WordPress/wp-includes/cron.php

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<?php
/**
* WordPress CRON API
*
* @package WordPress
*/
/**
* Schedules a hook to run only once.
*
* Schedules a hook which will be executed once by the Wordpress actions core at
* a time which you specify. The action will fire off when someone visits your
* WordPress site, if the schedule time has passed.
*
* @since 2.1.0
* @link http://codex.wordpress.org/Function_Reference/wp_schedule_single_event
*
* @param int $timestamp Timestamp for when to run the event.
* @param string $hook Action hook to execute when cron is run.
* @param array $args Optional. Arguments to pass to the hook's callback function.
*/
function wp_schedule_single_event( $timestamp, $hook, $args = array()) {
// don't schedule a duplicate if there's already an identical event due in the next 10 minutes
$next = wp_next_scheduled($hook, $args);
if ( $next && $next <= $timestamp + 600 )
return;
$crons = _get_cron_array();
$key = md5(serialize($args));
$crons[$timestamp][$hook][$key] = array( 'schedule' => false, 'args' => $args );
uksort( $crons, "strnatcasecmp" );
_set_cron_array( $crons );
}
/**
* Schedule a periodic event.
*
* Schedules a hook which will be executed by the WordPress actions core on a
* specific interval, specified by you. The action will trigger when someone
* visits your WordPress site, if the scheduled time has passed.
*
* @since 2.1.0
*
* @param int $timestamp Timestamp for when to run the event.
* @param string $recurrence How often the event should recur.
* @param string $hook Action hook to execute when cron is run.
* @param array $args Optional. Arguments to pass to the hook's callback function.
* @return bool|null False on failure, null when complete with scheduling event.
*/
function wp_schedule_event( $timestamp, $recurrence, $hook, $args = array()) {
$crons = _get_cron_array();
$schedules = wp_get_schedules();
$key = md5(serialize($args));
if ( !isset( $schedules[$recurrence] ) )
return false;
$crons[$timestamp][$hook][$key] = array( 'schedule' => $recurrence, 'args' => $args, 'interval' => $schedules[$recurrence]['interval'] );
uksort( $crons, "strnatcasecmp" );
_set_cron_array( $crons );
}
/**
* Reschedule a recurring event.
*
* @since 2.1.0
*
* @param int $timestamp Timestamp for when to run the event.
* @param string $recurrence How often the event should recur.
* @param string $hook Action hook to execute when cron is run.
* @param array $args Optional. Arguments to pass to the hook's callback function.
* @return bool|null False on failure. Null when event is rescheduled.
*/
function wp_reschedule_event( $timestamp, $recurrence, $hook, $args = array()) {
$crons = _get_cron_array();
$schedules = wp_get_schedules();
$key = md5(serialize($args));
$interval = 0;
// First we try to get it from the schedule
if ( 0 == $interval )
$interval = $schedules[$recurrence]['interval'];
// Now we try to get it from the saved interval in case the schedule disappears
if ( 0 == $interval )
$interval = $crons[$timestamp][$hook][$key]['interval'];
// Now we assume something is wrong and fail to schedule
if ( 0 == $interval )
return false;
while ( $timestamp < time() + 1 )
$timestamp += $interval;
wp_schedule_event( $timestamp, $recurrence, $hook, $args );
}
/**
* Unschedule a previously scheduled cron job.
*
* The $timestamp and $hook parameters are required, so that the event can be
* identified.
*
* @since 2.1.0
*
* @param int $timestamp Timestamp for when to run the event.
* @param string $hook Action hook, the execution of which will be unscheduled.
* @param array $args Arguments to pass to the hook's callback function.
* Although not passed to a callback function, these arguments are used
* to uniquely identify the scheduled event, so they should be the same
* as those used when originally scheduling the event.
*/
function wp_unschedule_event( $timestamp, $hook, $args = array() ) {
$crons = _get_cron_array();
$key = md5(serialize($args));
unset( $crons[$timestamp][$hook][$key] );
if ( empty($crons[$timestamp][$hook]) )
unset( $crons[$timestamp][$hook] );
if ( empty($crons[$timestamp]) )
unset( $crons[$timestamp] );
_set_cron_array( $crons );
}
/**
* Unschedule all cron jobs attached to a specific hook.
*
* @since 2.1.0
*
* @param string $hook Action hook, the execution of which will be unscheduled.
* @param mixed $args,... Optional. Event arguments.
*/
function wp_clear_scheduled_hook( $hook ) {
$args = array_slice( func_get_args(), 1 );
while ( $timestamp = wp_next_scheduled( $hook, $args ) )
wp_unschedule_event( $timestamp, $hook, $args );
}
/**
* Retrieve the next timestamp for a cron event.
*
* @since 2.1.0
*
* @param string $hook Action hook to execute when cron is run.
* @param array $args Optional. Arguments to pass to the hook's callback function.
* @return bool|int The UNIX timestamp of the next time the scheduled event will occur.
*/
function wp_next_scheduled( $hook, $args = array() ) {
$crons = _get_cron_array();
$key = md5(serialize($args));
if ( empty($crons) )
return false;
foreach ( $crons as $timestamp => $cron ) {
if ( isset( $cron[$hook][$key] ) )
return $timestamp;
}
return false;
}
/**
* Send request to run cron through HTTP request that doesn't halt page loading.
*
* @since 2.1.0
*
* @return null Cron could not be spawned, because it is not needed to run.
