Generate the client_id on the client, so we don't need a round trip to get it before we can send arbitrary RPCs.

This changes the Profile/Client relationship; we never needed to be transactional with them, so split them up entirely so we can reparent Clients.

api.py

@@ -36,14 +36,14 @@ def CreateChannel(google_user, client, instance_id, args):
   events = []
   if google_user:
     events.append({
-      'event_type':   'login',
-      'profile':      str(client.parent_key()),
-      'google_user':  google_user.email(),
+      'event_type':  'login',
+      'profile':     str(models.Client.profile.get_value_for_datastore(client)),
+      'google_user': google_user.email(),
     })
   else:
     events.append({
       'event_type': 'logout',
-      'profile':      str(client.parent_key()),
+      'profile':    str(models.Client.profile.get_value_for_datastore(client)),
     })
 
   return {
@@ -66,7 +66,10 @@ def Pin(google_user, client, instance_id, args):
 
   try:
     models.Subject.FindOrCreate(subject).Pin(
-        message, client.parent_key(), sender_message_id, instance)
+        message,
+        models.Client.profile.get_value_for_datastore(client),
+        sender_message_id,
+        instance)
   except models.DuplicateMessage:
     logging.warning('Duplicate pin: %s', sender_message_id)
     return {
@@ -90,7 +93,9 @@ def SendMessage(google_user, client, instance_id, args):
 
   try:
     models.Subject.FindOrCreate(subject).SendMessage(
-        message, client.parent_key(), sender_message_id)
+        message,
+        models.Client.profile.get_value_for_datastore(client),
+        sender_message_id)
   except models.DuplicateMessage:
     logging.warning('Duplicate message: %s', sender_message_id)
     return {
@@ -139,7 +144,9 @@ def Unpin(google_user, client, instance_id, args):
 
   try:
     models.Subject.FindOrCreate(subject).Unpin(
-        client.parent_key(), sender_message_id, instance.key())
+        models.Client.profile.get_value_for_datastore(client),
+        sender_message_id,
+        instance.key())
   except models.AccessDenied:
     logging.warning('Pin access denied')
     return {

lib/models.py

@@ -25,7 +25,8 @@ import utils
 
 
 # Profile
-# ↳ Client
+#
+# Client (⤴︎ Profile)
 #
 # Instance
 #
@@ -73,20 +74,20 @@ class Profile(db.Model):
 
 
 class Client(db.Model):
-  # parent=Profile
 
+  profile = db.ReferenceProperty(reference_class=Profile)
   first_seen = db.DateTimeProperty(required=True, auto_now_add=True)
 
   @classmethod
-  def FromProfile(cls, profile):
-    client = cls(parent=profile)
+  def FromProfile(cls, client_id, profile):
+    client = cls(key_name=client_id, profile=profile)
     client.put()
     return client
 
   @classmethod
-  def FromGoogleUser(cls, google_user):
+  def FromGoogleUser(cls, client_id, google_user):
     profile = Profile.FromGoogleUser(google_user)
-    return cls.FromProfile(profile)
+    return cls.FromProfile(client_id, profile)
 
 
 class Instance(db.Model):
@@ -308,7 +309,7 @@ class Subscription(db.Model):
     readable_only_by = (
         Subject.readable_only_by.get_value_for_datastore(subject))
     if (readable_only_by and
-        readable_only_by != client.parent_key()):
+        readable_only_by != Client.profile.get_value_for_datastore(client)):
       raise AccessDenied
 
     subscriptions = (

lib/session.py

@@ -23,15 +23,16 @@ from cosmopolite.lib import models
 def _CheckClientAndGoogleUser(client, google_user):
   if not google_user:
     # Nothing to check. If there's a user on the profile, it can stay there.
-    return client
+    return
 
-  client_profile_google_user = client.parent().google_user
+  client_profile_google_user = client.profile.google_user
   if client_profile_google_user:
     if client_profile_google_user == google_user:
-      return client
+      return
     else:
-      # Shared computer? Google account wins.
-      return models.Client.FromGoogleUser(google_user)
+      client.profile = models.Profile.FromGoogleUser(google_user)
+      client.put()
+      return
 
