Ticket #42758: cron.php

<?php
/**
 * WordPress Cron API
 *
 * @package WordPress
 */

/**
 * Schedules an event to run only once.
 *
 * Schedules a hook which will be triggered by WordPress at the specified time.
 * The action will trigger when someone visits your WordPress site if the scheduled
 * time has passed.
 *
 * Note that scheduling an event to occur within 10 minutes of an existing event
 * with the same action hook will be ignored unless you pass unique `$args` values
 * for each scheduled event.
 *
 * Use wp_next_scheduled() to prevent duplicate events.
 *
 * Use wp_schedule_event() to schedule a recurring event.
 *
 * @since 2.1.0
 * @link https://codex.wordpress.org/Function_Reference/wp_schedule_single_event
 *
 * @param int    $timestamp  Unix timestamp (UTC) for when to next run the event.
 * @param string $hook       Action hook to execute when the event is run.
 * @param array  $args       Optional. Array containing each separate argument to pass to the hook's callback function.
 * @return false|void False if the event did not get scheduled.
 */
function wp_schedule_single_event( $timestamp, $hook, $args = array()) {
        // Make sure timestamp is a positive integer
        if ( ! is_numeric( $timestamp ) || $timestamp <= 0 ) {
                return false;
        }

        // Don't schedule a duplicate if there's already an identical event due within 10 minutes of it
        $next = wp_next_scheduled($hook, $args);
        if ( $next && abs( $next - $timestamp ) <= 10 * MINUTE_IN_SECONDS ) {
                return false;
        }

        $crons = _get_cron_array();
        $event = (object) array( 'hook' => $hook, 'timestamp' => $timestamp, 'schedule' => false, 'args' => $args );

        /**
         * Filters a single event before it is scheduled.
         *
         * @since 3.1.0
         *
         * @param stdClass $event {
         *     An object containing an event's data.
         *
         *     @type string       $hook      Action hook to execute when the event is run.
         *     @type int          $timestamp Unix timestamp (UTC) for when to next run the event.
         *     @type string|false $schedule  How often the event should subsequently recur.
         *     @type array        $args      Array containing each separate argument to pass to the hook's callback function.
         *     @type int          $interval  The interval time in seconds for the schedule. Only present for recurring events.
         * }
         */
        $event = apply_filters( 'schedule_event', $event );

        // A plugin disallowed this event
        if ( ! $event )
                return false;

        $key = md5(serialize($event->args));

        $crons[$event->timestamp][$event->hook][$key] = array( 'schedule' => $event->schedule, 'args' => $event->args );
        uksort( $crons, "strnatcasecmp" );
        _set_cron_array( $crons );
}

/**
 * Schedules a recurring event.
 *
 * Schedules a hook which will be triggered by WordPress at the specified interval.
 * The action will trigger when someone visits your WordPress site if the scheduled
 * time has passed.
 *
 * Valid values for the recurrence are 'hourly', 'daily', and 'twicedaily'. These can
 * be extended using the {@see 'cron_schedules'} filter in wp_get_schedules().
 *
 * Note that scheduling an event to occur within 10 minutes of an existing event
 * with the same action hook will be ignored unless you pass unique `$args` values
 * for each scheduled event.
 *
 * Use wp_next_scheduled() to prevent duplicate events.
 *
 * Use wp_schedule_single_event() to schedule a non-recurring event.
 *
 * @since 2.1.0
 * @link https://codex.wordpress.org/Function_Reference/wp_schedule_event
 *
 * @param int    $timestamp  Unix timestamp (UTC) for when to next run the event.
 * @param string $recurrence How often the event should subsequently recur. See wp_get_schedules() for accepted values.
 * @param string $hook       Action hook to execute when the event is run.
 * @param array  $args       Optional. Array containing each separate argument to pass to the hook's callback function.
 * @return false|void False if the event did not get scheduled.
 */
function wp_schedule_event( $timestamp, $recurrence, $hook, $args = array()) {
        // Make sure timestamp is a positive integer
        if ( ! is_numeric( $timestamp ) || $timestamp <= 0 ) {
                return false;
        }