*/
function spawn_cron( $local_time ) {
/*
* do not even start the cron if local server timer has drifted
* such as due to power failure, or misconfiguration
*/
$timer_accurate = check_server_timer( $local_time );
if ( !$timer_accurate )
return;
//sanity check
$crons = _get_cron_array();
if ( !is_array($crons) )
return;
$keys = array_keys( $crons );
$timestamp = $keys[0];
if ( $timestamp > $local_time )
return;
/*
* multiple processes on multiple web servers can run this code concurrently
* try to make this as atomic as possible by setting doing_cron switch
*/
$flag = get_transient('doing_cron');
// clean up potential invalid value resulted from various system chaos
if ( $flag != 0 ) {
if ( $flag > $local_time + 10*60 || $flag < $local_time - 10*60 ) {
set_transient('doing_cron', 0);
$flag = 0;
}
}
//don't run if another process is currently running it
if ( $flag > $local_time )
return;
set_transient( 'doing_cron', $local_time + 30 );
add_action('wp_head', 'spawn_cron_request');
}
/**
* Run scheduled callbacks or spawn cron for all scheduled events.
*
* @since 2.1.0
*
* @return null When doesn't need to run Cron.
*/
function wp_cron() {
// Prevent infinite loops caused by lack of wp-cron.php
if ( strpos($_SERVER['REQUEST_URI'], '/wp-cron.php') !== false )
return;
$crons = _get_cron_array();
if ( !is_array($crons) )
return;
$keys = array_keys( $crons );
if ( isset($keys[0]) && $keys[0] > time() )
return;
$local_time = time();
$schedules = wp_get_schedules();
foreach ( $crons as $timestamp => $cronhooks ) {
if ( $timestamp > $local_time ) break;
foreach ( (array) $cronhooks as $hook => $args ) {
if ( isset($schedules[$hook]['callback']) && !call_user_func( $schedules[$hook]['callback'] ) )
continue;
spawn_cron( $local_time );
break 2;
}
}
}
/**
* Retrieve supported and filtered Cron recurrences.
*
* The supported recurrences are 'hourly' and 'daily'. A plugin may add more by
* hooking into the 'cron_schedules' filter. The filter accepts an array of
* arrays. The outer array has a key that is the name of the schedule or for
* example 'weekly'. The value is an array with two keys, one is 'interval' and
* the other is 'display'.
*
* The 'interval' is a number in seconds of when the cron job should run. So for
* 'hourly', the time is 3600 or 60*60. For weekly, the value would be
* 60*60*24*7 or 604800. The value of 'interval' would then be 604800.
*
* The 'display' is the description. For the 'weekly' key, the 'display' would
* be <code>__('Once Weekly')</code>.
*
* For your plugin, you will be passed an array. you can easily add your
* schedule by doing the following.
* <code>
* // filter parameter variable name is 'array'
* $array['weekly'] = array(
* 'interval' => 604800,
* 'display' => __('Once Weekly')
* );
* </code>
*
* @since 2.1.0
*
* @return array
*/
function wp_get_schedules() {
$schedules = array(
'hourly' => array( 'interval' => 3600, 'display' => __('Once Hourly') ),
'twicedaily' => array( 'interval' => 43200, 'display' => __('Twice Daily') ),
'daily' => array( 'interval' => 86400, 'display' => __('Once Daily') ),
);
return array_merge( apply_filters( 'cron_schedules', array() ), $schedules );
}
/**
* Retrieve Cron schedule for hook with arguments.
*
* @since 2.1.0
*
* @param string $hook Action hook to execute when cron is run.
* @param array $args Optional. Arguments to pass to the hook's callback function.
* @return string|bool False, if no schedule. Schedule on success.
*/
function wp_get_schedule($hook, $args = array()) {
$crons = _get_cron_array();
$key = md5(serialize($args));
if ( empty($crons) )
return false;
foreach ( $crons as $timestamp => $cron ) {
if ( isset( $cron[$hook][$key] ) )
return $cron[$hook][$key]['schedule'];
}
return false;
}
//
// Private functions
//
/**
* Retrieve cron info array option.
*
* @since 2.1.0
* @access private
*
* @return array CRON info array.
*/
function _get_cron_array() {
$cron = get_option('cron');
if ( ! is_array($cron) )
return false;
if ( !isset($cron['version']) )
$cron = _upgrade_cron_array($cron);
unset($cron['version']);
return $cron;
}
/**
* Updates the CRON option with the new CRON array.
*
* @since 2.1.0
* @access private
*
* @param array $cron Cron info array from {@link _get_cron_array()}.
*/
function _set_cron_array($cron) {
$cron['version'] = 2;
update_option( 'cron', $cron );
}
/**
* Upgrade a Cron info array.
*
* This function upgrades the Cron info array to version 2.
*
* @since 2.1.0
* @access private
*
* @param array $cron Cron info array from {@link _get_cron_array()}.
* @return array An upgraded Cron info array.
*/
function _upgrade_cron_array($cron) {
if ( isset($cron['version']) && 2 == $cron['version'])
return $cron;
$new_cron = array();
foreach ( (array) $cron as $timestamp => $hooks) {
foreach ( (array) $hooks as $hook => $args ) {
$key = md5(serialize($args['args']));
$new_cron[$timestamp][$hook][$key] = $args;
}
}
$new_cron['version'] = 2;
update_option( 'cron', $new_cron );
return $new_cron;
}
// stub for checking server timer accuracy, using outside standard time sources
function check_server_timer( $local_time ) {
return true;
}
function spawn_cron_request() {
?>
<script type="text/javascript">
/* <![CDATA[ */
window.setTimeout(function(){var x;if(window.XMLHttpRequest){x=new XMLHttpRequest();}else{try{x=new ActiveXObject('Msxml2.XMLHTTP');}catch(e){try{x=new ActiveXObject('Microsoft.XMLHTTP');}catch(e){};}}if(x){x.open('GET','<?php echo get_option('siteurl'); ?>/wp-cron.php?'+(new Date()).getTime(), true);x.send('');}},10);
/* ]]> */
</script>
<?php
}
?>