<?php
/**
* Sync server.
*
* @package automattic/jetpack-sync
*/
namespace Automattic\Jetpack\Sync;
use WP_Error;
/**
* Simple version of a Jetpack Sync Server - just receives arrays of events and
* issues them locally with the 'jetpack_sync_remote_action' action.
*/
class Server {
/**
* Codec used to decode sync events.
*
* @access private
*
* @var Automattic\Jetpack\Sync\Codec_Interface
*/
private $codec;
/**
* Maximum time for processing sync actions.
*
* @access public
*
* @var int
*/
const MAX_TIME_PER_REQUEST_IN_SECONDS = 15;
/**
* Prefix of the blog lock transient.
*
* @access public
*
* @var string
*/
const BLOG_LOCK_TRANSIENT_PREFIX = 'jp_sync_req_lock_';
/**
* Lifetime of the blog lock transient.
*
* @access public
*
* @var int
*/
const BLOG_LOCK_TRANSIENT_EXPIRY = 60; // Seconds.
/**
* Constructor.
*
* This is necessary because you can't use "new" when you declare instance properties >:(
*
* @access public
*/
public function __construct() {
$this->codec = new JSON_Deflate_Array_Codec();
}
/**
* Set the codec instance.
*
* @access public
*
* @param Automattic\Jetpack\Sync\Codec_Interface $codec Codec instance.
*/
public function set_codec( Codec_Interface $codec ) {
$this->codec = $codec;
}
/**
* Attempt to lock the request when the server receives concurrent requests from the same blog.
*
* @access public
*
* @param int $blog_id ID of the blog.
* @param int $expiry Blog lock transient lifetime.
* @return boolean True if succeeded, false otherwise.
*/
public function attempt_request_lock( $blog_id, $expiry = self::BLOG_LOCK_TRANSIENT_EXPIRY ) {
$transient_name = $this->get_concurrent_request_transient_name( $blog_id );
$locked_time = get_site_transient( $transient_name );
if ( $locked_time ) {
return false;
}
set_site_transient( $transient_name, microtime( true ), $expiry );
return true;
}
/**
* Retrieve the blog lock transient name for a particular blog.
*
* @access public
*
* @param int $blog_id ID of the blog.
* @return string Name of the blog lock transient.
*/
private function get_concurrent_request_transient_name( $blog_id ) {
return self::BLOG_LOCK_TRANSIENT_PREFIX . $blog_id;
}
/**
* Remove the request lock from a particular blog ID.
*
* @access public
*
* @param int $blog_id ID of the blog.
*/
public function remove_request_lock( $blog_id ) {
delete_site_transient( $this->get_concurrent_request_transient_name( $blog_id ) );
}
/**
* Receive and process sync events.
*
* @access public
*
* @param array $data Sync events.
* @param object $token The auth token used to invoke the API.
* @param int $sent_timestamp Timestamp (in seconds) when the actions were transmitted.
* @param string $queue_id ID of the queue from which the event was sent (`sync` or `full_sync`).
* @return array Processed sync events.
*/
public function receive( $data, $token = null, $sent_timestamp = null, $queue_id = null ) {
$start_time = microtime( true );
if ( ! is_array( $data ) ) {
return new WP_Error( 'action_decoder_error', 'Events must be an array' );
}
if ( $token && ! $this->attempt_request_lock( $token->blog_id ) ) {
/**
* Fires when the server receives two concurrent requests from the same blog
*
* @since 1.6.3
* @since-jetpack 4.2.0
*
* @param token The token object of the misbehaving site
*/
do_action( 'jetpack_sync_multi_request_fail', $token );
return new WP_Error( 'concurrent_request_error', 'There is another request running for the same blog ID' );
}
$events = wp_unslash( array_map( array( $this->codec, 'decode' ), $data ) );
$events_processed = array();
/**
* Fires when an array of actions are received from a remote Jetpack site
*
* @since 1.6.3
* @since-jetpack 4.2.0
*
* @param array Array of actions received from the remote site
*/
do_action( 'jetpack_sync_remote_actions', $events, $token );
foreach ( $events as $key => $event ) {
list( $action_name, $args, $user_id, $timestamp, $silent ) = $event;
/**
* Fires when an action is received from a remote Jetpack site
*
* @since 1.6.3
* @since-jetpack 4.2.0
*
* @param string $action_name The name of the action executed on the remote site
* @param array $args The arguments passed to the action
* @param int $user_id The external_user_id who did the action
* @param bool $silent Whether the item was created via import
* @param double $timestamp Timestamp (in seconds) when the action occurred
* @param double $sent_timestamp Timestamp (in seconds) when the action was transmitted
* @param string $queue_id ID of the queue from which the event was sent (sync or full_sync)
* @param array $token The auth token used to invoke the API
*/
do_action( 'jetpack_sync_remote_action', $action_name, $args, $user_id, $silent, $timestamp, $sent_timestamp, $queue_id, $token );
$events_processed[] = $key;
if ( microtime( true ) - $start_time > self::MAX_TIME_PER_REQUEST_IN_SECONDS ) {
break;
}
}
if ( $token ) {
$this->remove_request_lock( $token->blog_id );
}
return $events_processed;
}
}