From 20c03a155d2017101a098cefa602116a4a331d71 Mon Sep 17 00:00:00 2001
From: Igor Scheller <igor.scheller@igorshp.de>
Date: Tue, 7 Aug 2018 03:18:22 +0200
Subject: Implemented PSR-15 middleware handler

---
 src/Middleware/Dispatcher.php | 110 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 src/Middleware/Dispatcher.php

(limited to 'src/Middleware/Dispatcher.php')

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;
+    }
+}
-- 
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