wp_reschedule_event

wp_reschedule_event: 這個函式在WordPress中重新安排一個經常發生的事件。它以事件鉤子的名稱、預定的時間、重複發生的時間間隔和引數為引數，並返回一個布林值，表示該事件是否被重新安排。

重新安排一個經常性事件。

主要是內部使用，這需要之前執行的迴圈事件的UTC時間戳，並重新安排它的下一次執行。

要改變即將發生的事件，請使用wp_schedule_event()來改變重複發生的頻率。

function wp_reschedule_event( $timestamp, $recurrence, $hook, $args = array(), $wp_error = false ) {
	// Make sure timestamp is a positive integer.
	if ( ! is_numeric( $timestamp ) || $timestamp <= 0 ) {
		if ( $wp_error ) {
			return new WP_Error(
				'invalid_timestamp',
				__( 'Event timestamp must be a valid Unix timestamp.' )
			);
		}

		return false;
	}

	$schedules = wp_get_schedules();
	$interval  = 0;

	// First we try to get the interval 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 ) {
		$scheduled_event = wp_get_scheduled_event( $hook, $args, $timestamp );
		if ( $scheduled_event && isset( $scheduled_event->interval ) ) {
			$interval = $scheduled_event->interval;
		}
	}

	$event = (object) array(
		'hook'      => $hook,
		'timestamp' => $timestamp,
		'schedule'  => $recurrence,
		'args'      => $args,
		'interval'  => $interval,
	);

	/**
	 * Filter to preflight or hijack rescheduling of a recurring event.
	 *
	 * Returning a non-null value will short-circuit the normal rescheduling
	 * process, causing the function to return the filtered value instead.
	 *
	 * For plugins replacing wp-cron, return true if the event was successfully
	 * rescheduled, false or a WP_Error if not.
	 *
	 * @since 5.1.0
	 * @since 5.7.0 The `$wp_error` parameter was added, and a `WP_Error` object can now be returned.
	 *
	 * @param null|bool|WP_Error $pre      Value to return instead. Default null to continue adding the event.
	 * @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 $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.
	 * }
	 * @param bool               $wp_error Whether to return a WP_Error on failure.
	 */
	$pre = apply_filters( 'pre_reschedule_event', null, $event, $wp_error );

	if ( null !== $pre ) {
		if ( $wp_error && false === $pre ) {
			return new WP_Error(
				'pre_reschedule_event_false',
				__( 'A plugin prevented the event from being rescheduled.' )
			);
		}

		if ( ! $wp_error && is_wp_error( $pre ) ) {
			return false;
		}

		return $pre;
	}

	// Now we assume something is wrong and fail to schedule.
	if ( 0 == $interval ) {
		if ( $wp_error ) {
			return new WP_Error(
				'invalid_schedule',
				__( 'Event schedule does not exist.' )
			);
		}

		return false;
	}

	$now = time();

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

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