get_(meta_type)_metadata filter-hook . WP 3.1.0

Filters whether to retrieve metadata of a specific type.

The dynamic portion of the hook, $meta_type, refers to the meta object type (comment, post, term, or user). Returning a non-null value will effectively short-circuit the function.

Usage

add_filter( 'get_(meta_type)_metadata', 'filter_function_name_363', 10, 4 );
function filter_function_name_363( $value, $object_id, $meta_key, $single ){
	// filter...

	return $value;
}

$value(null/array/string)

The value get_metadata() should return - a single metadata value, or an array of values.

$object_id(int)

Object ID.

$meta_key(string)

Meta key.

$single(true/false)

Whether to return only the first value of the specified $meta_key.

Where the hook is called

$check = apply_filters( "get_{$meta_type}_metadata", null, $object_id, $meta_key, $single );

$check = apply_filters( "get_{$meta_type}_metadata", null, $object_id, $meta_key, true );

Where the hook is used (in WP core)

add_filter( 'get_post_metadata', array( $this, 'get_post_metadata' ), 10, 4 );

add_filter( 'get_term_metadata', 'wp_check_term_meta_support_prefilter' );

add_filter( 'get_blog_metadata', 'wp_check_site_meta_support_prefilter' );

add_filter( 'get_post_metadata', '_wp_preview_post_thumbnail_filter', 10, 3 );