X-Git-Url: http://www.privoxy.org/gitweb/?p=privoxy.git;a=blobdiff_plain;f=doc%2Fwebserver%2Fuser-manual%2Factions-file.html;h=3c39d976d4e007b6b12fe32cf627193458eee1be;hp=46d94b5267e566bf56872e2cf968d38b2175fd71;hb=23be303a582b85ccac7592d0135f0beb9cf170f6;hpb=2c66ecb8d319b2b32a371950e1f71e94f1f4347d diff --git a/doc/webserver/user-manual/actions-file.html b/doc/webserver/user-manual/actions-file.html index 46d94b52..3c39d976 100644 --- a/doc/webserver/user-manual/actions-file.html +++ b/doc/webserver/user-manual/actions-file.html @@ -1,2279 +1,1284 @@ - -
The actions files are used to define what actions - Privoxy takes for which URLs, and thus determines - how ad images, cookies and various other aspects of HTTP content and - transactions are handled, and on which sites (or even parts thereof). - There are a number of such actions, with a wide range of functionality. - Each action does something a little different. - These actions give us a veritable arsenal of tools with which to exert - our control, preferences and independence. Actions can be combined so that - their effects are aggregated when applied against a given set of URLs.
There - are three action files included with Privoxy with - differing purposes:
match-all.action - is used to define which - "actions" relating to banner-blocking, images, pop-ups, - content modification, cookie handling etc should be applied by default. - It should be the first actions file loaded -
default.action - defines many exceptions (both - positive and negative) from the default set of actions that's configured - in match-all.action. It is a set of rules that should - work reasonably well as-is for most users. This file is only supposed to - be edited by the developers. It should be the second actions file loaded. -
user.action - is intended to be for local site - preferences and exceptions. As an example, if your ISP or your bank - has specific requirements, and need special handling, this kind of - thing should go here. This file will not be upgraded. -
Edit Set to Cautious Set to Medium Set to Advanced -
These have increasing levels of aggressiveness and have no - influence on your browsing unless you select them explicitly in the - editor. A default installation should be pre-set to - Cautious. New users should try this for a while before - adjusting the settings to more aggressive levels. The more aggressive - the settings, then the more likelihood there is of problems such as sites - not working as they should. -
The Edit button allows you to turn each - action on/off individually for fine-tuning. The Cautious - button changes the actions list to low/safe settings which will activate - ad blocking and a minimal set of Privoxy's features, and subsequently - there will be less of a chance for accidental problems. The - Medium button sets the list to a medium level of - other features and a low level set of privacy features. The - Advanced button sets the list to a high level of - ad blocking and medium level of privacy. See the chart below. The latter - three buttons over-ride any changes via with the - Edit button. More fine-tuning can be done in the - lower sections of this internal page. -
While the actions file editor allows to enable these settings in all - actions files, they are only supposed to be enabled in the first one - to make sure you don't unintentionally overrule earlier rules. -
The default profiles, and their associated actions, as pre-defined in - default.action are: -
Table 1. Default Configurations
Feature | Cautious | Medium | Advanced |
---|---|---|---|
Ad-blocking Aggressiveness | medium | high | high |
Ad-filtering by size | no | yes | yes |
Ad-filtering by link | no | no | yes |
Pop-up killing | blocks only | blocks only | blocks only |
Privacy Features | low | medium | medium/high |
Cookie handling | none | session-only | kill |
Referer forging | no | yes | yes |
GIF de-animation | no | yes | yes |
Fast redirects | no | no | yes |
HTML taming | no | no | yes |
JavaScript taming | no | no | yes |
Web-bug killing | no | yes | yes |
Image tag reordering | no | yes | yes |
The list of actions files to be used are defined in the main configuration - file, and are processed in the order they are defined (e.g. - default.action is typically processed before - user.action). The content of these can all be viewed and - edited from http://config.privoxy.org/show-status. - The over-riding principle when applying actions, is that the last action that - matches a given URL wins. The broadest, most general rules go first - (defined in default.action), - followed by any exceptions (typically also in - default.action), which are then followed lastly by any - local preferences (typically in user.action). - Generally, user.action has the last word. -
An actions file typically has multiple sections. If you want to use - "aliases" in an actions file, you have to place the (optional) - alias section at the top of that file. - Then comes the default set of rules which will apply universally to all - sites and pages (be very careful with using such a - universal set in user.action or any other actions file after - default.action, because it will override the result - from consulting any previous file). And then below that, - exceptions to the defined universal policies. You can regard - user.action as an appendix to default.action, - with the advantage that it is a separate file, which makes preserving your - personal settings across Privoxy upgrades easier.
- Actions can be used to block anything you want, including ads, banners, or - just some obnoxious URL whose content you would rather not see. Cookies can be accepted - or rejected, or accepted only during the current browser session (i.e. not - written to disk), content can be modified, some JavaScripts tamed, user-tracking - fooled, and much more. See below for a complete list - of actions.
Note that some actions, like cookie suppression - or script disabling, may render some sites unusable that rely on these - techniques to work properly. Finding the right mix of actions is not always easy and - certainly a matter of personal taste. And, things can always change, requiring - refinements in the configuration. In general, it can be said that the more - "aggressive" your default settings (in the top section of the - actions file) are, the more exceptions for "trusted" sites you - will have to make later. If, for example, you want to crunch all cookies per - default, you'll have to make exceptions from that rule for sites that you - regularly use and that require cookies for actually useful purposes, like maybe - your bank, favorite shop, or newspaper.
