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get_registered_metadata( string $object_type, int $object_id, string $meta_key = '' )

Retrieves registered metadata for a specified object.

Description

The results include both meta that is registered specifically for the object’s subtype and meta that is registered for the entire object type.

Parameters

$object_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 the metadata is for.

$meta_key

(string) (Optional) Registered metadata key. If not specified, retrieve all registered metadata for the specified object.

Default value: ''

Return

(mixed) A single value or array of values for a key if specified. An array of all registered keys and values for an object ID if not. False if a given $meta_key is not registered.

Source

File: wp-includes/meta.php 

function get_registered_metadata( $object_type, $object_id, $meta_key = '' ) {
	$object_subtype = get_object_subtype( $object_type, $object_id );

	if ( ! empty( $meta_key ) ) {
		if ( ! empty( $object_subtype ) && ! registered_meta_key_exists( $object_type, $meta_key, $object_subtype ) ) {
			$object_subtype = '';
		}

		if ( ! registered_meta_key_exists( $object_type, $meta_key, $object_subtype ) ) {
			return false;
		}

		$meta_keys     = get_registered_meta_keys( $object_type, $object_subtype );
		$meta_key_data = $meta_keys[ $meta_key ];

		$data = get_metadata( $object_type, $object_id, $meta_key, $meta_key_data['single'] );

		return $data;
	}

	$data = get_metadata( $object_type, $object_id );
	if ( ! $data ) {
		return array();
	}

	$meta_keys = get_registered_meta_keys( $object_type );
	if ( ! empty( $object_subtype ) ) {
		$meta_keys = array_merge( $meta_keys, get_registered_meta_keys( $object_type, $object_subtype ) );
	}

	return array_intersect_key( $data, $meta_keys );
}

Uses

Uses Description
wp-includes/meta.php: get_object_subtype()

Returns the object subtype for a given object ID of a specific type.
wp-includes/meta.php: registered_meta_key_exists()

Checks if a meta key is registered.
wp-includes/meta.php: get_registered_meta_keys()

Retrieves a list of registered meta keys for an object type.
wp-includes/meta.php: get_metadata()

Retrieves the value of a metadata field for the specified object type and ID.

Changelog

Version Description
4.6.0 Introduced.

© 2003–2019 WordPress Foundation
Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/get_registered_metadata