Refactor Route Resolving and Dispatch (#2425)

- Split DispatchRoute. This allows us to run middleware after we figure out which route we're on, but before we actually execute the controller for that route.
- By making the route name explicitly available to middlewares, applications like CSRF and floodgate can set patterns based on route names instead of the path, which is an implementation detail.
- Support using route name match for CSRF extender, deprecate path match

src/Http/Middleware/ResolveRoute.php

@@ -0,0 +1,79 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Http\Middleware;
+
+use FastRoute\Dispatcher;
+use Flarum\Http\Exception\MethodNotAllowedException;
+use Flarum\Http\Exception\RouteNotFoundException;
+use Flarum\Http\RouteCollection;
+use Psr\Http\Message\ResponseInterface as Response;
+use Psr\Http\Message\ServerRequestInterface as Request;
+use Psr\Http\Server\MiddlewareInterface as Middleware;
+use Psr\Http\Server\RequestHandlerInterface as Handler;
+
+class ResolveRoute implements Middleware
+{
+    /**
+     * @var RouteCollection
+     */
+    protected $routes;
+
+    /**
+     * @var Dispatcher
+     */
+    protected $dispatcher;
+
+    /**
+     * Create the middleware instance.
+     *
+     * @param RouteCollection $routes
+     */
+    public function __construct(RouteCollection $routes)
+    {
+        $this->routes = $routes;
+    }
+
+    /**
+     * Resolve the given request from our route collection.
+     *
+     * @throws MethodNotAllowedException
+     * @throws RouteNotFoundException
+     */
+    public function process(Request $request, Handler $handler): Response
+    {
+        $method = $request->getMethod();
+        $uri = $request->getUri()->getPath() ?: '/';
+
+        $routeInfo = $this->getDispatcher()->dispatch($method, $uri);
+
+        switch ($routeInfo[0]) {
+            case Dispatcher::NOT_FOUND:
+                throw new RouteNotFoundException($uri);
+            case Dispatcher::METHOD_NOT_ALLOWED:
+                throw new MethodNotAllowedException($method);
+            case Dispatcher::FOUND:
+                $request = $request
+                    ->withAttribute('routeName', $routeInfo[1]['name'])
+                    ->withAttribute('routeHandler', $routeInfo[1]['handler'])
+                    ->withAttribute('routeParameters', $routeInfo[2]);
+
+                return $handler->handle($request);
+        }
+    }
+
+    protected function getDispatcher()
+    {
+        if (! isset($this->dispatcher)) {
+            $this->dispatcher = new Dispatcher\GroupCountBased($this->routes->getRouteData());
+        }
+
+        return $this->dispatcher;
+    }
+}