limits.php

<?php
/*
	Question2Answer by Gideon Greenspan and contributors
	http://www.question2answer.org/

	File: qa-include/qa-db-limits.php
	Description: Database-level access to tables which monitor rate limits


	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	More about this license: http://www.question2answer.org/license.php
*/

	if (!defined('QA_VERSION')) { // don't allow this page to be requested directly from browser
		header('Location: ../');
		exit;
	}


	function qa_db_limits_get($userid, $ip, $action)
/*
	Get rate limit information for $action from the database for user $userid and/or IP address $ip, if they're set.
	Return as an array with the limit type in the key, and a labelled array of the period and count.
*/
	{
		$selects=array();
		$arguments=array();

		if (isset($userid)) {
			$selects[]="(SELECT 'user' AS limitkey, period, count FROM ^userlimits WHERE userid=$ AND action=$)";
			$arguments[]=$userid;
			$arguments[]=$action;
		}

		if (isset($ip)) {
			$selects[]="(SELECT 'ip' AS limitkey, period, count FROM ^iplimits WHERE ip=COALESCE(INET_ATON($), 0) AND action=$)";
			$arguments[]=$ip;
			$arguments[]=$action;
		}

		if (count($selects)) {
			$query=qa_db_apply_sub(implode(' UNION ALL ', $selects), $arguments);
			return qa_db_read_all_assoc(qa_db_query_raw($query), 'limitkey');

		} else
			return array();
	}


	function qa_db_limits_user_add($userid, $action, $period, $count)
/*
	Increment the database rate limit count for user $userid and $action by $count within $period
*/
	{
		qa_db_query_sub(
			'INSERT INTO ^userlimits (userid, action, period, count) VALUES ($, $, #, #) '.
			'ON DUPLICATE KEY UPDATE count=IF(period=#, count+#, #), period=#',
			$userid, $action, $period, $count, $period, $count, $count, $period
		);
	}


	function qa_db_limits_ip_add($ip, $action, $period, $count)
/*
	Increment the database rate limit count for IP address $ip and $action by $count within $period
*/
	{
		qa_db_query_sub(
			'INSERT INTO ^iplimits (ip, action, period, count) VALUES (COALESCE(INET_ATON($), 0), $, #, #) '.
			'ON DUPLICATE KEY UPDATE count=IF(period=#, count+#, #), period=#',
			$ip, $action, $period, $count, $period, $count, $count, $period
		);
	}


/*
	Omit PHP closing tag to help avoid accidental output
*/