From 028ea79fff397a6d41bb968885cb1797560a93a3 Mon Sep 17 00:00:00 2001
From: Diogo Peralta Cordeiro <mail@diogo.site>
Date: Tue, 19 Oct 2021 23:46:01 +0100
Subject: [PATCH] [CORE][Router] Properly act on Accept headers

---
 plugins/ActivityPub/ActivityPub.php      | 45 ++++--------------------
 plugins/ActivityPub/Controller/Inbox.php |  6 ----
 src/Core/Router/RouteLoader.php          | 13 ++++++-
 3 files changed, 18 insertions(+), 46 deletions(-)

diff --git a/plugins/ActivityPub/ActivityPub.php b/plugins/ActivityPub/ActivityPub.php
index 569fc0fbd7..805d0f2e6a 100644
--- a/plugins/ActivityPub/ActivityPub.php
+++ b/plugins/ActivityPub/ActivityPub.php
@@ -39,6 +39,12 @@ class ActivityPub extends Plugin
      */
     public function onAddRoute(RouteLoader $r): bool
     {
+        $r->connect(
+            'activitypub_inbox',
+            '/inbox.json',
+            [Inbox::class, 'handle'],
+            options: ['accept' => self::$accept_headers, 'format' => self::$accept_headers[0]]
+        );
         $r->connect(
             'activitypub_actor_inbox',
             '/actor/{gsactor_id<\d+>}/inbox.json',
@@ -51,48 +57,9 @@ class ActivityPub extends Plugin
             [Inbox::class, 'handle'],
             options: ['accept' => self::$accept_headers, 'format' => self::$accept_headers[0]]
         );
-        $r->connect(
-            'activitypub_inbox',
-            '/inbox.json',
-            [Inbox::class, 'handle'],
-            options: ['accept' => self::$accept_headers, 'format' => self::$accept_headers[0]]
-        );
         return Event::next;
     }
 
-    /**
-     * Validate HTTP Accept headers
-     *
-     * @param bool $strict Strict mode
-     *
-     * @throws Exception when strict mode enabled
-     */
-    public static function validateAcceptHeader(array|string|null $accept, bool $strict): bool
-    {
-        if (\is_string($accept)
-            && \in_array($accept, self::$accept_headers)
-        ) {
-            return true;
-        } elseif (\is_array($accept)
-            && \count(
-                array_intersect($accept, self::$accept_headers),
-            ) > 0
-        ) {
-            return true;
-        }
-
-        if (!$strict) {
-            return false;
-        }
-
-        throw new Exception(
-            sprintf(
-                "HTTP Accept header error. Given: '%s'",
-                $accept,
-            ),
-        );
-    }
-
     /**
      * @throws Exception
      */
diff --git a/plugins/ActivityPub/Controller/Inbox.php b/plugins/ActivityPub/Controller/Inbox.php
index 11b35fad43..c38f52104f 100644
--- a/plugins/ActivityPub/Controller/Inbox.php
+++ b/plugins/ActivityPub/Controller/Inbox.php
@@ -47,12 +47,6 @@ class Inbox extends Controller
             }
         }
 
-        // Check accept header
-        ActivityPub::validateAcceptHeader(
-            $this->request->headers->get('accept'),
-            true,
-        );
-
         // TODO: Check if Actor can post
 
         // Get content
diff --git a/src/Core/Router/RouteLoader.php b/src/Core/Router/RouteLoader.php
index 91bf4133f5..48868dcbaf 100644
--- a/src/Core/Router/RouteLoader.php
+++ b/src/Core/Router/RouteLoader.php
@@ -100,6 +100,17 @@ class RouteLoader extends Loader
      */
     public function connect(string $id, string $uri_path, $target, ?array $options = [], ?array $param_reqs = [])
     {
+        // XXX: This hack can definitely be optimised by actually intersecting the arrays,
+        // maybe this helps: https://backbeat.tech/blog/symfony-routing-tricks-part-1
+        // see: https://symfony.com/index.php/doc/3.1/components/http_foundation.html#accessing-accept-headers-data
+        if (isset($options['accept'])) {
+            $accept_header_condition = '';
+            foreach ($options['accept'] as $accept) {
+                $accept_header_condition .= "('$accept' in request.getAcceptableContentTypes()) ||";
+            }
+            $accept_header_condition = substr($accept_header_condition, 0, -3);
+        }
+
         $this->rc->add(
             $id,
             new Route(
@@ -134,7 +145,7 @@ class RouteLoader extends Loader
                 methods: $options['http-methods'] ?? $options['methods'] ?? [],
                 // condition = ''    -- Symfony condition expression,
                 // see https://symfony.com/doc/current/routing.html#matching-expressions
-                condition: isset($options['accept']) ? "request.headers.get('Accept') in " . json_encode($options['accept']) : ($options['condition'] ?? ''),
+                condition: isset($options['accept']) ? $accept_header_condition : ($options['condition'] ?? ''),
             ),
         );
     }