<?php
namespace Automattic\WooCommerce\StoreApi\Utilities;
use WC_Rate_Limiter;
use WC_Cache_Helper;
/**
* RateLimits class.
*/
class RateLimits extends WC_Rate_Limiter {
/**
* Cache group.
*/
const CACHE_GROUP = 'store_api_rate_limit';
/**
* Rate limiting enabled default value.
*
* @var boolean
*/
const ENABLED = false;
/**
* Proxy support enabled default value.
*
* @var boolean
*/
const PROXY_SUPPORT = false;
/**
* Default amount of max requests allowed for the defined timeframe.
*
* @var int
*/
const LIMIT = 25;
/**
* Default time in seconds before rate limits are reset.
*
* @var int
*/
const SECONDS = 10;
/**
* Gets a cache prefix.
*
* @param string $action_id Identifier of the action.
* @return string
*/
protected static function get_cache_key( $action_id ): string {
return WC_Cache_Helper::get_cache_prefix( 'store_api_rate_limit' . $action_id );
}
/**
* Get current rate limit row from DB and normalize types. This query is not cached, and returns
* a new rate limit row if none exists.
*
* @param string $action_id Identifier of the action.
*
* @return object Object containing reset and remaining.
*/
protected static function get_rate_limit_row( string $action_id ): object {
global $wpdb;
$time = time();
$row = $wpdb->get_row(
$wpdb->prepare(
"
SELECT rate_limit_expiry as reset, rate_limit_remaining as remaining
FROM {$wpdb->prefix}wc_rate_limits
WHERE rate_limit_key = %s
AND rate_limit_expiry > %s
",
$action_id,
$time
),
'OBJECT'
);
if ( empty( $row ) ) {
$options = self::get_options();
return (object) [
'reset' => (int) $options->seconds + $time,
'remaining' => (int) $options->limit,
];
}
return (object) [
'reset' => (int) $row->reset,
'remaining' => (int) $row->remaining,
];
}
/**
* Returns current rate limit values using cache where possible.
*
* @param string $action_id Identifier of the action.
*
* @return object
*/
public static function get_rate_limit( string $action_id ): object {
$current_limit = self::get_cached( $action_id );
if ( false === $current_limit ) {
$current_limit = self::get_rate_limit_row( $action_id );
self::set_cache( $action_id, $current_limit );
}
return $current_limit;
}
/**
* If exceeded, seconds until reset.
*
* @param string $action_id Identifier of the action.
*
* @return bool|int
*/
public static function is_exceeded_retry_after( string $action_id ) {
$current_limit = self::get_rate_limit( $action_id );
$time = time();
// Before the next run is allowed, retry forbidden.
if ( $time <= (int) $current_limit->reset && 0 === (int) $current_limit->remaining ) {
return (int) $current_limit->reset - $time;
}
// 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.
*
* @return object Current rate limits.
*/
public static function update_rate_limit( string $action_id ): object {
global $wpdb;
$options = self::get_options();
$time = time();
$rate_limit_expiry = $time + (int) $options->seconds;
$wpdb->query(
$wpdb->prepare(
"INSERT INTO {$wpdb->prefix}wc_rate_limits
(`rate_limit_key`, `rate_limit_expiry`, `rate_limit_remaining`)
VALUES
(%s, %d, %d)
ON DUPLICATE KEY UPDATE
`rate_limit_remaining` = IF(`rate_limit_expiry` < %d, VALUES(`rate_limit_remaining`), GREATEST(`rate_limit_remaining` - 1, 0)),
`rate_limit_expiry` = IF(`rate_limit_expiry` < %d, VALUES(`rate_limit_expiry`), `rate_limit_expiry`);
",
$action_id,
$rate_limit_expiry,
(int) $options->limit - 1,
$time,
$time
)
);
$current_limit = self::get_rate_limit_row( $action_id );
self::set_cache( $action_id, $current_limit );
return $current_limit;
}
/**
* Retrieve a cached store api rate limit.
*
* @param string $action_id Identifier of the action.
* @return false|object
*/
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 object $current_limit Current limit object with expiry and retries remaining.
* @return bool
*/
protected static function set_cache( $action_id, $current_limit ): bool {
return wp_cache_set( self::get_cache_key( $action_id ), $current_limit, self::CACHE_GROUP );
}
/**
* Return options for Rate Limits, to be returned by the "woocommerce_store_api_rate_limit_options" filter.
*
* @return object Default options.
*/
public static function get_options(): object {
$default_options = [
/**
* Filters the Store API rate limit check, which is disabled by default.
*
* This can be used also to disable the rate limit check when testing API endpoints via a REST API client.
*/
'enabled' => self::ENABLED,
/**
* Filters whether proxy support is enabled for the Store API rate limit check. This is disabled by default.
*
* If the store is behind a proxy, load balancer, CDN etc. the user can enable this to properly obtain
* the client's IP address through standard transport headers.
*/
'proxy_support' => self::PROXY_SUPPORT,
'limit' => self::LIMIT,
'seconds' => self::SECONDS,
];
return (object) array_merge( // By using array_merge we ensure we get a properly populated options object.
$default_options,
/**
* Filters options for Rate Limits.
*
* @param array $rate_limit_options Array of option values.
* @return array
*
* @since 8.9.0
*/
apply_filters(
'woocommerce_store_api_rate_limit_options',
$default_options
)
);
}
/**
* Gets a single option through provided name.
*
* @param string $option Option name.
*
* @return mixed
*/
public static function get_option( $option ) {
if ( ! is_string( $option ) || ! defined( 'RateLimits::' . strtoupper( $option ) ) ) {
return null;
}
return self::get_options()[ $option ];
}
}