rewrite error handlers

server/core.py

@@ -1,12 +1,24 @@
+from __future__ import annotations
+
 import asyncio
 from contextlib import asynccontextmanager
-from typing import Any, Generator, Optional, Self
+from typing import TYPE_CHECKING, Any, Generator, Optional, Self
 
 import asyncpg
 from fastapi import Depends, FastAPI, status
+from fastapi.exceptions import HTTPException, RequestValidationError
 from fastapi.openapi.utils import get_openapi
-from fastapi.responses import ORJSONResponse
+from fastapi.responses import ORJSONResponse, Response
+from fastapi.utils import is_body_allowed_for_status_code
 from utils.config import KanaeConfig
+from utils.errors import (
+    HTTPExceptionMessage,
+    RequestValidationErrorDetails,
+    RequestValidationErrorMessage,
+)
+
+if TYPE_CHECKING:
+    from utils.request import RouteRequest
 
 __title__ = "Kanae"
 __description__ = """
@@ -36,12 +48,50 @@ def __init__(
             version=__version__,
             dependencies=[Depends(self.get_db)],
             default_response_class=ORJSONResponse,
+            responses={400: {"model": RequestValidationErrorMessage}},
             loop=self.loop,
             redoc_url="/docs",
             docs_url=None,
             lifespan=self.lifespan,
         )
         self.config = config
+        self.add_exception_handler(
+            HTTPException,
+            self.http_exception_handler,  # type: ignore
+        )
+        self.add_exception_handler(
+            RequestValidationError,
+            self.request_validation_error_handler,  # type: ignore
+        )
+
+    ### Exception Handlers
+
+    async def http_exception_handler(
+        self, request: RouteRequest, exc: HTTPException
+    ) -> Response:
+        headers = getattr(exc, "headers", None)
+        if not is_body_allowed_for_status_code(exc.status_code):
+            return Response(status_code=exc.status_code, headers=headers)
+        message = HTTPExceptionMessage(detail=exc.detail)
+        return ORJSONResponse(
+            content=message.model_dump(), status_code=exc.status_code, headers=headers
+        )
+
+    async def request_validation_error_handler(
+        self, request: RouteRequest, exc: RequestValidationError
+    ) -> ORJSONResponse:
+        message = RequestValidationErrorMessage(
+            errors=[
+                RequestValidationErrorDetails(
+                    detail=exception["msg"], context=exception["ctx"]["error"]
+                )
+                for exception in exc.errors()
+            ]
+        )
+
+        return ORJSONResponse(
+            content=message.model_dump(), status_code=status.HTTP_400_BAD_REQUEST
+        )
 
     ### Server-related utilities
 

server/utils/errors.py

@@ -12,3 +12,18 @@ class NotFoundException(HTTPException):
     def __init__(self, detail: str = HTTP_404_DETAIL):
         self.status_code = 404
         self.detail = detail
+
+
+class RequestValidationErrorDetails(BaseModel, frozen=True):
+    detail: str
+    context: str
+
+
+class RequestValidationErrorMessage(BaseModel, frozen=True):
+    result: str = "error"
+    errors: list[RequestValidationErrorDetails]
+
+
+class HTTPExceptionMessage(BaseModel, frozen=True):
+    result: str = "error"
+    detail: str