        $crons = _get_cron_array();
        $schedules = wp_get_schedules();

        if ( !isset( $schedules[$recurrence] ) )
                return false;

        $event = (object) array( 'hook' => $hook, 'timestamp' => $timestamp, 'schedule' => $recurrence, 'args' => $args, 'interval' => $schedules[$recurrence]['interval'] );
        /** This filter is documented in wp-includes/cron.php */
        $event = apply_filters( 'schedule_event', $event );

        // A plugin disallowed this event
        if ( ! $event )
                return false;

        $key = md5(serialize($event->args));

        $crons[$event->timestamp][$event->hook][$key] = array( 'schedule' => $event->schedule, 'args' => $event->args, 'interval' => $event->interval );
        uksort( $crons, "strnatcasecmp" );
        _set_cron_array( $crons );
}

/**
 * Reschedules a recurring event.
 *
 * @since 2.1.0
 *
 * @param int    $timestamp  Unix timestamp (UTC) for when to next run the event.
 * @param string $recurrence How often the event should subsequently recur. See wp_get_schedules() for accepted values.
 * @param string $hook       Action hook to execute when the event is run.
 * @param array  $args       Optional. Array containing each separate argument to pass to the hook's callback function.
 * @return false|void False if the event did not get rescheduled.
 */
function wp_reschedule_event( $timestamp, $recurrence, $hook, $args = array() ) {
        // Make sure timestamp is a positive integer
        if ( ! is_numeric( $timestamp ) || $timestamp <= 0 ) {
                return false;
        }

        $crons = _get_cron_array();
        $schedules = wp_get_schedules();
        $key = md5( serialize( $args ) );
        $interval = 0;

        // First we try to get it from the schedule
        if ( isset( $schedules[ $recurrence ] ) ) {
                $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;
        }

        $now = time();

        if ( $timestamp >= $now ) {
                $timestamp = $now + $interval;
        } else {
                $timestamp = $now + ( $interval - ( ( $now - $timestamp ) % $interval ) );
        }

        wp_schedule_event( $timestamp, $recurrence, $hook, $args );
}

/**
 * Unschedule a previously scheduled event.
 *
 * The $timestamp and $hook parameters are required so that the event can be
 * identified.
 *
 * @since 2.1.0
 *
 * @param int    $timestamp Unix timestamp (UTC) of the event.
 * @param string $hook      Action hook of the event.
 * @param array  $args      Optional. Array containing each separate argument to pass to the hook's callback function.
 *                          Although not passed to a callback, these arguments are used to uniquely identify the
 *                          event, so they should be the same as those used when originally scheduling the event.
 * @return false|void False if the event did not get unscheduled.
 */
function wp_unschedule_event( $timestamp, $hook, $args = array() ) {
        // Make sure timestamp is a positive integer
        if ( ! is_numeric( $timestamp ) || $timestamp <= 0 ) {
                return false;
        }

        $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 );
}

/**
 * Unschedules all events attached to the hook with the specified arguments.
 *
 * @since 2.1.0
 *
 * @param string $hook Action hook, the execution of which will be unscheduled.
 * @param array $args Optional. Arguments that were to be passed to the hook's callback function.
 */
function wp_clear_scheduled_hook( $hook, $args = array() ) {
        // Backward compatibility
        // Previously this function took the arguments as discrete vars rather than an array like the rest of the API
        if ( !is_array($args) ) {
                _deprecated_argument( __FUNCTION__, '3.0.0', __('This argument has changed to an array to match the behavior of the other cron functions.') );
                $args = array_slice( func_get_args(), 1 );
        }

        // This logic duplicates wp_next_scheduled()
        // It's required due to a scenario where wp_unschedule_event() fails due to update_option() failing,
        // and, wp_next_scheduled() returns the same schedule in an infinite loop.
        $crons = _get_cron_array();
        if ( empty( $crons ) )
                return;

