. On Unixish platforms,
7270 <ulink url="file:///etc/privoxy/templates/"><filename>/etc/privoxy/templates/</filename></ulink>.
7274 The templates are basically normal HTML files, but with place-holders (called symbols
7275 or exports), which <application>Privoxy</application> fills at run time. It
7276 is possible to edit the templates with a normal text editor, should you want
7277 to customize them. (<emphasis>Not recommended for the casual
7278 user</emphasis>). Should you create your own custom templates, you should use
7279 the <filename>config</filename> setting <link linkend="templdir">templdir</link>
7280 to specify an alternate location, so your templates do not get overwritten
7284 Note that just like in configuration files, lines starting
7285 with <literal>#</literal> are ignored when the templates are filled in.
7289 The place-holders are of the form <literal>@name@</literal>, and you will
7290 find a list of available symbols, which vary from template to template,
7291 in the comments at the start of each file. Note that these comments are not
7292 always accurate, and that it's probably best to look at the existing HTML
7293 code to find out which symbols are supported and what they are filled in with.
7297 A special application of this substitution mechanism is to make whole
7298 blocks of HTML code disappear when a specific symbol is set. We use this
7299 for many purposes, one of them being to include the beta warning in all
7300 our user interface (CGI) pages when <application>Privoxy</application>
7301 is in an alpha or beta development stage:
7306 <!-- @if-unstable-start -->
7308 ... beta warning HTML code goes here ...
7310 <!-- if-unstable-end@ --></screen>
7314 If the "unstable" symbol is set, everything in between and including
7315 <literal>@if-unstable-start</literal> and <literal>if-unstable-end@</literal>
7316 will disappear, leaving nothing but an empty comment:
7320 <screen><!-- --></screen>
7324 There's also an if-then-else construct and an <literal>#include</literal>
7325 mechanism, but you'll sure find out if you are inclined to edit the
7330 All templates refer to a style located at
7331 <ulink url="http://config.privoxy.org/send-stylesheet"><literal>http://config.privoxy.org/send-stylesheet</literal></ulink>.
7332 This is, of course, locally served by <application>Privoxy</application>
7333 and the source for it can be found and edited in the
7334 <filename>cgi-style.css</filename> template.
7339 <!-- ~ End section ~ -->
7343 <!-- ~~~~~ New section ~~~~~ -->
7345 <sect1 id="contact"><title>Contacting the Developers, Bug Reporting and Feature
7348 <!-- Include contacting.sgml boilerplate: -->
7350 <!-- end boilerplate -->
7354 <!-- ~ End section ~ -->
7357 <!-- ~~~~~ New section ~~~~~ -->
7358 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
7360 <!-- Include copyright.sgml: -->
7362 <!-- end copyright -->
7365 <application>Privoxy</application> is free software; you can
7366 redistribute it and/or modify it under the terms of the
7367 <citetitle>GNU General Public License</citetitle>, version 2,
7368 as published by the Free Software Foundation and included in
7372 <!-- ~~~~~ New section ~~~~~ -->
7373 <sect2><title>License</title>
7375 <screen><![ RCDATA [ &GPLv2; ]]></screen>
7379 <!-- ~ End section ~ -->
7382 <!-- ~~~~~ New section ~~~~~ -->
7384 <sect2 id="history"><title>History</title>
7385 <!-- Include history.sgml: -->
7387 <!-- end history -->
7390 <sect2 id="authors"><title>Authors</title>
7391 <!-- Include p-authors.sgml: -->
7393 <!-- end authors -->
7398 <!-- ~ End section ~ -->
7401 <!-- ~~~~~ New section ~~~~~ -->
7402 <sect1 id="seealso"><title>See Also</title>
7403 <!-- Include seealso.sgml: -->
7405 <!-- end seealso -->
7410 <!-- ~~~~~ New section ~~~~~ -->
7411 <sect1 id="appendix"><title>Appendix</title>
7414 <!-- ~~~~~ New section ~~~~~ -->
7416 <title>Regular Expressions</title>
7418 <application>Privoxy</application> uses Perl-style <quote>regular
7419 expressions</quote> in its <link linkend="actions-file">actions
7420 files</link> and <link linkend="filter-file">filter file</link>,
7421 through the <ulink url="http://www.pcre.org/">PCRE</ulink> and
7424 <ulink url="http://www.oesterhelt.org/pcrs/">PCRS</ulink> libraries.
