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wp_schedule_single_event()

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概述

wp_schedule_single_event() 是 WordPress 中用于调度一次性事件的函数，它会在指定的 UTC 时间触发一个 Hook。事件将在用户访问站点时执行，如果调度时间已过。开发者需注意避免重复事件，并可使用相关函数进行管理。

关键要点

  • 函数用于调度一次性事件，基于 Unix 时间戳（UTC）指定执行时间。
  • 参数包括 $timestamp（必需，时间戳）、$hook（必需，动作 Hook）、$args（可选，传递给回调函数的参数数组）和 $wp_error（可选，是否在失败时返回 WP_Error）。
  • 返回值为 bool 或 WP_Error，成功时返回 true，失败时返回 false 或 WP_Error。
  • 注意：在 10 分钟内调度相同 Hook 的事件会被视为重复，除非 $args 值唯一；使用 wp_next_scheduled() 防止重复，wp_schedule_event() 用于周期性事件。
  • 内部机制涉及 cron 数组管理，包括重复事件检查和过滤器应用（如 pre_schedule_event 和 schedule_event）。

代码示例

function do_this_in_an_hour( $arg1, $arg2, $arg3 ) {
    // do something
}
add_action( 'my_new_event', 'do_this_in_an_hour', 10, 3 );

wp_schedule_single_event( time() + 3600, 'my_new_event', array( $arg1, $arg2, $arg3 ) );

注意事项

  • 在 PHP 8.0+ 中，$args 数组的命名键不再被忽略，而是作为命名参数传递给回调函数。
  • 建议使用 WordPress 时间常量（如 DAY_IN_SECONDS）来增强代码可读性。
  • 确保将调度调用放在函数内，以避免每次页面访问都创建新事件。
📄 原文内容

Schedules an event to run only once.

Description

Schedules a hook which will be triggered by WordPress at the specified UTC 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.

Parameters

$timestampintrequired
Unix timestamp (UTC) for when to next run the event.
$hookstringrequired
Action hook to execute when the event is run.
$argsarrayoptional
Array containing arguments to pass to the hook’s callback function. Each value in the array is passed to the callback as an individual parameter.
The array keys are ignored.

Default:array()

$wp_errorbooloptional
Whether to return a WP_Error on failure.

Default:false

Return

bool|WP_Error True if event successfully scheduled. False or WP_Error on failure.

Source

function wp_schedule_single_event( $timestamp, $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;
	}

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

	/**
	 * Filter to override scheduling an event.
	 *
	 * Returning a non-null value will short-circuit adding the event to the
	 * cron array, causing the function to return the filtered value instead.
	 *
	 * Both single events and recurring events are passed through this filter;
	 * single events have `$event->schedule` as false, whereas recurring events
	 * have this set to a recurrence from wp_get_schedules(). Recurring
	 * events also have the integer recurrence interval set as `$event->interval`.
	 *
	 * For plugins replacing wp-cron, it is recommended you check for an
	 * identical event within ten minutes and apply the 'schedule_event'
	 * filter to check if another plugin has disallowed the event before scheduling.
	 *
	 * Return true if the event was scheduled, 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 $result   The value to return instead. Default null to continue adding the event.
	 * @param object             $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  Optional. The interval time in seconds for the schedule. Only present for recurring events.
	 * }
	 * @param bool               $wp_error Whether to return a WP_Error on failure.
	 */
	$pre = apply_filters( 'pre_schedule_event', null, $event, $wp_error );

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

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

		return $pre;
	}

	/*
	 * Check for a duplicated event.
	 *
	 * Don't schedule an event if there's already an identical event
	 * within 10 minutes.
	 *
	 * When scheduling events within ten minutes of the current time,
	 * all past identical events are considered duplicates.
	 *
	 * When scheduling an event with a past timestamp (ie, before the
	 * current time) all events scheduled within the next ten minutes
	 * are considered duplicates.
	 */
	$crons = _get_cron_array();

