Customize

Response

Normally, when pre-request finds that the user input parameter does not meet the requirements, it will directly interrupt the processing and return the discovered problem to the requester. The default JSON type of response format provided by pre-request is as follows:

{
    "respCode": 400,
    "respMsg": "Error Message",
    "result": {}
}

In some scenarios, we need different response formats. Pre-request provides the ability to customize the response. You need to implement a class that inherits from BaseResponse to implement your own data response processing.

from flask import make_response
from pre_request import BaseResponse

class CustomResponse(BaseResponse):

  def make_response(
          cls,
          error: "ParamsValueError",
          fuzzy: bool = False,
          formatter: t.Optional[t.Callable] = None
  ):
      result = {
          "code": 900,
          "rst": {}
      }

      from flask import make_response  # pylint: disable=import-outside-toplevel
      response = make_response(json.dumps(result))
      response.headers["Content-Type"] = "application/json; charset=utf-8"
      return response

from pre_request import pre

pre.add_response(CusResponse)

Formatter

If you feel that the custom response class is too complicated, we also provide the function of a custom formatting function. The pre-request will give priority to calling your custom function to generate a response string.

def custom_formatter(error: ParamsValueError):
  """ 自定义结果格式化函数
  """
  return {
      "code": 411,
      "msg": "hello",
      "sss": "tt",
  }

from pre_request import pre
pre.add_formatter(custom_formatter)

Filter

pre-request 提供了丰富的过滤器插件。但是面对各式各样的业务需求，您可能也觉得pre-request无法满足您。因此pre-request 提供了自定义过滤器功能，让您可以更加自身的业务需求去扩展pre-request框架。

通常情况下，自定义的过滤器需要继承自 BaseFilter 类。

from pre_request import BaseFilter

class CustomFilter(BaseFilter):

    def filter_required(self):
        """ 检查当前过滤式，是否必须要执行
        """
        return True

    def __call__(self, *args, **kwargs):
        """ 自定义过滤器时需要实现的主要功能
        """
        super().__call__()

        if self.rule.direct_type == int and self.key == "number" and self.value != 10086:
            raise ParamsValueError(message="any error messages you want")

        return self.value + 1

如上所示，您至少需要实现 filter_required 和 __call__ 方法。在运行您的过滤器之前，先调用 filter_required 方法判断当前过滤器是否需要被执行，然后再调用 __call__ 方法运行过滤器。

最后，您需要在项目初始化时将自定义过滤器安装到pre-request中

from pre_request import pre

pre.add_filter(CustomFilter)

Store Key

By default, pre-request stores formatted input parameters in ~flask.g.params and the params parameter of the current function。 You can set the store_key parameter of the pre-request to change the storage key of the parameter.

from pre_request import pre
pre.store_key = "pre_params"