7426 <application>PCRS</application> libraries.
7430 If you are reading this, you probably don't understand what <quote>regular
7431 expressions</quote> are, or what they can do. So this will be a very brief
7432 introduction only. A full explanation would require a <ulink
7433 url="http://www.oreilly.com/catalog/regex/">book</ulink> ;-)
7437 Regular expressions provide a language to describe patterns that can be
7438 run against strings of characters (letter, numbers, etc), to see if they
7439 match the string or not. The patterns are themselves (sometimes complex)
7440 strings of literal characters, combined with wild-cards, and other special
7441 characters, called meta-characters. The <quote>meta-characters</quote> have
7442 special meanings and are used to build complex patterns to be matched against.
7443 Perl Compatible Regular Expressions are an especially convenient
7444 <quote>dialect</quote> of the regular expression language.
7448 To make a simple analogy, we do something similar when we use wild-card
7449 characters when listing files with the <command>dir</command> command in DOS.
7450 <literal>*.*</literal> matches all filenames. The <quote>special</quote>
7451 character here is the asterisk which matches any and all characters. We can be
7452 more specific and use <literal>?</literal> to match just individual
7453 characters. So <quote>dir file?.text</quote> would match
7454 <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
7455 matching, using a similar technique to <quote>regular expressions</quote>!
7459 Regular expressions do essentially the same thing, but are much, much more
7460 powerful. There are many more <quote>special characters</quote> and ways of
7461 building complex patterns however. Let's look at a few of the common ones,
7462 and then some examples:
7467 <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
7468 <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
7470 </simplelist></para>
7474 <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
7477 </simplelist></para>
7481 <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
7484 </simplelist></para>
7488 <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
7491 </simplelist></para>
7495 <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
7496 the following character should be taken literally. This is used where one of the
7497 special characters (e.g. <quote>.</quote>) needs to be taken literally and
7498 not as a special meta-character. Example: <quote>example\.com</quote>, makes
7499 sure the period is recognized only as a period (and not expanded to its
7500 meta-character meaning of any single character).
7502 </simplelist></para>
7506 <emphasis>[ ]</emphasis> - Characters enclosed in brackets will be matched if
7507 any of the enclosed characters are encountered. For instance, <quote>[0-9]</quote>
7508 matches any numeric digit (zero through nine). As an example, we can combine
7509 this with <quote>+</quote> to match any digit one of more times: <quote>[0-9]+</quote>.
7511 </simplelist></para>
7515 <emphasis>( )</emphasis> - parentheses are used to group a sub-expression,
7516 or multiple sub-expressions.
7518 </simplelist></para>
7522 <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
7523 <quote>or</quote> conditional statement. A match is successful if the
7524 sub-expression on either side of <quote>|</quote> matches. As an example:
7525 <quote>/(this|that) example/</quote> uses grouping and the bar character
7526 and would match either <quote>this example</quote> or <quote>that
7527 example</quote>, and nothing else.
7529 </simplelist></para>
7532 These are just some of the ones you are likely to use when matching URLs with
7533 <application>Privoxy</application>, and is a long way from a definitive
7534 list. This is enough to get us started with a few simple examples which may
7535 be more illuminating:
7539 <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
7540 that uses the common combination of <quote>.</quote> and <quote>*</quote> to
7541 denote any character, zero or more times. In other words, any string at all.
