Closes #700 - Subscribers can now be turned on and off

app/Http/Middleware/SubscribersConfigured.php

@@ -0,0 +1,40 @@
+<?php
+
+/*
+ * This file is part of Cachet.
+ *
+ * (c) Cachet HQ <support@cachethq.io>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace CachetHQ\Cachet\Http\Middleware;
+
+use CachetHQ\Cachet\Facades\Setting;
+use Closure;
+use Illuminate\Support\Facades\Redirect;
+
+class SubscribersConfigured
+{
+    /**
+     * We're verifying that subscribers is both enabled and configured.
+     *
+     * @param \Illuminate\Http\Request $request
+     * @param \Closure                 $next
+     *
+     * @return mixed
+     */
+    public function handle($request, Closure $next)
+    {
+        $isEnabled = Setting::get('enable_subscribers', false);
+        $mailAddress = env('MAIL_ADDRESS', false);
+        $mailFrom = env('MAIL_NAME', false);
+
+        if (!($isEnabled && $mailAddress && $mailFrom)) {
+            return Redirect::route('status-page');
+        }
+
+        return $next($request);
+    }
+}