Implemented PSR-15 middleware handler

10 files changed, 591 insertions, 252 deletions

diff --git a/composer.json b/composer.json
index df9ee57b..911df1f5 100644
--- a/composer.json
+++ b/composer.json
@@ -15,11 +15,13 @@
     ],
     "require": {
         "php": ">=7.0.0",
+        "ext-gettext": "*",
         "erusev/parsedown": "^1.6",
         "illuminate/container": "5.5.*",
         "illuminate/database": "5.5.*",
         "illuminate/support": "^5.5",
         "psr/container": "^1.0",
+        "psr/http-server-middleware": "^1.0",
         "psr/log": "^1.0",
         "symfony/http-foundation": "^3.3",
         "symfony/psr-http-message-bridge": "^1.0",
diff --git a/locale/de_DE.UTF-8/LC_MESSAGES/default.mo b/locale/de_DE.UTF-8/LC_MESSAGES/default.mo
index 3939e870..8b3b7dcf 100644
--- a/locale/de_DE.UTF-8/LC_MESSAGES/default.mo
+++ b/locale/de_DE.UTF-8/LC_MESSAGES/default.mo
diff --git a/locale/de_DE.UTF-8/LC_MESSAGES/default.po b/locale/de_DE.UTF-8/LC_MESSAGES/default.po
index 7187b32c..49973ca9 100644
--- a/locale/de_DE.UTF-8/LC_MESSAGES/default.po
+++ b/locale/de_DE.UTF-8/LC_MESSAGES/default.po
@@ -2,7 +2,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: Engelsystem 2.0\n"
 "POT-Creation-Date: 2017-12-29 19:01+0100\n"
-"PO-Revision-Date: 2017-12-29 19:03+0100\n"
+"PO-Revision-Date: 2018-08-07 02:00+0200\n"
 "Last-Translator: msquare <msquare@notrademark.de>\n"
 "Language-Team: \n"
 "Language: de_DE\n"
@@ -2874,13 +2874,13 @@ msgstr ""
 "keine Nummer hast, bitte einfach \"-\" angeben."
 
 #: /Users/msquare/workspace/projects/engelsystem/public/index.php:218
-msgid "No Access"
-msgstr "Kein Zugriff"
+msgid "Page not found"
+msgstr "Seite nicht gefunden"
 
 #: /Users/msquare/workspace/projects/engelsystem/public/index.php:219
 msgid ""
-"You don't have permission to view this page . You probably have to sign in "
-"or register in order to gain access!"
+"This page could not be found or you don't have permission to view it. You "
+"probably have to sign in or register in order to gain access!"
 msgstr ""
-"Du hast keinen Zugriff auf diese Seite. Registriere Dich und logge Dich "
-"bitte ein, um Zugriff zu erhalten!"
+"Diese Seite existiert nicht oder Du hast keinen Zugriff. Melde Dich an um Zugriff "
+"zu erhalten!"
diff --git a/public/index.php b/public/index.php
index db4c4294..88e57252 100644
--- a/public/index.php
+++ b/public/index.php
@@ -1,252 +1,27 @@
 <?php
 
-use Engelsystem\Http\Request;
+use Engelsystem\Application;
+use Engelsystem\Middleware\Dispatcher;
+use Engelsystem\Middleware\ExceptionHandler;
+use Engelsystem\Middleware\LegacyMiddleware;
+use Engelsystem\Middleware\NotFoundResponse;
+use Engelsystem\Middleware\SendResponseHandler;
+use Psr\Http\Message\ServerRequestInterface;
 
 require_once realpath(__DIR__ . '/../includes/engelsystem.php');
 
-$free_pages = [
-    'admin_event_config',
-    'angeltypes',
-    'api',
-    'atom',
-    'credits',
-    'ical',
-    'login',
-    'public_dashboard',
-    'rooms',
-    'shift_entries',
-    'shifts',
-    'shifts_json_export',
-    'shifts_json_export_all',
-    'stats',
-    'users',
-    'user_driver_licenses',
-    'user_password_recovery',
-    'user_worklog'
-];
+/** @var Application $app */
+$app = app();
 
-// Gewünschte Seite/Funktion
-$page = '';
-$title = '';
-$content = '';
+/** @var ServerRequestInterface $request */
+$request = $app->get('psr7.request');
 
-/** @var Request $request */
-$request = $app->get('request');
-$page = $request->query->get('p');
-if (empty($page)) {
-    $page = $request->path();
-    $page = str_replace('-', '_', $page);
-}
-if ($page == '/') {
-    $page = isset($user) ? 'news' : 'login';
-}
-
-if (
-    preg_match('/^\w*$/i', $page)
-    && (
-        in_array($page, $free_pages)
-        || (isset($privileges) && in_array($page, $privileges))
-    )
-) {
-    $title = $page;
-
-    switch ($page) {
-        case 'api':
-            error('Api disabled temporarily.');
-            redirect(page_link_to());
-            break;
-        case 'ical':
-            require_once realpath(__DIR__ . '/../includes/pages/user_ical.php');
-            user_ical();
-            break;