   # User just signed in. Their anonymous profile gets permanently
   # associated with this Google account.
@@ -44,14 +45,17 @@ def _CheckClientAndGoogleUser(client, google_user):
     # profile.
     # TODO(flamingcow): Fetch-then-store uniqueness is a race.
     google_profile = profiles[0]
-    google_profile.MergeFrom(client.parent_key())
-    return models.Client.FromProfile(google_profile)
+    google_profile.MergeFrom(
+        models.Client.profile.get_value_for_datastore(client))
+    client.profile = google_profile
+    client.put()
+    return
 
   # First time signin.
-  client_profile = client.parent()
+  client_profile = client.profile
   client_profile.google_user = google_user
   client_profile.put()
-  return client
+  return
 
 
 def session_required(handler):
@@ -65,21 +69,16 @@ def session_required(handler):
 
   @functools.wraps(handler)
   def FindOrCreateSession(self):
-    client_key = auth.ParseKey(self.request_json.get('client_id', None))
+    client_id = self.request_json['client_id']
 
-    # The hunt for a Profile begins.
-    if client_key:
-      self.client = _CheckClientAndGoogleUser(
-          models.Client.get(client_key),
-          self.verified_google_user)
+    self.client = models.Client.get_by_key_name(client_id)
+
+    if self.client:
+      _CheckClientAndGoogleUser(self.client, self.verified_google_user)
     else:
-      self.client = models.Client.FromGoogleUser(self.verified_google_user)
+      self.client = models.Client.FromGoogleUser(
+          client_id, self.verified_google_user)
 
-    ret = handler(self)
-    if client_key != self.client.key():
-      # Tell the client that this changed
-      ret['client_id'] = auth.Sign(self.client.key())
-
-    return ret
+    return handler(self)
 
   return FindOrCreateSession

static/cosmopolite.js

@@ -96,6 +96,10 @@ var Cosmopolite = function(
    */
   this.profilePromises_ = [];
 
+  if (!localStorage[this.namespace_ + ':client_id']) {
+    localStorage[this.namespace_ + ':client_id'] = this.uuid_();
+  }
+
   /**
    * @type {string}
    * @private
@@ -639,7 +643,7 @@ Cosmopolite.prototype.onReceiveMessage_ = function(data) {
       }
       break;
     case 'logout_complete':
-      localStorage.removeItem(this.namespace_ + ':client_id');
+      localStorage[this.namespace_ + ':client_id'] = this.uuid_();
       localStorage.removeItem(this.namespace_ + ':google_user_id');
       if (this.socket_) {
         this.socket_.close();
@@ -751,6 +755,7 @@ Cosmopolite.prototype.sendRPCs_ = function(commands, opt_delay) {
   }
   var request = {
     'instance_id': this.instanceID_,
+    'client_id': localStorage[this.namespace_ + ':client_id'],
     'commands': []
   };
   commands.forEach(function(command) {
@@ -762,9 +767,6 @@ Cosmopolite.prototype.sendRPCs_ = function(commands, opt_delay) {
     }
     request.commands.push(request_command);
   });
-  if (this.namespace_ + ':client_id' in localStorage) {
-    request['client_id'] = localStorage[this.namespace_ + ':client_id'];
-  }
   if (this.namespace_ + ':google_user_id' in localStorage) {
     request['google_user_id'] =
         localStorage[this.namespace_ + ':google_user_id'];
@@ -797,9 +799,6 @@ Cosmopolite.prototype.sendRPCs_ = function(commands, opt_delay) {
       localStorage[this.namespace_ + ':google_user_id'] =
           data['google_user_id'];
     }
-    if ('client_id' in data) {
-      localStorage[this.namespace_ + ':client_id'] = data['client_id'];
-    }
 
     if (data['status'] == 'retry') {
       // Discard delay
@@ -852,10 +851,6 @@ Cosmopolite.prototype.sendRPCs_ = function(commands, opt_delay) {
  * @private
  */
 Cosmopolite.prototype.maySendRPC_ = function() {
-  if (!(this.namespace_ + ':client_id' in localStorage)) {
-    return false;
-  }
-
   if (this.channelState_ != Cosmopolite.ChannelState_.OPEN) {
     return false;
   }