From 1b4b55ac23f434cb3123d4951d230636d8dcb184 Mon Sep 17 00:00:00 2001
From: Ian Gulliver <ian@isinglasstheater.org>
Date: Sat, 7 Jun 2014 23:06:17 -0700
Subject: [PATCH] Cache named profiles in memory in the Python application,
 since they're immutable once written.

---
 lib/models.py  | 15 +++++++++++++++
 lib/session.py |  6 +-----
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/lib/models.py b/lib/models.py
index 44a5cdd..fb2388a 100644
--- a/lib/models.py
+++ b/lib/models.py
@@ -47,6 +47,21 @@ class AccessDenied(Exception):
 class Profile(db.Model):
   google_user = db.UserProperty()
 
+  _cache = {}
+
+  @classmethod
+  @db.transactional()
+  def FindOrCreate(cls, google_user):
+    key_name = google_user.user_id()
+    if key_name in cls._cache:
+      return cls._cache[key_name]
+    profile = cls.get_by_key_name(key_name)
+    if not profile:
+      profile = cls(key_name=key_name, google_user=google_user)
+      profile.put()
+    cls._cache[key_name] = profile
+    return profile
+
   def MergeFrom(self, source_profile):
     # This is non-transactional and racy (new messages can be introduced by the
     # old client after we start). This is hard to solve because we're not in
diff --git a/lib/session.py b/lib/session.py
index a06280d..68268a1 100644
--- a/lib/session.py
+++ b/lib/session.py
@@ -23,11 +23,7 @@ from cosmopolite.lib import models
 def CreateClientAndProfile(client_id, google_user):
   if google_user:
     # We're going to need a profile for this user regardless
-    profile = models.Profile.get_by_key_name(google_user.user_id())
-    if not profile:
-      profile = models.Profile(
-          key_name=google_user.user_id(), google_user=google_user)
-      profile.put()
+    profile = models.Profile.FindOrCreate(google_user)
   else:
     profile = None