ActivityPub: Very-very early implementation of ActivityPub protocol

Webfinger and host-meta works at least

Related to #61 issue

Web/Presenters/ActivityPubPresenter.php

@@ -0,0 +1,51 @@
+<?php declare(strict_types=1);
+namespace openvk\Web\Presenters;
+use openvk\Web\Models\Repositories\Users;
+
+final class ActivityPubPresenter extends OpenVKPresenter
+{    
+    function renderWellKnown(): void
+    {
+        if ($_SERVER['REQUEST_URI'] == "/.well-known/host-meta") {
+            $data = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
+            . "<XRD xmlns=\"http://docs.oasis-open.org/ns/xri/xrd-1.0\">\n"
+            . "  <Link rel=\"lrdd\" template=\"" . ovk_scheme(true) . $_SERVER["SERVER_NAME"] . "/.well-known/webfinger?resource={uri}\">\n"
+            . "</XRD>\n";
+
+            header("Content-Type: application/xrd+xml; charset=utf-8");
+            exit($data);
+        } else if ($this->startsWith($_SERVER["REQUEST_URI"], '/.well-known/webfinger') && $this->startsWith($this->requestParam("resource"), 'acct:')) {
+            $username = array();
+            $subject = substr($this->requestParam("resource"), 5, strlen($this->requestParam("resource")));
+            preg_match('/([a-zA-Z0-9-_]+)@([a-zA-Z0-9-_\.]+)/', $subject, $username);
+            $username = $username[1];
+
+            $user = (new Users)->getByShortURL($username);
+
+            if($user !== null) {
+                $response->subject = $this->requestParam("resource");
+                
+                $response->links[] = array(
+                    'rel' => 'self',
+                    'href' => ovk_scheme(true) . $_SERVER["SERVER_NAME"] . '/id' . $user->getId(),
+                    'type' => 'application/activity+json'
+                );
+
+                header("Access-Control-Allow-Origin: *");
+                $this->returnJson((array) $response);
+            } else {
+                header("HTTP/2 404 Not Found");
+                exit();
+            };
+        } else {
+            header("HTTP/2 404 Not Found");
+            exit();
+        }
+    }
+
+    private function startsWith($string, $startString)
+    {
+        $len = strlen($startString);
+        return (substr($string, 0, $len) === $startString);
+    }
+}

Web/di.yml

@@ -22,6 +22,7 @@ services:
     - openvk\Web\Presenters\TopicsPresenter
     - openvk\Web\Presenters\ThemepacksPresenter
     - openvk\Web\Presenters\VKAPIPresenter
+    - openvk\Web\Presenters\ActivityPubPresenter
     - openvk\Web\Models\Repositories\Users
     - openvk\Web\Models\Repositories\Posts
     - openvk\Web\Models\Repositories\Photos

Web/routes.yml

@@ -265,6 +265,10 @@ routes:
       handler: "About->sandbox"
     - url: "/internal/wall{num}"
       handler: "Wall->wallEmbedded"
+    - url: "/.well-known/{?uri}"
+      handler: "ActivityPub->WellKnown"
+      placeholders:
+          uri: ".+"
     - url: "/{?shortCode}"
       handler: "UnknownTextRouteStrategy->delegate"
       placeholders: