Simple view where control flow is determined by exception

view_with_exception.py

def get_user():
    # Get request token from request object
    user = get_user_by_token(token)
    if user:
        return user
    raise HTTPException(status=401)


def check_and_create_new_bucket(name, user):
    if bucket_exists(name, user):
        raise HTTPException(status=400, data={'name': 'Already exists'})
    return create_bucket(name, user)


class TodoBucketListAPIView(BaseMethodView):
    def post(self):
        try:
            user = get_user()
            validator = NewBucketValidator(request.POST)
            validator.validate(raise_exception=True)
            bucket = check_and_create_new_bucket(validator.name, user=user)
            resp_data = format_new_bucket(bucket)
            return make_response(data=resp_data, status=201)
        except HTTPException as e:
            return make_response(status=e.status, data=e.data)
        except ValidationError as e:
            return make_response(status=400, data=e.errors)