Introduce middlewares

Author: phpbg

readme.md

@@ -2,6 +2,9 @@
 This is a library that allow you to build a [RTSP/1.0](https://www.ietf.org/rfc/rfc2326.txt) server.
 
 # Examples
+
+## Bare minimum server
+
 This is a very minimal server that will
  * dump requests
  * reply with 200 OK (which is not very useful :-)):
@@ -32,6 +35,59 @@ echo "Open any decent video player (e.g. vlc, mpv) and open rtsp://localhost:554
 $loop->run();
 ```
 
+## Server with middleware stack
+This is almost the same example as the previous one, but with a more flexible and trendy middleware stack.
+
+`phpbg/rtsp` comes with some handy middlewares that will help you build a rfc compliant application:
+* `AutoCseq`: automatically add cseq header to your responses
+* `AutoContentLength`: automatically add content-length to your responses
+
+```php
+require __DIR__ . '/../vendor/autoload.php';
+
+$loop = React\EventLoop\Factory::create();
+
+//Normal port is 554 but we use 5540 instead to avoid root required
+$socket = new \React\Socket\TcpServer('tcp://0.0.0.0:5540', $loop);
+
+$middlewares = [
+    function (\PhpBg\Rtsp\Message\Request $request, \React\Socket\ConnectionInterface $connection, $next) {
+        // echo request middleware
+        echo $request;
+        return $next($request, $connection);
+    },
+    function (\PhpBg\Rtsp\Message\Request $request, \React\Socket\ConnectionInterface $connection, $next) {
+        // echo response middleware
+        $response = $next($request, $connection);
+        if (!($response instanceof \React\Promise\PromiseInterface)) {
+            $response = new \React\Promise\FulfilledPromise($response);
+        }
+        return $response->then(function($resolvedResponse) {
+            echo $resolvedResponse."\r\n";
+            return $resolvedResponse;
+        });
+    },
+    new \PhpBg\Rtsp\Middleware\AutoCseq(),
+    new \PhpBg\Rtsp\Middleware\AutoContentLength(),
+    function (\PhpBg\Rtsp\Message\Request $request, \React\Socket\ConnectionInterface $connection) {
+        // 200 OK response middleware
+        return \PhpBg\Rtsp\Message\MessageFactory::response();
+    }
+];
+
+$server = new \PhpBg\Rtsp\Server(new \PhpBg\Rtsp\Middleware\MiddlewareStack($middlewares));
+
+$server->on('error', function (\Exception $e) {
+    echo $e->getMessage() . "\r\n";
+    echo $e->getTraceAsString() . "\r\n";
+});
+
+$server->listen($socket);
+echo "Server started\r\n";
+echo "Open any decent video player (e.g. vlc, mpv) and open rtsp://localhost:5540\r\n";
+$loop->run();
+```
+
 # Install
 
 ```

src/Middleware/AutoContentLength.php

@@ -0,0 +1,67 @@
+<?php
+
+/**
+ * MIT License
+ *
+ * Copyright (c) 2018 Samuel CHEMLA
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+namespace PhpBg\Rtsp\Middleware;
+
+use PhpBg\Rtsp\Message\Request;
+use PhpBg\Rtsp\Message\Response;
+use React\Promise\FulfilledPromise;
+use React\Promise\PromiseInterface;
+use React\Socket\ConnectionInterface;
+
+/**
+ * Middleware that automatically add content-length header to responses that contains a body.
+ * As explained in https://www.ietf.org/rfc/rfc2326.txt, the presence of a body implies
+ *   * either you close the connection after the body, to let the receiver detect the end of the body
+ *   * either you set a content-length header: this is what this middleware does
+ *
+ * If no body is present then this header won't be added because its value is implicitly 0.
+ */
+class AutoContentLength
+{
+
+    /**
+     * This middleware just looks like a standard middleware: invokable, receive request and return response
+     *
+     * @param Request $request
+     * @param ConnectionInterface $connection
+     * @param callable $next
+     * @return Response|PromiseInterface
+     */
+    public function __invoke(Request $request, ConnectionInterface $connection, callable $next)
+    {
+        $response = $next($request, $connection);
+        if (!($response instanceof PromiseInterface)) {
+            $response = new FulfilledPromise($response);
+        }
+        return $response->then(function (Response $resolvedResponse) use ($request) {
+            if (isset($resolvedResponse->body) && !$resolvedResponse->hasHeader('content-length')) {
+                $resolvedResponse->setHeader('content-length', strlen($resolvedResponse->body));
+            }
+            return $resolvedResponse;
+        });
+    }
+}

