<?php
/**
* Provide basic rate limiting functionality via WP Options API.
*
* Currently only provides a simple limit by delaying action by X seconds.
*
* Example usage:
*
* When an action runs, call set_rate_limit, e.g.:
*
* WC_Rate_Limiter::set_rate_limit( "{$my_action_name}_{$user_id}", $delay );
*
* This sets a timestamp for future timestamp after which action can run again.
*
*
* Then before running the action again, check if the action is allowed to run, e.g.:
*
* if ( WC_Rate_Limiter::retried_too_soon( "{$my_action_name}_{$user_id}" ) ) {
* add_notice( 'Sorry, too soon!' );
* }
*
* @package WooCommerce\Classes
* @version 3.9.0
* @since 3.9.0
*/
defined( 'ABSPATH' ) || exit;
/**
* Rate limit class.
*/
class WC_Rate_Limiter {
/**
* Cache group.
*/
const CACHE_GROUP = 'wc_rate_limit';
/**
* Hook in methods.
*/
public static function init() {
add_action( 'woocommerce_cleanup_rate_limits', array( __CLASS__, 'cleanup' ) );
}
/**
* Constructs key name from action identifier.
* Left in for backwards compatibility.
*
* @param string $action_id Identifier of the action.
* @return string
*/
public static function storage_id( $action_id ) {
return $action_id;
}
/**
* Gets a cache prefix.
*
* @param string $action_id Identifier of the action.
* @return string
*/
protected static function get_cache_key( $action_id ) {
return WC_Cache_Helper::get_cache_prefix( 'rate_limit' . $action_id );
}
/**
* Retrieve a cached rate limit.
*
* @param string $action_id Identifier of the action.
* @return bool|int
*/
protected static function get_cached( $action_id ) {
return wp_cache_get( self::get_cache_key( $action_id ), self::CACHE_GROUP );
}
/**
* Cache a rate limit.
*
* @param string $action_id Identifier of the action.
* @param int $expiry Timestamp when the limit expires.
* @return bool
*/
protected static function set_cache( $action_id, $expiry ) {
return wp_cache_set( self::get_cache_key( $action_id ), $expiry, self::CACHE_GROUP );
}
/**
* Returns true if the action is not allowed to be run by the rate limiter yet, false otherwise.
*
* @param string $action_id Identifier of the action.
* @return bool
*/
public static function retried_too_soon( $action_id ) {
global $wpdb;
$next_try_allowed_at = self::get_cached( $action_id );
if ( false === $next_try_allowed_at ) {
$next_try_allowed_at = $wpdb->get_var(
$wpdb->prepare(
"
SELECT rate_limit_expiry
FROM {$wpdb->prefix}wc_rate_limits
WHERE rate_limit_key = %s
",
$action_id
)
);
self::set_cache( $action_id, $next_try_allowed_at );
}
// No record of action running, so action is allowed to run.
if ( null === $next_try_allowed_at ) {
return false;
}
// Before the next run is allowed, retry forbidden.
if ( time() <= $next_try_allowed_at ) {
return true;
}
// After the next run is allowed, retry allowed.
return false;
}
/**
* Sets the rate limit delay in seconds for action with identifier $id.
*
* @param string $action_id Identifier of the action.
* @param int $delay Delay in seconds.
* @return bool True if the option setting was successful, false otherwise.
*/
public static function set_rate_limit( $action_id, $delay ) {
global $wpdb;
$next_try_allowed_at = time() + $delay;
$result = $wpdb->replace(
$wpdb->prefix . 'wc_rate_limits',
array(
'rate_limit_key' => $action_id,
'rate_limit_expiry' => $next_try_allowed_at,
),
array( '%s', '%d' )
);
self::set_cache( $action_id, $next_try_allowed_at );
return false !== $result;
}
/**
* Cleanup expired rate limits from the database and clear caches.
*/
public static function cleanup() {
global $wpdb;
$wpdb->query(
$wpdb->prepare(
"DELETE FROM {$wpdb->prefix}wc_rate_limits WHERE rate_limit_expiry < %d",
time()
)
);
if ( class_exists( 'WC_Cache_Helper' ) ) {
WC_Cache_Helper::invalidate_cache_group( self::CACHE_GROUP );
}
}
}
WC_Rate_Limiter::init();