Added CSRF Extender (#2095)

framework/core/src/Extend/Csrf.php

@@ -0,0 +1,32 @@
+<?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\Extend;
+
+use Flarum\Extension\Extension;
+use Illuminate\Contracts\Container\Container;
+
+class Csrf implements ExtenderInterface
+{
+    protected $csrfExemptPaths = [];
+
+    public function exemptPath(string $path)
+    {
+        $this->csrfExemptPaths[] = $path;
+
+        return $this;
+    }
+
+    public function extend(Container $container, Extension $extension = null)
+    {
+        $container->extend('flarum.http.csrfExemptPaths', function ($existingExemptPaths) {
+            return array_merge($existingExemptPaths, $this->csrfExemptPaths);
+        });
+    }
+}