src/Middleware/AutoCseq.php

@@ -0,0 +1,62 @@
+<?php
+
+/**
+ * MIT License
+ *
+ * Copyright (c) 2018 Samuel CHEMLA
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+namespace PhpBg\Rtsp\Middleware;
+
+use PhpBg\Rtsp\Message\Request;
+use PhpBg\Rtsp\Message\Response;
+use React\Promise\FulfilledPromise;
+use React\Promise\PromiseInterface;
+use React\Socket\ConnectionInterface;
+
+/**
+ * Middleware that automatically add cseq header to responses as required by https://www.ietf.org/rfc/rfc2326.txt
+ */
+class AutoCseq
+{
+
+    /**
+     * This middleware just looks like a standard middleware: invokable, receive request and return response
+     *
+     * @param Request $request
+     * @param ConnectionInterface $connection
+     * @param callable $next
+     * @return Response|PromiseInterface
+     */
+    public function __invoke(Request $request, ConnectionInterface $connection, callable $next)
+    {
+        $response = $next($request, $connection);
+        if (!($response instanceof PromiseInterface)) {
+            $response = new FulfilledPromise($response);
+        }
+        return $response->then(function (Response $resolvedResponse) use ($request) {
+            if (!$resolvedResponse->hasHeader('cseq') && $request->hasHeader('cseq')) {
+                $resolvedResponse->setHeader('cseq', $request->getHeader('cseq'));
+            }
+            return $resolvedResponse;
+        });
+    }
+}

src/Middleware/MiddlewareStack.php

@@ -0,0 +1,92 @@
+<?php
+
+/**
+ * MIT License
+ *
+ * Copyright (c) 2018 Samuel CHEMLA
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+namespace PhpBg\Rtsp\Middleware;
+
+use PhpBg\Rtsp\Message\Request;
+use PhpBg\Rtsp\Message\Response;
+use React\Promise\PromiseInterface;
+use React\Socket\ConnectionInterface;
+
+/**
+ * Middleware that run a stack of middlewares
+ */
+class MiddlewareStack
+{
+    /**
+     * @var callable[]
+     */
+    protected $middlewares;
+
+    /**
+     * @param callable[] $middlewares Stack of middlewares you want to run
+     */
+    public function __construct(array $middlewares)
+    {
+        if (empty($middlewares)) {
+            throw new \RuntimeException('No middleware to run');
+        }
+        $this->middlewares = array_values($middlewares);
+    }
+
+    /**
+     * This middleware just looks like a standard middleware: invokable, receive request and return response
+     * It has no $next handler because it is meant to be the last middleware in stack
+     *
+     * @param Request $request
+     * @param ConnectionInterface $connection
+     * @return Response|PromiseInterface
+     */
+    public function __invoke(Request $request, ConnectionInterface $connection)
+    {
+        return $this->call($request, $connection, 0);
+    }
+
+    /**
+     * Recursively executes middlewares
+     *
+     * @param Request $request
+     * @param ConnectionInterface $connection
+     * @param int $position
+     * @return mixed
+     */
+    protected function call(Request $request, ConnectionInterface $connection, int $position)
+    {
+        // final request handler will be invoked without a next handler
+        if (!isset($this->middlewares[$position + 1])) {
+            $handler = $this->middlewares[$position];
+            return $handler($request, $connection);
+        }
+
+        $next = function (Request $request, ConnectionInterface $connection) use ($position) {
+            return $this->call($request, $connection, $position + 1);
+        };
+
+        // invoke middleware request handler with next handler
+        $handler = $this->middlewares[$position];
+        return $handler($request, $connection, $next);
+    }
+}

src/Server.php

@@ -128,11 +128,12 @@ protected function handleRequest(Request $request, ConnectionInterface $connecti
         }
         // Convert all non-promise response to promises
         // There is little overhead for this, but this allows simpler code
-        if (!isset($response) || !$response instanceof PromiseInterface) {
+        if (!($response instanceof PromiseInterface)) {
             $response = new FulfilledPromise($response);
         }
 
-        $response->done(function ($resolvedResponse) use ($connection) {
+        // We should probably use done() instead of then(), but done() is only part of ExtendedPromiseInterface
+        $response->then(function ($resolvedResponse) use ($connection) {
             if ($resolvedResponse instanceof Response) {
                 $connection->write($resolvedResponse->toTransport());
                 return;