git-svn-id: https://msi/svn/firstRepo/Service/branches/Slim3@40 0f545695-f87b-41b6-9a03-7f16563b5454

Slim/MiddlewareAwareTrait.php

@@ -0,0 +1,118 @@
+<?php
+/**
+ * Slim Framework (http://slimframework.com)
+ *
+ * @link      https://github.com/slimphp/Slim
+ * @copyright Copyright (c) 2011-2015 Josh Lockhart
+ * @license   https://github.com/slimphp/Slim/blob/3.x/LICENSE.md (MIT License)
+ */
+namespace Slim;
+
+use RuntimeException;
+use SplStack;
+use SplDoublyLinkedList;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Message\ResponseInterface;
+use UnexpectedValueException;
+
+/**
+ * Middleware
+ *
+ * This is an internal class that enables concentric middleware layers. This
+ * class is an implementation detail and is used only inside of the Slim
+ * application; it is not visible to—and should not be used by—end users.
+ */
+trait MiddlewareAwareTrait
+{
+    /**
+     * Middleware call stack
+     *
+     * @var  \SplStack
+     * @link http://php.net/manual/class.splstack.php
+     */
+    protected $stack;
+
+    /**
+     * Middleware stack lock
+     *
+     * @var bool
+     */
+    protected $middlewareLock = false;
+
+    /**
+     * Add middleware
+     *
+     * This method prepends new middleware to the application middleware stack.
+     *
+     * @param callable $callable Any callable that accepts three arguments:
+     *                           1. A Request object
+     *                           2. A Response object
+     *                           3. A "next" middleware callable
+     * @return static
+     *
+     * @throws RuntimeException         If middleware is added while the stack is dequeuing
+     * @throws UnexpectedValueException If the middleware doesn't return an instance of \Psr\Http\Message\ResponseInterface
+     */
+    protected function addMiddleware(callable $callable)
+    {
+        if ($this->middlewareLock) {
+            throw new RuntimeException('Middleware can’t be added once the stack is dequeuing');
+        }
+
+        if (is_null($this->stack)) {
+            $this->seedMiddlewareStack();
+        }
+        $next = $this->stack->top();
+        $this->stack[] = function (ServerRequestInterface $req, ResponseInterface $res) use ($callable, $next) {
+            $result = call_user_func($callable, $req, $res, $next);
+            if ($result instanceof ResponseInterface === false) {
+                throw new UnexpectedValueException('Middleware must return instance of \Psr\Http\Message\ResponseInterface');
+            }
+
+            return $result;
+        };
+
+        return $this;
+    }
+
+    /**
+     * Seed middleware stack with first callable
+     *
+     * @param callable $kernel The last item to run as middleware
+     *
+     * @throws RuntimeException if the stack is seeded more than once
+     */
+    protected function seedMiddlewareStack(callable $kernel = null)
+    {
+        if (!is_null($this->stack)) {
+            throw new RuntimeException('MiddlewareStack can only be seeded once.');
+        }
+        if ($kernel === null) {
+            $kernel = $this;
+        }
+        $this->stack = new SplStack;
+        $this->stack->setIteratorMode(SplDoublyLinkedList::IT_MODE_LIFO | SplDoublyLinkedList::IT_MODE_KEEP);
+        $this->stack[] = $kernel;
+    }
+
+    /**
+     * Call middleware stack
+     *
+     * @param  ServerRequestInterface $req A request object
+     * @param  ResponseInterface      $res A response object
+     *
+     * @return ResponseInterface
+     */
+    public function callMiddlewareStack(ServerRequestInterface $req, ResponseInterface $res)
+    {
+        if (is_null($this->stack)) {
+            $this->seedMiddlewareStack();
+        }
+        /** @var callable $start */
+        $start = $this->stack->top();
+        $this->middlewareLock = true;
+        $resp = $start($req, $res);
+        $this->middlewareLock = false;
+        return $resp;
+    }
+}