Add member util functions

This adds some useful utils, get_or_fetch and handle role change. These utils handle errors themselves, so can simplify implementations within the commands.

1 files changed, 47 insertions, 0 deletions

diff --git a/bot/utils/members.py b/bot/utils/members.py
new file mode 100644
index 00000000..9c8c8dd8
--- /dev/null
+++ b/bot/utils/members.py
@@ -0,0 +1,47 @@
+import logging
+import typing as t
+
+import discord
+
+log = logging.getLogger(__name__)
+
+
+async def get_or_fetch_member(guild: discord.Guild, member_id: int) -> t.Optional[discord.Member]:
+    """
+    Attempt to get a member from cache; on failure fetch from the API.
+
+    Return `None` to indicate the member could not be found.
+    """
+    if member := guild.get_member(member_id):
+        log.trace("%s retrieved from cache.", member)
+    else:
+        try:
+            member = await guild.fetch_member(member_id)
+        except discord.errors.NotFound:
+            log.trace("Failed to fetch %d from API.", member_id)
+            return None
+        log.trace("%s fetched from API.", member)
+    return member
+
+
+async def handle_role_change(
+    member: discord.Member,
+    coro: t.Callable[..., t.Coroutine],
+    role: discord.Role
+) -> None:
+    """
+    Change `member`'s cooldown role via awaiting `coro` and handle errors.
+
+    `coro` is intended to be `discord.Member.add_roles` or `discord.Member.remove_roles`.
+    """
+    try:
+        await coro(role)
+    except discord.NotFound:
+        log.debug(f"Failed to change role for {member} ({member.id}): member not found")
+    except discord.Forbidden:
+        log.debug(
+            f"Forbidden to change role for {member} ({member.id}); "
+            f"possibly due to role hierarchy"
+        )
+    except discord.HTTPException as e:
+        log.error(f"Failed to change role for {member} ({member.id}): {e.status} {e.code}")