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

	if ( $event->timestamp < time() + 10 * MINUTE_IN_SECONDS ) {
		$min_timestamp = 0;
	} else {
		$min_timestamp = $event->timestamp - 10 * MINUTE_IN_SECONDS;
	}

	if ( $event->timestamp < time() ) {
		$max_timestamp = time() + 10 * MINUTE_IN_SECONDS;
	} else {
		$max_timestamp = $event->timestamp + 10 * MINUTE_IN_SECONDS;
	}

	foreach ( $crons as $event_timestamp => $cron ) {
		if ( $event_timestamp < $min_timestamp ) {
			continue;
		}

		if ( $event_timestamp > $max_timestamp ) {
			break;
		}

		if ( isset( $cron[ $event->hook ][ $key ] ) ) {
			$duplicate = true;
			break;
		}
	}

	if ( $duplicate ) {
		if ( $wp_error ) {
			return new WP_Error(
				'duplicate_event',
				__( 'A duplicate event already exists.' )
			);
		}

		return false;
	}

	/**
	 * Modify an event before it is scheduled.
	 *
	 * @since 3.1.0
	 *
	 * @param object|false $event {
	 *     An object containing an event's data, or boolean false to prevent the event from being scheduled.
	 *
	 *     @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  Optional. 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 ) {
		if ( $wp_error ) {
			return new WP_Error(
				'schedule_event_false',
				__( 'A plugin disallowed this event.' )
			);
		}

		return false;
	}

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

	return _set_cron_array( $crons, $wp_error );
}

View all references View on Trac View on GitHub

Hooks

apply_filters( ‘pre_schedule_event’, null|bool|WP_Error $result, object $event, bool $wp_error )

Filter to override scheduling an event.

apply_filters( ‘schedule_event’, object|false $event )

Modify an event before it is scheduled.

Uses Description
_get_cron_array()wp-includes/cron.php

Retrieves cron info array option.
_set_cron_array()wp-includes/cron.php

Updates the cron option with the new cron array.
__()wp-includes/l10n.php

Retrieves the translation of $text.
apply_filters()wp-includes/plugin.php

Calls the callback functions that have been added to a filter hook.
is_wp_error()wp-includes/load.php

Checks whether the given variable is a WordPress Error.
WP_Error::__construct()wp-includes/class-wp-error.php

Initializes the error.

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Used by Description
wp_delete_all_temp_backups()wp-includes/update.php

Schedules the removal of all contents in the temporary backup directory.
_wp_batch_update_comment_type()wp-includes/comment.php

Updates the comment type for a batch of comments.
_wp_batch_split_terms()wp-includes/taxonomy.php

Splits a batch of shared taxonomy terms.
WP_Automatic_Updater::after_core_update()wp-admin/includes/class-wp-automatic-updater.php

Checks whether to send an email and avoid processing future updates after attempting a core update.
File_Upload_Upgrader::__construct()wp-admin/includes/class-file-upload-upgrader.php

Construct the upgrader for a form.
wp_import_handle_upload()wp-admin/includes/import.php

Handles importer uploading and adds attachment.
wp_version_check()wp-includes/update.php

Checks WordPress version against the newest version.
_future_post_hook()wp-includes/post.php

Hook used to schedule publication for a post marked for the future.
_publish_post_hook()wp-includes/post.php

Hook to schedule pings and enclosures when a post is published.
check_and_publish_future_post()wp-includes/post.php

Publishes future post and make sure post ID has future post status.

Show 5 moreShow less

Changelog

Version Description
5.7.0 The $wp_error parameter was added.
5.1.0 Return value modified to boolean indicating success or failure, ‘pre_schedule_event’ filter added to short-circuit the function.
2.1.0 Introduced.

User Contributed Notes

  1. Skip to note 6 content


    Codex


    You must log in to vote on the helpfulness of this noteVote results for this note: 4You must log in to vote on the helpfulness of this note

    Schedule an event one hour from now with arguments

    function do_this_in_an_hour( $arg1, $arg2, $arg3 ) {
    // do something
}
add_action( 'my_new_event', 'do_this_in_an_hour', 10, 3 );

// put this line inside a function, 
// presumably in response to something the user does
// otherwise it will schedule a new event on every page visit

wp_schedule_single_event( time() + 3600, 'my_new_event', array( $arg1, $arg2, $arg3 ) );

// time() + 3600 = one hour from now.

  2. Skip to note 7 content


    Codex


    You must log in to vote on the helpfulness of this noteVote results for this note: 3You must log in to vote on the helpfulness of this note

    Schedule an event one hour from now

    function do_this_in_an_hour() {

    // do something
}
add_action( 'my_new_event','do_this_in_an_hour' );

// put this line inside a function, 
// presumably in response to something the user does
// otherwise it will schedule a new event on every page visit

wp_schedule_single_event( time() + 3600, 'my_new_event' );

// time() + 3600 = one hour from now.

  5. Skip to note 10 content


    Tofandel


    You must log in to vote on the helpfulness of this noteVote results for this note: -2You must log in to vote on the helpfulness of this note

    The doc says “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.”

    The code says otherwise, there is no check on $args for duplicate, only the 10 minutes time..