Automatically return allowed HTTP methods for OPTIONS per specific endpoint

src/App/Router.php

@@ -41,6 +41,7 @@ use Friendica\Module\Special\Options;
 use Friendica\Network\HTTPException;
 use Friendica\Network\HTTPException\MethodNotAllowedException;
 use Friendica\Network\HTTPException\NotFoundException;
+use Friendica\Util\Router\FriendicaGroupCountBased;
 use Psr\Log\LoggerInterface;
 
 /**
@@ -134,9 +135,7 @@ class Router
 		$this->logger                  = $logger;
 		$this->dice_profiler_threshold = $config->get('system', 'dice_profiler_threshold', 0);
 
-		$this->routeCollector = isset($routeCollector) ?
+		$this->routeCollector = $routeCollector ?? new RouteCollector(new Std(), new GroupCountBased());
-			$routeCollector :
-			new RouteCollector(new Std(), new GroupCountBased());
 
 		if ($this->baseRoutesFilepath && !file_exists($this->baseRoutesFilepath)) {
 			throw new HTTPException\InternalServerErrorException('Routes file path does\'n exist.');
@@ -155,9 +154,7 @@ class Router
 	 */
 	public function loadRoutes(array $routes)
 	{
-		$routeCollector = (isset($this->routeCollector) ?
+		$routeCollector = ($this->routeCollector ?? new RouteCollector(new Std(), new GroupCountBased()));
-			$this->routeCollector :
-			new RouteCollector(new Std(), new GroupCountBased()));
 
 		$this->addRoutes($routeCollector, $routes);
 
@@ -175,7 +172,10 @@ class Router
 			if ($this->isGroup($config)) {
 				$this->addGroup($route, $config, $routeCollector);
 			} elseif ($this->isRoute($config)) {
-				$routeCollector->addRoute($config[1], $route, $config[0]);
+				// Always add the OPTIONS endpoint to a route
+				$httpMethods   = (array) $config[1];
+				$httpMethods[] = Router::OPTIONS;
+				$routeCollector->addRoute($httpMethods, $route, $config[0]);
 			} else {
 				throw new HTTPException\InternalServerErrorException("Wrong route config for route '" . print_r($route, true) . "'");
 			}
@@ -258,24 +258,27 @@ class Router
 		$cmd = $this->args->getCommand();
 		$cmd = '/' . ltrim($cmd, '/');
 
-		$dispatcher = new Dispatcher\GroupCountBased($this->getCachedDispatchData());
+		$dispatcher = new FriendicaGroupCountBased($this->getCachedDispatchData());
 
 		$this->parameters = [];
 
+		// Check if the HTTP method ist OPTIONS and return the special Options Module with the possible HTTP methods
+		if ($this->args->getMethod() === static::OPTIONS) {
+			$routeOptions = $dispatcher->getOptions($cmd);
+
+			$moduleClass      = Options::class;
+			$this->parameters = ['allowedMethods' => $routeOptions];
+		} else {
 			$routeInfo = $dispatcher->dispatch($this->args->getMethod(), $cmd);
 			if ($routeInfo[0] === Dispatcher::FOUND) {
 				$moduleClass      = $routeInfo[1];
 				$this->parameters = $routeInfo[2];
 			} elseif ($routeInfo[0] === Dispatcher::METHOD_NOT_ALLOWED) {
-			if ($this->args->getMethod() === static::OPTIONS) {
-				// Default response for HTTP OPTIONS requests in case there is no special treatment
-				$moduleClass = Options::class;
-			} else {
 				throw new HTTPException\MethodNotAllowedException($this->l10n->t('Method not allowed for this module. Allowed method(s): %s', implode(', ', $routeInfo[1])));
-			}
 			} else {
 				throw new HTTPException\NotFoundException($this->l10n->t('Page not found.'));
 			}
+		}
 
 		return $moduleClass;
 	}

src/Module/Special/Options.php

@@ -1,16 +1,48 @@
 <?php
+/**
+ * @copyright Copyright (C) 2010-2022, the Friendica project
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
 
 namespace Friendica\Module\Special;
 
 use Friendica\App\Router;
 use Friendica\BaseModule;
 