7542 So we start with a literal forward slash, then our regular expression pattern
7543 (<quote>.*</quote>) another literal forward slash, the string
7544 <quote>banners</quote>, another forward slash, and lastly another
7545 <quote>.*</quote>. We are building
7546 a directory path here. This will match any file with the path that has a
7547 directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
7548 any characters, and this could conceivably be more forward slashes, so it
7549 might expand into a much longer looking path. For example, this could match:
7550 <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
7551 <quote>/banners/annoying.html</quote>, or almost an infinite number of other
7552 possible combinations, just so it has <quote>banners</quote> in the path
7557 And now something a little more complex:
7561 <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
7562 We have several literal forward slashes again (<quote>/</quote>), so we are
7563 building another expression that is a file path statement. We have another
7564 <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
7565 it matches our expression. The only true literal that <emphasis>must
7566 match</emphasis> our pattern is <application>adv</application>, together with
7567 the forward slashes. What comes after the <quote>adv</quote> string is the
7572 Remember the <quote>?</quote> means the preceding expression (either a
7573 literal character or anything grouped with <quote>(...)</quote> in this case)
7574 can exist or not, since this means either zero or one match. So
7575 <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
7576 individual sub-expressions: <quote>(er)</quote>,
7577 <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
7578 means <quote>or</quote>. We have two of those. For instance,
7579 <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
7580 <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
7581 attempt at matching as many variations of <quote>advertisement</quote>, and
7582 similar, as possible. So this would expand to match just <quote>adv</quote>,
7583 or <quote>advert</quote>, or <quote>adverts</quote>, or
7584 <quote>advertising</quote>, or <quote>advertisement</quote>, or
7585 <quote>advertisements</quote>. You get the idea. But it would not match
7586 <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
7587 changing our regular expression to:
7588 <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
7593 <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
7594 another path statement with forward slashes. Anything in the square brackets
7595 <quote>[ ]</quote> can be matched. This is using <quote>0-9</quote> as a
7596 shorthand expression to mean any digit one through nine. It is the same as
7597 saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
7598 means one or more of the preceding expression must be included. The preceding
7599 expression here is what is in the square brackets -- in this case, any digit
7600 one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
7601 This includes a <quote>|</quote>, so this needs to match the expression on
7602 either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
7603 side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
7604 since the <quote>?</quote> means the letter <quote>e</quote> is optional and
7605 can be matched once or not at all. So we are building an expression here to
7606 match image GIF or JPEG type image file. It must include the literal
7607 string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
7608 (which is now a literal, and not a special character, since it is escaped
7609 with <quote>\</quote>), and lastly either <quote>gif</quote>, or
7610 <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
7611 include: <quote>//advert1.jpg</quote>,
7612 <quote>/nasty/ads/advert1234.gif</quote>,
7613 <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
7614 <quote>advert1.gif</quote> (no leading slash), or
7615 <quote>/adverts232.jpg</quote> (the expression does not include an
7616 <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
7617 in the expression anywhere).
7621 We are barely scratching the surface of regular expressions here so that you
7622 can understand the default <application>Privoxy</application>
7623 configuration files, and maybe use this knowledge to customize your own
7624 installation. There is much, much more that can be done with regular
7625 expressions. Now that you know enough to get started, you can learn more on
7630 More reading on Perl Compatible Regular expressions:
7631 <ulink url="http://perldoc.perl.org/perlre.html">http://perldoc.perl.org/perlre.html</ulink>
7635 For information on regular expression based substitutions and their applications
7636 in filters, please see the <link linkend="filter-file">filter file tutorial</link>
7641 <!-- ~ End section ~ -->
7644 <!-- ~~~~~ New section ~~~~~ -->
7646 <title>Privoxy's Internal Pages</title>
7649 Since <application>Privoxy</application> proxies each requested
7650 web page, it is easy for <application>Privoxy</application> to
7651 trap certain special URLs. In this way, we can talk directly to
7652 <application>Privoxy</application>, and see how it is
7653 configured, see how our rules are being applied, change these
7654 rules and other configuration options, and even turn
7655 <application>Privoxy's</application> filtering off, all with
7661 The URLs listed below are the special ones that allow direct access
7662 to <application>Privoxy</application>. Of course,
7663 <application>Privoxy</application> must be running to access these. If
7664 not, you will get a friendly error message. Internet access is not
7677 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
7681 There is a shortcut: <ulink url="http://p.p/">http://p.p/</ulink> (But it
7682 doesn't provide a fall-back to a real page, in case the request is not
7683 sent through <application>Privoxy</application>)
7689 Show information about the current configuration, including viewing and
7690 editing of actions files:
7694 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
7701 Show the source code version numbers:
7705 <ulink url="http://config.privoxy.org/show-version">http://config.privoxy.org/show-version</ulink>
7712 Show the browser's request headers:
7716 <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
7723 Show which actions apply to a URL and why:
7727 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
7734 Toggle Privoxy on or off. This feature can be turned off/on in the main
7735 <filename>config</filename> file. When toggled <quote>off</quote>, <quote>Privoxy</quote>
