<?php
/**
* A pseudo-CRON daemon for scheduling WordPress tasks
*
* WP Cron is triggered when the site receives a visit. In the scenario
* where a site may not receive enough visits to execute scheduled tasks
* in a timely manner, this file can be called directly or via a server
* CRON daemon for X number of times.
*
* Defining DISABLE_WP_CRON as true and calling this file directly are
* mutually exclusive and the latter does not rely on the former to work.
*
* The HTTP request to this file will not slow down the visitor who happens to
* visit when the cron job is needed to run.
*
* @package WordPress
*/
ignore_user_abort( true );
/* Don't make the request block till we finish, if possible. */
if ( function_exists( 'fastcgi_finish_request' ) && version_compare( phpversion(), '7.0.16', '>=' ) ) {
if ( ! headers_sent() ) {
header( 'Expires: Wed, 11 Jan 1984 05:00:00 GMT' );
header( 'Cache-Control: no-cache, must-revalidate, max-age=0' );
}
fastcgi_finish_request();
}
if ( ! empty( $_POST ) || defined( 'DOING_AJAX' ) || defined( 'DOING_CRON' ) ) {
die();
}
/**
* Tell WordPress we are doing the CRON task.
*
* @var bool
*/
define( 'DOING_CRON', true );
if ( ! defined( 'ABSPATH' ) ) {
/** Set up WordPress environment */
require_once __DIR__ . '/wp-load.php';
}
/**
* Retrieves the cron lock.
*
* Returns the uncached `doing_cron` transient.
*
* @ignore
* @since 3.3.0
*
* @global wpdb $wpdb WordPress database abstraction object.
*
* @return string|false Value of the `doing_cron` transient, 0|false otherwise.
*/
function _get_cron_lock() {
global $wpdb;
$value = 0;
if ( wp_using_ext_object_cache() ) {
/*
* Skip local cache and force re-fetch of doing_cron transient
* in case another process updated the cache.
*/
$value = wp_cache_get( 'doing_cron', 'transient', true );
} else {
$row = $wpdb->get_row( $wpdb->prepare( "SELECT option_value FROM $wpdb->options WHERE option_name = %s LIMIT 1", '_transient_doing_cron' ) );
if ( is_object( $row ) ) {
$value = $row->option_value;
}
}
return $value;
}
$crons = wp_get_ready_cron_jobs();
if ( empty( $crons ) ) {
die();
}
$gmt_time = microtime( true );
// The cron lock: a unix timestamp from when the cron was spawned.
$doing_cron_transient = get_transient( 'doing_cron' );
// Use global $doing_wp_cron lock, otherwise use the GET lock. If no lock, try to grab a new lock.
if ( empty( $doing_wp_cron ) ) {
if ( empty( $_GET['doing_wp_cron'] ) ) {
// Called from external script/job. Try setting a lock.
if ( $doing_cron_transient && ( $doing_cron_transient + WP_CRON_LOCK_TIMEOUT > $gmt_time ) ) {
return;
}
$doing_wp_cron = sprintf( '%.22F', microtime( true ) );
$doing_cron_transient = $doing_wp_cron;
set_transient( 'doing_cron', $doing_wp_cron );
} else {
$doing_wp_cron = $_GET['doing_wp_cron'];
}
}
/*
* The cron lock (a unix timestamp set when the cron was spawned),
* must match $doing_wp_cron (the "key").
*/
if ( $doing_cron_transient !== $doing_wp_cron ) {
return;
}
foreach ( $crons as $timestamp => $cronhooks ) {
if ( $timestamp > $gmt_time ) {
break;
}
foreach ( $cronhooks as $hook => $keys ) {
foreach ( $keys as $k => $v ) {
$schedule = $v['schedule'];
if ( $schedule ) {
wp_reschedule_event( $timestamp, $schedule, $hook, $v['args'] );
}
wp_unschedule_event( $timestamp, $hook, $v['args'] );
/**
* Fires scheduled events.
*
* @ignore
* @since 2.1.0
*
* @param string $hook Name of the hook that was scheduled to be fired.
* @param array $args The arguments to be passed to the hook.
*/
do_action_ref_array( $hook, $v['args'] );
// If the hook ran too long and another cron process stole the lock, quit.
if ( _get_cron_lock() !== $doing_wp_cron ) {
return;
}
}
}
}
if ( _get_cron_lock() === $doing_wp_cron ) {
delete_transient( 'doing_cron' );
}
die();
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