python - Flask-restful - 自定义错误处理

Question

我想为 Flask-restful API 定义自定义错误处理。

文档中建议的方法 here就是做以下事情:

errors = {
    'UserAlreadyExistsError': {
        'message': "A user with that username already exists.",
        'status': 409,
    },
    'ResourceDoesNotExist': {
        'message': "A resource with that ID no longer exists.",
        'status': 410,
        'extra': "Any extra information you want.",
    },
}
app = Flask(__name__)
api = flask_restful.Api(app, errors=errors)

现在我发现这种格式非常有吸引力，但是当发生异常时我需要指定更多参数。比如遇到ResourceDoesNotExist，想指定什么id不存在。

目前，我正在做以下事情:

app = Flask(__name__)
api = flask_restful.Api(app)


class APIException(Exception):
    def __init__(self, code, message):
        self._code = code
        self._message = message

    @property
    def code(self):
        return self._code

    @property
    def message(self):
        return self._message

    def __str__(self):
        return self.__class__.__name__ + ': ' + self.message


class ResourceDoesNotExist(APIException):
    """Custom exception when resource is not found."""
    def __init__(self, model_name, id):
        message = 'Resource {} {} not found'.format(model_name.title(), id)
        super(ResourceNotFound, self).__init__(404, message)


class MyResource(Resource):
    def get(self, id):
        try:
            model = MyModel.get(id)
            if not model:
               raise ResourceNotFound(MyModel.__name__, id)
        except APIException as e:
            abort(e.code, str(e))

当使用不存在的 id 调用时，MyResource 将返回以下 JSON:

{'message': 'ResourceDoesNotExist: Resource MyModel 5 not found'}

这工作正常，但我想改为使用 Flask-restful 错误处理。

Answer 1

根据 the docs

Flask-RESTful will call the handle_error() function on any 400 or 500 error that happens on a Flask-RESTful route, and leave other routes alone.

您可以利用它来实现所需的功能。唯一的缺点是必须创建自定义 Api。

class CustomApi(flask_restful.Api):

    def handle_error(self, e):
        flask_restful.abort(e.code, str(e))

如果您保留定义的异常，当异常发生时，您将获得与

相同的行为

class MyResource(Resource):
    def get(self, id):
        try:
            model = MyModel.get(id)
            if not model:
               raise ResourceNotFound(MyModel.__name__, id)
        except APIException as e:
            abort(e.code, str(e))