We have tried to provide you with reasonable rules to start from in the - distribution actions files. But there is no general rule of thumb on these - things. There just are too many variables, and sites are constantly changing. - Sooner or later you will want to change the rules (and read this chapter again :).
The easiest way to edit the actions files is with a browser by - using our browser-based editor, which can be reached from http://config.privoxy.org/show-status. - Note: the config file option enable-edit-actions must be enabled for - this to work. The editor allows both fine-grained control over every single - feature on a per-URL basis, and easy choosing from wholesale sets of defaults - like "Cautious", "Medium" or - "Advanced". Warning: the "Advanced" setting is more - aggressive, and will be more likely to cause problems for some sites. - Experienced users only! -
If you prefer plain text editing to GUIs, you can of course also directly edit the - the actions files with your favorite text editor. Look at - default.action which is richly commented with many - good examples.
Actions files are divided into sections. There are special sections, - like the "alias" sections which will - be discussed later. For now let's concentrate on regular sections: They have a - heading line (often split up to multiple lines for readability) which consist - of a list of actions, separated by whitespace and enclosed in curly braces. - Below that, there is a list of URL and tag patterns, each on a separate line.
To determine which actions apply to a request, the URL of the request is - compared to all URL patterns in each "action file". - Every time it matches, the list of applicable actions for the request is - incrementally updated, using the heading of the section in which the - pattern is located. The same is done again for tags and tag patterns later on.
If multiple applying sections set the same action differently, - the last match wins. If not, the effects are aggregated. - E.g. a URL might match a regular section with a heading line of { - +handle-as-image }, - then later another one with just { - +block }, resulting - in both actions to apply. And there may well be - cases where you will want to combine actions together. Such a section then - might look like:
{ +handle-as-image +block{Banner ads.} } + + + + + |
Get rid of HTML and JavaScript annoyances, banner advertisements (by size), - do fun text replacements, add personalized effects, etc.
All instances of text-based type, most notably HTML and JavaScript, to which - this action applies, can be filtered on-the-fly through the specified regular - expression based substitutions. (Note: as of version 3.0.3 plain text documents - are exempted from filtering, because web servers often use the - text/plain MIME type for all files whose type they don't know.) -
Parameterized.
The name of a content filter, as defined in the filter file. - Filters can be defined in one or more files as defined by the - filterfile - option in the config file. - default.filter is the collection of filters - supplied by the developers. Locally defined filters should go - in their own file, such as user.filter. -
When used in its negative form, - and without parameters, all filtering is completely disabled. -
For your convenience, there are a number of pre-defined filters available - in the distribution filter file that you can use. See the examples below for - a list. -
Filtering requires buffering the page content, which may appear to - slow down page rendering since nothing is displayed until all content has - passed the filters. (It does not really take longer, but seems that way - since the page is not incrementally displayed.) This effect will be more - noticeable on slower connections. -
"Rolling your own" - filters requires a knowledge of - "Regular - Expressions" and - "HTML". - This is very powerful feature, and potentially very intrusive. - Filters should be used with caution, and where an equivalent - "action" is not available. -
The amount of data that can be filtered is limited to the - buffer-limit - option in the main config file. The - default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered - data, and all pending data, is passed through unfiltered. -
Inappropriate MIME types, such as zipped files, are not filtered at all. - (Again, only text-based types except plain text). Encrypted SSL data - (from HTTPS servers) cannot be filtered either, since this would violate - the integrity of the secure transaction. In some situations it might - be necessary to protect certain text, like source code, from filtering - by defining appropriate -filter exceptions. -
Compressed content can't be filtered either, unless Privoxy - is compiled with zlib support (requires at least Privoxy 3.0.7), - in which case Privoxy will decompress the content before filtering - it. -
If you use a Privoxy version without zlib support, but want filtering to work on - as much documents as possible, even those that would normally be sent compressed, - you must use the prevent-compression - action in conjunction with filter. -
Content filtering can achieve some of the same effects as the - block - action, i.e. it can be used to block ads and banners. But the mechanism - works quite differently. One effective use, is to block ad banners - based on their size (see below), since many of these seem to be somewhat - standardized. -
Feedback with suggestions for new or - improved filters is particularly welcome! -
The below list has only the names and a one-line description of each - predefined filter. There are more - verbose explanations of what these filters do in the filter file chapter. -
+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse. |
+filter{js-events} # Kill all JS event bindings and timers (Radically destructive! Only for extra nasty sites). |
+filter{html-annoyances} # Get rid of particularly annoying HTML abuse. |
+filter{content-cookies} # Kill cookies that come in the HTML or JS content. |
+filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups). |
+filter{unsolicited-popups} # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability. |
+filter{all-popups} # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability. |
+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective. |
+filter{banners-by-size} # Kill banners by size. |
+filter{banners-by-link} # Kill banners by their links to known clicktrackers. |
+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking). |
+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap. |
+filter{jumping-windows} # Prevent windows from resizing and moving themselves. |
+filter{frameset-borders} # Give frames a border and make them resizable. |
+filter{demoronizer} # Fix MS's non-standard use of standard charsets. |
+filter{shockwave-flash} # Kill embedded Shockwave Flash objects. |
+filter{quicktime-kioskmode} # Make Quicktime movies saveable. |
+filter{fun} # Text replacements for subversive browsing fun! |
+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably. |
+filter{ie-exploits} # Disable some known Internet Explorer bug exploits. |
+filter{site-specifics} # Cure for site-specific problems. Don't apply generally! |
+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags. |
+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement. |
+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation. |
+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation. |
+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this. |
Force Privoxy to treat a document as if it was in some kind of text format.
