Flask之Response

def full_dispatch_request(self) -> Response:
       self.try_trigger_before_first_request_functions()
       try:
           request_started.send(self)
           rv = self.preprocess_request()
           if rv is None:
               # rv 是视图函数的返回结果
               rv = self.dispatch_request()
       except Exception as e:
           rv = self.handle_user_exception(e)
       return self.finalize_request(rv)
​

   def finalize_request(
       self,
       rv: t.Union[ResponseReturnValue, HTTPException],
       from_error_handler: bool = False,
  ) -> Response:
       response = self.make_response(rv)
      ...

def make_response(self, rv: ResponseReturnValue) -> Response:
      status = headers = None
      if isinstance(rv, tuple):
          len_rv = len(rv)
          if len_rv == 3:
              rv, status, headers = rv
          elif len_rv == 2:
              if isinstance(rv[1], (Headers, dict, tuple, list)):
                  rv, headers = rv
              else:
                  rv, status = rv
          else:
              raise TypeError(
                  "The view function did not return a valid response tuple."
                  " The tuple must have the form (body, status, headers),"
                  " (body, status), or (body, headers)."
      if rv is None:
          raise TypeError(
              f"The view function for {request.endpoint!r} did not"
              " return a valid response. The function either returned"
              " None or ended without a return statement."
      if not isinstance(rv, self.response_class):
          if isinstance(rv, (str, bytes, bytearray)):
              rv = self.response_class(rv, status=status, headers=headers)
              status = headers = None
          elif isinstance(rv, dict):
              rv = jsonify(rv)
          elif isinstance(rv, BaseResponse) or callable(rv):
                  rv = self.response_class.force_type(rv, request.environ)
              except TypeError as e:
                  raise TypeError(
                      f"{e}\nThe view function did not return a valid"
                      " response. The return type must be a string,"
                      " dict, tuple, Response instance, or WSGI"
                      f" callable, but it was a {type(rv).__name__}."
                  ).with_traceback(sys.exc_info()[2]) from None
          else:
              raise TypeError(
                  "The view function did not return a valid"
                  " response. The return type must be a string,"
                  " dict, tuple, Response instance, or WSGI"
                  f" callable, but it was a {type(rv).__name__}."
      rv = t.cast(Response, rv)
      # prefer the status if it was provided
      if status is not None:
          if isinstance(status, (str, bytes, bytearray)):
              rv.status = status # type: ignore
          else:
              rv.status_code = status
      # extend existing headers with provided headers