feat: add get_user method

to check if already registered

src/aioappsrv/app.py

@@ -6,7 +6,7 @@ from typing import Callable, Awaitable
 
 from aiohttp import ClientSession, web
 
-from .matrix import Event, EventType
+from .matrix import Event, EventType, User
 from .utils import mx_message, fmt_mxid
 
 class AppService:
@@ -99,6 +99,18 @@ class AppService:
 			"Content-Type": "application/json",
 		}
 
+	async def get_user(self, mxid: str) -> User | None:
+		async with self._client.request(
+			method="GET",
+			url=f"{self.client_api}/profile/{mxid}",
+			headers=self.api_headers,
+		) as res:
+			if res.status == 404:
+				return None
+			res.raise_for_status()
+			doc = await res.json()
+			return User(**doc)
+
 	async def register_mxid(self, mxid: str) -> None:
 		bare_mxid = fmt_mxid(mxid, full=False)
 		async with self._client.request(