Declares a document as text, even if the "Content-Type:" isn't detected as such. -
Boolean.
N/A -
As explained above, - Privoxy tries to only filter files that are - in some kind of text format. The same restrictions apply to - content-type-overwrite. - force-text-mode declares a document as text, - without looking at the "Content-Type:" first. -
Warning |
Think twice before activating this action. Filtering binary data - with regular expressions can cause file damage. - |
+force-text-mode - |
Change the forwarding settings based on User-Agent or request origin
Overrules the forward directives in the configuration file. -
Multi-value.
"forward ." to use a direct connection without any additional proxies.
"forward 127.0.0.1:8123" to use the HTTP proxy listening at 127.0.0.1 port 8123. -
"forward-socks4a 127.0.0.1:9050 ." to use the socks4a proxy listening at - 127.0.0.1 port 9050. Replace "forward-socks4a" with "forward-socks4" - to use a socks4 connection (with local DNS resolution) instead, use "forward-socks5" - for socks5 connections (with remote DNS resolution). -
"forward-socks4a 127.0.0.1:9050 proxy.example.org:8000" to use the socks4a proxy - listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000. - Replace "forward-socks4a" with "forward-socks4" to use a socks4 connection - (with local DNS resolution) instead, use "forward-socks5" - for socks5 connections (with remote DNS resolution). -
This action takes parameters similar to the - forward directives in the configuration - file, but without the URL pattern. It can be used as replacement, but normally it's only - used in cases where matching based on the request URL isn't sufficient. -
Warning |
Please read the description for the forward directives before - using this action. Forwarding to the wrong people will reduce your privacy and increase the - chances of man-in-the-middle attacks. - If the ports are missing or invalid, default values will be used. This might change - in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy - to exit. - Use the show-url-info CGI page - to verify that your forward settings do what you thought the do. - |
# Always use direct connections for requests previously tagged as
-# "User-Agent: fetch libfetch/2.0" and make sure
-# resuming downloads continues to work.
-# This way you can continue to use Tor for your normal browsing,
-# without overloading the Tor network with your FreeBSD ports updates
-# or downloads of bigger files like ISOs.
-# Note that HTTP headers are easy to fake and therefore their
-# values are as (un)trustworthy as your clients and users.
-{+forward-override{forward .} \
- -hide-if-modified-since \
- -overwrite-last-modified \
-}
-TAG:^User-Agent: fetch libfetch/2\.0$
- |
Mark URLs that should be replaced by empty documents if they get blocked
This action alone doesn't do anything noticeable. It just marks URLs. - If the block action also applies, - the presence or absence of this mark decides whether an HTML "BLOCKED" - page, or an empty document will be sent to the client as a substitute for the blocked content. - The empty document isn't literally empty, but actually contains a single space. -
Boolean.
N/A -
Some browsers complain about syntax errors if JavaScript documents - are blocked with Privoxy's - default HTML page; this option can be used to silence them. - And of course this action can also be used to eliminate the Privoxy - BLOCKED message in frames. -
The content type for the empty document can be specified with - content-type-overwrite{}, - but usually this isn't necessary. -
# Block all documents on example.org that end with ".js", -# but send an empty document instead of the usual HTML message. -{+block{Blocked JavaScript} +handle-as-empty-document} -example.org/.*\.js$ - |
Mark URLs as belonging to images (so they'll be replaced by images if they do get blocked, rather than HTML pages)
This action alone doesn't do anything noticeable. It just marks URLs as images. - If the block action also applies, - the presence or absence of this mark decides whether an HTML "blocked" - page, or a replacement image (as determined by the set-image-blocker action) will be sent to the - client as a substitute for the blocked content. -
Boolean.
N/A -
The below generic example section is actually part of default.action. - It marks all URLs with well-known image file name extensions as images and should - be left intact. -
Users will probably only want to use the handle-as-image action in conjunction with - block, to block sources of banners, whose URLs don't - reflect the file type, like in the second example section. -
Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad - frames require an HTML page to be sent, or they won't display properly. - Forcing handle-as-image in this situation will not replace the - ad frame with an image, but lead to error messages. -
# Generic image extensions: -# -{+handle-as-image} -/.*\.(gif|jpg|jpeg|png|bmp|ico)$ + |
Pretend to use different language settings.
Deletes or replaces the "Accept-Language:" HTTP header in client requests. -
Parameterized.
Keyword: "block", or any user defined value. -
Faking the browser's language settings can be useful to make a - foreign User-Agent set with - hide-user-agent - more believable. -
However some sites with content in different languages check the - "Accept-Language:" to decide which one to take by default. - Sometimes it isn't possible to later switch to another language without - changing the "Accept-Language:" header first. -
Therefore it's a good idea to either only change the - "Accept-Language:" header to languages you understand, - or to languages that aren't wide spread. -
Before setting the "Accept-Language:" header - to a rare language, you should consider that it helps to - make your requests unique and thus easier to trace. - If you don't plan to change this header frequently, - you should stick to a common language. -
# Pretend to use Canadian language settings. -{+hide-accept-language{en-ca} \ -+hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \ -} -/ |
Prevent download menus for content you prefer to view inside the browser.
Deletes or replaces the "Content-Disposition:" HTTP header set by some servers. -
Parameterized.
