Merge branch 'release-v0.26.0' of github.com:matrix-org/synapse v0.26.0

9 files changed, 164 insertions, 121 deletions

diff --git a/synapse/rest/client/v1/admin.py b/synapse/rest/client/v1/admin.py
index 1197158fdc..5022808ea9 100644
--- a/synapse/rest/client/v1/admin.py
+++ b/synapse/rest/client/v1/admin.py
@@ -137,8 +137,8 @@ class DeactivateAccountRestServlet(ClientV1RestServlet):
     PATTERNS = client_path_patterns("/admin/deactivate/(?P<target_user_id>[^/]*)")
 
     def __init__(self, hs):
-        self._auth_handler = hs.get_auth_handler()
         super(DeactivateAccountRestServlet, self).__init__(hs)
+        self._deactivate_account_handler = hs.get_deactivate_account_handler()
 
     @defer.inlineCallbacks
     def on_POST(self, request, target_user_id):
@@ -149,7 +149,7 @@ class DeactivateAccountRestServlet(ClientV1RestServlet):
         if not is_admin:
             raise AuthError(403, "You are not a server admin")
 
-        yield self._auth_handler.deactivate_account(target_user_id)
+        yield self._deactivate_account_handler.deactivate_account(target_user_id)
         defer.returnValue((200, {}))
 
 
@@ -309,7 +309,7 @@ class ResetPasswordRestServlet(ClientV1RestServlet):
         super(ResetPasswordRestServlet, self).__init__(hs)
         self.hs = hs
         self.auth = hs.get_auth()
-        self.auth_handler = hs.get_auth_handler()
+        self._set_password_handler = hs.get_set_password_handler()
 
     @defer.inlineCallbacks
     def on_POST(self, request, target_user_id):
@@ -330,7 +330,7 @@ class ResetPasswordRestServlet(ClientV1RestServlet):
 
         logger.info("new_password: %r", new_password)
 
-        yield self.auth_handler.set_password(
+        yield self._set_password_handler.set_password(
             target_user_id, new_password, requester
         )
         defer.returnValue((200, {}))
diff --git a/synapse/rest/client/v1/logout.py b/synapse/rest/client/v1/logout.py
index 6add754782..ca49955935 100644
--- a/synapse/rest/client/v1/logout.py
+++ b/synapse/rest/client/v1/logout.py
@@ -16,6 +16,7 @@
 from twisted.internet import defer
 
 from synapse.api.auth import get_access_token_from_request
+from synapse.api.errors import AuthError
 
 from .base import ClientV1RestServlet, client_path_patterns
 
@@ -30,15 +31,30 @@ class LogoutRestServlet(ClientV1RestServlet):
 
     def __init__(self, hs):
         super(LogoutRestServlet, self).__init__(hs)
+        self._auth = hs.get_auth()
         self._auth_handler = hs.get_auth_handler()
+        self._device_handler = hs.get_device_handler()
 
     def on_OPTIONS(self, request):
         return (200, {})
 
     @defer.inlineCallbacks
     def on_POST(self, request):
-        access_token = get_access_token_from_request(request)
-        yield self._auth_handler.delete_access_token(access_token)
+        try:
+            requester = yield self.auth.get_user_by_req(request)
+        except AuthError:
+            # this implies the access token has already been deleted.
+            pass
+        else:
+            if requester.device_id is None:
+                # the acccess token wasn't associated with a device.
+                # Just delete the access token
+                access_token = get_access_token_from_request(request)
+                yield self._auth_handler.delete_access_token(access_token)
+            else:
+                yield self._device_handler.delete_device(
+                    requester.user.to_string(), requester.device_id)
+
         defer.returnValue((200, {}))
 
 
@@ -49,6 +65,7 @@ class LogoutAllRestServlet(ClientV1RestServlet):
         super(LogoutAllRestServlet, self).__init__(hs)
         self.auth = hs.get_auth()
         self._auth_handler = hs.get_auth_handler()
+        self._device_handler = hs.get_device_handler()
 
     def on_OPTIONS(self, request):
         return (200, {})
@@ -57,6 +74,12 @@ class LogoutAllRestServlet(ClientV1RestServlet):
     def on_POST(self, request):
         requester = yield self.auth.get_user_by_req(request)
         user_id = requester.user.to_string()
+
+        # first delete all of the user's devices
+        yield self._device_handler.delete_all_devices_for_user(user_id)
+
+        # .. and then delete any access tokens which weren't associated with
+        # devices.
         yield self._auth_handler.delete_access_tokens_for_user(user_id)
         defer.returnValue((200, {}))
 
diff --git a/synapse/rest/client/v2_alpha/_base.py b/synapse/rest/client/v2_alpha/_base.py
index 1f5bc24cc3..77434937ff 100644
--- a/synapse/rest/client/v2_alpha/_base.py
+++ b/synapse/rest/client/v2_alpha/_base.py
@@ -15,12 +15,13 @@
 
