536: Add endpoint to resolve frontend user by auth method and username (#539)

* Add endpoint to resolve frontend user by auth method and username

* Require client ID for frontend user lookup

* Remove unnecessary if check

* Fix PromptRepository -> UserRepository

* Convert to protocol User

* Move User prep

* Address review comments

* 404 -> HTTP_404_NOT_FOUND

backend/oasst_backend/api/v1/frontend_users.py

@@ -1,4 +1,5 @@
 import datetime
+from typing import Optional
 from uuid import UUID
 
 from fastapi import APIRouter, Depends, Query
@@ -6,6 +7,7 @@ from oasst_backend.api import deps
 from oasst_backend.api.v1 import utils
 from oasst_backend.models import ApiClient
 from oasst_backend.prompt_repository import PromptRepository
+from oasst_backend.user_repository import UserRepository
 from oasst_shared.schemas import protocol
 from sqlmodel import Session
 from starlette.status import HTTP_204_NO_CONTENT
@@ -13,6 +15,22 @@ from starlette.status import HTTP_204_NO_CONTENT
 router = APIRouter()
 
 
+@router.get("/{auth_method}/{username}", response_model=protocol.User)
+def query_frontend_user(
+    auth_method: str,
+    username: str,
+    api_client_id: Optional[UUID] = None,
+    api_client: ApiClient = Depends(deps.get_api_client),
+    db: Session = Depends(deps.get_db),
+):
+    """
+    Query frontend user.
+    """
+    ur = UserRepository(db, api_client)
+    user = ur.query_frontend_user(auth_method, username, api_client_id)
+    return protocol.User(id=user.username, display_name=user.display_name, auth_method=user.auth_method)
+
+
 @router.get("/{username}/messages", response_model=list[protocol.Message])
 def query_frontend_user_messages(
     username: str,

backend/oasst_backend/user_repository.py

@@ -1,9 +1,12 @@
 from typing import Optional
+from uuid import UUID
 
 from oasst_backend.models import ApiClient, Message, User
+from oasst_shared.exceptions import OasstError, OasstErrorCode
 from oasst_shared.schemas import protocol as protocol_schema
 from oasst_shared.schemas.protocol import LeaderboardStats
 from sqlmodel import Session, func
+from starlette.status import HTTP_403_FORBIDDEN, HTTP_404_NOT_FOUND
 
 
 class UserRepository:
@@ -11,6 +14,27 @@ class UserRepository:
         self.db = db
         self.api_client = api_client
 
+    def query_frontend_user(
+        self, auth_method: str, username: str, api_client_id: Optional[UUID] = None
+    ) -> Optional[User]:
+        if not api_client_id:
+            api_client_id = self.api_client.id
+
+        if not self.api_client.trusted and api_client_id != self.api_client.id:
+            # Unprivileged API client asks for foreign user
+            raise OasstError("Forbidden", OasstErrorCode.API_CLIENT_NOT_AUTHORIZED, HTTP_403_FORBIDDEN)
+
+        user: User = (
+            self.db.query(User)
+            .filter(User.auth_method == auth_method, User.username == username, User.api_client_id == api_client_id)
+            .first()
+        )
+
+        if user is None:
+            raise OasstError("User not found", OasstErrorCode.USER_NOT_FOUND, HTTP_404_NOT_FOUND)
+
+        return user
+
     def lookup_client_user(self, client_user: protocol_schema.User, create_missing: bool = True) -> Optional[User]:
         if not client_user:
             return None

oasst-shared/oasst_shared/exceptions/oasst_api_error.py

@@ -9,7 +9,7 @@ class OasstErrorCode(IntEnum):
     Ranges:
          0-1000: general errors
       1000-2000: tasks endpoint
-      2000-3000: prompt_repository
+      2000-3000: prompt_repository, task_repository, user_repository
       3000-4000: external resources
     """
 
@@ -45,6 +45,7 @@ class OasstErrorCode(IntEnum):
     TASK_NOT_ACK = 2104
     TASK_ALREADY_DONE = 2105
     TASK_NOT_COLLECTIVE = 2106
+    USER_NOT_FOUND = 2200
 
     # 3000-4000: external resources
     HUGGINGFACE_API_ERROR = 3001