Keyword: "block", or any user defined value. -
Some servers set the "Content-Disposition:" HTTP header for - documents they assume you want to save locally before viewing them. - The "Content-Disposition:" header contains the file name - the browser is supposed to use by default. -
In most browsers that understand this header, it makes it impossible to - just view the document, without downloading it first, - even if it's just a simple text file or an image. -
Removing the "Content-Disposition:" header helps - to prevent this annoyance, but some browsers additionally check the - "Content-Type:" header, before they decide if they can - display a document without saving it first. In these cases, you have - to change this header as well, before the browser stops displaying - download menus. -
It is also possible to change the server's file name suggestion - to another one, but in most cases it isn't worth the time to set - it up. -
This action will probably be removed in the future, - use server-header filters instead. -
# Disarm the download link in Sourceforge's patch tracker -{ -filter \ - +content-type-overwrite{text/plain}\ - +hide-content-disposition{block} } - .sourceforge.net/tracker/download\.php |
Prevent yet another way to track the user's steps between sessions.
Deletes the "If-Modified-Since:" HTTP client header or modifies its value. -
Parameterized.
Keyword: "block", or a user defined value that specifies a range of hours. -
Removing this header is useful for filter testing, where you want to force a real - reload instead of getting status code "304", which would cause the - browser to use a cached copy of the page. -
Instead of removing the header, hide-if-modified-since can - also add or subtract a random amount of time to/from the header's value. - You specify a range of minutes where the random factor should be chosen from and - Privoxy does the rest. A negative value means - subtracting, a positive value adding. -
Randomizing the value of the "If-Modified-Since:" makes - it less likely that the server can use the time as a cookie replacement, - but you will run into caching problems if the random range is too high. -
It is a good idea to only use a small negative value and let - overwrite-last-modified - handle the greater changes. -
It is also recommended to use this action together with - crunch-if-none-match, - otherwise it's more or less pointless. -
# Let the browser revalidate but make tracking based on the time less likely. -{+hide-if-modified-since{-60} \ - +overwrite-last-modified{randomize} \ - +crunch-if-none-match} -/ |
Keep your (old and ill) browser from telling web servers your email address
Deletes any existing "From:" HTTP header, or replaces it with the - specified string. -
Parameterized.
Keyword: "block", or any user defined value. -
The keyword "block" will completely remove the header - (not to be confused with the block - action). -
Alternately, you can specify any value you prefer to be sent to the web - server. If you do, it is a matter of fairness not to use any address that - is actually used by a real person. -
This action is rarely needed, as modern web browsers don't send - "From:" headers anymore. -
+hide-from-header{block} |
+hide-from-header{spam-me-senseless@sittingduck.example.com} |
Conceal which link you followed to get to a particular site
Deletes the "Referer:" (sic) HTTP header from the client request, - or replaces it with a forged one. -
Parameterized.
"conditional-block" to delete the header completely if the host has changed.
"conditional-forge" to forge the header if the host has changed.
"block" to delete the header unconditionally.
"forge" to pretend to be coming from the homepage of the server we are talking to.
Any other string to set a user defined referrer.
conditional-block is the only parameter, - that isn't easily detected in the server's log file. If it blocks the - referrer, the request will look like the visitor used a bookmark or - typed in the address directly. -
Leaving the referrer unmodified for requests on the same host - allows the server owner to see the visitor's "click path", - but in most cases she could also get that information by comparing - other parts of the log file: for example the User-Agent if it isn't - a very common one, or the user's IP address if it doesn't change between - different requests. -
Always blocking the referrer, or using a custom one, can lead to - failures on servers that check the referrer before they answer any - requests, in an attempt to prevent their content from being - embedded or linked to elsewhere. -
Both conditional-block and forge - will work with referrer checks, as long as content and valid referring page - are on the same host. Most of the time that's the case. -
- hide-referer is an alternate spelling of - hide-referrer and the two can be can be freely - substituted with each other. ("referrer" is the - correct English spelling, however the HTTP specification has a bug - it - requires it to be spelled as "referer".) -
+hide-referrer{forge} |
+hide-referrer{http://www.yahoo.com/} |
Try to conceal your type of browser and client operating system
Replaces the value of the "User-Agent:" HTTP header - in client requests with the specified value. -
Parameterized.
Any user-defined string. -
Warning |
This can lead to problems on web sites that depend on looking at this header in - order to customize their content for different browsers (which, by the - way, is NOT the right thing to do: good web sites - work browser-independently). - |
Using this action in multi-user setups or wherever different types of - browsers will access the same Privoxy is - not recommended. In single-user, single-browser - setups, you might use it to delete your OS version information from - the headers, because it is an invitation to exploit known bugs for your - OS. It is also occasionally useful to forge this in order to access - sites that won't let you in otherwise (though there may be a good - reason in some cases). Example of this: some MSN sites will not - let Mozilla enter, yet forging to a - Netscape 6.1 user-agent works just fine. - (Must be just a silly MS goof, I'm sure :-). -
More information on known user-agent strings can be found at - http://www.user-agents.org/ - and - http://en.wikipedia.org/wiki/User_agent. -
+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)} |
Prevent abuse of Privoxy as a TCP proxy relay or disable SSL for untrusted sites
Specifies to which ports HTTP CONNECT requests are allowable. -
Parameterized.
