Question

wp_next_scheduled( string $hook,  array $args = array() )

Retrieve the next timestamp for an event.

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description

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参数

$hook

(string) (Required) Action hook to execute when event is run.

$args

(array) (Optional) Arguments to pass to the hook's callback function.

Default value: array()

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返回值

(false|int) The Unix timestamp of the next time the scheduled event will occur.

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源代码

File: wp-includes/cron.php

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;
}

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更新日志

Version	description
2.1.0	Introduced.

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相关函数

Uses

• wp-includes/cron.php: _get_cron_array()

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Used By

• wp-includes/cron.php: wp_schedule_single_event()
• wp-includes/update.php: wp_schedule_update_checks()
• wp-includes/update.php: wp_version_check()
• wp-includes/post.php: _publish_post_hook()
• wp-includes/ms-functions.php: wp_schedule_update_network_counts()

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User Contributed Notes

1. Skip to note content You must log in to vote on the helpfulness of this noteVote results for this note: 0You must log in to vote on the helpfulness of this note Contributed by ub3rst4r

   Note the $args parameter! Not specifying the $args parameter in wp_next_scheduled but having $args for wp_schedule_event will cause many events to be scheduled (instead of just one).

   Bad Example:

   
   if ( ! wp_next_scheduled( 'myevent' ) ) { // This will always be false
   	wp_schedule_event( time(), 'daily', 'myevent', array( false ) );
   }
   

   Good Example:

   
   $args = array( false );
   if ( ! wp_next_scheduled( 'myevent', $args ) ) {
   	wp_schedule_event( time(), 'daily', 'myevent', $args );
   }
   

Be careful when using arguments! WordPress doesn’t compare them 1:1 so you have to pay attention what type these are.

It’s because WP generates a hash out of them: md5( serialize( $args ) )

So when you have:

wp_schedule_event( time(), 'daily', 'action_hook', array( 123 ) );

And use a string because ie. the value was taken from the meta:

wp_next_scheduled( 'action_hook', array( '123' ) );

It will return false.