-        case 'atom':
-            require_once realpath(__DIR__ . '/../includes/pages/user_atom.php');
-            user_atom();
-            break;
-        case 'shifts_json_export':
-            require_once realpath(__DIR__ . '/../includes/controller/shifts_controller.php');
-            shifts_json_export_controller();
-            break;
-        case 'shifts_json_export_all':
-            require_once realpath(__DIR__ . '/../includes/controller/shifts_controller.php');
-            shifts_json_export_all_controller();
-            break;
-        case 'stats':
-            require_once realpath(__DIR__ . '/../includes/pages/guest_stats.php');
-            guest_stats();
-            break;
-        case 'user_password_recovery':
-            require_once realpath(__DIR__ . '/../includes/controller/users_controller.php');
-            $title = user_password_recovery_title();
-            $content = user_password_recovery_controller();
-            break;
-        case 'public_dashboard':
-            list($title, $content) = public_dashboard_controller();
-            break;
-        case 'angeltypes':
-            list($title, $content) = angeltypes_controller();
-            break;
-        case 'shift_entries':
-            list($title, $content) = shift_entries_controller();
-            break;
-        case 'shifts':
-            list($title, $content) = shifts_controller();
-            break;
-        case 'users':
-            list($title, $content) = users_controller();
-            break;
-        case 'user_angeltypes':
-            list($title, $content) = user_angeltypes_controller();
-            break;
-        case 'user_driver_licenses':
-            list($title, $content) = user_driver_licenses_controller();
-            break;
-        case 'shifttypes':
-            list($title, $content) = shifttypes_controller();
-            break;
-        case 'admin_event_config':
-            list($title, $content) = event_config_edit_controller();
-            break;
-        case 'rooms':
-            list($title, $content) = rooms_controller();
-            break;
-        case 'news':
-            $title = news_title();
-            $content = user_news();
-            break;
-        case 'news_comments':
-            require_once realpath(__DIR__ . '/../includes/pages/user_news.php');
-            $title = user_news_comments_title();
-            $content = user_news_comments();
-            break;
-        case 'user_meetings':
-            $title = meetings_title();
-            $content = user_meetings();
-            break;
-        case 'user_myshifts':
-            $title = myshifts_title();
-            $content = user_myshifts();
-            break;
-        case 'user_shifts':
-            $title = shifts_title();
-            $content = user_shifts();
-            break;
-        case 'user_worklog':
-            list($title, $content) = user_worklog_controller();
-            break;
-        case 'user_messages':
-            $title = messages_title();
-            $content = user_messages();
-            break;
-        case 'user_questions':
-            $title = questions_title();
-            $content = user_questions();
-            break;
-        case 'user_settings':
-            $title = settings_title();
-            $content = user_settings();
-            break;
-        case 'login':
-            $title = login_title();
-            $content = guest_login();
-            break;
-        case 'register':
-            $title = register_title();
-            $content = guest_register();
-            break;
-        case 'logout':
-            $title = logout_title();
-            $content = guest_logout();
-            break;
-        case 'admin_questions':
-            $title = admin_questions_title();
-            $content = admin_questions();
-            break;
-        case 'admin_user':
-            $title = admin_user_title();
-            $content = admin_user();
-            break;
-        case 'admin_arrive':
-            $title = admin_arrive_title();
-            $content = admin_arrive();
-            break;
-        case 'admin_active':