+/**
+ * Returns the allowed HTTP methods based on the route information
+ *
+ * It's a special class which shouldn't be called directly
+ *
+ * @see Router::getModuleClass()
+ */
 class Options extends BaseModule
 {
 	protected function options(array $request = [])
 	{
+		$allowedMethods = $this->parameters['AllowedMethods'] ?? [];
+
+		if (empty($allowedMethods)) {
+			$allowedMethods = Router::ALLOWED_METHODS;
+		}
+
 		// @see https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/OPTIONS
-		$this->response->setHeader(implode(',', Router::ALLOWED_METHODS), 'Allow');
+		$this->response->setHeader(implode(',', $allowedMethods), 'Allow');
 		$this->response->setStatus(204);
 	}
 }

src/Util/Router/FriendicaGroupCountBased.php

@@ -0,0 +1,62 @@
+<?php
+/**
+ * @copyright Copyright (C) 2010-2022, the Friendica project
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Friendica\Util\Router;
+
+use FastRoute\Dispatcher\GroupCountBased;
+
+/**
+ * Extends the Fast-Router collector for getting the possible HTTP method options for a given URI
+ */
+class FriendicaGroupCountBased extends GroupCountBased
+{
+	/**
+	 * Returns all possible HTTP methods for a given URI
+	 *
+	 * @param $uri
+	 *
+	 * @return array
+	 *
+	 * @todo Distinguish between an invalid route and the asterisk (*) default route
+	 */
+	public function getOptions($uri): array
+	{
+		$varRouteData = $this->variableRouteData;
+
+		// Find allowed methods for this URI by matching against all other HTTP methods as well
+		$allowedMethods = [];
+
+		foreach ($this->staticRouteMap as $method => $uriMap) {
+			if (isset($uriMap[$uri])) {
+				$allowedMethods[] = $method;
+			}
+		}
+
+		foreach ($varRouteData as $method => $routeData) {
+			$result = $this->dispatchVariableRoute($routeData, $uri);
+			if ($result[0] === self::FOUND) {
+				$allowedMethods[] = $method;
+			}
+		}
+
+		return $allowedMethods;
+	}
+}

tests/src/Module/Special/OptionsTest.php

@@ -10,7 +10,7 @@ use Friendica\Test\FixtureTest;
 
 class OptionsTest extends FixtureTest
 {
-	public function testOptions()
+	public function testOptionsAll()
 	{
 		$this->useHttpMethod(Router::OPTIONS);
 
@@ -25,4 +25,22 @@ class OptionsTest extends FixtureTest
 		], $response->getHeaders());
 		self::assertEquals(implode(',', Router::ALLOWED_METHODS), $response->getHeaderLine('Allow'));
 	}
+
+	public function testOptionsSpecific()
+	{
+		$this->useHttpMethod(Router::OPTIONS);
+
+		$response = (new Options(DI::l10n(), DI::baseUrl(), DI::args(), DI::logger(), DI::profiler(), DI::apiResponse(), [], [
+			'AllowedMethods' => [Router::GET, Router::POST],
+		]))->run();
+
+		self::assertEmpty((string)$response->getBody());
+		self::assertEquals(204, $response->getStatusCode());
+		self::assertEquals('No Content', $response->getReasonPhrase());
+		self::assertEquals([
+			'Allow'                       => [implode(',', [Router::GET, Router::POST])],
+			ICanCreateResponses::X_HEADER => ['html'],
+		], $response->getHeaders());
+		self::assertEquals(implode(',', [Router::GET, Router::POST]), $response->getHeaderLine('Allow'));
+	}
 }

tests/src/Util/Router/FriendicaGroupCountBasedTest.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace Friendica\Test\src\Util\Router;
+
+use FastRoute\DataGenerator\GroupCountBased;
+use FastRoute\RouteCollector;
+use FastRoute\RouteParser\Std;
+use Friendica\Module\Special\Options;
+use Friendica\Test\MockedTest;
+use Friendica\Util\Router\FriendicaGroupCountBased;
+
+class FriendicaGroupCountBasedTest extends MockedTest
+{
+	public function testOptions()
+	{
+		$collector = new RouteCollector(new Std(), new GroupCountBased());
+		$collector->addRoute('GET', '/get', Options::class);
+		$collector->addRoute('POST', '/post', Options::class);
+		$collector->addRoute('GET', '/multi', Options::class);
+		$collector->addRoute('POST', '/multi', Options::class);
+
+		$dispatcher = new FriendicaGroupCountBased($collector->getData());
+
+		self::assertEquals(['GET'], $dispatcher->getOptions('/get'));
+		self::assertEquals(['POST'], $dispatcher->getOptions('/post'));
+		self::assertEquals(['GET', 'POST'], $dispatcher->getOptions('/multi'));
+	}
+}