api: Add an api endpoint for GET /users/{id}

This adds a new API endpoint for querying basic data on a single other
user in the organization, reusing the existing infrastructure (and
view function!) for getting data on all users in an organization.

Fixes #12277.

zerver/lib/users.py

@@ -395,15 +395,29 @@ def get_custom_profile_field_values(custom_profile_field_values:
     return profiles_by_user_id
 
 def get_raw_user_data(realm: Realm, acting_user: UserProfile, client_gravatar: bool,
+                      target_user: Optional[UserProfile]=None,
                       include_custom_profile_fields: bool=True) -> Dict[int, Dict[str, str]]:
-    user_dicts = get_realm_user_dicts(realm.id)
+    """Fetches data about the target user(s) appropriate for sending to
+    acting_user via the standard format for the Zulip API.  If
+    target_user is None, we fetch all users in the realm.
+    """
     profiles_by_user_id = None
     custom_profile_field_data = None
+    # target_user is an optional parameter which is passed when user data of a specific user
+    # is required. It is 'None' otherwise.
+    if target_user is not None:
+        user_dicts = [user_profile_to_user_row(target_user)]
+    else:
+        user_dicts = get_realm_user_dicts(realm.id)
 
     if include_custom_profile_fields:
         base_query = CustomProfileFieldValue.objects.select_related("field")
         # TODO: Consider optimizing this query away with caching.
         custom_profile_field_values = base_query.filter(user_profile__realm_id=realm.id)
+        if target_user is not None:
+            custom_profile_field_values = base_query.filter(user_profile=target_user)
+        else:
+            custom_profile_field_values = base_query.filter(user_profile__realm_id=realm.id)
         profiles_by_user_id = get_custom_profile_field_values(custom_profile_field_values)
 
     result = {}

zerver/tests/test_users.py

@@ -1336,6 +1336,22 @@ class GetProfileTest(ZulipTestCase):
         self.assertFalse(result['is_bot'])
         self.assertTrue(result['is_admin'])
 
+        # Tests the GET ../users/{id} api endpoint.
+        user = self.example_user('hamlet')
+        result = ujson.loads(self.client_get('/json/users/{}'.format(user.id)).content)
+        self.assertEqual(result['members'][0]['email'], user.email)
+        self.assertEqual(result['members'][0]['full_name'], user.full_name)
+        self.assertIn("user_id", result['members'][0])
+        self.assertNotIn("profile_data", result['members'][0])
+        self.assertFalse(result['members'][0]['is_bot'])
+        self.assertFalse(result['members'][0]['is_admin'])
+
+        result = ujson.loads(self.client_get('/json/users/{}?include_custom_profile_fields=true'.format(user.id)).content)
+
+        self.assertIn('profile_data', result['members'][0])
+        result = self.client_get('/json/users/{}?'.format(30))
+        self.assert_json_error(result, "No such user")
+
     def test_api_get_empty_profile(self) -> None:
         """
         Ensure GET /users/me returns a max message id and returns successfully

zerver/views/users.py

@@ -395,7 +395,7 @@ def get_bots_backend(request: HttpRequest, user_profile: UserProfile) -> HttpRes
     return json_success({'bots': list(map(bot_info, bot_profiles))})
 
 @has_request_variables
-def get_members_backend(request: HttpRequest, user_profile: UserProfile,
+def get_members_backend(request: HttpRequest, user_profile: UserProfile, user_id: Optional[int]=None,
                         include_custom_profile_fields: bool=REQ(validator=check_bool,
                                                                 default=False),
                         client_gravatar: bool=REQ(validator=check_bool, default=False)
@@ -411,7 +411,13 @@ def get_members_backend(request: HttpRequest, user_profile: UserProfile,
         # If email addresses are only available to administrators,
         # clients cannot compute gravatars, so we force-set it to false.
         client_gravatar = False
+    target_user = None
+    if user_id is not None:
+        target_user = access_user_by_id(user_profile, user_id, allow_deactivated=True,
+                                        read_only=True)
+
     members = get_raw_user_data(realm, user_profile, client_gravatar=client_gravatar,
+                                target_user=target_user,
                                 include_custom_profile_fields=include_custom_profile_fields)
     return json_success({'members': members.values()})
 

zproject/urls.py

@@ -146,7 +146,8 @@ v1_api_and_json_patterns = [
     url(r'^users/(?!me/)(?P<email>[^/]*)/presence$', rest_dispatch,
         {'GET': 'zerver.views.presence.get_presence_backend'}),
     url(r'^users/(?P<user_id>[0-9]+)$', rest_dispatch,
-        {'PATCH': 'zerver.views.users.update_user_backend',
+        {'GET': 'zerver.views.users.get_members_backend',
+         'PATCH': 'zerver.views.users.update_user_backend',
          'DELETE': 'zerver.views.users.deactivate_user_backend'}),
     url(r'^bots$', rest_dispatch,
         {'GET': 'zerver.views.users.get_bots_backend',