Trac Spam Filtering

A plugin is being developed that will allow different ways to reject contributions that contain spam. This plugin requires Trac release 0.10. It should also work with 0.11dev (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 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 ​Python syntax for regular expressions.

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

IP Blacklisting

The ip_blacklist filter uses the third-party Python library ​dnspython to make DNS requests to a configurable list of IP blacklist servers.

IP Throttling

The 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 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 akismet filter uses the ​Akismet web service to check content for possible spam.

The use of this filter requires a ​Wordpress API key. The API key is configured in 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 ​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 ​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 spambayes-dev for help.

WebAdmin Integration

Since version 0.2, the SpamFilter plugin provides integration with WebAdmin for configuration and monitoring. For monitoring 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 here.

Recommended versions:

Trac	Spam Filter
0.10	latest
0.11dev	latest

See TracPlugins for instructions on building and installing plugins.

Enabling the Plugin

If you install the plugin globally (as described here), you'll also need to enable it in trac.ini as follows:

[components]
tracspamfilter.* = enabled

Further Reading / Alternate Solution

Please read ​this link.

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See also: TracPlugins, PluginList