fastapi-sqlalchemy-asyncpg/app/exception_handlers.py
2025-08-23 20:04:23 +02:00

79 lines
2.5 KiB
Python

import orjson
from fastapi import FastAPI, Request
from fastapi.responses import JSONResponse
from rotoger import AppStructLogger
from sqlalchemy.exc import SQLAlchemyError
from fastapi.exceptions import ResponseValidationError
logger = AppStructLogger().get_logger()
#TODO: add reasoning for this in readme plus higligh using re-raise in db session
async def sqlalchemy_exception_handler(
request: Request, exc: SQLAlchemyError
) -> JSONResponse:
request_path = request.url.path
try:
raw_body = await request.body()
request_body = orjson.loads(raw_body) if raw_body else None
except orjson.JSONDecodeError:
request_body = None
await logger.aerror(
"Database error occurred",
sql_error=repr(exc),
request_url=request_path,
request_body=request_body,
)
return JSONResponse(
status_code=500,
content={"message": "A database error occurred. Please try again later."},
)
async def response_validation_exception_handler(
request: Request, exc: ResponseValidationError
) -> JSONResponse:
request_path = request.url.path
try:
raw_body = await request.body()
request_body = orjson.loads(raw_body) if raw_body else None
except orjson.JSONDecodeError:
request_body = None
errors = exc.errors()
# Check if this is a None/null response case
is_none_response = False
for error in errors:
# Check for null input pattern
if error.get("input") is None and "valid dictionary" in error.get("msg", ""):
is_none_response = True
break
await logger.aerror(
"Response validation error occurred",
validation_errors=errors,
request_url=request_path,
request_body=request_body,
is_none_response=is_none_response,
)
if is_none_response:
# Return 404 when response is None (resource not found)
return JSONResponse(
status_code=404,
content={"no_response": "The requested resource was not found"},
)
else:
# Return 422 when response exists but doesn't match expected format
return JSONResponse(
status_code=422,
content={"response_format_error": errors},
)
def register_exception_handlers(app: FastAPI) -> None:
"""Register all exception handlers with the FastAPI app."""
app.add_exception_handler(SQLAlchemyError, sqlalchemy_exception_handler)
app.add_exception_handler(ResponseValidationError, response_validation_exception_handler)