Request limiting, config improvements

* Added middleware to limit concurrent  request and request body size
* The default configuration now has the defaults

src/Configuration.php

@@ -15,7 +15,18 @@ class Configuration
 
     public static function createDefault(): Configuration
     {
-        return new Configuration();
+        return new Configuration([
+            "publish.overwrite_ids" => false,
+            "publish.reject_duplicates" => false,
+            "server.address" => "127.0.0.1:9000",
+            "server.enable_api" => true,
+            "server.limits.max_concurrent" => 100,
+            "server.limits.max_request_body" => 102400,
+            "server.cors.allow_origin" => "*",
+            "server.cors.csp" => "default-src * 'self' http: 'unsafe-eval' 'unsafe-inline'; connect-src * 'self'",
+            "subscribe.allow_anonymous" => true,
+            "security.jwt_secret" => "!ChangeThisMercureHubJWTSecretKey!",
+        ]);
     }
 
     public static function fromFile(string $file): Configuration

src/Http/Server.php

@@ -17,6 +17,8 @@ use Psr\Log\NullLogger;
 use React\EventLoop\Loop;
 use React\EventLoop\LoopInterface;
 use React\Http\HttpServer;
+use React\Http\Middleware\LimitConcurrentRequestsMiddleware;
+use React\Http\Middleware\RequestBodyBufferMiddleware;
 use React\Socket\SecureServer;
 use React\Socket\ServerInterface;
 use SplObjectStorage;
@@ -90,7 +92,15 @@ class Server
      */
     private function createHttpServer(): HttpServer
     {  
-        $stack = [
+        $stack = [];
+
+        $maxConcurrent = $this->config->get("server.limits.max_concurrent", 100);
+        $maxRequestBody = $this->config->get("server.limits.max_request_body", 102400);
+
+        $stack[] = new LimitConcurrentRequestsMiddleware($maxConcurrent);
+        $stack[] = new RequestBodyBufferMiddleware($maxRequestBody);
+
+        $stack = [ ...$stack,
             $this->responseMiddleware = new ResponseMiddleware(
                 config: $this->config,
                 logger: $this->logger->withName("http"),
@@ -99,6 +109,7 @@ class Server
                 config: $this->config
             ),
         ];
+
         if ($this->config->getEnableWebSockets()) {
             $stack = [ ...$stack, 
                 $this->webSocketHandler   = new WebSocketHandler(
@@ -109,6 +120,7 @@ class Server
             ];
             $this->logger->warning("The WebSocket support is incomplete and insecure, but enabling it as requested.");
         }
+
         $stack = [ ...$stack, 
             $this->mercureHandler     = new MercureHandler(
                 config: $this->config,