Fix media repo breaking

changelog.d/5593.bugfix

@@ -0,0 +1 @@
+Fix regression in 1.1rc1 where OPTIONS requests to the media repo would fail.

synapse/http/server.py

@@ -353,16 +353,33 @@ def render(self, request):
         """
         Render the request, using an asynchronous render handler if it exists.
         """
-        render_callback_name = "_async_render_" + request.method.decode("ascii")
+        render_callback_name = "render_" + request.method.decode("ascii")
+        async_render_callback_name = "_async_" + render_callback_name
 
-        if hasattr(self, render_callback_name):
-            # Call the handler
-            callback = getattr(self, render_callback_name)
-            defer.ensureDeferred(callback(request))
+        # Try and get the async renderer
+        callback = getattr(self, async_render_callback_name, None)
 
+        # If it doesn't exist, try and get a regular renderer
+        if not callback:
+            callback = getattr(self, render_callback_name, None)
+
+        # No renderer for this request method. Fall back to Twisted's "not
+        # found" handling.
+        if not callback:
+            return super().render(request)
+
+        resp = callback(request)
+
+        # If it's a coroutine, turn it into a Deferred
+        if isinstance(resp, types.CoroutineType):
+            resp = defer.ensureDeferred(resp)
+
+        # If it's a Deferred, return NOT_DONE_YET as it doesn't have a
+        # value yet
+        if not isinstance(resp, defer.Deferred):
             return NOT_DONE_YET
-        else:
-            super().render(request)
+
+        return resp
 
 
 def _options_handler(request):

synapse/rest/media/v1/preview_url_resource.py

@@ -95,6 +95,7 @@ def __init__(self, hs, media_repo, media_storage):
         )
 
     def render_OPTIONS(self, request):
+        request.setHeader(b"Allow", b"OPTIONS, GET")
         return respond_with_json(request, 200, {}, send_cors=True)
 
     @wrap_json_request_handler

synapse/util/logcontext.py

@@ -24,6 +24,7 @@
 
 import logging
 import threading
+import types
 
 from twisted.internet import defer, threads
 
@@ -544,6 +545,9 @@ def run_in_background(f, *args, **kwargs):
         # by synchronous exceptions, so let's turn them into Failures.
         return defer.fail()
 
+    if isinstance(res, types.CoroutineType):
+        res = defer.ensureDeferred(res)
+
     if not isinstance(res, defer.Deferred):
         return res
 

tests/rest/media/v1/test_url_preview.py

@@ -460,3 +460,15 @@ def test_blacklisted_ipv6_range(self):
                 "error": "DNS resolution failure during URL preview generation",
             },
         )
+
+    def test_OPTIONS(self):
+        """
+        OPTIONS returns the OPTIONS.
+        """
+        request, channel = self.make_request(
+            "OPTIONS", "url_preview?url=http://example.com", shorthand=False
+        )
+        request.render(self.preview_url)
+        self.pump()
+        self.assertEqual(channel.code, 200)
+        self.assertEqual(channel.json_body, {})