Avoid looking up emails when rendering messages.

We now fetch email -> id mappings for messages ONLY if
it potentially uses the !avatar(foo@example.com) syntax.

zerver/lib/bugdown/__init__.py

@@ -45,7 +45,6 @@ from zerver.lib.url_preview import preview as link_preview
 from zerver.models import (
     all_realm_filters,
     get_active_streams,
-    get_active_user_dicts_in_realm,
     get_system_bot,
     Message,
     Realm,
@@ -78,6 +77,9 @@ if False:
     # mypy requires the Optional to be inside Union
     ElementStringNone = Union[Element, Optional[Text]]
 
+AVATAR_REGEX = r'!avatar\((?P<email>[^)]*)\)'
+GRAVATAR_REGEX = r'!gravatar\((?P<email>[^)]*)\)'
+
 class BugdownRenderingException(Exception):
     pass
 
@@ -718,7 +720,7 @@ class Avatar(markdown.inlinepatterns.Pattern):
         profile_id = None
 
         if db_data is not None:
-            user_dict = db_data['by_email'].get(email)
+            user_dict = db_data['email_info'].get(email)
             if user_dict is not None:
                 profile_id = user_dict['id']
 
@@ -728,6 +730,17 @@ class Avatar(markdown.inlinepatterns.Pattern):
         img.set('alt', email)
         return img
 
+def possible_avatar_emails(content):
+    # type: (Text) -> Set[Text]
+    emails = set()
+    for regex in [AVATAR_REGEX, GRAVATAR_REGEX]:
+        matches = re.findall(regex, content)
+        for email in matches:
+            if email:
+                emails.add(email)
+
+    return emails
+
 path_to_name_to_codepoint = os.path.join(settings.STATIC_ROOT, "generated", "emoji", "name_to_codepoint.json")
 with open(path_to_name_to_codepoint) as name_to_codepoint_file:
     name_to_codepoint = ujson.load(name_to_codepoint_file)
@@ -1280,8 +1293,8 @@ class Bugdown(markdown.Extension):
         md.parser.blockprocessors.add('indent', ListIndentProcessor(md.parser), '<ulist')
 
         # Note that !gravatar syntax should be deprecated long term.
-        md.inlinePatterns.add('avatar', Avatar(r'!avatar\((?P<email>[^)]*)\)'), '>backtick')
-        md.inlinePatterns.add('gravatar', Avatar(r'!gravatar\((?P<email>[^)]*)\)'), '>backtick')
+        md.inlinePatterns.add('avatar', Avatar(AVATAR_REGEX), '>backtick')
+        md.inlinePatterns.add('gravatar', Avatar(GRAVATAR_REGEX), '>backtick')
 
         md.inlinePatterns.add('stream_subscribe_button',
                               StreamSubscribeButton(r'!_stream_subscribe_button\((?P<stream_name>(?:[^)\\]|\\\)|\\)*)\)'), '>backtick')
@@ -1475,6 +1488,31 @@ def log_bugdown_error(msg):
     could cause an infinite exception loop."""
     logging.getLogger('').error(msg)
 
+def get_email_info(realm_id, emails):
+    # type: (int, Set[Text]) -> Dict[Text, FullNameInfo]
+    if not emails:
+        return dict()
+
+    q_list = {
+        Q(email__iexact=email.strip().lower())
+        for email in emails
+    }
+
+    rows = UserProfile.objects.filter(
+        realm_id=realm_id
+    ).filter(
+        functools.reduce(lambda a, b: a | b, q_list),
+    ).values(
+        'id',
+        'email',
+    )
+
+    dct = {
+        row['email'].strip().lower(): row
+        for row in rows
+    }
+    return dct
+
 def get_full_name_info(realm_id, full_names):
     # type: (int, Set[Text]) -> Dict[Text, FullNameInfo]
     if not full_names:
@@ -1541,7 +1579,6 @@ def do_convert(content, message=None, message_realm=None, possible_words=None, s
     global db_data
     if message is not None:
         assert message_realm is not None  # ensured above if message is not None
-        realm_users = get_active_user_dicts_in_realm(message_realm)
         realm_streams = get_active_streams(message_realm).values('id', 'name')
 
         if possible_words is None:
@@ -1550,8 +1587,11 @@ def do_convert(content, message=None, message_realm=None, possible_words=None, s
         full_names = possible_mentions(content)
         full_name_info = get_full_name_info(message_realm.id, full_names)
 
+        emails = possible_avatar_emails(content)
+        email_info = get_email_info(message_realm.id, emails)
+
         db_data = {'possible_words': possible_words,
-                   'by_email': dict((user['email'].lower(), user) for user in realm_users),
+                   'email_info': email_info,
                    'full_name_info': full_name_info,
                    'emoji': message_realm.get_emoji(),
                    'sent_by_bot': sent_by_bot,

zerver/tests/test_bugdown.py

@@ -1034,6 +1034,19 @@ class BugdownErrorTests(ZulipTestCase):
 
 
 class BugdownAvatarTestCase(ZulipTestCase):
+    def test_possible_avatar_emails(self):
+        # type: () -> None
+        content = '''
+            hello !avatar(foo@example.com) my email is ignore@ignore.com
+            !gravatar(bar@yo.tv)
+
+            smushing!avatar(hamlet@example.org) is allowed
+        '''
+        self.assertEqual(
+            bugdown.possible_avatar_emails(content),
+            {'foo@example.com', 'bar@yo.tv', 'hamlet@example.org'},
+        )
+
     def test_avatar_with_id(self):
         # type: () -> None
         sender_user_profile = self.example_user('othello')

zerver/tests/test_messages.py

@@ -577,7 +577,7 @@ class StreamMessagesTest(ZulipTestCase):
         with queries_captured() as queries:
             send_message()
 
-        self.assert_length(queries, 15)
+        self.assert_length(queries, 14)
 
     def test_stream_message_dict(self):
         # type: () -> None

zerver/tests/test_signup.py

@@ -314,7 +314,7 @@ class LoginTest(ZulipTestCase):
         with queries_captured() as queries:
             self.register(self.nonreg_email('test'), "test")
         # Ensure the number of queries we make is not O(streams)
-        self.assert_length(queries, 65)
+        self.assert_length(queries, 64)
         user_profile = self.nonreg_user('test')
         self.assertEqual(get_session_dict_user(self.client.session), user_profile.id)
         self.assertFalse(user_profile.enable_stream_desktop_notifications)

zerver/tests/test_subs.py

@@ -1629,7 +1629,7 @@ class SubscriptionAPITest(ZulipTestCase):
                     streams_to_sub,
                     dict(principals=ujson.dumps([email1, email2])),
                 )
-        self.assert_length(queries, 41)
+        self.assert_length(queries, 40)
 
         self.assert_length(events, 7)
         for ev in [x for x in events if x['event']['type'] not in ('message', 'stream')]: