Package: libcgi-application-plugin-ratelimit-perl (1.0-3)

Perl module for limiting the runmode call rate per user

CGI::Application::Plugin::RateLimit provides protection against a user calling a runmode too frequently. A typical use-case might be a contact form that sends email. You'd like to allow your users to send you messages, but thousands of messages from a single user would be a problem.

This module works by maintaining a database of hits to protected runmodes. It then checks this database to determine if a new hit should be allowed based on past activity by the user. The user's identity is, by default, tied to login (via REMOTE_USER) or IP address (via REMOTE_IP) if login info is not available. You may provide your own identity function via the identity_callback() method.

To use this module you must create a table in your database with the following schema (using MySQL-syntax, although other DBs may work as well with minor alterations):

 CREATE TABLE rate_limit_hits (
     user_id   VARCHAR(255)      NOT NULL,
     action    VARCHAR(255)      NOT NULL,
     timestamp UNSIGNED INTEGER  NOT NULL,
     INDEX (user_id, action, timestamp)
  );

You may feel free to vary the storage-type and size of user_id and action to match your usage. For example, if your identity_callback() always returns an integer you could make user_id an integer column.

This table should be periodically cleared of old data. Anything older than the maximum timeframe being used can be safely deleted.

IMPORTANT NOTE: The protection offered by this module is not perfect. Identifying a user on the internet is very hard and a sophisticated attacker can work around these checks, by switching IPs or automating login creation.