owncloud/core

<?php
/**
 * @author Bernhard Posselt <dev@bernhard-posselt.com>
 * @author Georg Ehrke <georg@owncloud.com>
 * @author Lukas Reschke <lukas@statuscode.ch>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 * @author Thomas Tanghus <thomas@tanghus.net>
 *
 * @copyright Copyright (c) 2018, ownCloud GmbH
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * 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, version 3,
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */

namespace OC\AppFramework\Http;

use \OC\AppFramework\Middleware\MiddlewareDispatcher;
use \OC\AppFramework\Http;
use \OC\AppFramework\Utility\ControllerMethodReflector;

use OCP\AppFramework\Controller;
use OCP\AppFramework\Http\Response;
use OCP\AppFramework\Http\DataResponse;
use OCP\IRequest;

/**
 * Class to dispatch the request to the middleware dispatcher
 */
class Dispatcher {
    private $middlewareDispatcher;
    private $protocol;
    private $reflector;
    private $request;

    /**
     * @param Http $protocol the http protocol with contains all status headers
     * @param MiddlewareDispatcher $middlewareDispatcher the dispatcher which
     * runs the middleware
     * @param ControllerMethodReflector $reflector the reflector that is used to inject
     * the arguments for the controller
     * @param IRequest $request the incoming request
     */
    public function __construct(
        Http $protocol,
        MiddlewareDispatcher $middlewareDispatcher,
        ControllerMethodReflector $reflector,
        IRequest $request
    ) {
        $this->protocol = $protocol;
        $this->middlewareDispatcher = $middlewareDispatcher;
        $this->reflector = $reflector;
        $this->request = $request;
    }

    /**
     * Handles a request and calls the dispatcher on the controller
     * @param Controller $controller the controller which will be called
     * @param string $methodName the method name which will be called on
     * the controller
     * @return array $array[0] contains a string with the http main header,
     * $array[1] contains headers in the form: $key => value, $array[2] contains
     * the response output
     * @throws \Exception
     */
    public function dispatch(Controller $controller, $methodName) {
        $out = [null, [], null];

        try {
            // prefill reflector with everything thats needed for the
            // middlewares
            $this->reflector->reflect($controller, $methodName);

            $this->middlewareDispatcher->beforeController(
                $controller,
                $methodName
            );
            $response = $this->executeController($controller, $methodName);

            // if an exception appears, the middleware checks if it can handle the
            // exception and creates a response. If no response is created, it is
            // assumed that theres no middleware who can handle it and the error is
            // thrown again
        } catch (\Exception $exception) {
            $response = $this->middlewareDispatcher->afterException(
                $controller,
                $methodName,
                $exception
            );
            if ($response === null) {
                throw $exception;
            }
        }

        $response = $this->middlewareDispatcher->afterController(
            $controller,
            $methodName,
            $response
        );

        // depending on the cache object the headers need to be changed
        $out[0] = $this->protocol->getStatusHeader(
            $response->getStatus(),
            $response->getLastModified(),
            $response->getETag()
        );
        $out[1] = \array_merge($response->getHeaders());
        $out[2] = $response->getCookies();
        $out[3] = $this->middlewareDispatcher->beforeOutput(
            $controller,
            $methodName,
            $response->render()
        );
        $out[4] = $response;

        return $out;
    }

    /**
     * Uses the reflected parameters, types and request parameters to execute
     * the controller
     * @param Controller $controller the controller to be executed
     * @param string $methodName the method on the controller that should be executed
     * @return Response
     */
    private function executeController($controller, $methodName) {
        $arguments = [];

        // valid types that will be casted
        $types = ['int', 'integer', 'bool', 'boolean', 'float'];

        foreach ($this->reflector->getParameters() as $param => $default) {
            // try to get the parameter from the request object and cast
            // it to the type annotated in the @param annotation
            $value = $this->request->getParam($param, $default);
            $type = $this->reflector->getType($param);

            // if this is submitted using GET or a POST form, 'false' should be
            // converted to false
            if (($type === 'bool' || $type === 'boolean') &&
                $value === 'false' &&
                (
                    $this->request->method === 'GET' ||
                    \strpos(
                        $this->request->getHeader('Content-Type') ?? '',
                        'application/x-www-form-urlencoded'
                    ) !== false
                )
            ) {
                $value = false;
            } elseif ($value !== null && \in_array($type, $types)) {
                \settype($value, $type);
            }

            $arguments[] = $value;
        }

        $response = \call_user_func_array([$controller, $methodName], $arguments);

        // format response
        if ($response instanceof DataResponse || !($response instanceof Response)) {
            // get format from the url format or request format parameter
            $format = $this->request->getParam('format');

            // if none is given try the first Accept header
            if ($format === null) {
                $headers = $this->request->getHeader('Accept') ?? '';
                $format = $controller->getResponderByHTTPHeader($headers);
            }

            $response = $controller->buildResponse($response, $format);
        }

        return $response;
    }
}