Title: WP_REST_Server::match_request_to_handler
Published: December 9, 2020
Last modified: April 28, 2025

---

# WP_REST_Server::match_request_to_handler( WP_REST_Request $request ): array|󠀁[WP_Error](https://developer.wordpress.org/reference/classes/wp_error/)󠁿

## In this article

 * [Parameters](https://developer.wordpress.org/reference/classes/wp_rest_server/match_request_to_handler/?output_format=md#parameters)
 * [Return](https://developer.wordpress.org/reference/classes/wp_rest_server/match_request_to_handler/?output_format=md#return)
 * [Source](https://developer.wordpress.org/reference/classes/wp_rest_server/match_request_to_handler/?output_format=md#source)
 * [Related](https://developer.wordpress.org/reference/classes/wp_rest_server/match_request_to_handler/?output_format=md#related)
 * [Changelog](https://developer.wordpress.org/reference/classes/wp_rest_server/match_request_to_handler/?output_format=md#changelog)

[ Back to top](https://developer.wordpress.org/reference/classes/wp_rest_server/match_request_to_handler/?output_format=md#wp--skip-link--target)

This function’s access is marked private. This means it is not intended for use 
by plugin or theme developers, only by core. It is listed here for completeness.

Matches a request object to its handler.

## 󠀁[Parameters](https://developer.wordpress.org/reference/classes/wp_rest_server/match_request_to_handler/?output_format=md#parameters)󠁿

 `$request`[WP_REST_Request](https://developer.wordpress.org/reference/classes/wp_rest_request/)
required

The request object.

## 󠀁[Return](https://developer.wordpress.org/reference/classes/wp_rest_server/match_request_to_handler/?output_format=md#return)󠁿

 array|[WP_Error](https://developer.wordpress.org/reference/classes/wp_error/) The
route and request handler on success or a [WP_Error](https://developer.wordpress.org/reference/classes/wp_error/)
instance if no handler was found.

## 󠀁[Source](https://developer.wordpress.org/reference/classes/wp_rest_server/match_request_to_handler/?output_format=md#source)󠁿

    ```php
    protected function match_request_to_handler( $request ) {
    	$method = $request->get_method();
    	$path   = $request->get_route();

    	$with_namespace = array();

    	foreach ( $this->get_namespaces() as $namespace ) {
    		if ( str_starts_with( trailingslashit( ltrim( $path, '/' ) ), $namespace ) ) {
    			$with_namespace[] = $this->get_routes( $namespace );
    		}
    	}

    	if ( $with_namespace ) {
    		$routes = array_merge( ...$with_namespace );
    	} else {
    		$routes = $this->get_routes();
    	}

    	foreach ( $routes as $route => $handlers ) {
    		$match = preg_match( '@^' . $route . '$@i', $path, $matches );

    		if ( ! $match ) {
    			continue;
    		}

    		$args = array();

    		foreach ( $matches as $param => $value ) {
    			if ( ! is_int( $param ) ) {
    				$args[ $param ] = $value;
    			}
    		}

    		foreach ( $handlers as $handler ) {
    			$callback = $handler['callback'];

    			// Fallback to GET method if no HEAD method is registered.
    			$checked_method = $method;
    			if ( 'HEAD' === $method && empty( $handler['methods']['HEAD'] ) ) {
    				$checked_method = 'GET';
    			}
    			if ( empty( $handler['methods'][ $checked_method ] ) ) {
    				continue;
    			}

    			if ( ! is_callable( $callback ) ) {
    				return array( $route, $handler );
    			}

    			$request->set_url_params( $args );
    			$request->set_attributes( $handler );

    			$defaults = array();

    			foreach ( $handler['args'] as $arg => $options ) {
    				if ( isset( $options['default'] ) ) {
    					$defaults[ $arg ] = $options['default'];
    				}
    			}

    			$request->set_default_params( $defaults );

    			return array( $route, $handler );
    		}
    	}

    	return new WP_Error(
    		'rest_no_route',
    		__( 'No route was found matching the URL and request method.' ),
    		array( 'status' => 404 )
    	);
    }
    ```

[View all references](https://developer.wordpress.org/reference/files/wp-includes/rest-api/class-wp-rest-server.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/6.9.4/src/wp-includes/rest-api/class-wp-rest-server.php#L1152)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/rest-api/class-wp-rest-server.php#L1152-L1223)

## 󠀁[Related](https://developer.wordpress.org/reference/classes/wp_rest_server/match_request_to_handler/?output_format=md#related)󠁿

| Uses | Description | 
| [WP_REST_Server::get_namespaces()](https://developer.wordpress.org/reference/classes/wp_rest_server/get_namespaces/)`wp-includes/rest-api/class-wp-rest-server.php` |

Retrieves namespaces registered on the server.

  | 
| [WP_REST_Server::get_routes()](https://developer.wordpress.org/reference/classes/wp_rest_server/get_routes/)`wp-includes/rest-api/class-wp-rest-server.php` |

Retrieves the route map.

  | 
| [__()](https://developer.wordpress.org/reference/functions/__/)`wp-includes/l10n.php` |

Retrieves the translation of $text.

  | 
| [trailingslashit()](https://developer.wordpress.org/reference/functions/trailingslashit/)`wp-includes/formatting.php` |

Appends a trailing slash.

  | 
| [WP_Error::__construct()](https://developer.wordpress.org/reference/classes/wp_error/__construct/)`wp-includes/class-wp-error.php` |

Initializes the error.

  |

[Show 3 more](https://developer.wordpress.org/reference/classes/wp_rest_server/match_request_to_handler/?output_format=md#)
[Show less](https://developer.wordpress.org/reference/classes/wp_rest_server/match_request_to_handler/?output_format=md#)

| Used by | Description | 
| [WP_REST_Server::serve_batch_request_v1()](https://developer.wordpress.org/reference/classes/wp_rest_server/serve_batch_request_v1/)`wp-includes/rest-api/class-wp-rest-server.php` |

Serves the batch/v1 request.

  | 
| [WP_REST_Server::dispatch()](https://developer.wordpress.org/reference/classes/wp_rest_server/dispatch/)`wp-includes/rest-api/class-wp-rest-server.php` |

Matches the request to a callback and call it.

  | 
| [WP_REST_Server::embed_links()](https://developer.wordpress.org/reference/classes/wp_rest_server/embed_links/)`wp-includes/rest-api/class-wp-rest-server.php` |

Embeds the links from the data into the request.

  |

## 󠀁[Changelog](https://developer.wordpress.org/reference/classes/wp_rest_server/match_request_to_handler/?output_format=md#changelog)󠁿

| Version | Description | 
| [5.6.0](https://developer.wordpress.org/reference/since/5.6.0/) | Introduced. |

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