7736 continues to run, but only as a pass-through proxy, with no actions taking
7741 <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
7745 Short cuts. Turn off, then on:
7749 <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
7754 <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
7763 These may be bookmarked for quick reference. See next.
7767 <sect3 id="bookmarklets">
7768 <title>Bookmarklets</title>
7770 Below are some <quote>bookmarklets</quote> to allow you to easily access a
7771 <quote>mini</quote> version of some of <application>Privoxy's</application>
7772 special pages. They are designed for MS Internet Explorer, but should work
7773 equally well in Netscape, Mozilla, and other browsers which support
7774 JavaScript. They are designed to run directly from your bookmarks - not by
7775 clicking the links below (although that should work for testing).
7778 To save them, right-click the link and choose <quote>Add to Favorites</quote>
7779 (IE) or <quote>Add Bookmark</quote> (Netscape). You will get a warning that
7780 the bookmark <quote>may not be safe</quote> - just click OK. Then you can run the
7781 Bookmarklet directly from your favorites/bookmarks. For even faster access,
7782 you can put them on the <quote>Links</quote> bar (IE) or the <quote>Personal
7783 Toolbar</quote> (Netscape), and run them with a single click.
7792 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=enabled','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Enable</ulink>
7799 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=disabled','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Disable</ulink>
7806 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=toggle','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Toggle Privoxy</ulink> (Toggles between enabled and disabled)
7813 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y','ijbstatus','width=250,height=2,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy- View Status</ulink>
7819 <ulink url="javascript:w=Math.floor(screen.width/2);h=Math.floor(screen.height*0.9);void(window.open('http://www.privoxy.org/actions/index.php?url='+escape(location.href),'Feedback','screenx='+w+',width='+w+',height='+h+',scrollbars=yes,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Submit Actions File Feedback</ulink>
7825 <ulink url="javascript:void(window.open('http://config.privoxy.org/show-url-info?url='+escape(location.href),'Why').focus());">Privoxy - Why?</ulink>
7832 Credit: The site which gave us the general idea for these bookmarklets is
7833 <ulink url="http://www.bookmarklets.com/">www.bookmarklets.com</ulink>. They
7834 have more information about bookmarklets.
7843 <!-- ~~~~~ New section ~~~~~ -->
7845 <title>Chain of Events</title>
7847 Let's take a quick look at how some of <application>Privoxy's</application>
7848 core features are triggered, and the ensuing sequence of events when a web
7849 page is requested by your browser:
7856 First, your web browser requests a web page. The browser knows to send
7857 the request to <application>Privoxy</application>, which will in turn,
7858 relay the request to the remote web server after passing the following
7864 <application>Privoxy</application> traps any request for its own internal CGI
7865 pages (e.g <ulink url="http://p.p/">http://p.p/</ulink>) and sends the CGI page back to the browser.
7870 Next, <application>Privoxy</application> checks to see if the URL
7872 linkend="BLOCK"><quote>+block</quote></link> patterns. If
7873 so, the URL is then blocked, and the remote web server will not be contacted.
7874 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>
7876 <link linkend="HANDLE-AS-EMPTY-DOCUMENT"><quote>+handle-as-empty-document</quote></link>
7877 are then checked, and if there is no match, an
7878 HTML <quote>BLOCKED</quote> page is sent back to the browser. Otherwise, if
7879 it does match, an image is returned for the former, and an empty text
7880 document for the latter. The type of image would depend on the setting of
7881 <link linkend="SET-IMAGE-BLOCKER"><quote>+set-image-blocker</quote></link>
7882 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
7887 Untrusted URLs are blocked. If URLs are being added to the
7888 <filename>trust</filename> file, then that is done.
7893 If the URL pattern matches the <link
7894 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link> action,
7895 it is then processed. Unwanted parts of the requested URL are stripped.