-            $title = admin_active_title();
-            $content = admin_active();
-            break;
-        case 'admin_free':
-            $title = admin_free_title();
-            $content = admin_free();
-            break;
-        case 'admin_news':
-            require_once realpath(__DIR__ . '/../includes/pages/admin_news.php');
-            $content = admin_news();
-            break;
-        case 'admin_rooms':
-            $title = admin_rooms_title();
-            $content = admin_rooms();
-            break;
-        case 'admin_groups':
-            $title = admin_groups_title();
-            $content = admin_groups();
-            break;
-        case 'admin_import':
-            $title = admin_import_title();
-            $content = admin_import();
-            break;
-        case 'admin_shifts':
-            $title = admin_shifts_title();
-            $content = admin_shifts();
-            break;
-        case 'admin_log':
-            $title = admin_log_title();
-            $content = admin_log();
-            break;
-        case 'credits':
-            require_once realpath(__DIR__ . '/../includes/pages/guest_credits.php');
-            $title = credits_title();
-            $content = guest_credits();
-            break;
-        default:
-            require_once realpath(__DIR__ . '/../includes/pages/guest_start.php');
-            $content = guest_start();
-            break;
-    }
-} else {
-    // Wenn schon eingeloggt, keine-Berechtigung-Seite anzeigen
-    if (isset($user)) {
-        $title = _('No Access');
-        $content = _('You don\'t have permission to view this page . You probably have to sign in or register in order to gain access!');
-    } else {
-        // Sonst zur Loginseite leiten
-        redirect(page_link_to('login'));
-    }
-}
-
-$event_config = EventConfig();
-
-$parameters = [
-    'key' => (isset($user) ? $user['api_key'] : ''),
-];
-if ($page == 'user_meetings') {
-    $parameters['meetings'] = 1;
-}
-
-echo view(__DIR__ . '/../templates/layout.html', [
-    'theme'          => isset($user) ? $user['color'] : config('theme'),
-    'title'          => $title,
-    'atom_link'      => ($page == 'news' || $page == 'user_meetings')
-        ? ' <link href="'
-        . page_link_to('atom', $parameters)
-        . '" type = "application/atom+xml" rel = "alternate" title = "Atom Feed">'
-        : '',
-    'start_page_url' => page_link_to('/'),
-    'credits_url'    => page_link_to('credits'),
-    'menu'           => make_menu(),
-    'content'        => msg() . $content,
-    'header_toolbar' => header_toolbar(),
-    'faq_url'        => config('faq_url'),
-    'contact_email'  => config('contact_email'),
-    'locale'         => locale(),
-    'event_info'     => EventConfig_info($event_config) . ' <br />'
+$dispatcher = new Dispatcher([
+    SendResponseHandler::class,
+    ExceptionHandler::class,
+    LegacyMiddleware::class,
+    NotFoundResponse::class,
 ]);
+$dispatcher->setContainer($app);
+
+$dispatcher->handle($request);
diff --git a/src/Middleware/Dispatcher.php b/src/Middleware/Dispatcher.php
new file mode 100644
index 00000000..774040fb
--- /dev/null
+++ b/src/Middleware/Dispatcher.php
@@ -0,0 +1,110 @@
+<?php
+
+namespace Engelsystem\Middleware;
+
+use Engelsystem\Application;
+use InvalidArgumentException;
+use LogicException;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\MiddlewareInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+
+class Dispatcher implements MiddlewareInterface, RequestHandlerInterface
+{
+    /** @var MiddlewareInterface[] */
+    protected $stack;
+
+    /** @var Application */
+    protected $container;
+
+    /** @var RequestHandlerInterface */
+    protected $next;
+
+    /**
+     * @param MiddlewareInterface[] $stack
+     * @param Application|null      $container
+     */
+    public function __construct($stack = [], Application $container = null)
+    {
+        $this->stack = $stack;
+        $this->container = $container;
+    }
+
+    /**
+     * Process an incoming server request and return a response, optionally delegating
+     * response creation to a handler.