        $key = md5( serialize( $args ) );
        foreach ( $crons as $timestamp => $cron ) {
                if ( isset( $cron[ $hook ][ $key ] ) ) {
                        wp_unschedule_event( $timestamp, $hook, $args );
                }
        }
}

/**
 * Unschedules all events attached to the hook.
 *
 * Can be useful for plugins when deactivating to clean up the cron queue.
 *
 * @since 4.9.0
 *
 * @param string $hook Action hook, the execution of which will be unscheduled.
 */
function wp_unschedule_hook( $hook ) {
        $crons = _get_cron_array();

        foreach( $crons as $timestamp => $args ) {
                unset( $crons[ $timestamp ][ $hook ] );

                if ( empty( $crons[ $timestamp ] ) ) {
                        unset( $crons[ $timestamp ] );
                }
        }

        _set_cron_array( $crons );
}

/**
 * Retrieve the next timestamp for an event.
 *
 * @since 2.1.0
 *
 * @param string $hook Action hook of the event.
 * @param array  $args Optional. Array containing each separate argument to pass to the hook's callback function.
 *                     Although not passed to a callback, these arguments are used to uniquely identify the
 *                     event, so they should be the same as those used when originally scheduling the event.
 * @return false|int The Unix timestamp of the next time the event will occur. False if the event doesn't exist.
 */
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;
}

/**
 * Sends a request to run cron through HTTP request that doesn't halt page loading.
 *
 * @since 2.1.0
 *
 * @param int $gmt_time Optional. Unix timestamp (UTC). Default 0 (current time is used).
 */
function spawn_cron( $gmt_time = 0 ) {
        if ( ! $gmt_time )
                $gmt_time = microtime( true );

        if ( defined('DOING_CRON') || isset($_GET['doing_wp_cron']) )
                return;

        /*
         * Get the cron lock, which is a Unix timestamp of when the last cron was spawned
         * and has not finished running.
         *
         * Multiple processes on multiple web servers can run this code concurrently,
         * this lock attempts to make spawning as atomic as possible.
         */
        $lock = get_transient('doing_cron');

        if ( $lock > $gmt_time + 10 * MINUTE_IN_SECONDS )
                $lock = 0;

        // don't run if another process is currently running it or more than once every 60 sec.
        if ( $lock + WP_CRON_LOCK_TIMEOUT > $gmt_time )
                return;

        //sanity check
        $crons = _get_cron_array();
        if ( !is_array($crons) )
                return;

        $keys = array_keys( $crons );
        if ( isset($keys[0]) && $keys[0] > $gmt_time )
                return;

        if ( defined( 'ALTERNATE_WP_CRON' ) && ALTERNATE_WP_CRON ) {
                if ( 'GET' !== $_SERVER['REQUEST_METHOD'] || defined( 'DOING_AJAX' ) ||  defined( 'XMLRPC_REQUEST' ) ) {
                        return;
                }

                $doing_wp_cron = sprintf( '%.22F', $gmt_time );
                set_transient( 'doing_cron', $doing_wp_cron );

                ob_start();
                wp_redirect( add_query_arg( 'doing_wp_cron', $doing_wp_cron, wp_unslash( $_SERVER['REQUEST_URI'] ) ) );
                echo ' ';

                // flush any buffers and send the headers
                while ( @ob_end_flush() );
                flush();

                WP_DEBUG ? include_once( ABSPATH . 'wp-cron.php' ) : @include_once( ABSPATH . 'wp-cron.php' );
                return;
        }

        // Set the cron lock with the current unix timestamp, when the cron is being spawned.
        $doing_wp_cron = sprintf( '%.22F', $gmt_time );
        set_transient( 'doing_cron', $doing_wp_cron );