7900 Now the rest of the client browser's request headers are processed. If any
7901 of these match any of the relevant actions (e.g. <link
7902 linkend="HIDE-USER-AGENT"><quote>+hide-user-agent</quote></link>,
7903 etc.), headers are suppressed or forged as determined by these actions and
7909 Now the web server starts sending its response back (i.e. typically a web
7915 First, the server headers are read and processed to determine, among other
7916 things, the MIME type (document type) and encoding. The headers are then
7917 filtered as determined by the
7918 <link linkend="CRUNCH-INCOMING-COOKIES"><quote>+crunch-incoming-cookies</quote></link>,
7919 <link linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>,
7920 and <link linkend="DOWNGRADE-HTTP-VERSION"><quote>+downgrade-http-version</quote></link>
7926 If any <link linkend="FILTER"><quote>+filter</quote></link> action
7928 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
7929 action applies (and the document type fits the action), the rest of the page is
7930 read into memory (up to a configurable limit). Then the filter rules (from
7931 <filename>default.filter</filename> and any other filter files) are
7932 processed against the buffered content. Filters are applied in the order
7933 they are specified in one of the filter files. Animated GIFs, if present,
7934 are reduced to either the first or last frame, depending on the action
7935 setting.The entire page, which is now filtered, is then sent by
7936 <application>Privoxy</application> back to your browser.
7939 If neither a <link linkend="FILTER"><quote>+filter</quote></link> action
7941 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
7942 matches, then <application>Privoxy</application> passes the raw data through
7943 to the client browser as it becomes available.
7948 As the browser receives the now (possibly filtered) page content, it
7949 reads and then requests any URLs that may be embedded within the page
7950 source, e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
7951 frames), sounds, etc. For each of these objects, the browser issues a
7952 separate request (this is easily viewable in <application>Privoxy's</application>
7953 logs). And each such request is in turn processed just as above. Note that a
7954 complex web page will have many, many such embedded URLs. If these
7955 secondary requests are to a different server, then quite possibly a very
7956 differing set of actions is triggered.
7963 NOTE: This is somewhat of a simplistic overview of what happens with each URL
7964 request. For the sake of brevity and simplicity, we have focused on
7965 <application>Privoxy's</application> core features only.
7971 <!-- ~~~~~ New section ~~~~~ -->
7972 <sect2 id="actionsanat">
7973 <title>Troubleshooting: Anatomy of an Action</title>
7976 The way <application>Privoxy</application> applies
7977 <link linkend="ACTIONS">actions</link> and <link linkend="FILTER">filters</link>
7978 to any given URL can be complex, and not always so
7979 easy to understand what is happening. And sometimes we need to be able to
7980 <emphasis>see</emphasis> just what <application>Privoxy</application> is
7981 doing. Especially, if something <application>Privoxy</application> is doing
7982 is causing us a problem inadvertently. It can be a little daunting to look at
7983 the actions and filters files themselves, since they tend to be filled with
7984 <link linkend="regex">regular expressions</link> whose consequences are not
7989 One quick test to see if <application>Privoxy</application> is causing a problem
7990 or not, is to disable it temporarily. This should be the first troubleshooting
7991 step. See <link linkend="bookmarklets">the Bookmarklets</link> section on a quick
7992 and easy way to do this (be sure to flush caches afterward!). Looking at the
7993 logs is a good idea too. (Note that both the toggle feature and logging are
7994 enabled via <filename>config</filename> file settings, and may need to be
7995 turned <quote>on</quote>.)
7998 Another easy troubleshooting step to try is if you have done any
7999 customization of your installation, revert back to the installed
8000 defaults and see if that helps. There are times the developers get complaints
8001 about one thing or another, and the problem is more related to a customized
8002 configuration issue.
8006 <application>Privoxy</application> also provides the
8007 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8008 page that can show us very specifically how <application>actions</application>
8009 are being applied to any given URL. This is a big help for troubleshooting.