+     *
+     * Could be used to group middleware
+     *
+     * @param ServerRequestInterface  $request
+     * @param RequestHandlerInterface $handler
+     * @return ResponseInterface
+     */
+    public function process(
+        ServerRequestInterface $request,
+        RequestHandlerInterface $handler
+    ): ResponseInterface {
+        $this->next = $handler;
+
+        return $this->handle($request);
+    }
+
+    /**
+     * Handle the request and return a response.
+     *
+     * It calls all configured middleware and handles their response
+     *
+     * @param ServerRequestInterface $request
+     * @return ResponseInterface
+     */
+    public function handle(ServerRequestInterface $request): ResponseInterface
+    {
+        $middleware = array_shift($this->stack);
+
+        if (!$middleware) {
+            if ($this->next) {
+                return $this->next->handle($request);
+            }
+
+            throw new LogicException('Middleware queue is empty');
+        }
+
+        if (is_string($middleware)) {
+            $middleware = $this->resolveMiddleware($middleware);
+        }
+
+        if (!$middleware instanceof MiddlewareInterface) {
+            throw new InvalidArgumentException('Middleware is no instance of ' . MiddlewareInterface::class);
+        }
+
+        return $middleware->process($request, $this);
+    }
+
+    /**
+     * Resolve the middleware with the container
+     *
+     * @param string $middleware
+     * @return MiddlewareInterface
+     */
+    protected function resolveMiddleware($middleware)
+    {
+        if (!$this->container instanceof Application) {
+            throw new InvalidArgumentException('Unable to resolve middleware ' . $middleware);
+        }
+
+        if ($this->container->has($middleware)) {
+            return $this->container->get($middleware);
+        }
+
+        return $this->container->make($middleware);
+    }
+
+    /**
+     * @param Application $container
+     */
+    public function setContainer(Application $container)
+    {
+        $this->container = $container;
+    }
+}
diff --git a/src/Middleware/ExceptionHandler.php b/src/Middleware/ExceptionHandler.php
new file mode 100644
index 00000000..a5db0337
--- /dev/null
+++ b/src/Middleware/ExceptionHandler.php
@@ -0,0 +1,48 @@
+<?php
+
+namespace Engelsystem\Middleware;
+
+use Engelsystem\Exceptions\Handler as ExceptionsHandler;
+use Psr\Container\ContainerInterface;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\MiddlewareInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+
+class ExceptionHandler implements MiddlewareInterface
+{
+    /** @var ContainerInterface */
+    protected $container;
+
+    /**
+     * @param ContainerInterface $container
+     */
+    public function __construct(ContainerInterface $container)
+    {
+        $this->container = $container;
+    }
+
+    /**
+     * Handles any exceptions that occurred inside other middleware while returning it to the default response handler
+     *
+     * Should be added at the beginning
+     *
+     * @param ServerRequestInterface  $request
+     * @param RequestHandlerInterface $handler
+     * @return ResponseInterface
+     */
+    public function process(
+        ServerRequestInterface $request,
+        RequestHandlerInterface $handler
+    ): ResponseInterface {
+        try {
+            return $handler->handle($request);
+        } catch (\Throwable $e) {
+            /** @var ExceptionsHandler $handler */
+            $handler = $this->container->get('error.handler');
+            $content = $handler->exceptionHandler($e, true);
+
+            return response($content, 500);
+        }
+    }
+}
diff --git a/src/Middleware/LegacyMiddleware.php b/src/Middleware/LegacyMiddleware.php
new file mode 100644
index 00000000..41b2e471
--- /dev/null
+++ b/src/Middleware/LegacyMiddleware.php
@@ -0,0 +1,284 @@
+<?php
+
+namespace Engelsystem\Middleware;
+
+use Engelsystem\Http\Request;
+use Psr\Container\ContainerInterface;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\MiddlewareInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+
+class LegacyMiddleware implements MiddlewareInterface
+{
+    protected $free_pages = [
+        'admin_event_config',
+        'angeltypes',
+        'api',
+        'atom',
+        'credits',
+        'ical',
+        'login',
+        'public_dashboard',
+        'rooms',
+        'shift_entries',
+        'shifts',
+        'shifts_json_export',
+        'shifts_json_export_all',
+        'stats',
+        'users',
+        'user_driver_licenses',
+        'user_password_recovery',
+        'user_worklog'
+    ];
+
+    /** @var ContainerInterface */
+    protected $container;
+
+    /**
+     * @param ContainerInterface $container
+     */
+    public function __construct(ContainerInterface $container)