 """This module contains base REST classes for constructing client v1 servlets.
 """
-
-from synapse.api.urls import CLIENT_V2_ALPHA_PREFIX
+import logging
 import re
 
-import logging
+from twisted.internet import defer
 
+from synapse.api.errors import InteractiveAuthIncompleteError
+from synapse.api.urls import CLIENT_V2_ALPHA_PREFIX
 
 logger = logging.getLogger(__name__)
 
@@ -57,3 +58,37 @@ def set_timeline_upper_limit(filter_json, filter_timeline_limit):
         filter_json['room']['timeline']["limit"] = min(
             filter_json['room']['timeline']['limit'],
             filter_timeline_limit)
+
+
+def interactive_auth_handler(orig):
+    """Wraps an on_POST method to handle InteractiveAuthIncompleteErrors
+
+    Takes a on_POST method which returns a deferred (errcode, body) response
+    and adds exception handling to turn a InteractiveAuthIncompleteError into
+    a 401 response.
+
+    Normal usage is:
+
+    @interactive_auth_handler
+    @defer.inlineCallbacks
+    def on_POST(self, request):
+        # ...
+        yield self.auth_handler.check_auth
+            """
+    def wrapped(*args, **kwargs):
+        res = defer.maybeDeferred(orig, *args, **kwargs)
+        res.addErrback(_catch_incomplete_interactive_auth)
+        return res
+    return wrapped
+
+
+def _catch_incomplete_interactive_auth(f):
+    """helper for interactive_auth_handler
+
+    Catches InteractiveAuthIncompleteErrors and turns them into 401 responses
+
+    Args:
+        f (failure.Failure):
+    """
+    f.trap(InteractiveAuthIncompleteError)
+    return 401, f.value.result
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index 726e0a2826..385a3ad2ec 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -19,14 +19,14 @@ from twisted.internet import defer
 
 from synapse.api.auth import has_access_token
 from synapse.api.constants import LoginType
-from synapse.api.errors import Codes, LoginError, SynapseError
+from synapse.api.errors import Codes, SynapseError
 from synapse.http.servlet import (
     RestServlet, assert_params_in_request,
     parse_json_object_from_request,
 )
 from synapse.util.async import run_on_reactor
 from synapse.util.msisdn import phone_number_to_msisdn
-from ._base import client_v2_patterns
+from ._base import client_v2_patterns, interactive_auth_handler
 
 logger = logging.getLogger(__name__)
 
@@ -98,56 +98,61 @@ class PasswordRestServlet(RestServlet):
         self.auth = hs.get_auth()
         self.auth_handler = hs.get_auth_handler()
         self.datastore = self.hs.get_datastore()
+        self._set_password_handler = hs.get_set_password_handler()
 
+    @interactive_auth_handler
     @defer.inlineCallbacks
     def on_POST(self, request):
-        yield run_on_reactor()
-
         body = parse_json_object_from_request(request)
 
-        authed, result, params, _ = yield self.auth_handler.check_auth([
-            [LoginType.PASSWORD],
-            [LoginType.EMAIL_IDENTITY],
-            [LoginType.MSISDN],
-        ], body, self.hs.get_ip_from_request(request))
-
-        if not authed:
-            defer.returnValue((401, result))
+        # there are two possibilities here. Either the user does not have an
+        # access token, and needs to do a password reset; or they have one and
+        # need to validate their identity.
+        #
+        # In the first case, we offer a couple of means of identifying
+        # themselves (email and msisdn, though it's unclear if msisdn actually
+        # works).
+        #
+        # In the second case, we require a password to confirm their identity.
 