8013 First, enter one URL (or partial URL) at the prompt, and then
8014 <application>Privoxy</application> will tell us
8015 how the current configuration will handle it. This will not
8016 help with filtering effects (i.e. the <link
8017 linkend="FILTER"><quote>+filter</quote></link> action) from
8018 one of the filter files since this is handled very
8019 differently and not so easy to trap! It also will not tell you about any other
8020 URLs that may be embedded within the URL you are testing. For instance, images
8021 such as ads are expressed as URLs within the raw page source of HTML pages. So
8022 you will only get info for the actual URL that is pasted into the prompt area
8023 -- not any sub-URLs. If you want to know about embedded URLs like ads, you
8024 will have to dig those out of the HTML source. Use your browser's <quote>View
8025 Page Source</quote> option for this. Or right click on the ad, and grab the
8030 Let's try an example, <ulink url="http://google.com">google.com</ulink>,
8031 and look at it one section at a time in a sample configuration (your real
8032 configuration may vary):
8037 Matches for http://www.google.com:
8039 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8041 {+change-x-forwarded-for{block}
8042 +deanimate-gifs {last}
8043 +fast-redirects {check-decoded-url}
8044 +filter {refresh-tags}
8045 +filter {img-reorder}
8046 +filter {banners-by-size}
8048 +filter {jumping-windows}
8049 +filter {ie-exploits}
8050 +hide-from-header {block}
8051 +hide-referrer {forge}
8052 +session-cookies-only
8053 +set-image-blocker {pattern}
8056 { -session-cookies-only }
8062 In file: user.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8063 (no matches in this file)
8068 This is telling us how we have defined our
8069 <link linkend="ACTIONS"><quote>actions</quote></link>, and
8070 which ones match for our test case, <quote>google.com</quote>.
8071 Displayed is all the actions that are available to us. Remember,
8072 the <literal>+</literal> sign denotes <quote>on</quote>. <literal>-</literal>
8073 denotes <quote>off</quote>. So some are <quote>on</quote> here, but many
8074 are <quote>off</quote>. Each example we try may provide a slightly different
8075 end result, depending on our configuration directives.
8079 is for our <filename>default.action</filename> file. The large, multi-line
8080 listing, is how the actions are set to match for all URLs, i.e. our default
8081 settings. If you look at your <quote>actions</quote> file, this would be the
8082 section just below the <quote>aliases</quote> section near the top. This
8083 will apply to all URLs as signified by the single forward slash at the end
8084 of the listing -- <quote> / </quote>.
8088 But we have defined additional actions that would be exceptions to these general
8089 rules, and then we list specific URLs (or patterns) that these exceptions
8090 would apply to. Last match wins. Just below this then are two explicit
8091 matches for <quote>.google.com</quote>. The first is negating our previous
8092 cookie setting, which was for <link
8093 linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>
8094 (i.e. not persistent). So we will allow persistent cookies for google, at
8095 least that is how it is in this example. The second turns
8096 <emphasis>off</emphasis> any <link
8097 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link>
8098 action, allowing this to take place unmolested. Note that there is a leading
8099 dot here -- <quote>.google.com</quote>. This will match any hosts and
8100 sub-domains, in the google.com domain also, such as
8101 <quote>www.google.com</quote> or <quote>mail.google.com</quote>. But it would not
8102 match <quote>www.google.de</quote>! So, apparently, we have these two actions
8103 defined as exceptions to the general rules at the top somewhere in the lower
8104 part of our <filename>default.action</filename> file, and
8105 <quote>google.com</quote> is referenced somewhere in these latter sections.
8109 Then, for our <filename>user.action</filename> file, we again have no hits.
8110 So there is nothing google-specific that we might have added to our own, local
8111 configuration. If there was, those actions would over-rule any actions from
8112 previously processed files, such as <filename>default.action</filename>.