A comma-separated list of ports or port ranges (the latter using dashes, with the minimum - defaulting to 0 and the maximum to 65K). -
By default, i.e. if no limit-connect action applies, - Privoxy allows HTTP CONNECT requests to all - ports. Use limit-connect if fine-grained control - is desired for some or all destinations. -
The CONNECT methods exists in HTTP to allow access to secure websites - ("https://" URLs) through proxies. It works very simply: - the proxy connects to the server on the specified port, and then - short-circuits its connections to the client and to the remote server. - This means CONNECT-enabled proxies can be used as TCP relays very easily. -
Privoxy relays HTTPS traffic without seeing - the decoded content. Websites can leverage this limitation to circumvent Privoxy's - filters. By specifying an invalid port range you can disable HTTPS entirely. -
+limit-connect{443} # Port 443 is OK. + A comma-separated list of ports or port ranges (the latter + using dashes, with the minimum defaulting to 0 and the maximum + to 65K). +By default, i.e. if no limit-connect action applies, Privoxy allows HTTP CONNECT requests to + all ports. Use limit-connect if + fine-grained control is desired for some or all + destinations. + +The CONNECT methods exists in HTTP to allow access to secure + websites ("https://" URLs) through + proxies. It works very simply: the proxy connects to the server + on the specified port, and then short-circuits its connections + to the client and to the remote server. This means + CONNECT-enabled proxies can be used as TCP relays very + easily. + +Privoxy relays HTTPS + traffic without seeing the decoded content. Websites can + leverage this limitation to circumvent Privoxy's filters. By specifying an + invalid port range you can disable HTTPS entirely. +
8.5.27. prevent-compression
+ 8.5.27. prevent-compression+ +
+
8.5.28. overwrite-last-modified
+ 8.5.28. overwrite-last-modified+ +
+
8.5.29. redirect
+ 8.5.29. + redirect+ +
+
8.5.30. server-header-filter
+ 8.5.30. server-header-filter+ +
+
8.5.31. server-header-tagger
+ 8.5.31. server-header-tagger+ +
+
8.5.32. session-cookies-only
8.5.33. set-image-blocker
8.5.34. SummaryNote that many of these actions have the potential to cause a page to - misbehave, possibly even not to display at all. There are many ways - a site designer may choose to design his site, and what HTTP header - content, and other criteria, he may depend on. There is no way to have hard - and fast rules for all sites. See the Appendix for a brief example on troubleshooting - actions. 8.6. AliasesCustom "actions", known to Privoxy - as "aliases", can be defined by combining other actions. - These can in turn be invoked just like the built-in actions. - Currently, an alias name can contain any character except space, tab, - "=", - "{" and "}", but we strongly - recommend that you only use "a" to "z", - "0" to "9", "+", and "-". - Alias names are not case sensitive, and are not required to start with a - "+" or "-" sign, since they are merely textually - expanded. Aliases can be used throughout the actions file, but they must be - defined in a special section at the top of the file! - And there can only be one such section per actions file. Each actions file may - have its own alias section, and the aliases defined in it are only visible - within that file. There are two main reasons to use aliases: One is to save typing for frequently - used combinations of actions, the other one is a gain in flexibility: If you - decide once how you want to handle shops by defining an alias called - "shop", you can later change your policy on shops in - one place, and your changes will take effect everywhere - in the actions file where the "shop" alias is used. Calling aliases - by their purpose also makes your actions files more readable. Currently, there is one big drawback to using aliases, though: - Privoxy's built-in web-based action file - editor honors aliases when reading the actions files, but it expands - them before writing. So the effects of your aliases are of course preserved, - but the aliases themselves are lost when you edit sections that use aliases - with it. Now let's define some aliases...
+
+
+ 8.5.32. session-cookies-only+ +
+
+
+
+
+ 8.5.33. set-image-blocker+ +
+
+
+
+
+
+ 8.5.34. + Summary+ +Note that many of these actions have the potential to cause a page + to misbehave, possibly even not to display at all. There are many + ways a site designer may choose to design his site, and what HTTP + header content, and other criteria, he may depend on. There is no way + to have hard and fast rules for all sites. See the Appendix for a brief example on + troubleshooting actions. +
+ 8.6. Aliases+ +Custom "actions", known to Privoxy as "aliases", + can be defined by combining other actions. These can in turn be invoked + just like the built-in actions. Currently, an alias name can contain + any character except space, tab, "=", + "{" and "}", but + we strongly + recommend that you only use "a" + to "z", "0" to + "9", "+", and + "-". Alias names are not case sensitive, and + are not required to start with a "+" or + "-" sign, since they are merely textually + expanded. + +Aliases can be used throughout the actions file, but they + must be defined in a special + section at the top of the file! And there can only be one + such section per actions file. Each actions file may have its own alias + section, and the aliases defined in it are only visible within that + file. + +There are two main reasons to use aliases: One is to save typing for + frequently used combinations of actions, the other one is a gain in + flexibility: If you decide once how you want to handle shops by + defining an alias called "shop", you can + later change your policy on shops in one place, and your changes will take effect + everywhere in the actions file where the "shop" alias is used. Calling aliases by their purpose + also makes your actions files more readable. + +Currently, there is one big drawback to using aliases, though: + Privoxy's built-in web-based action + file editor honors aliases when reading the actions files, but it + expands them before writing. So the effects of your aliases are of + course preserved, but the aliases themselves are lost when you edit + sections that use aliases with it. + +Now let's define some aliases... + +
...and put them to use. These sections would appear in the lower part of an - actions file and define exceptions to the default actions (as specified further - up for the "/" pattern):
...and put them to use. These sections would appear in the lower + part of an actions file and define exceptions to the default actions + (as specified further up for the "/" + pattern): + +
Aliases like "shop" and "fragile" are typically used for - "problem" sites that require more than one action to be disabled - in order to function properly. 8.7. Actions Files TutorialThe above chapters have shown which actions files - there are and how they are organized, how actions are specified and applied - to URLs, how patterns work, and how to - define and use aliases. Now, let's look at an - example match-all.action, default.action - and user.action file and see how all these pieces come together: 8.7.1. match-all.actionRemember all actions are disabled when matching starts, - so we have to explicitly enable the ones we want. While the match-all.action file only contains a - single section, it is probably the most important one. It has only one - pattern, "/", but this pattern - matches all URLs. Therefore, the set of - actions used in this "default" section will - be applied to all requests as a start. It can be partly or - wholly overridden by other actions files like default.action - and user.action, but it will still be largely responsible - for your overall browsing experience. Again, at the start of matching, all actions are disabled, so there is - no need to disable any actions here. (Remember: a "+" - preceding the action name enables the action, a "-" disables!). - Also note how this long line has been made more readable by splitting it into - multiple lines with line continuation.
