Add middleware handler (#39)

* Middleware

* Run within cubex

* Remove middleware from cubex core

* 7.3 not supported

.circleci/config.yml

@@ -22,10 +22,6 @@ defaults: &defaults
 
 version: 2
 jobs:
-  build-php73:
-    <<: *defaults
-    docker:
-      - image: php:7.3-alpine
   build-php74:
     <<: *defaults
     docker:
@@ -39,6 +35,5 @@ workflows:
   version: 2
   build:
     jobs:
-      - build-php73
       - build-php74
       - build-php80

composer.json

@@ -18,7 +18,7 @@
     "optimize-autoloader": true
   },
   "require": {
-    "php": ">=7.3",
+    "php": ">=7.4",
     "ext-json": "*",
     "packaged/config": "~1.5",
     "packaged/context": "~1.4",

src/Middleware/Middleware.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace Cubex\Middleware;
+
+use Packaged\Context\Context;
+use Packaged\Routing\Handler\Handler;
+use Symfony\Component\HttpFoundation\Response;
+
+abstract class Middleware implements MiddlewareInterface
+{
+  protected Handler $_next;
+
+  public function setNext(Handler $handler): Handler
+  {
+    $this->_next = $handler;
+    return $this;
+  }
+
+  protected function next(Context $c): Response
+  {
+    return $this->_next->handle($c);
+  }
+}

src/Middleware/MiddlewareHandler.php

@@ -0,0 +1,41 @@
+<?php
+namespace Cubex\Middleware;
+
+use Packaged\Context\Context;
+use Packaged\Routing\Handler\Handler;
+use Symfony\Component\HttpFoundation\Response;
+
+class MiddlewareHandler implements Handler
+{
+  /** @var \Cubex\Middleware\MiddlewareInterface[] */
+  protected array $_middlewares = [];
+  /**
+   * @var \Packaged\Routing\Handler\Handler
+   */
+  protected Handler $_handler;
+
+  public function __construct(Handler $handler)
+  {
+    $this->_handler = $handler;
+  }
+
+  public function add(MiddlewareInterface $middleware)
+  {
+    $this->_middlewares[] = $middleware;
+    return $this;
+  }
+
+  public function handle(Context $c): Response
+  {
+    $handler = $this->_handler;
+    if($this->_middlewares)
+    {
+      foreach($this->_middlewares as $middleware)
+      {
+        $handler = $middleware->setNext($handler);
+      }
+    }
+
+    return $handler->handle($c);
+  }
+}

src/Middleware/MiddlewareInterface.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace Cubex\Middleware;
+
+use Packaged\Routing\Handler\Handler;
+
+interface MiddlewareInterface extends Handler
+{
+  public function setNext(Handler $handler): Handler;
+}