-        user_id = None
-        requester = None
-
-        if LoginType.PASSWORD in result:
-            # if using password, they should also be logged in
+        if has_access_token(request):
             requester = yield self.auth.get_user_by_req(request)
-            user_id = requester.user.to_string()
-            if user_id != result[LoginType.PASSWORD]:
-                raise LoginError(400, "", Codes.UNKNOWN)
-        elif LoginType.EMAIL_IDENTITY in result:
-            threepid = result[LoginType.EMAIL_IDENTITY]
-            if 'medium' not in threepid or 'address' not in threepid:
-                raise SynapseError(500, "Malformed threepid")
-            if threepid['medium'] == 'email':
-                # For emails, transform the address to lowercase.
-                # We store all email addreses as lowercase in the DB.
-                # (See add_threepid in synapse/handlers/auth.py)
-                threepid['address'] = threepid['address'].lower()
-            # if using email, we must know about the email they're authing with!
-            threepid_user_id = yield self.datastore.get_user_id_by_threepid(
-                threepid['medium'], threepid['address']
+            params = yield self.auth_handler.validate_user_via_ui_auth(
+                requester, body, self.hs.get_ip_from_request(request),
             )
-            if not threepid_user_id:
-                raise SynapseError(404, "Email address not found", Codes.NOT_FOUND)
-            user_id = threepid_user_id
+            user_id = requester.user.to_string()
         else:
-            logger.error("Auth succeeded but no known type!", result.keys())
-            raise SynapseError(500, "", Codes.UNKNOWN)
+            requester = None
+            result, params, _ = yield self.auth_handler.check_auth(
+                [[LoginType.EMAIL_IDENTITY], [LoginType.MSISDN]],
+                body, self.hs.get_ip_from_request(request),
+            )
+
+            if LoginType.EMAIL_IDENTITY in result:
+                threepid = result[LoginType.EMAIL_IDENTITY]
+                if 'medium' not in threepid or 'address' not in threepid:
+                    raise SynapseError(500, "Malformed threepid")
+                if threepid['medium'] == 'email':
+                    # For emails, transform the address to lowercase.
+                    # We store all email addreses as lowercase in the DB.
+                    # (See add_threepid in synapse/handlers/auth.py)
+                    threepid['address'] = threepid['address'].lower()
+                # if using email, we must know about the email they're authing with!
+                threepid_user_id = yield self.datastore.get_user_id_by_threepid(
+                    threepid['medium'], threepid['address']
+                )
+                if not threepid_user_id:
+                    raise SynapseError(404, "Email address not found", Codes.NOT_FOUND)
+                user_id = threepid_user_id
+            else:
+                logger.error("Auth succeeded but no known type!", result.keys())
+                raise SynapseError(500, "", Codes.UNKNOWN)
 
         if 'new_password' not in params:
             raise SynapseError(400, "", Codes.MISSING_PARAM)
         new_password = params['new_password']
 
-        yield self.auth_handler.set_password(
+        yield self._set_password_handler.set_password(
             user_id, new_password, requester
         )
 
@@ -161,52 +166,32 @@ class DeactivateAccountRestServlet(RestServlet):
     PATTERNS = client_v2_patterns("/account/deactivate$")
 
     def __init__(self, hs):
+        super(DeactivateAccountRestServlet, self).__init__()
         self.hs = hs
         self.auth = hs.get_auth()
         self.auth_handler = hs.get_auth_handler()
-        super(DeactivateAccountRestServlet, self).__init__()
+        self._deactivate_account_handler = hs.get_deactivate_account_handler()
 
+    @interactive_auth_handler
     @defer.inlineCallbacks
     def on_POST(self, request):
         body = parse_json_object_from_request(request)
 
-        # if the caller provides an access token, it ought to be valid.
-        requester = None
-        if has_access_token(request):
-            requester = yield self.auth.get_user_by_req(
-                request,
-            )  # type: synapse.types.Requester
+        requester = yield self.auth.get_user_by_req(request)
 
         # allow ASes to dectivate their own users
-        if requester and requester.app_service:
-            yield self.auth_handler.deactivate_account(
+        if requester.app_service:
+            yield self._deactivate_account_handler.deactivate_account(
                 requester.user.to_string()
             )
             defer.returnValue((200, {}))
 
-        authed, result, params, _ = yield self.auth_handler.check_auth([
-            [LoginType.PASSWORD],
-        ], body, self.hs.get_ip_from_request(request))
-
-        if not authed:
-            defer.returnValue((401, result))
-
-        if LoginType.PASSWORD in result:
-            user_id = result[LoginType.PASSWORD]
-            # if using password, they should also be logged in
-            if requester is None:
-                raise SynapseError(
-                    400,
-                    "Deactivate account requires an access_token",
-                    errcode=Codes.MISSING_TOKEN
-                )
-            if requester.user.to_string() != user_id:
-                raise LoginError(400, "", Codes.UNKNOWN)
-        else:
-            logger.error("Auth succeeded but no known type!", result.keys())
-            raise SynapseError(500, "", Codes.UNKNOWN)
-
-        yield self.auth_handler.deactivate_account(user_id)
+        yield self.auth_handler.validate_user_via_ui_auth(
+            requester, body, self.hs.get_ip_from_request(request),
+        )
+        yield self._deactivate_account_handler.deactivate_account(
+            requester.user.to_string(),
+        )
         defer.returnValue((200, {}))
 
