Don't prepare the response body for HEAD requests in WP_Test_REST_Pos…

…t_Types_Controller.

src/wp-includes/rest-api/endpoints/class-wp-rest-post-types-controller.php

@@ -109,6 +109,11 @@ public function get_items_permissions_check( $request ) {
 	 * @return WP_REST_Response|WP_Error Response object on success, or WP_Error object on failure.
 	 */
 	public function get_items( $request ) {
+		if ( $request->is_method( 'HEAD' ) ) {
+			// Return early as this handler doesn't add any response headers.
+			return new WP_REST_Response();
+		}
+
 		$data  = array();
 		$types = get_post_types( array( 'show_in_rest' => true ), 'objects' );
 
@@ -159,6 +164,10 @@ public function get_item( $request ) {
 			);
 		}
 
+		if ( $request->is_method( 'HEAD' ) ) {
+			return new WP_REST_Response();
+		}
+
 		$data = $this->prepare_item_for_response( $obj, $request );
 
 		return rest_ensure_response( $data );

tests/phpunit/tests/rest-api/rest-post-types-controller.php

@@ -44,14 +44,32 @@ public function test_get_items() {
 		$this->assertArrayNotHasKey( 'revision', $data );
 	}
 
-	public function test_get_items_invalid_permission_for_context() {
+	/**
+	 * @dataProvider data_readable_http_methods
+	 * @ticket 56481
+	 *
+	 * @param string $method HTTP method to use.
+	 */
+	public function test_get_items_invalid_permission_for_context( $method ) {
 		wp_set_current_user( 0 );
-		$request = new WP_REST_Request( 'GET', '/wp/v2/types' );
+		$request = new WP_REST_Request( $method, '/wp/v2/types' );
 		$request->set_param( 'context', 'edit' );
 		$response = rest_get_server()->dispatch( $request );
 		$this->assertErrorResponse( 'rest_cannot_view', $response, 401 );
 	}
 
+	/**
+	 * Data provider intended to provide HTTP method names for testing GET and HEAD requests.
+	 *
+	 * @return array
+	 */
+	public static function data_readable_http_methods() {
+		return array(
+			'GET request'  => array( 'GET' ),
+			'HEAD request' => array( 'HEAD' ),
+		);
+	}
+
 	public function test_get_item() {
 		$request  = new WP_REST_Request( 'GET', '/wp/v2/types/post' );
 		$response = rest_get_server()->dispatch( $request );
@@ -60,6 +78,24 @@ public function test_get_item() {
 		$this->assertSame( array( 'category', 'post_tag' ), $data['taxonomies'] );
 	}
 
+	/**
+	 * @ticket 56481
+	 */
+	public function test_get_item_with_head_request_should_not_prepare_post_type_data() {
+		$request   = new WP_REST_Request( 'HEAD', '/wp/v2/types/post' );
+		$hook_name = 'rest_prepare_post_type';
+		$filter    = new MockAction();
+		$callback  = array( $filter, 'filter' );
+		add_filter( $hook_name, $callback );
+		$response = rest_get_server()->dispatch( $request );
+		remove_filter( $hook_name, $callback );
+
+		$this->assertSame( 200, $response->get_status(), 'The response status should be 200.' );
+
+		$this->assertSame( 0, $filter->get_call_count(), 'The "' . $hook_name . '" filter was called when it should not be for HEAD requests.' );
+		$this->assertNull( $response->get_data(), 'The server should not generate a body in response to a HEAD request.' );
+	}
+
 	/**
 	 * @ticket 53656
 	 */
@@ -106,8 +142,14 @@ public function test_get_item_page() {
 		$this->assertSame( array(), $data['taxonomies'] );
 	}
 
-	public function test_get_item_invalid_type() {
-		$request  = new WP_REST_Request( 'GET', '/wp/v2/types/invalid' );
+	/**
+	 * @dataProvider data_readable_http_methods
+	 * @ticket 56481
+	 *
+	 * @param string $method HTTP method to use.
+	 */
+	public function test_get_item_invalid_type( $method ) {
+		$request  = new WP_REST_Request( $method, '/wp/v2/types/invalid' );
 		$response = rest_get_server()->dispatch( $request );
 		$this->assertErrorResponse( 'rest_type_invalid', $response, 404 );
 	}
@@ -121,9 +163,15 @@ public function test_get_item_edit_context() {
 		$this->check_post_type_object_response( 'edit', $response );
 	}
 
-	public function test_get_item_invalid_permission_for_context() {
+	/**
+	 * @dataProvider data_readable_http_methods
+	 * @ticket 56481
+	 *
+	 * @param string $method HTTP method to use.
+	 */
+	public function test_get_item_invalid_permission_for_context( $method ) {
 		wp_set_current_user( 0 );
-		$request = new WP_REST_Request( 'GET', '/wp/v2/types/post' );
+		$request = new WP_REST_Request( $method, '/wp/v2/types/post' );
 		$request->set_param( 'context', 'edit' );
 		$response = rest_get_server()->dispatch( $request );
 		$this->assertErrorResponse( 'rest_forbidden_context', $response, 401 );
@@ -245,6 +293,22 @@ public function additional_field_get_callback( $response_data ) {
 		return 123;
 	}
 
+	/**
+	 * @ticket 56481
+	 */
+	public function test_get_items_with_head_request_should_not_prepare_post_types_data() {
+		$request   = new WP_REST_Request( 'HEAD', '/wp/v2/types' );
+		$hook_name = 'rest_prepare_post_type';
+		$filter    = new MockAction();
+		$callback  = array( $filter, 'filter' );
+		add_filter( $hook_name, $callback );
+		$response = rest_get_server()->dispatch( $request );
+		remove_filter( $hook_name, $callback );
+		$this->assertSame( 200, $response->get_status(), 'The response status should be 200.' );
+		$this->assertSame( 0, $filter->get_call_count(), 'The "' . $hook_name . '" filter was called when it should not be for HEAD requests.' );
+		$this->assertNull( $response->get_data(), 'The server should not generate a body in response to a HEAD request.' );
+	}
+
 	protected function check_post_type_obj( $context, $post_type_obj, $data, $links ) {
 		$this->assertSame( $post_type_obj->label, $data['name'] );
 		$this->assertSame( $post_type_obj->name, $data['slug'] );