        /**
         * Filters the cron request arguments.
         *
         * @since 3.5.0
         * @since 4.5.0 The `$doing_wp_cron` parameter was added.
         *
         * @param array $cron_request_array {
         *     An array of cron request URL arguments.
         *
         *     @type string $url  The cron request URL.
         *     @type int    $key  The 22 digit GMT microtime.
         *     @type array  $args {
         *         An array of cron request arguments.
         *
         *         @type int  $timeout   The request timeout in seconds. Default .01 seconds.
         *         @type bool $blocking  Whether to set blocking for the request. Default false.
         *         @type bool $sslverify Whether SSL should be verified for the request. Default false.
         *     }
         * }
         * @param string $doing_wp_cron The unix timestamp of the cron lock.
         */
        $cron_request = apply_filters( 'cron_request', array(
                'url'  => add_query_arg( 'doing_wp_cron', $doing_wp_cron, site_url( 'wp-cron.php' ) ),
                'key'  => $doing_wp_cron,
                'args' => array(
                        'timeout'   => 0.01,
                        'blocking'  => false,
                        /** This filter is documented in wp-includes/class-wp-http-streams.php */
                        'sslverify' => apply_filters( 'https_local_ssl_verify', false )
                )
        ), $doing_wp_cron );

        wp_remote_post( $cron_request['url'], $cron_request['args'] );
}

/**
 * Run scheduled callbacks or spawn cron for all scheduled events.
 *
 * @since 2.1.0
 */
function wp_cron() {
        // Prevent infinite loops caused by lack of wp-cron.php
        if ( strpos($_SERVER['REQUEST_URI'], '/wp-cron.php') !== false || ( defined('DISABLE_WP_CRON') && DISABLE_WP_CRON ) )
                return;

        if ( false === $crons = _get_cron_array() )
                return;

        $gmt_time = microtime( true );
        $keys = array_keys( $crons );
        if ( isset($keys[0]) && $keys[0] > $gmt_time )
                return;

        $schedules = wp_get_schedules();
        foreach ( $crons as $timestamp => $cronhooks ) {
                if ( $timestamp > $gmt_time ) break;
                foreach ( (array) $cronhooks as $hook => $args ) {
                        if ( isset($schedules[$hook]['callback']) && !call_user_func( $schedules[$hook]['callback'] ) )
                                continue;
                        apply_action( $hook, $args );
                        spawn_cron( $gmt_time );
                        break 2;
                }
        }
}

/**
 * Retrieve supported event recurrence schedules.
 *
 * The default supported recurrences are 'hourly', 'twicedaily', and 'daily'. A plugin may
 * add more by hooking into the {@see '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 `__( 'Once Weekly' )`.
 *
 * For your plugin, you will be passed an array. you can easily add your
 * schedule by doing the following.
 *
 *     // Filter parameter variable name is 'array'.
 *     $array['weekly'] = array(
 *         'interval' => 604800,
 *         'display'  => __( 'Once Weekly' )
 *     );
 *
 *
 * @since 2.1.0
 *
 * @return array
 */
function wp_get_schedules() {
        $schedules = array(
                'hourly'     => array( 'interval' => HOUR_IN_SECONDS,      'display' => __( 'Once Hourly' ) ),
                'twicedaily' => array( 'interval' => 12 * HOUR_IN_SECONDS, 'display' => __( 'Twice Daily' ) ),
                'daily'      => array( 'interval' => DAY_IN_SECONDS,       'display' => __( 'Once Daily' ) ),
        );
        /**
         * Filters the non-default cron schedules.
         *
         * @since 2.1.0
         *
         * @param array $new_schedules An array of non-default cron schedules. Default empty.
         */
        return array_merge( apply_filters( 'cron_schedules', array() ), $schedules );
}

/**
 * Retrieve the recurrence schedule for an event.
 *
 * @see wp_get_schedules() for available schedules.
 *
 * @since 2.1.0
 *
 * @param string $hook Action hook to identify the event.
 * @param array $args Optional. Arguments passed to the event's callback function.
 * @return string|false False, if no schedule. Schedule name on success.
 */
function wp_get_schedule($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 false|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 $cron Cron info array from _get_cron_array().
 */
function _set_cron_array($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 $cron Cron info array from _get_cron_array().
 * @return array An upgraded Cron info array.
 */
function _upgrade_cron_array($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;
}