[FEATURE] Overriding Validation Error default schema used in API document

In my app, I customize RequestValidationError response using exception_handler as below:

@app.exception_handler(RequestValidationError)
async def request_validation_exception_handler(_request: Request, exc: RequestValidationError) -> JSONResponse:
    data = {
        "error": {
            "code": Error.REQUEST_VALIDATION_ERROR.value,
            "message": "Intput data is invalid.",
            "detail": exc.errors(),
        }
    }
    return JSONResponse(content=data, status_code=HTTP_422_UNPROCESSABLE_ENTITY)

The generated API document includes automatically the default Validation Error schema, HTTPValidationError, in all POST or PUT path operations. So I need to add my responses definition one by one.

responses = {
    422: {'model': APIErrorResponse, 'description': 'Validation Error'}
}


@router.post("/", responses={**responses})
async def create_user(user_in: UserCreate):
    """Create new user.
    """

@router.put("/", responses={**responses})
async def update_user(user_in: UserUpdate):
    """Update user.
    """

It would be useful if we are able to override the Validation Error default schema used in API document.

[otsuka]

@tiangolo Thanks a lot!

Using the responses parameter in include_router() method, the API documentation now reflects the custom validation error schema.

[tiangolo]

You can set the responses parameter at the router level: https://fastapi.tiangolo.com/tutorial/bigger-applications/