+    {
+        $this->container = $container;
+    }
+
+    /**
+     * Handle the request the old way
+     *
+     * Should be used before a 404 is send
+     *
+     * @param ServerRequestInterface  $request
+     * @param RequestHandlerInterface $handler
+     * @return ResponseInterface
+     */
+    public function process(
+        ServerRequestInterface $request,
+        RequestHandlerInterface $handler
+    ): ResponseInterface {
+        global $user;
+        global $privileges;
+
+        /** @var Request $appRequest */
+        $appRequest = $this->container->get('request');
+
+        // Default page content
+        $content = '';
+
+        $page = $appRequest->query->get('p');
+        if (empty($page)) {
+            $page = $appRequest->path();
+            $page = str_replace('-', '_', $page);
+        }
+        if ($page == '/') {
+            $page = isset($user) ? 'news' : 'login';
+        }
+
+        if (
+            preg_match('/^\w+$/i', $page)
+            && (
+                in_array($page, $this->free_pages)
+                || (isset($privileges) && in_array($page, $privileges))
+            )
+        ) {
+            $title = $page;
+
+            switch ($page) {
+                case 'api':
+                    error('Api disabled temporarily.');
+                    redirect(page_link_to());
+                    break;
+                case 'ical':
+                    require_once realpath(__DIR__ . '/../includes/pages/user_ical.php');
+                    user_ical();
+                    break;
+                case 'atom':
+                    require_once realpath(__DIR__ . '/../includes/pages/user_atom.php');
+                    user_atom();
+                    break;
+                case 'shifts_json_export':
+                    require_once realpath(__DIR__ . '/../includes/controller/shifts_controller.php');
+                    shifts_json_export_controller();
+                    break;
+                case 'shifts_json_export_all':
+                    require_once realpath(__DIR__ . '/../includes/controller/shifts_controller.php');
+                    shifts_json_export_all_controller();
+                    break;
+                case 'stats':
+                    require_once realpath(__DIR__ . '/../includes/pages/guest_stats.php');
+                    guest_stats();
+                    break;
+                case 'user_password_recovery':
+                    require_once realpath(__DIR__ . '/../includes/controller/users_controller.php');
+                    $title = user_password_recovery_title();
+                    $content = user_password_recovery_controller();
+                    break;
+                case 'public_dashboard':
+                    list($title, $content) = public_dashboard_controller();
+                    break;
+                case 'angeltypes':
+                    list($title, $content) = angeltypes_controller();
+                    break;
+                case 'shift_entries':
+                    list($title, $content) = shift_entries_controller();
+                    break;
+                case 'shifts':
+                    list($title, $content) = shifts_controller();
+                    break;
+                case 'users':
+                    list($title, $content) = users_controller();
+                    break;
+                case 'user_angeltypes':
+                    list($title, $content) = user_angeltypes_controller();
+                    break;
+                case 'user_driver_licenses':
+                    list($title, $content) = user_driver_licenses_controller();
+                    break;
+                case 'shifttypes':
+                    list($title, $content) = shifttypes_controller();
+                    break;
+                case 'admin_event_config':
+                    list($title, $content) = event_config_edit_controller();
+                    break;
+                case 'rooms':
+                    list($title, $content) = rooms_controller();
+                    break;
+                case 'news':
+                    $title = news_title();
+                    $content = user_news();
+                    break;
+                case 'news_comments':
+                    require_once realpath(__DIR__ . '/../includes/pages/user_news.php');
+                    $title = user_news_comments_title();
+                    $content = user_news_comments();
+                    break;
+                case 'user_meetings':
+                    $title = meetings_title();
+                    $content = user_meetings();
+                    break;
+                case 'user_myshifts':
+                    $title = myshifts_title();
+                    $content = user_myshifts();
+                    break;
