guilds: handle banner changes like user avatar changes

just like user avatars, the client can just send the icon hash, we need
to check that first beforehand.

 - guilds: add description update
 - utils: move to_update() from blueprints.users to there

litecord/blueprints/guilds.py

@@ -35,6 +35,7 @@ from ..schemas import (
 )
 from .channels import channel_ack
 from .checks import guild_check, guild_owner_check, guild_perm_check
+from litecord.utils import to_update
 
 from litecord.errors import BadRequest
 
@@ -293,14 +294,17 @@ async def _update_guild(guild_id):
 
         await _guild_update_icon('splash', guild_id, j['splash'])
 
-    if 'banner' in j:
+    # small guild to work with to_update()
+    guild = await app.storage.get_guild(guild_id)
+
+    if to_update(j, guild, 'banner'):
         if not await app.storage.has_feature(guild_id, 'VERIFIED'):
             raise BadRequest('guild is not verified')
 
         await _guild_update_icon('banner', guild_id, j['banner'])
 
     fields = ['verification_level', 'default_message_notifications',
-              'explicit_content_filter', 'afk_timeout']
+              'explicit_content_filter', 'afk_timeout', 'description']
 
     for field in [f for f in fields if f in j]:
         await app.db.execute(f"""

litecord/blueprints/users.py

@@ -32,10 +32,11 @@ from litecord.auth import token_check, hash_data, check_username_usage
 from litecord.blueprints.guild.mod import remove_member
 
 from litecord.enums import PremiumType
-from litecord.images import parse_data_uri
+from litecord.images import parse_data_uri, ImageError
 from litecord.permissions import base_permissions
 
 from litecord.blueprints.auth import check_password
+from litecord.utils import to_update
 
 bp = Blueprint('user', __name__)
 log = Logger(__name__)
@@ -185,10 +186,6 @@ async def _try_discrim_patch(user_id, new_discrim: str):
         })
 
 
-def to_update(j: dict, user: dict, field: str):
-    return field in j and j[field] and j[field] != user[field]
-
-
 async def _check_pass(j, user):
     # Do not do password checks on unclaimed accounts
     if user['email'] is None:

litecord/schemas.py

@@ -281,7 +281,10 @@ GUILD_UPDATE = {
 
     'icon': {'type': 'b64_icon', 'required': False, 'nullable': True},
     'splash': {'type': 'b64_icon', 'required': False, 'nullable': True},
-    'banner': {'type': 'b64_icon', 'required': False, 'nullable': True},
+
+    # TODO: does splash also respect when its just a string pointing to the
+    # hash, just like in USER_UPDATE.avatar?
+    'banner': {'type': 'string', 'required': False, 'nullable': True},
 
     'description': {
         'type': 'string', 'required': False,

litecord/utils.py

@@ -174,3 +174,8 @@ def yield_chunks(input_list: Sequence[Any], chunk_size: int):
     # make the chunks
     for idx in range(0, len(input_list), chunk_size):
         yield input_list[idx:idx + chunk_size]
+
+def to_update(j: dict, orig: dict, field: str) -> bool:
+    """Compare values to check if j[field] is actually updating
+    the value in orig[field]. Useful for icon checks."""
+    return field in j and j[field] and j[field] != orig[field]