Use get_user_profile_by_* functions to get UserProfiles.

We had a few bugs where we were using a raw Django database query to
get a UserProfile object.  This might seem OK, but going through
memcached is more efficient, and also guarantees that we get back the
.select_related() version of the object, so that if we later access
related fields like user_profile.realm.domain, we don't end up doing a
second database query as well.

Fixing these should in practice save a substantial number of database
queries on handling update_status_list requests, which happen very
often and access user_profile.realm.domain.

(imported from commit 0a2027da1b5bbc7a4f6c6927aca498530d7a4977)

humbug/backends.py

@@ -21,7 +21,7 @@ class EmailAuthBackend(object):
             return None
 
         try:
-            user_profile = UserProfile.objects.get(email__iexact=username)
+            user_profile = get_user_profile_by_email(username)
             if user_profile.check_password(password):
                 return user_profile
         except UserProfile.DoesNotExist:

zephyr/lib/actions.py

@@ -770,7 +770,7 @@ def do_update_user_activity(user_profile, client, query, log_time):
     activity.save(update_fields=["last_visit", "count"])
 
 def process_user_activity_event(event):
-    user_profile = UserProfile.objects.get(id=event["user_profile_id"])
+    user_profile = get_user_profile_by_id(event["user_profile_id"])
     client = get_client(event["client"])
     log_time = timestamp_to_datetime(event["time"])
     query = event["query"]
@@ -865,14 +865,14 @@ def update_message_flags(user_profile, operation, flag, messages, all):
     queue_json_publish("user_activity", event, process_update_message_flags)
 
 def process_user_presence_event(event):
-    user_profile = UserProfile.objects.get(id=event["user_profile_id"])
+    user_profile = get_user_profile_by_id(event["user_profile_id"])
     client = get_client(event["client"])
     log_time = timestamp_to_datetime(event["time"])
     status = event["status"]
     return do_update_user_presence(user_profile, client, log_time, status)
 
 def process_update_message_flags(event):
-    user_profile = UserProfile.objects.get(id=event["user_profile_id"])
+    user_profile = get_user_profile_by_id(event["user_profile_id"])
     try:
         until_id = event["until_id"]
         messages = event["messages"]
@@ -1313,7 +1313,7 @@ def handle_missedmessage_emails(user_profile_id, missed_email_events):
     message_ids = [event.get('message_id') for event in missed_email_events]
     timestamp = timestamp_to_datetime(event.get('timestamp'))
 
-    user_profile = UserProfile.objects.get(id=user_profile_id)
+    user_profile = get_user_profile_by_id(user_profile_id)
     messages = [um.message for um in UserMessage.objects.filter(user_profile=user_profile,
                                                                 message__id__in=message_ids,
                                                                 flags=~UserMessage.flags.read)]