From 8e1ed09dff902c84beb9dff59305aa78e8772d81 Mon Sep 17 00:00:00 2001
From: "Paul \"LeoNerd\" Evans" <paul@matrix.org>
Date: Wed, 24 Aug 2016 13:01:53 +0100
Subject: [PATCH] Move static knowledge of protocol metadata into AS handler;
 cache the result

---
 synapse/handlers/appservice.py             | 26 ++++++++++++++++++++--
 synapse/rest/client/v2_alpha/thirdparty.py | 21 +----------------
 2 files changed, 25 insertions(+), 22 deletions(-)

diff --git a/synapse/handlers/appservice.py b/synapse/handlers/appservice.py
index 6273ff524..1c5c5ec30 100644
--- a/synapse/handlers/appservice.py
+++ b/synapse/handlers/appservice.py
@@ -37,6 +37,13 @@ def log_failure(failure):
 
 class ApplicationServicesHandler(object):
 
+    PROTOCOL_META = {
+        # TODO(paul): Declare kinds of metadata in here
+        "gitter": {
+            "user_fields": ["username"],
+        }
+    }
+
     def __init__(self, hs):
         self.store = hs.get_datastore()
         self.is_mine_id = hs.is_mine_id
@@ -48,6 +55,7 @@ class ApplicationServicesHandler(object):
 
         self.current_max = 0
         self.is_processing = False
+        self.supported_protocols = None
 
     @defer.inlineCallbacks
     def notify_interested_services(self, current_id):
@@ -177,10 +185,24 @@ class ApplicationServicesHandler(object):
 
     @defer.inlineCallbacks
     def get_3pe_protocols(self):
+        # The set of supported AS protocols and the metadata about them is
+        # effectively static during the lifetime of a homeserver process. We
+        # can look this up once and just cache it.
+        if self.supported_protocols:
+            defer.returnValue(self.supported_protocols)
+
         services = yield self.store.get_app_services()
-        protocols = set()
+        protocols = {}
         for s in services:
-            protocols.update(s.protocols)
+            for p in s.protocols:
+                if p in self.PROTOCOL_META:
+                    protocols[p] = self.PROTOCOL_META[p]
+                else:
+                    # We don't know any metadata for it, but we'd best at least
+                    # still declare that we know it exists
+                    protocols[p] = {}
+
+        self.supported_protocols = protocols
         defer.returnValue(protocols)
 
     @defer.inlineCallbacks
diff --git a/synapse/rest/client/v2_alpha/thirdparty.py b/synapse/rest/client/v2_alpha/thirdparty.py
index ae7901551..bbc3e9b96 100644
--- a/synapse/rest/client/v2_alpha/thirdparty.py
+++ b/synapse/rest/client/v2_alpha/thirdparty.py
@@ -28,13 +28,6 @@ logger = logging.getLogger(__name__)
 class ThirdPartyProtocolsServlet(RestServlet):
     PATTERNS = client_v2_patterns("/thirdparty/protocols", releases=())
 
-    META = {
-        # TODO(paul): Declare kinds of metadata in here
-        "gitter": {
-            "user_fields": ["username"],
-        }
-    }
-
     def __init__(self, hs):
         super(ThirdPartyProtocolsServlet, self).__init__()
 
@@ -46,19 +39,7 @@ class ThirdPartyProtocolsServlet(RestServlet):
         yield self.auth.get_user_by_req(request)
 
         protocols = yield self.appservice_handler.get_3pe_protocols()
-
-        result = {}
-        # TODO(paul): Eventually this kind of metadata wants to come from the
-        #   ASes themselves
-        for protocol in protocols:
-            if protocol in self.META:
-                result[protocol] = self.META[protocol]
-            else:
-                # We don't know any metadata for it, but we'd best at least
-                # still declare that we know it exists
-                result[protocol] = {}
-
-        defer.returnValue((200, result))
+        defer.returnValue((200, protocols))
 
 
 class ThirdPartyUserServlet(RestServlet):