Add custom parameter to REST API request of a custom post type?

Question

I registered a custom post type called wasb_message with show_in_rest set to true and rest_base set to 'messages' so the resource is reachable at endpoint https://mydomain/wp-json/wp/v2/messages (using the WP_REST_Posts_Controller class). The custom post type has a custom meta field called wasb_status with an integer value, how can I add a custom parameter so when I do a get request to endpoint https://mydomain/wp-json/wp/v2/messages?status=2 I retrieve messages with wasb_status equal to 2 without register a new route?

I read this code reference page and this old question but I can't get it working, using Postman to send get request I get:

{ "code": "rest_invalid_param", "message": "Parametro(i) non valido(i): status", "data": { "status": 400, "params": { "status": "Stato non consentito." }, "details": { "status": { "code": "rest_forbidden_status", "message": "Stato non consentito.", "data": { "status": 401 } } } } } 

Answer 1

I solved following this answer and writing:

public function query_wasb_messages_by_status( $args, $request ) { if ( ! is_null( $request->get_param( 'message_status' ) ) ) { $args['meta_query'] = array( '_wasb_message_status' => array( 'key' => '_wasb_message_status', 'value' => (int) $request->get_param( 'message_status' ), 'compare' => '=', 'type' => 'numeric' ) ); } return $args; } add_filter( 'rest_wasb_message_query', array( $this, 'query_wasb_messages_by_status'), 10, 2 ); 

My problem is I used status as parameter name but status already exists for posts ('draft', 'published', etc...) so I changed the name to message_status...

Answer 2

As per the reply by Haris it should be something like this:

function wasb_rest_parameter($args, $request) { if( isset($request["wasb_status"]) && is_numeric($request["wasb_status"]) ) { $args['meta_key'] = 'wasb_status'; $args['meta_value'] = intval($request["wasb_status"]); } return $args; } add_filter('rest_wasb_message_query', 'wasb_rest_parameter', 10, 2); 

Not yet tested. If it does not work, will update the answer.