metadata_exists()

最后更新于：2021-11-27 15:58:21

metadata_exists( string$meta_type, int$object_id, string$meta_key)

Determines if a meta field with the given key exists for the given object ID.

参数

$meta_type: (string) (Required) Type of object metadata is for. Accepts ‘post’, ‘comment’, ‘term’, ‘user’, or any other object type with an associated meta table.
$object_id: (int) (Required) ID of the object metadata is for.
$meta_key: (string) (Required) Metadata key.

响应

(bool) Whether a meta field with the given key exists.

源文件

文件: gc-includes/meta.php

function metadata_exists( $meta_type, $object_id, $meta_key ) {
	if ( ! $meta_type || ! is_numeric( $object_id ) ) {
		return false;
	}

	$object_id = absint( $object_id );
	if ( ! $object_id ) {
		return false;
	}

	/** This filter is documented in gc-includes/meta.php */
	$check = apply_filters( "get_{$meta_type}_metadata", null, $object_id, $meta_key, true, $meta_type );
	if ( null !== $check ) {
		return (bool) $check;
	}

	$meta_cache = gc_cache_get( $object_id, $meta_type . '_meta' );

	if ( ! $meta_cache ) {
		$meta_cache = update_meta_cache( $meta_type, array( $object_id ) );
		$meta_cache = $meta_cache[ $object_id ];
	}

	if ( isset( $meta_cache[ $meta_key ] ) ) {
		return true;
	}

	return false;
}

// Check and get a term meta

if ( metadata_exists( 'term', $term_id, '_meta_key' ) ) {
	$meta_value = get_term_meta( $term_id, '_meta_key', true );
}

// Check and get a post meta

if ( metadata_exists( 'post', $post_id, '_meta_key' ) ) {
	$meta_value = get_post_meta( $post_id, '_meta_key', true );
}

// Check and get a user meta

if ( metadata_exists( 'user', $user_id, '_meta_key' ) ) {
	$meta_value = get_user_meta( $user_id, '_meta_key', true );
}