Enhance Discord authentication and guild management by implementing caching for user and guild data to reduce API calls and improve performance. Update error handling for Discord API responses and refactor the guilds listing logic in the dashboard to streamline data retrieval. Adjust retry logic for rate limits and improve session error handling in the authentication flow.

bot/api/discord_auth.py

@@ -13,7 +13,9 @@
 
 from __future__ import annotations
 
+import asyncio
 import re
+import time
 from typing import Any
 
 import aiohttp
@@ -26,6 +28,17 @@ ADMINISTRATOR = 0x8
 
 GUILD_PATH_RE = re.compile(r"^/api/v1/guilds/(\d+)(?:/|$)")
 
+# Short-lived process caches — cut Discord 429s from dashboard reloads
+_USER_CACHE_TTL = 60.0
+_GUILDS_CACHE_TTL = 60.0
+_user_cache: dict[str, tuple[float, dict[str, Any]]] = {}
+_guilds_cache: dict[str, tuple[float, list[dict[str, Any]]]] = {}
+_guilds_inflight: dict[str, asyncio.Future[list[dict[str, Any]]]] = {}
+
+
+def _token_key(access_token: str) -> str:
+    return f"{access_token[:12]}:{len(access_token)}:{access_token[-8:]}"
+
 
 def _parse_admin_ids() -> list[str]:
     import os
@@ -46,33 +59,92 @@ def can_manage_guild(guild: dict[str, Any]) -> bool:
     return bool(perms & ADMINISTRATOR) or bool(perms & MANAGE_GUILD)
 
 
+def _discord_auth_error(status: int) -> HTTPException:
+    if status == 429:
+        return HTTPException(
+            status_code=429,
+            detail="Discord rate limit — please wait a few seconds and retry.",
+        )
+    if status in (401, 403):
+        return HTTPException(
+            status_code=401,
+            detail="Invalid or expired Discord access token. Please sign out and sign in again.",
+        )
+    return HTTPException(
+        status_code=403,
+        detail=f"Discord API error ({status}).",
+    )
+
+
 async def fetch_user_guilds(access_token: str) -> list[dict[str, Any]]:
+    key = _token_key(access_token)
+    cached = _guilds_cache.get(key)
+    if cached and cached[0] > time.monotonic():
+        return cached[1]
+
+    existing = _guilds_inflight.get(key)
+    if existing is not None:
+        return await existing
+
+    loop = asyncio.get_running_loop()
+    fut: asyncio.Future[list[dict[str, Any]]] = loop.create_future()
+    _guilds_inflight[key] = fut
+
+    try:
+        guilds = await _fetch_user_guilds_uncached(access_token)
+        _guilds_cache[key] = (time.monotonic() + _GUILDS_CACHE_TTL, guilds)
+        fut.set_result(guilds)
+        return guilds
+    except Exception as exc:
+        fut.set_exception(exc)
+        raise
+    finally:
+        _guilds_inflight.pop(key, None)
+
+
+async def _fetch_user_guilds_uncached(access_token: str) -> list[dict[str, Any]]:
+    max_attempts = 3
     async with aiohttp.ClientSession() as session:
-        async with session.get(
-            "https://discord.com/api/users/@me/guilds",
-            headers={"Authorization": f"Bearer {access_token}"},
-        ) as resp:
-            if resp.status != 200:
-                raise HTTPException(
-                    status_code=403,
-                    detail="Invalid or expired Discord access token.",
-                )
-            data = await resp.json()
-            return data if isinstance(data, list) else []
+        for attempt in range(1, max_attempts + 1):
+            async with session.get(
+                "https://discord.com/api/users/@me/guilds",
+                headers={"Authorization": f"Bearer {access_token}"},
+            ) as resp:
+                if resp.status == 200:
+                    data = await resp.json()
+                    return data if isinstance(data, list) else []
+
+                if resp.status == 429 and attempt < max_attempts:
+                    retry_after = 1.0
+                    try:
+                        body = await resp.json()
+                        retry_after = float(body.get("retry_after", 1))
+                    except Exception:
+                        retry_after = float(resp.headers.get("Retry-After", "1") or 1)
+                    await asyncio.sleep(min(max(retry_after, 0.3), 5.0))
+                    continue
+
+                raise _discord_auth_error(resp.status)
+
+    raise _discord_auth_error(429)
 
 
 async def verify_discord_token(access_token: str) -> dict[str, Any]:
+    key = _token_key(access_token)
+    cached = _user_cache.get(key)
+    if cached and cached[0] > time.monotonic():
+        return cached[1]
+
     async with aiohttp.ClientSession() as session:
         async with session.get(
             "https://discord.com/api/users/@me",
             headers={"Authorization": f"Bearer {access_token}"},
         ) as resp:
             if resp.status != 200:
-                raise HTTPException(
-                    status_code=403,
-                    detail="Invalid or expired Discord access token.",
-                )
-            return await resp.json()
+                raise _discord_auth_error(resp.status)
+            user = await resp.json()
+            _user_cache[key] = (time.monotonic() + _USER_CACHE_TTL, user)
+            return user
 
 
 async def user_can_manage_guild(access_token: str, guild_id: int) -> bool: