Fix handling of initial messages on channel creation by returning them in the

RPC response instead of over the channel.

api.py

@@ -66,10 +66,11 @@ class SetValue(webapp2.RequestHandler):
           entry_value=entry_value)
 
     entry.put()
-    clients = (models.Client.all(keys_only=True)
+    msg = entry.ToMessage()
+    clients = (models.Client.all()
                .ancestor(self.client.parent_key()))
     for client in clients:
-      entry.SendToClient(client)
+      client.SendMessage(msg)
 
     return {}
 
@@ -108,12 +109,10 @@ class CreateChannel(webapp2.RequestHandler):
     token = channel.create_channel(
         client_id=str(self.client.key()),
         duration_minutes=config.CHANNEL_DURATION_SECONDS / 60)
-    entries = (models.StateEntry.all()
-               .ancestor(self.client.parent_key()))
-    for entry in entries:
-      entry.SendToClient(self.client.key())
     return {
       'token': token,
+      'messages': [x.ToMessage()
+                   for x in self.client.parent().GetStateEntries()],
     }
 
 

lib/models.py

@@ -52,9 +52,7 @@ class Profile(db.Model):
     # Merge from another profile into this one, using last_set time as the
     # arbiter.
     my_states = {}
-    for state_entry in (StateEntry.all()
-                        .ancestor(self)
-                        .run()):
+    for state_entry in self.GetStateEntries():
       my_states[state_entry.entry_key] = state_entry
 
     for state_entry in (StateEntry.all()
@@ -73,6 +71,10 @@ class Profile(db.Model):
             entry_value=state_entry.entry_value
             ).put()
 
+  @db.transactional()
+  def GetStateEntries(self):
+    return StateEntry.all().ancestor(self)
+
 
 class Client(db.Model):
   first_seen = db.DateTimeProperty(required=True, auto_now_add=True)
@@ -89,18 +91,21 @@ class Client(db.Model):
     profile = Profile.FromGoogleUser(google_user)
     return cls.FromProfile(profile)
 
+  def SendMessage(self, msg):
+    channel.send_message(str(self.key()), json.dumps(msg))
+
 
 class StateEntry(db.Model):
   last_set = db.DateTimeProperty(required=True, auto_now=True)
   entry_key = db.StringProperty(required=True)
   entry_value = db.StringProperty(required=True)
 
-  def SendToClient(self, client_id):
-    channel.send_message(str(client_id), json.dumps({
-        'message_type': 'state',
-        'key': self.entry_key,
-        'value': self.entry_value,
-    }))
+  def ToMessage(self):
+    return {
+      'message_type': 'state',
+      'key': self.entry_key,
+      'value': self.entry_value,
+    }
 
 
 class Subject(db.Model):

static/cosmopolite.js

@@ -168,6 +168,11 @@ cosmopolite.Client.prototype.onCreateChannel_ = function(data) {
     onmessage: this.$.proxy(this.onSocketMessage_, this),
     onerror: this.$.proxy(this.onSocketError_, this),
   });
+  // Handle messages that were immediately available as if they came over the
+  // channel.
+  for (var i = 0; i < data['messages'].length; ++i) {
+    this.onServerMessage_(data['messages'][i]);
+  }
 };
 
 cosmopolite.Client.prototype.onSocketOpen_ = function() {
@@ -184,12 +189,14 @@ cosmopolite.Client.prototype.onSocketClose_ = function() {
 };
 
 cosmopolite.Client.prototype.onSocketMessage_ = function(msg) {
-  console.log('message: ' + msg.data);
-  var parsed = JSON.parse(msg.data);
-  switch (parsed.message_type) {
+  this.onServerMessage_(JSON.parse(msg.data));
+};
+
+cosmopolite.Client.prototype.onServerMessage_ = function(msg) {
+  switch (msg.message_type) {
     case 'state':
-      var key = parsed['key'];
-      var value = parsed['value'];
+      var key = msg['key'];
+      var value = msg['value'];
       if (this.stateCache_[key] == value) {
         // Duplicate message.
         break;
@@ -200,10 +207,11 @@ cosmopolite.Client.prototype.onSocketMessage_ = function(msg) {
       }
       break;
     default:
-      console.log('Unknown message type: ' + parsed.message_type);
+      // Client out of date? Force refresh?
+      console.log('Unknown message type: ' + msg.message_type);
       break;
   }
-}
+};
 
 cosmopolite.Client.prototype.onSocketError_ = function(msg) {
   console.log('Socket error: ' + msg);