+                case 'user_shifts':
+                    $title = shifts_title();
+                    $content = user_shifts();
+                    break;
+                case 'user_worklog':
+                    list($title, $content) = user_worklog_controller();
+                    break;
+                case 'user_messages':
+                    $title = messages_title();
+                    $content = user_messages();
+                    break;
+                case 'user_questions':
+                    $title = questions_title();
+                    $content = user_questions();
+                    break;
+                case 'user_settings':
+                    $title = settings_title();
+                    $content = user_settings();
+                    break;
+                case 'login':
+                    $title = login_title();
+                    $content = guest_login();
+                    break;
+                case 'register':
+                    $title = register_title();
+                    $content = guest_register();
+                    break;
+                case 'logout':
+                    $title = logout_title();
+                    $content = guest_logout();
+                    break;
+                case 'admin_questions':
+                    $title = admin_questions_title();
+                    $content = admin_questions();
+                    break;
+                case 'admin_user':
+                    $title = admin_user_title();
+                    $content = admin_user();
+                    break;
+                case 'admin_arrive':
+                    $title = admin_arrive_title();
+                    $content = admin_arrive();
+                    break;
+                case 'admin_active':
+                    $title = admin_active_title();
+                    $content = admin_active();
+                    break;
+                case 'admin_free':
+                    $title = admin_free_title();
+                    $content = admin_free();
+                    break;
+                case 'admin_news':
+                    require_once realpath(__DIR__ . '/../includes/pages/admin_news.php');
+                    $content = admin_news();
+                    break;
+                case 'admin_rooms':
+                    $title = admin_rooms_title();
+                    $content = admin_rooms();
+                    break;
+                case 'admin_groups':
+                    $title = admin_groups_title();
+                    $content = admin_groups();
+                    break;
+                case 'admin_import':
+                    $title = admin_import_title();
+                    $content = admin_import();
+                    break;
+                case 'admin_shifts':
+                    $title = admin_shifts_title();
+                    $content = admin_shifts();
+                    break;
+                case 'admin_log':
+                    $title = admin_log_title();
+                    $content = admin_log();
+                    break;
+                case 'credits':
+                    require_once realpath(__DIR__ . '/../includes/pages/guest_credits.php');
+                    $title = credits_title();
+                    $content = guest_credits();
+                    break;
+                default:
+                    require_once realpath(__DIR__ . '/../includes/pages/guest_start.php');
+                    $content = guest_start();
+                    break;
+            }
+        } else {
+            return $handler->handle($request);
+        }
+
+        if (empty($title) and empty($content)) {
+            return $handler->handle($request);
+        }
+
+        $event_config = EventConfig();
+
+        $parameters = [
+            'key' => (isset($user) ? $user['api_key'] : ''),
+        ];
+        if ($page == 'user_meetings') {
+            $parameters['meetings'] = 1;
+        }
+
+        return response(view(__DIR__ . '/../../templates/layout.html', [
+            'theme'          => isset($user) ? $user['color'] : config('theme'),
+            'title'          => $title,
+            'atom_link'      => ($page == 'news' || $page == 'user_meetings')
+                ? ' <link href="'
+                . page_link_to('atom', $parameters)
+                . '" type = "application/atom+xml" rel = "alternate" title = "Atom Feed">'
+                : '',
+            'start_page_url' => page_link_to('/'),
+            'credits_url'    => page_link_to('credits'),
+            'menu'           => make_menu(),
+            'content'        => msg() . $content,
+            'header_toolbar' => header_toolbar(),
+            'faq_url'        => config('faq_url'),
+            'contact_email'  => config('contact_email'),
+            'locale'         => locale(),
