Fix fetching media when using proxy

synapse/http/matrixfederationclient.py

@@ -216,6 +216,15 @@ class MatrixFederationHttpClient(object):
             self.agent = Agent.usingEndpointFactory(
                 reactor, MatrixFederationEndpointFactory(hs), pool=pool
             )
+
+        file_pool = HTTPConnectionPool(reactor)
+        file_pool.retryAutomatically = False
+        file_pool.maxPersistentPerHost = 5
+        file_pool.cachedConnectionTimeout = 10
+
+        self.file_agent = Agent.usingEndpointFactory(
+            reactor, MatrixFederationEndpointFactory(hs), pool=file_pool
+        )
         self.clock = hs.get_clock()
         self._store = hs.get_datastore()
         self.version_string_bytes = hs.version_string.encode('ascii')
@@ -238,6 +247,7 @@ class MatrixFederationHttpClient(object):
         ignore_backoff=False,
         backoff_on_404=False,
         span=None,
+        agent=None,
     ):
         """
         Sends a request to the given server.
@@ -357,9 +367,12 @@ class MatrixFederationHttpClient(object):
                         for key, value in iteritems(carrier):
                             headers_dict[key.encode("ascii")] = [value.encode("ascii")]
 
+                        if not agent:
+                            agent = self.agent
+
                         # we don't want all the fancy cookie and redirect handling that
                         # treq.request gives: just use the raw Agent.
-                        request_deferred = self.agent.request(
+                        request_deferred = agent.request(
                             method_bytes,
                             url_bytes,
                             headers=Headers(headers_dict),
@@ -757,6 +770,7 @@ class MatrixFederationHttpClient(object):
             request,
             retry_on_dns_fail=retry_on_dns_fail,
             ignore_backoff=ignore_backoff,
+            agent=self.file_agent,
         )
 
         headers = dict(response.headers.getAllRawHeaders())