Aliases like "shop" and "fragile" are typically used for "problem" sites that require more than one action to be + disabled in order to function properly. +
+ 8.7. Actions + Files Tutorial+ +The above chapters have shown which + actions files there are and how they are organized, how actions are + specified and applied to URLs, how patterns work, and how to define + and use aliases. Now, let's + look at an example match-all.action, + default.action and user.action file and see how all these pieces come + together: + +
+ 8.7.1. + match-all.action+ +Remember all actions + are disabled when matching starts, so we have to + explicitly enable the ones we want. + +While the match-all.action file only + contains a single section, it is probably the most important one. It + has only one pattern, "/", but this pattern matches all URLs. Therefore, the + set of actions used in this "default" + section will be applied to + all requests as a start. It can be partly or wholly + overridden by other actions files like default.action and user.action, but it will still be largely responsible + for your overall browsing experience. + +Again, at the start of matching, all actions are disabled, so + there is no need to disable any actions here. (Remember: a + "+" preceding the action name enables the + action, a "-" disables!). Also note how + this long line has been made more readable by splitting it into + multiple lines with line continuation. + +
The default behavior is now set. 8.7.2. default.actionIf you aren't a developer, there's no need for you to edit the - default.action file. It is maintained by - the Privoxy developers and if you disagree with some of the - sections, you should overrule them in your user.action. Understanding the default.action file can - help you with your user.action, though. The first section in this file is a special section for internal use - that prevents older Privoxy versions from reading the file:
The default behavior is now set. +
+ 8.7.2. + default.action+ +If you aren't a developer, there's no need for you to edit the + default.action file. It is maintained by + the Privoxy developers and if you + disagree with some of the sections, you should overrule them in your + user.action. + +Understanding the default.action file + can help you with your user.action, + though. + +The first section in this file is a special section for internal + use that prevents older Privoxy + versions from reading the file: + +
After that comes the (optional) alias section. We'll use the example - section from the above chapter on aliases, - that also explains why and how aliases are used:
After that comes the (optional) alias section. We'll use the + example section from the above chapter on aliases, that also + explains why and how aliases are used: + +
The first of our specialized sections is concerned with "fragile" - sites, i.e. sites that require minimum interference, because they are either - very complex or very keen on tracking you (and have mechanisms in place that - make them unusable for people who avoid being tracked). We will simply use - our pre-defined fragile alias instead of stating the list - of actions explicitly:
The first of our specialized sections is concerned with + "fragile" sites, i.e. sites that require + minimum interference, because they are either very complex or very + keen on tracking you (and have mechanisms in place that make them + unusable for people who avoid being tracked). We will simply use our + pre-defined fragile alias instead of stating + the list of actions explicitly: + +
Shopping sites are not as fragile, but they typically - require cookies to log in, and pop-up windows for shopping - carts or item details. Again, we'll use a pre-defined alias:
Shopping sites are not as fragile, but they typically require + cookies to log in, and pop-up windows for shopping carts or item + details. Again, we'll use a pre-defined alias: + +
The fast-redirects - action, which may have been enabled in match-all.action, - breaks some sites. So disable it for popular sites where we know it misbehaves:
The fast-redirects action, + which may have been enabled in match-all.action, breaks some sites. So disable it + for popular sites where we know it misbehaves: + +
It is important that Privoxy knows which - URLs belong to images, so that if they are to - be blocked, a substitute image can be sent, rather than an HTML page. - Contacting the remote site to find out is not an option, since it - would destroy the loading time advantage of banner blocking, and it - would feed the advertisers information about you. We can mark any - URL as an image with the handle-as-image action, - and marking all URLs that end in a known image file extension is a - good start:
It is important that Privoxy + knows which URLs belong to images, so that if they are to be blocked, + a substitute image can be sent, rather than an HTML page. Contacting + the remote site to find out is not an option, since it would destroy + the loading time advantage of banner blocking, and it would feed the + advertisers information about you. We can mark any URL as an image + with the handle-as-image action, + and marking all URLs that end in a known image file extension is a + good start: + +
And then there are known banner sources. They often use scripts to - generate the banners, so it won't be visible from the URL that the - request is for an image. Hence we block them and - mark them as images in one go, with the help of our - +block-as-image alias defined above. (We could of - course just as well use +block - +handle-as-image here.) - Remember that the type of the replacement image is chosen by the - set-image-blocker - action. Since all URLs have matched the default section with its - +set-image-blocker{pattern} - action before, it still applies and needn't be repeated:
And then there are known banner sources. They often use scripts to + generate the banners, so it won't be visible from the URL that the + request is for an image. Hence we block them and mark them as images in + one go, with the help of our +block-as-image + alias defined above. (We could of course just as well use +block +handle-as-image here.) + Remember that the type of the replacement image is chosen by the + set-image-blocker + action. Since all URLs have matched the default section with its + +set-image-blocker{pattern} + action before, it still applies and needn't be repeated: + +
