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.