Badge sync: also support removal of all badges

Removal is stored as '' for the HTML. This way there is still the expiry
date, which means we won't repeatedly check for changes.

pillar/badge_sync.py

@@ -77,7 +77,7 @@ def find_users_to_sync() -> typing.Iterable[SyncUser]:
 
 
 def fetch_badge_html(session: requests.Session, user: SyncUser, size: str) \
-        -> typing.Optional[BadgeHTML]:
+        -> str:
     """Fetch a Blender ID badge for this user.
 
     :param session:
@@ -99,30 +99,24 @@ def fetch_badge_html(session: requests.Session, user: SyncUser, size: str) \
 
     if resp.status_code == 204:
         my_log.debug('No badges for user %s', user.user_id)
-        return None
+        return ''
     if resp.status_code == 403:
         my_log.warning('Tried fetching %s for user %s but received a 403: %s',
                        url, user.user_id, resp.text)
-        return None
+        return ''
     if resp.status_code == 400:
         my_log.warning('Blender ID did not accept our GET request at %s for user %s: %s',
                        url, user.user_id, resp.text)
-        return None
+        return ''
     if resp.status_code == 500:
         my_log.warning('Blender ID returned an internal server error on %s for user %s, '
                        'aborting all badge refreshes: %s', url, user.user_id, resp.text)
         raise StopRefreshing()
     if resp.status_code == 404:
         my_log.warning('Blender ID has no user %s for our user %s', user.bid_user_id, user.user_id)
-        return None
+        return ''
     resp.raise_for_status()
-
-    my_log.debug('Received new badge HTML from %s for user %s', url, user.user_id)
-    badge_expiry = badge_expiry_config()
-    return BadgeHTML(
-        html=resp.text,
-        expires=utcnow() + badge_expiry,
-    )
+    return resp.text
 
 
 def refresh_all_badges(only_user_id: typing.Optional[bson.ObjectId] = None, *,
@@ -164,18 +158,22 @@ def refresh_all_badges(only_user_id: typing.Optional[bson.ObjectId] = None, *,
             my_log.debug('Skipping user %s', user_info.user_id)
             continue
         try:
-            badge_info = fetch_badge_html(session, user_info, 's')
+            badge_html = fetch_badge_html(session, user_info, 's')
         except StopRefreshing:
             my_log.error('Blender ID has internal problems, stopping badge refreshing at user %s',
                          user_info)
             break
 
+        update = {'badges': {
+            'html': badge_html,
+            'expires': utcnow() + badge_expiry,
+        }}
         num_updates += 1
         my_log.info('Updating badges HTML for Blender ID %s, user %s',
                     user_info.bid_user_id, user_info.user_id)
         if not dry_run:
             result = users_coll.update_one({'_id': user_info.user_id},
-                                           {'$set': {'badges': badge_info._asdict()}})
+                                           {'$set': update})
             if result.matched_count != 1:
                 my_log.warning('Unable to update badges for user %s', user_info.user_id)
     my_log.info('Updated badges of %d users%s', num_updates, ' (dry-run)' if dry_run else '')