8113 <filename>user.action</filename> typically has the last word. This is the
8114 best place to put hard and fast exceptions,
8118 And finally we pull it all together in the bottom section and summarize how
8119 <application>Privoxy</application> is applying all its <quote>actions</quote>
8120 to <quote>google.com</quote>:
8131 +change-x-forwarded-for{block}
8132 -client-header-filter{hide-tor-exit-notation}
8133 -content-type-overwrite
8134 -crunch-client-header
8135 -crunch-if-none-match
8136 -crunch-incoming-cookies
8137 -crunch-outgoing-cookies
8138 -crunch-server-header
8139 +deanimate-gifs {last}
8140 -downgrade-http-version
8143 -filter {content-cookies}
8144 -filter {all-popups}
8145 -filter {banners-by-link}
8146 -filter {tiny-textforms}
8147 -filter {frameset-borders}
8148 -filter {demoronizer}
8149 -filter {shockwave-flash}
8150 -filter {quicktime-kioskmode}
8152 -filter {crude-parental}
8153 -filter {site-specifics}
8154 -filter {js-annoyances}
8155 -filter {html-annoyances}
8156 +filter {refresh-tags}
8157 -filter {unsolicited-popups}
8158 +filter {img-reorder}
8159 +filter {banners-by-size}
8161 +filter {jumping-windows}
8162 +filter {ie-exploits}
8169 -handle-as-empty-document
8171 -hide-accept-language
8172 -hide-content-disposition
8173 +hide-from-header {block}
8174 -hide-if-modified-since
8175 +hide-referrer {forge}
8178 -overwrite-last-modified
8179 -prevent-compression
8181 -server-header-filter{xml-to-html}
8182 -server-header-filter{html-to-xml}
8183 -session-cookies-only
8184 +set-image-blocker {pattern} </screen>
8188 Notice the only difference here to the previous listing, is to
8189 <quote>fast-redirects</quote> and <quote>session-cookies-only</quote>,
8190 which are activated specifically for this site in our configuration,
8191 and thus show in the <quote>Final Results</quote>.
8195 Now another example, <quote>ad.doubleclick.net</quote>:
8201 { +block{Domains starts with "ad"} }
8204 { +block{Domain contains "ad"} }
8207 { +block{Doubleclick banner server} +handle-as-image }
8208 .[a-vx-z]*.doubleclick.net
8213 We'll just show the interesting part here - the explicit matches. It is
8214 matched three different times. Two <quote>+block{}</quote> sections,
8215 and a <quote>+block{} +handle-as-image</quote>,
8216 which is the expanded form of one of our aliases that had been defined as:
8217 <quote>+block-as-image</quote>. (<link
8218 linkend="ALIASES"><quote>Aliases</quote></link> are defined in
8219 the first section of the actions file and typically used to combine more
8224 Any one of these would have done the trick and blocked this as an unwanted
8225 image. This is unnecessarily redundant since the last case effectively
8226 would also cover the first. No point in taking chances with these guys
8227 though ;-) Note that if you want an ad or obnoxious
8228 URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
8229 is done here -- as both a <link
8230 linkend="BLOCK"><quote>+block{}</quote></link>
8231 <emphasis>and</emphasis> an
8232 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>.
8233 The custom alias <quote><literal>+block-as-image</literal></quote> just
8234 simplifies the process and make it more readable.
8238 One last example. Let's try <quote>http://www.example.net/adsl/HOWTO/</quote>.
8239 This one is giving us problems. We are getting a blank page. Hmmm ...
8245 Matches for http://www.example.net/adsl/HOWTO/:
8247 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8251 +change-x-forwarded-for{block}
8252 -client-header-filter{hide-tor-exit-notation}
8253 -content-type-overwrite
8254 -crunch-client-header
8255 -crunch-if-none-match
8256 -crunch-incoming-cookies
8257 -crunch-outgoing-cookies
8258 -crunch-server-header
8260 -downgrade-http-version
8261 +fast-redirects {check-decoded-url}
8263 -filter {content-cookies}
8264 -filter {all-popups}
8265 -filter {banners-by-link}
8266 -filter {tiny-textforms}
8267 -filter {frameset-borders}
8268 -filter {demoronizer}
8269 -filter {shockwave-flash}
8270 -filter {quicktime-kioskmode}
8272 -filter {crude-parental}
8273 -filter {site-specifics}
8274 -filter {js-annoyances}
8275 -filter {html-annoyances}
8276 +filter {refresh-tags}
8277 -filter {unsolicited-popups}
8278 +filter {img-reorder}
8279 +filter {banners-by-size}
8281 +filter {jumping-windows}
8282 +filter {ie-exploits}
8289 -handle-as-empty-document
8291 -hide-accept-language
8292 -hide-content-disposition
8293 +hide-from-header{block}
8294 +hide-referer{forge}
8296 -overwrite-last-modified
8297 +prevent-compression
8299 -server-header-filter{xml-to-html}
8300 -server-header-filter{html-to-xml}
8301 +session-cookies-only
8302 +set-image-blocker{blank} }
8305 { +block{Path contains "ads".} +handle-as-image }
8311 Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote> in our
8312 configuration! But we did not want this at all! Now we see why we get the
8313 blank page. It is actually triggering two different actions here, and
8314 the effects are aggregated so that the URL is blocked, and &my-app; is told
8315 to treat the block as if it were an image. But this is, of course, all wrong.
