add websockets subscribe endpoint

Author: michielbdejong

solid/appinfo/routes.php

@@ -54,7 +54,9 @@
         ['name' => 'solidWebhook#listWebhooks', 'url' => '/webhook/list', 'verb' => 'GET'],
         ['name' => 'solidWebhook#register', 'url' => '/webhook/register', 'verb' => 'POST'],
         ['name' => 'solidWebhook#unregister', 'url' => '/webhook/unregister', 'verb' => 'POST'],
-        
+
+        ['name' => 'solidWebsocket#register', 'url' => '/websocket/register', 'verb' => 'POST'],
+
         ['name' => 'app#appLauncher', 'url' => '/', 'verb' => 'GET'],
     ]
 ];

solid/lib/Controller/SolidWebsocketController.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace OCA\Solid\Controller;
+
+use OCP\AppFramework\Controller;
+use OCP\AppFramework\Http\DataResponse;
+
+class SolidWebhookController extends Controller
+{
+    /**
+     * @PublicPage
+     * @NoAdminRequired
+     * @NoCSRFRequired
+     */
+    public function register(): DataResponse
+    {
+        $pubsub = getenv("PUBSUB_URL") ?: "http://pubsub:8080";
+        return new DataResponse([
+            "@context" => "https://www.w3.org/ns/solid/notification/v1",
+            "type" => "WebSocketSubscription2021",
+            "source" => $pubsub . "/?type=WebSocketSubscription2021"
+        ]);
+    }
+}

solid/lib/WellKnown/SolidHandler.php

@@ -31,6 +31,12 @@ public function handle(string $service, IRequestContext $context, ?IResponse $pr
 		if (strlen($webhooksRegisterEndpoint) == 0) {
 			$webhooksRegisterEndpoint = $this->urlGenerator->linkToRoute('solid.app.appLauncher') . 'webhook/register';
 		}
+
+		$websocketsRegisterEndpoint = $this->urlGenerator->linkToRoute('solid.solidWebsocket.register');
+		// FIXME: this shouldn't happen:
+		if (strlen($websocketsRegisterEndpoint) == 0) {
+			$websocketsRegisterEndpoint = $this->urlGenerator->linkToRoute('solid.app.appLauncher') . 'websocket/register';
+		}
 		$body = [
 			"@context" => [
 				"https://www.w3.org/ns/solid/notification/v1"
@@ -39,6 +45,7 @@ public function handle(string $service, IRequestContext $context, ?IResponse $pr
 				[
 					"id" => "websocketNotification",
 					"type" => ["WebSocketSubscription2021"],
+					"subscription" => $websocketsRegisterEndpoint,
 					"feature" => []
 				],
 				[