+            'event_info'     => EventConfig_info($event_config) . ' <br />'
+        ]));
+    }
+}
diff --git a/src/Middleware/NotFoundResponse.php b/src/Middleware/NotFoundResponse.php
new file mode 100644
index 00000000..c5d51d2d
--- /dev/null
+++ b/src/Middleware/NotFoundResponse.php
@@ -0,0 +1,47 @@
+<?php
+
+namespace Engelsystem\Middleware;
+
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\MiddlewareInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+
+class NotFoundResponse implements MiddlewareInterface
+{
+    /**
+     * Returns a 404: Page not found response
+     *
+     * Should be the last middleware
+     *
+     * @param ServerRequestInterface  $request
+     * @param RequestHandlerInterface $handler
+     * @return ResponseInterface
+     */
+    public function process(
+        ServerRequestInterface $request,
+        RequestHandlerInterface $handler
+    ): ResponseInterface {
+        global $user;
+        $event_config = EventConfig();
+        $content = info(
+            _('This page could not be found or you don\'t have permission to view it. You probably have to sign in or register in order to gain access!'),
+            true
+        );
+
+        return response(view(__DIR__ . '/../../templates/layout.html', [
+            'theme'          => isset($user) ? $user['color'] : config('theme'),
+            'title'          => _('Page not found'),
+            'atom_link'      => '',
+            'start_page_url' => page_link_to('/'),
+            'credits_url'    => page_link_to('credits'),
+            'menu'           => make_menu(),
+            'content'        => msg() . $content,
+            'header_toolbar' => header_toolbar(),
+            'faq_url'        => config('faq_url'),
+            'contact_email'  => config('contact_email'),
+            'locale'         => locale(),
+            'event_info'     => EventConfig_info($event_config) . ' <br />'
+        ]), 404);
+    }
+}
diff --git a/src/Middleware/SendResponseHandler.php b/src/Middleware/SendResponseHandler.php
new file mode 100644
index 00000000..06406fe0
--- /dev/null
+++ b/src/Middleware/SendResponseHandler.php
@@ -0,0 +1,45 @@
+<?php
+
+namespace Engelsystem\Middleware;
+
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\MiddlewareInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+
+class SendResponseHandler implements MiddlewareInterface
+{
+    /**
+     * Send the server response to the client
+     *
+     * This should be the first middleware
+     *
+     * @param ServerRequestInterface  $request
+     * @param RequestHandlerInterface $handler
+     * @return ResponseInterface
+     */
+    public function process(
+        ServerRequestInterface $request,
+        RequestHandlerInterface $handler
+    ): ResponseInterface {
+        $response = $handler->handle($request);
+
+        if (!headers_sent()) {
+            header(sprintf(
+                'HTTP/%s %s %s',
+                $response->getProtocolVersion(),
+                $response->getStatusCode(),
+                $response->getReasonPhrase()
+            ), true, $response->getStatusCode());
+
+            foreach ($response->getHeaders() as $name => $values) {
+                foreach ($values as $value) {
+                    header($name . ': ' . $value, false);
+                }
+            }
+        }
+
+        echo $response->getBody();
+        return $response;
+    }
+}
diff --git a/src/helpers.php b/src/helpers.php
index c3c727ec..2a90dcde 100644
--- a/src/helpers.php
+++ b/src/helpers.php
@@ -6,13 +6,15 @@ use Engelsystem\Config\Config;
 use Engelsystem\Http\Request;
 use Engelsystem\Renderer\Renderer;
 use Engelsystem\Routing\UrlGenerator;
+use Psr\Http\Message\ResponseInterface;
 use Symfony\Component\HttpFoundation\Session\SessionInterface;
+use Zend\Diactoros\Stream;
 
 /**
  * Get the global app instance
  *
  * @param string $id
- * @return mixed
+ * @return mixed|Application
  */
 function app($id = null)
 {
@@ -81,6 +83,32 @@ function request($key = null, $default = null)
 }
 
 /**
+ * @param string $content
+ * @param int    $status
+ * @param array  $headers
+ * @return ResponseInterface
+ */
+function response($content = '', $status = 200, $headers = [])
+{
+    /** @var ResponseInterface $response */
+    $response = app('psr7.response');
+
+    /** @var Stream $stream */
+    $stream = app()->make(Stream::class, ['stream' => 'php://memory', 'mode' => 'wb+']);
+    $stream->write($content);
+    $stream->rewind();
+
+    $response = $response
+        ->withBody($stream)
+        ->withStatus($status);
+    foreach ($headers as $key => $value) {
+        $response = $response->withAddedHeader($key, $value);
+    }
+
+    return $response;
+}
+
+/**
  * @param string $key
  * @param mixed  $default
  * @return SessionInterface|mixed