[FreeNetwork] First steps porting webfinger/lrdd to v3, GET webfinger requests already have a basic result

components/FreeNetwork/Util/XrdController.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace Component\FreeNetwork\Util;
+
+use App\Core\Controller;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\RequestStack;
+use XML_XRD;
+
+abstract class XrdController extends Controller
+{
+    protected string $default_mimetype = Discovery::JRD_MIMETYPE;
+
+    protected XML_XRD $xrd;
+
+    /*
+     * Configures $this->xrd which will later be printed. Must be
+     * implemented by child classes.
+     */
+    abstract protected function setXRD();
+
+    public function __construct(RequestStack $requestStack)
+    {
+        parent::__construct($requestStack);
+
+        if ($this->request->headers->get('format', null) === null) {
+            $this->request->headers->set('format', $this->default_mimetype);
+        }
+
+        $this->xrd = new XML_XRD();
+    }
+
+    public function handle(Request $request): array
+    {
+        $this->setXRD();
+        return ['xrd' => $this->xrd, 'default_mimetype' => $this->default_mimetype];
+    }
+}