Primer commit del sistema separado falta mejorar mucho

vendor/react/http/src/Io/MiddlewareRunner.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace React\Http\Io;
+
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use React\Promise\PromiseInterface;
+
+/**
+ * [Internal] Middleware runner to expose an array of middleware request handlers as a single request handler callable
+ *
+ * @internal
+ */
+final class MiddlewareRunner
+{
+    /**
+     * @var callable[]
+     */
+    private $middleware;
+
+    /**
+     * @param callable[] $middleware
+     */
+    public function __construct(array $middleware)
+    {
+        $this->middleware = \array_values($middleware);
+    }
+
+    /**
+     * @param ServerRequestInterface $request
+     * @return ResponseInterface|PromiseInterface<ResponseInterface>
+     * @throws \Exception
+     */
+    public function __invoke(ServerRequestInterface $request)
+    {
+        if (empty($this->middleware)) {
+            throw new \RuntimeException('No middleware to run');
+        }
+
+        return $this->call($request, 0);
+    }
+
+    /** @internal */
+    public function call(ServerRequestInterface $request, $position)
+    {
+        // final request handler will be invoked without a next handler
+        if (!isset($this->middleware[$position + 1])) {
+            $handler = $this->middleware[$position];
+            return $handler($request);
+        }
+
+        $that = $this;
+        $next = function (ServerRequestInterface $request) use ($that, $position) {
+            return $that->call($request, $position + 1);
+        };
+
+        // invoke middleware request handler with next handler
+        $handler = $this->middleware[$position];
+        return $handler($request, $next);
+    }
+}