One of the most important jobs of Privoxy - is to block banners. Many of these can be "blocked" - by the filter{banners-by-size} - action, which we enabled above, and which deletes the references to banner - images from the pages while they are loaded, so the browser doesn't request - them anymore, and hence they don't need to be blocked here. But this naturally - doesn't catch all banners, and some people choose not to use filters, so we - need a comprehensive list of patterns for banner URLs here, and apply the - block action to them. First comes many generic patterns, which do most of the work, by - matching typical domain and path name components of banners. Then comes - a list of individual patterns for specific sites, which is omitted here - to keep the example short:
One of the most important jobs of Privoxy is to block banners. Many of these can + be "blocked" by the filter{banners-by-size} action, + which we enabled above, and which deletes the references to banner + images from the pages while they are loaded, so the browser doesn't + request them anymore, and hence they don't need to be blocked here. + But this naturally doesn't catch all banners, and some people choose + not to use filters, so we need a comprehensive list of patterns for + banner URLs here, and apply the block action to them. + +First comes many generic patterns, which do most of the work, by + matching typical domain and path name components of banners. Then + comes a list of individual patterns for specific sites, which is + omitted here to keep the example short: + +
It's quite remarkable how many advertisers actually call their banner - servers ads.company.com, or call the directory - in which the banners are stored simply "banners". So the above - generic patterns are surprisingly effective. But being very generic, they necessarily also catch URLs that we don't want - to block. The pattern .*ads. e.g. catches - "nasty-ads.nasty-corp.com" as intended, - but also "downloads.sourcefroge.net" or - "adsl.some-provider.net." So here come some - well-known exceptions to the +block - section above. Note that these are exceptions to exceptions from the default! Consider the URL - "downloads.sourcefroge.net": Initially, all actions are deactivated, - so it wouldn't get blocked. Then comes the defaults section, which matches the - URL, but just deactivates the block - action once again. Then it matches .*ads., an exception to the - general non-blocking policy, and suddenly - +block applies. And now, it'll match - .*loads., where -block - applies, so (unless it matches again further down) it ends up - with no block action applying.
It's quite remarkable how many advertisers actually call their + banner servers ads.company.com, + or call the directory in which the banners are stored simply + "banners". So the above generic patterns + are surprisingly effective. + +But being very generic, they necessarily also catch URLs that we + don't want to block. The pattern .*ads. e.g. + catches "nasty-ads.nasty-corp.com" as intended, but + also "downloads.sourcefroge.net" or "adsl.some-provider.net." So here come + some well-known exceptions to the +block section above. + +Note that these are exceptions to exceptions from the default! + Consider the URL "downloads.sourcefroge.net": Initially, all actions + are deactivated, so it wouldn't get blocked. Then comes the defaults + section, which matches the URL, but just deactivates the block action + once again. Then it matches .*ads., an + exception to the general non-blocking policy, and suddenly +block applies. + And now, it'll match .*loads., where + -block + applies, so (unless it matches again further down) it ends up with no + block + action applying. + +
Filtering source code can have nasty side effects, - so make an exception for our friends at sourceforge.net, - and all paths with "cvs" in them. Note that - -filter - disables all filters in one fell swoop!
Filtering source code can have nasty side effects, so make an + exception for our friends at sourceforge.net, and all paths with + "cvs" in them. Note that -filter + disables all + filters in one fell swoop! + +
The actual default.action is of course much more - comprehensive, but we hope this example made clear how it works. 8.7.3. user.actionSo far we are painting with a broad brush by setting general policies, - which would be a reasonable starting point for many people. Now, - you might want to be more specific and have customized rules that - are more suitable to your personal habits and preferences. These would - be for narrowly defined situations like your ISP or your bank, and should - be placed in user.action, which is parsed after all other - actions files and hence has the last word, over-riding any previously - defined actions. user.action is also a - safe place for your personal settings, since - default.action is actively maintained by the - Privoxy developers and you'll probably want - to install updated versions from time to time. So let's look at a few examples of things that one might typically do in - user.action:
As aliases are local to the actions - file that they are defined in, you can't use the ones from - default.action, unless you repeat them here:
The actual default.action is of course + much more comprehensive, but we hope this example made clear how it + works. +
+ 8.7.3. + user.action+ +So far we are painting with a broad brush by setting general + policies, which would be a reasonable starting point for many people. + Now, you might want to be more specific and have customized rules + that are more suitable to your personal habits and preferences. These + would be for narrowly defined situations like your ISP or your bank, + and should be placed in user.action, which + is parsed after all other actions files and hence has the last word, + over-riding any previously defined actions. user.action is also a safe place for your + personal settings, since default.action is + actively maintained by the Privoxy + developers and you'll probably want to install updated versions from + time to time. + +So let's look at a few examples of things that one might typically + do in user.action: + +
As aliases are local to + the actions file that they are defined in, you can't use the ones + from default.action, unless you repeat them + here: + +
Say you have accounts on some sites that you visit regularly, and - you don't want to have to log in manually each time. So you'd like - to allow persistent cookies for these sites. The - allow-all-cookies alias defined above does exactly - that, i.e. it disables crunching of cookies in any direction, and the - processing of cookies to make them only temporary.