 
diff --git a/synapse/rest/client/v2_alpha/devices.py b/synapse/rest/client/v2_alpha/devices.py
index 5321e5abbb..35d58b367a 100644
--- a/synapse/rest/client/v2_alpha/devices.py
+++ b/synapse/rest/client/v2_alpha/devices.py
@@ -17,9 +17,9 @@ import logging
 
 from twisted.internet import defer
 
-from synapse.api import constants, errors
+from synapse.api import errors
 from synapse.http import servlet
-from ._base import client_v2_patterns
+from ._base import client_v2_patterns, interactive_auth_handler
 
 logger = logging.getLogger(__name__)
 
@@ -60,8 +60,11 @@ class DeleteDevicesRestServlet(servlet.RestServlet):
         self.device_handler = hs.get_device_handler()
         self.auth_handler = hs.get_auth_handler()
 
+    @interactive_auth_handler
     @defer.inlineCallbacks
     def on_POST(self, request):
+        requester = yield self.auth.get_user_by_req(request)
+
         try:
             body = servlet.parse_json_object_from_request(request)
         except errors.SynapseError as e:
@@ -77,14 +80,10 @@ class DeleteDevicesRestServlet(servlet.RestServlet):
                 400, "No devices supplied", errcode=errors.Codes.MISSING_PARAM
             )
 
-        authed, result, params, _ = yield self.auth_handler.check_auth([
-            [constants.LoginType.PASSWORD],
-        ], body, self.hs.get_ip_from_request(request))
-
-        if not authed:
-            defer.returnValue((401, result))
+        yield self.auth_handler.validate_user_via_ui_auth(
+            requester, body, self.hs.get_ip_from_request(request),
+        )
 
-        requester = yield self.auth.get_user_by_req(request)
         yield self.device_handler.delete_devices(
             requester.user.to_string(),
             body['devices'],
@@ -115,6 +114,7 @@ class DeviceRestServlet(servlet.RestServlet):
         )
         defer.returnValue((200, device))
 
+    @interactive_auth_handler
     @defer.inlineCallbacks
     def on_DELETE(self, request, device_id):
         requester = yield self.auth.get_user_by_req(request)
@@ -130,19 +130,13 @@ class DeviceRestServlet(servlet.RestServlet):
             else:
                 raise
 
-        authed, result, params, _ = yield self.auth_handler.check_auth([
-            [constants.LoginType.PASSWORD],
-        ], body, self.hs.get_ip_from_request(request))
-
-        if not authed:
-            defer.returnValue((401, result))
-
-        # check that the UI auth matched the access token
-        user_id = result[constants.LoginType.PASSWORD]
-        if user_id != requester.user.to_string():
-            raise errors.AuthError(403, "Invalid auth")
+        yield self.auth_handler.validate_user_via_ui_auth(
+            requester, body, self.hs.get_ip_from_request(request),
+        )
 
-        yield self.device_handler.delete_device(user_id, device_id)
+        yield self.device_handler.delete_device(
+            requester.user.to_string(), device_id,
+        )
         defer.returnValue((200, {}))
 
     @defer.inlineCallbacks
diff --git a/synapse/rest/client/v2_alpha/groups.py b/synapse/rest/client/v2_alpha/groups.py
index 089ec71c81..f762dbfa9a 100644
--- a/synapse/rest/client/v2_alpha/groups.py
+++ b/synapse/rest/client/v2_alpha/groups.py
@@ -38,7 +38,7 @@ class GroupServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
+        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
         group_description = yield self.groups_handler.get_group_profile(
@@ -74,7 +74,7 @@ class GroupSummaryServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
+        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
         get_group_summary = yield self.groups_handler.get_group_summary(
@@ -148,7 +148,7 @@ class GroupCategoryServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, group_id, category_id):
-        requester = yield self.auth.get_user_by_req(request)
+        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
         category = yield self.groups_handler.get_group_category(
@@ -200,7 +200,7 @@ class GroupCategoriesServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
+        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
         category = yield self.groups_handler.get_group_categories(
@@ -225,7 +225,7 @@ class GroupRoleServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, group_id, role_id):
-        requester = yield self.auth.get_user_by_req(request)
+        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
         category = yield self.groups_handler.get_group_role(
@@ -277,7 +277,7 @@ class GroupRolesServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
+        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
         category = yield self.groups_handler.get_group_roles(
@@ -348,7 +348,7 @@ class GroupRoomServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
+        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
         result = yield self.groups_handler.get_rooms_in_group(group_id, requester_user_id)
@@ -369,7 +369,7 @@ class GroupUsersServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
+        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
         result = yield self.groups_handler.get_users_in_group(group_id, requester_user_id)
@@ -672,7 +672,7 @@ class PublicisedGroupsForUserServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, user_id):
-        yield self.auth.get_user_by_req(request)
+        yield self.auth.get_user_by_req(request, allow_guest=True)
 
