register_rest_field() │ WP 4.7.0

Registers a new field on an existing WordPress object type.

Uses: wp_parse_args()
1 time — 0.000001 sec (speed of light) | 50000 times — 0.04 sec (speed of light) | PHP 7.1.11, WP 4.9.8

No Hooks.

Return

null. Nothing.

Usage

register_rest_field( $object_type, $attribute, $args );
$object_type(string|array) (required)
Object(s) the field is being registered to, "post"|"term"|"comment" etc.
$attribute(string) (required)
The attribute name.
$args(array)

An array of arguments used to handle the registered field.

Default: array()

  • get_callback(callable|null)
    Optional. The callback function used to retrieve the field value. The function will be passed the prepared object data.
    Default: 'null', the field will not be returned in the response

  • update_callback(callable|null)
    Optional. The callback function used to set and update the field value. The function will be passed the model object, like WP_Post.
    Default: 'null', the value cannot be set or updated

  • schema(array|null)
    Optional. The schema for this field.
    Default: 'null', no schema entry will be returned

Notes

  • Global. Array. $wp_rest_additional_fields Holds registered fields, organized by object type.

Changelog

Since 4.7.0 Introduced.

Code of register_rest_field() WP 6.0

wp-includes/rest-api.php 
function register_rest_field( $object_type, $attribute, $args = array() ) {
	global $wp_rest_additional_fields;

	$defaults = array(
		'get_callback'    => null,
		'update_callback' => null,
		'schema'          => null,
	);

	$args = wp_parse_args( $args, $defaults );

	$object_types = (array) $object_type;

	foreach ( $object_types as $object_type ) {
		$wp_rest_additional_fields[ $object_type ][ $attribute ] = $args;
	}
}

REST API