Say you have accounts on some sites that you visit regularly, and + you don't want to have to log in manually each time. So you'd like to + allow persistent cookies for these sites. The allow-all-cookies alias defined above does exactly + that, i.e. it disables crunching of cookies in any direction, and the + processing of cookies to make them only temporary. + +
Your bank is allergic to some filter, but you don't know which, so you disable them all:
Some file types you may not want to filter for various reasons:
Your bank is allergic to some filter, but you don't know which, so + you disable them all: + +
Some file types you may not want to filter for various + reasons: + +
Example of a simple block action. Say you've - seen an ad on your favourite page on example.com that you want to get rid of. - You have right-clicked the image, selected "copy image location" - and pasted the URL below while removing the leading http://, into a - { +block{} } section. Note that { +handle-as-image - } need not be specified, since all URLs ending in - .gif will be tagged as images by the general rules as set - in default.action anyway:
Example of a simple block + action. Say you've seen an ad on your favourite page on example.com + that you want to get rid of. You have right-clicked the image, + selected "copy image location" and pasted + the URL below while removing the leading http://, into a { +block{} } section. Note that { + +handle-as-image } need not be specified, since all URLs ending + in .gif will be tagged as images by the + general rules as set in default.action anyway: + +
The URLs of dynamically generated banners, especially from large banner - farms, often don't use the well-known image file name extensions, which - makes it impossible for Privoxy to guess - the file type just by looking at the URL. - You can use the +block-as-image alias defined above for - these cases. - Note that objects which match this rule but then turn out NOT to be an - image are typically rendered as a "broken image" icon by the - browser. Use cautiously.
The URLs of dynamically generated banners, especially from large + banner farms, often don't use the well-known image file name + extensions, which makes it impossible for Privoxy to guess the file type just by looking + at the URL. You can use the +block-as-image + alias defined above for these cases. Note that objects which match + this rule but then turn out NOT to be an image are typically rendered + as a "broken image" icon by the browser. + Use cautiously. + +
Now you noticed that the default configuration breaks Forbes Magazine, - but you were too lazy to find out which action is the culprit, and you - were again too lazy to give feedback, so - you just used the fragile alias on the site, and - -- whoa! -- it worked. The fragile - aliases disables those actions that are most likely to break a site. Also, - good for testing purposes to see if it is Privoxy - that is causing the problem or not. We later find other regular sites - that misbehave, and add those to our personalized list of troublemakers:
Now you noticed that the default configuration breaks Forbes + Magazine, but you were too lazy to find out which action is the + culprit, and you were again too lazy to give feedback, so you just used the fragile alias on the site, and -- whoa! -- it worked. The + fragile aliases disables those actions that + are most likely to break a site. Also, good for testing purposes to + see if it is Privoxy that is causing + the problem or not. We later find other regular sites that misbehave, + and add those to our personalized list of troublemakers: + +
You like the "fun" text replacements in default.filter, - but it is disabled in the distributed actions file. - So you'd like to turn it on in your private, - update-safe config, once and for all:
Note that the above is not really a good idea: There are exceptions - to the filters in default.action for things that - really shouldn't be filtered, like code on CVS->Web interfaces. Since - user.action has the last word, these exceptions - won't be valid for the "fun" filtering specified here. You might also worry about how your favourite free websites are - funded, and find that they rely on displaying banner advertisements - to survive. So you might want to specifically allow banners for those - sites that you feel provide value to you:
You like the "fun" text replacements in + default.filter, but it is disabled in the + distributed actions file. So you'd like to turn it on in your + private, update-safe config, once and for all: + +
Note that the above is not really a good idea: There are + exceptions to the filters in default.action + for things that really shouldn't be filtered, like code on + CVS->Web interfaces. Since user.action + has the last word, these exceptions won't be valid for the + "fun" filtering specified here. + +You might also worry about how your favourite free websites are + funded, and find that they rely on displaying banner advertisements + to survive. So you might want to specifically allow banners for those + sites that you feel provide value to you: + +
Note that allow-ads has been aliased to - -block, - -filter{banners-by-size}, and - -filter{banners-by-link} above. Invoke another alias here to force an over-ride of the MIME type application/x-sh which typically would open a download type - dialog. In my case, I want to look at the shell script, and then I can save - it should I choose to.
user.action is generally the best place to define - exceptions and additions to the default policies of - default.action. Some actions are safe to have their - default policies set here though. So let's set a default policy to have a - "blank" image as opposed to the checkerboard pattern for - ALL sites. "/" of course matches all URL - paths and patterns:
|
+
Note that allow-ads has been aliased to + -block, -filter{banners-by-size}, + and -filter{banners-by-link} + above.
+ +Invoke another alias here to force an over-ride of the MIME type + application/x-sh which typically would open + a download type dialog. In my case, I want to look at the shell + script, and then I can save it should I choose to.
+ +
+ +{ handle-as-text } + /.*\.sh$ ++ |
+
user.action is generally the best place + to define exceptions and additions to the default policies of + default.action. Some actions are safe to + have their default policies set here though. So let's set a default + policy to have a "blank" image as opposed + to the checkerboard pattern for ALL sites. "/" of + course matches all URL paths and patterns:
+ +
+ +{ +set-image-blocker{blank} } +/ # ALL sites ++ |
+