= Trac Spam Filtering =
[[PageOutline(2-3)]]

A plugin is being developed that will allow different ways to reject contributions that contain spam. This plugin requires Trac release [milestone:0.10]. It should also work with [milestone:0.11]dev (if not, let us know).

== Supported Filtering Strategies ==

Prior to version 0.2.x, the SpamFilter plugin would reject a submission if any single filter strategy said it was spam. Since 0.2, the individual strategies assign scores (“karma”) to submitted content, and the total karma determines whether a submission is rejected or not.

=== Regular Expressions ===

The [source:sandbox/spam-filter/tracspamfilter/filters/regex.py regex] filter reads a list of regular expressions from a wiki page named “BadContent”, each regular expression being on a separate line inside the first code block on the page, using the [http://docs.python.org/lib/re-syntax.html Python syntax] for regular expressions.

If any of those regular expressions matches the submitted content, the submission will be rejected.

=== IP Blacklisting ===

The [source:sandbox/spam-filter/tracspamfilter/filters/ip_blacklist.py ip_blacklist] filter uses the third-party Python library [http://www.dnspython.org/ dnspython] to make DNS requests to a configurable list of IP blacklist servers.

=== IP Throttling ===

The [source:sandbox/spam-filter/tracspamfilter/filters/ip_throttle.py ip_throttle] filter limits the number of posts per hour allowed from a single IP.

The maximum number of posts per hour is configured in [wiki:TracIni trac.ini]:

{{{
[spam-filter]
max_posts_by_ip = 5
}}}

When this limit is exceeded, the filter starts giving submissions negative karma as specified by the `ip_throttle_karma` option.

''(since version 0.2)''

=== Akismet ===

The [source:sandbox/spam-filter/tracspamfilter/filters/akismet.py akismet] filter uses the [http://akismet.com/ Akismet] web service to check content for possible spam.

The use of this filter requires a [http://www.wordpress.com Wordpress] API key. The API key is configured in [wiki:TracIni trac.ini] in a separate section:

For version 0.1.x of the plugin:

{{{
[akismet]
api_key = 1234567890
}}}

For version 0.2.x:

{{{
[spam-filter]
akismet_api_key = 1234567890
}}}

=== Bayes ===

''TODO''

> (The code in svn uses [http://spambayes.org SpamBayes], which is a logical choice.  It would make sense to use a custom tokenizer, however, rather than the email-centric one that is included with [http://spambayes.org SpamBayes].  The bigger issue is that some form of training is required (e.g. the API could be extended so that (optionally) authenticated users (and the other filters) could report contributions as spam (using automatic training to assume that everything else is ham); however, this is a complex change).  An alternative to this would be a script that could be periodically executed that would train all existing contributions as ham, and gather spam from an appropriate source.  If you decide to continue with this in the future, please don't hestiate to ask [mailto:spambayes-dev@python.org spambayes-dev] for help.

== WebAdmin Integration ==

Since version 0.2, the SpamFilter plugin provides integration with WebAdmin for configuration, monitoring, and training. For monitoring and training purposes, it optionally logs all activity to a table in the database. Upgrading the environment is necessary to install the database table required for this logging.

== Get the Plugin ==

The SpamFilter plugin is currently only available through Subversion:
{{{
  svn co http://svn.edgewall.com/repos/trac/sandbox/spam-filter
}}}

You can browse the source [source:sandbox/spam-filter here].

Recommended versions: 
|| Trac 	         || Spam Filter ||
|| [milestone:0.10] 	 || latest ||
|| [milestone:0.11]dev 	 || latest ||

See TracPlugins for instructions on building and installing plugins.

== Enabling the Plugin ==

If you install the plugin globally (as described [wiki:TracPlugins#ForAllProjects here]), you'll also need to enable it in [wiki:TracIni trac.ini] as follows:
{{{
[components]
tracspamfilter.* = enabled
}}}

== Further Reading ==

 * More info about SpamFilter (and screenshots): [http://www.cmlenz.net/blog/2006/11/managing_trac_s.html Managing Trac Spam]
 * An alternate solution based on mod_security: [http://madwifi.org/wiki/FightingTracSpam Fighting Trac Spam].

== Users Note ==
 * For '''ip_blacklist''' feature you need '''dnspython''' installed , you can do it via `easy_install dnspython`
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See also: TracPlugins, PluginList