wp-includes/rest-api.php:871Sends the "Allow" header to state all methods that can be sent to the current route.
$responseWP_REST_Response$serverWP_REST_Server$requestWP_REST_RequestWP_REST_Responsefunction rest_send_allow_header( $response, $server, $request ) { $matched_route = $response->get_matched_route(); if ( ! $matched_route ) { return $response; } $routes = $server->get_routes(); $allowed_methods = array(); // Get the allowed methods across the routes. foreach ( $routes[ $matched_route ] as $_handler ) { foreach ( $_handler['methods'] as $handler_method => $value ) { if ( ! empty( $_handler['permission_callback'] ) ) { $permission = call_user_func( $_handler['permission_callback'], $request ); $allowed_methods[ $handler_method ] = true === $permission; } else { $allowed_methods[ $handler_method ] = true; } } } // Strip out all the methods that are not allowed (false values). $allowed_methods = array_filter( $allowed_methods ); if ( $allowed_methods ) { $response->header( 'Allow', implode( ', ', array_map( 'strtoupper', array_keys( $allowed_methods ) ) ) ); } return $response;}Introduced in 4.4.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/rest-api.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.