Filters into default_{$object_type}_metadata and adds in default value.

$value mixed Required

Current value passed to filter.

$object_id int Required

ID of the object metadata is for.

$meta_key string Required

Metadata key.

$single bool Required

If true, return only the first value of the specified $meta_key.
This parameter has no effect if $meta_key is not specified.

$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.

mixed An array of default values if $single is false.
The default value of the meta field if $single is true.

File: wp-includes/meta.php. View all references

function filter_default_metadata( $value, $object_id, $meta_key, $single, $meta_type ) {
	global $wp_meta_keys;

	if ( wp_installing() ) {
		return $value;
	}

	if ( ! is_array( $wp_meta_keys ) || ! isset( $wp_meta_keys[ $meta_type ] ) ) {
		return $value;
	}

	$defaults = array();
	foreach ( $wp_meta_keys[ $meta_type ] as $sub_type => $meta_data ) {
		foreach ( $meta_data as $_meta_key => $args ) {
			if ( $_meta_key === $meta_key && array_key_exists( 'default', $args ) ) {
				$defaults[ $sub_type ] = $args;
			}
		}
	}

	if ( ! $defaults ) {
		return $value;
	}

	// If this meta type does not have subtypes, then the default is keyed as an empty string.
	if ( isset( $defaults[''] ) ) {
		$metadata = $defaults[''];
	} else {
		$sub_type = get_object_subtype( $meta_type, $object_id );
		if ( ! isset( $defaults[ $sub_type ] ) ) {
			return $value;
		}
		$metadata = $defaults[ $sub_type ];
	}

	if ( $single ) {
		$value = $metadata['default'];
	} else {
		$value = array( $metadata['default'] );
	}

	return $value;
}