add trust hosts middleware

src/Illuminate/Http/Middleware/TrustHosts.php

@@ -0,0 +1,73 @@
+<?php
+
+namespace Illuminate\Http\Middleware;
+
+use Illuminate\Contracts\Foundation\Application;
+use Illuminate\Http\Request;
+
+abstract class TrustHosts
+{
+    /**
+     * The application instance.
+     *
+     * @var \Illuminate\Contracts\Foundation\Application
+     */
+    protected $app;
+
+    /**
+     * Create a new middleware instance.
+     *
+     * @param  \Illuminate\Contracts\Foundation\Application  $app
+     * @return void
+     */
+    public function __construct(Application $app)
+    {
+        $this->app = $app;
+    }
+
+    /**
+     * Get the host patterns that should be trusted.
+     *
+     * @return array
+     */
+    abstract public function hosts();
+
+    /**
+     * Handle the incoming request.
+     *
+     * @param  \Illuminate\Http\Request  $request
+     * @param  callable  $next
+     * @return \Illuminate\Http\Response
+     */
+    public function handle(Request $request, $next)
+    {
+        if ($this->shouldSpecifyTrustedHosts()) {
+            Request::setTrustedHosts(array_filter($this->hosts()));
+        }
+
+        return $next($request);
+    }
+
+    /**
+     * Determine if the application should specify trusted hosts.
+     *
+     * @return bool
+     */
+    protected function shouldSpecifyTrustedHosts()
+    {
+        return config('app.env') !== 'local' &&
+               ! $this->app->runningUnitTests();
+    }
+
+    /**
+     * Get a regular expression matching the application URL and all of its subdomains.
+     *
+     * @return string|null
+     */
+    protected function allSubdomainsOfApplicationUrl()
+    {
+        if ($host = parse_url($this->app['config']->get('app.url'), PHP_URL_HOST)) {
+            return '^(.+\.)?'.preg_quote($host).'$';
+        }
+    }
+}