8316 We could now add a new action below this (or better in our own
8317 <filename>user.action</filename> file) that explicitly
8318 <emphasis>un</emphasis> blocks (
8319 <link linkend="BLOCK"><quote>{-block}</quote></link>) paths with
8320 <quote>adsl</quote> in them (remember, last match in the configuration
8321 wins). There are various ways to handle such exceptions. Example:
8333 Now the page displays ;-)
8334 Remember to flush your browser's caches when making these kinds of changes to
8335 your configuration to insure that you get a freshly delivered page! Or, try
8336 using <literal>Shift+Reload</literal>.
8340 But now what about a situation where we get no explicit matches like
8347 { +block{Path starts with "ads".} +handle-as-image }
8353 That actually was very helpful and pointed us quickly to where the problem
8354 was. If you don't get this kind of match, then it means one of the default
8355 rules in the first section of <filename>default.action</filename> is causing
8356 the problem. This would require some guesswork, and maybe a little trial and
8357 error to isolate the offending rule. One likely cause would be one of the
8358 <link linkend="FILTER"><quote>+filter</quote></link> actions.
8359 These tend to be harder to troubleshoot.
8360 Try adding the URL for the site to one of aliases that turn off
8361 <link linkend="FILTER"><quote>+filter</quote></link>:
8369 .worldpay.com # for quietpc.com
8377 <quote><literal>{ shop }</literal></quote> is an <quote>alias</quote> that expands to
8378 <quote><literal>{ -filter -session-cookies-only }</literal></quote>.
8379 Or you could do your own exception to negate filtering:
8387 # Disable ALL filter actions for sites in this section
8395 This would turn off all filtering for these sites. This is best
8396 put in <filename>user.action</filename>, for local site
8397 exceptions. Note that when a simple domain pattern is used by itself (without
8398 the subsequent path portion), all sub-pages within that domain are included
8399 automatically in the scope of the action.
8403 Images that are inexplicably being blocked, may well be hitting the
8404 <link linkend="FILTER-BANNERS-BY-SIZE"><quote>+filter{banners-by-size}</quote></link>
8406 that images of certain sizes are ad banners (works well
8407 <emphasis>most of the time</emphasis> since these tend to be standardized).
8411 <quote><literal>{ fragile }</literal></quote> is an alias that disables most
8412 actions that are the most likely to cause trouble. This can be used as a
8413 last resort for problem sites.
8419 # Handle with care: easy to break
8421 mybank.example.com</screen>
8426 <emphasis>Remember to flush caches!</emphasis> Note that the
8427 <literal>mail.google</literal> reference lacks the TLD portion (e.g.
8428 <quote>.com</quote>). This will effectively match any TLD with
8429 <literal>google</literal> in it, such as <literal>mail.google.de.</literal>,
8433 If this still does not work, you will have to go through the remaining
8434 actions one by one to find which one(s) is causing the problem.
8443 This program is free software; you can redistribute it
8444 and/or modify it under the terms of the GNU General
8445 Public License as published by the Free Software
8446 Foundation; either version 2 of the License, or (at
8447 your option) any later version.
8449 This program is distributed in the hope that it will
8450 be useful, but WITHOUT ANY WARRANTY; without even the
8451 implied warranty of MERCHANTABILITY or FITNESS FOR A
8452 PARTICULAR PURPOSE. See the GNU General Public
8453 License for more details.
8455 The GNU General Public License should be included with
8456 this file. If not, you can view it at
8457 http://www.gnu.org/copyleft/gpl.html
8458 or write to the Free Software Foundation, Inc.,
8459 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,