         result = yield self.groups_handler.get_publicised_groups_for_user(
             user_id
@@ -697,7 +697,7 @@ class PublicisedGroupsForUsersServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_POST(self, request):
-        yield self.auth.get_user_by_req(request)
+        yield self.auth.get_user_by_req(request, allow_guest=True)
 
         content = parse_json_object_from_request(request)
         user_ids = content["user_ids"]
@@ -724,7 +724,7 @@ class GroupsForUserServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
         result = yield self.groups_handler.get_joined_groups(requester_user_id)
diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py
index 9e2f7308ce..e9d88a8895 100644
--- a/synapse/rest/client/v2_alpha/register.py
+++ b/synapse/rest/client/v2_alpha/register.py
@@ -27,7 +27,7 @@ from synapse.http.servlet import (
 )
 from synapse.util.msisdn import phone_number_to_msisdn
 
-from ._base import client_v2_patterns
+from ._base import client_v2_patterns, interactive_auth_handler
 
 import logging
 import hmac
@@ -176,6 +176,7 @@ class RegisterRestServlet(RestServlet):
         self.device_handler = hs.get_device_handler()
         self.macaroon_gen = hs.get_macaroon_generator()
 
+    @interactive_auth_handler
     @defer.inlineCallbacks
     def on_POST(self, request):
         yield run_on_reactor()
@@ -325,14 +326,10 @@ class RegisterRestServlet(RestServlet):
                     [LoginType.MSISDN, LoginType.EMAIL_IDENTITY],
                 ])
 
-        authed, auth_result, params, session_id = yield self.auth_handler.check_auth(
+        auth_result, params, session_id = yield self.auth_handler.check_auth(
             flows, body, self.hs.get_ip_from_request(request)
         )
 
-        if not authed:
-            defer.returnValue((401, auth_result))
-            return
-
         if registered_user_id is not None:
             logger.info(
                 "Already registered user ID %r for this session",
diff --git a/synapse/rest/client/versions.py b/synapse/rest/client/versions.py
index e984ea47db..2ecb15deee 100644
--- a/synapse/rest/client/versions.py
+++ b/synapse/rest/client/versions.py
@@ -30,6 +30,7 @@ class VersionsRestServlet(RestServlet):
                 "r0.0.1",
                 "r0.1.0",
                 "r0.2.0",
+                "r0.3.0",
             ]
         })
 
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 723f7043f4..40d2e664eb 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -25,7 +25,8 @@ from synapse.util.stringutils import random_string
 from synapse.util.caches.expiringcache import ExpiringCache
 from synapse.http.client import SpiderHttpClient
 from synapse.http.server import (
-    request_handler, respond_with_json_bytes
+    request_handler, respond_with_json_bytes,
+    respond_with_json,
 )
 from synapse.util.async import ObservableDeferred
 from synapse.util.stringutils import is_ascii
@@ -78,6 +79,9 @@ class PreviewUrlResource(Resource):
             self._expire_url_cache_data, 10 * 1000
         )
 
+    def render_OPTIONS(self, request):
+        return respond_with_json(request, 200, {}, send_cors=True)
+
     def render_GET(self, request):
         self._async_render_GET(request)
         return NOT_DONE_YET
@@ -348,11 +352,16 @@ class PreviewUrlResource(Resource):
     def _expire_url_cache_data(self):
         """Clean up expired url cache content, media and thumbnails.
         """
-
         # TODO: Delete from backup media store
 
         now = self.clock.time_msec()
 
+        logger.info("Running url preview cache expiry")
+
+        if not (yield self.store.has_completed_background_updates()):
+            logger.info("Still running DB updates; skipping expiry")
+            return
+
         # First we delete expired url cache entries
         media_ids = yield self.store.get_expired_url_cache(now)
 
@@ -426,8 +435,7 @@ class PreviewUrlResource(Resource):
 
         yield self.store.delete_url_cache_media(removed_media)
 
-        if removed_media:
-            logger.info("Deleted %d media from url cache", len(removed_media))
+        logger.info("Deleted %d media from url cache", len(removed_media))
 
 
 def decode_and_calc_og(body, media_uri, request_encoding=None):