In FastAPI, HTTPExceptions are used to represent specific HTTP status codes and error messages. By creating a custom exception handler, you can customize the way these exceptions are handled and provide more informative responses to clients.
Creating a Custom Exception Handler
Create a Function:
Python
from fastapi import FastAPI, Request, Response, status
app = FastAPI()
@app.exception_handler(HTTPException)
async def http_exception_handler(request: Request, exc: HTTPException) -> Response:
# Custom exception handling logic
return Response(content=”An error occurred”, status_code=exc.status_code)
Customize the Response:
You can customize the response content, status code, or headers based on the specific exception. For example:
Python
@app.exception_handler(HTTPException)
async def http_exception_handler(request: Request, exc: HTTPException) -> Response:
if exc.status_code == 404:
return Response(content=”Resource not found”, status_code=404)
else:
return Response(content=”An error occurred”, status_code=exc.status_code)
Handling Specific Exceptions
You can create separate exception handlers for specific types of HTTPExceptions:
Python
@app.exception_handler(HTTPException)
async def http_exception_handler(request: Request, exc: HTTPException) -> Response:
if isinstance(exc, HTTPException):
if exc.status_code == 404:
# Handle 404 exceptions
elif exc.status_code == 401:
# Handle 401 exceptions
else:
# Handle other exceptions
else:
# Handle other types of exceptions
By creating custom exception handlers, you can provide a more planned and informative error response to your clients, improving the overall user experience of your FastAPI application.
