redux-saga catch无法加载资源：net :: ERR_CONNECTION_REFUSED

Question

我使用axios拨打后端服务器的电话。 借助redux-saga我可以轻松控制服务器的副作用。

import {call, put, takeEvery} from "redux-saga/effects";
import {REQUEST_FAILED, REQUEST_SUCCESS, ROOT_URL, SUBMIT_USERNAME_PASSWORD} from "../../constants";
import axios from "axios/index";

const shootApiTokenAuth = (values) => {
  const {username, password} = values;
  return axios.post(`${ROOT_URL}/api-token-auth/`,
    {username, password});
};

function* shootAPI(action) {
  try {
    const res = yield call(shootApiTokenAuth, action.payload);
    const {history} = action.payload;
    yield put({
      type: REQUEST_SUCCESS,
      payload: res
    });
    history.push('/companies'); //push user to `/companies` page
  } catch (err) {
    yield put({
      type: REQUEST_FAILED,
      payload: err
    });
  }
}

export function* watchSubmitBtn() {
  yield takeEvery(SUBMIT_USERNAME_PASSWORD, shootAPI);
}

问题：后端服务器关闭时。 它不会向我返回任何错误。 并且浏览器将引发错误Failed to load resource: net::ERR_CONNECTION_REFUSED

我已经看到了有关回调方法的先前答案，但我更喜欢axios和redux-saga不callback

我尝试过console.log(err) 。 而且我仍在搜索它们以获取错误消息并将其与服务器响应错误区分开的方法。

Error: Network Error
    at createError (createError.js:16)
    at XMLHttpRequest.handleError (xhr.js:87)

题：
如何使用axios和redux-saga捕获err ？

Answer 1

如果将try / catch放在axios请求本身周围，则可以更详细地了解原因。

https://gist.github.com/fgilio/230ccd514e9381fafa51608fcf137253

您可能希望拥有一个自定义错误格式和一个错误减少程序，以处理各种不同类型的错误。 例如，如果收到响应，则可以将其解析并将其添加到错误中，否则您将知道将使用“糟糕”页面或类似内容来处理应用程序级错误。

Answer 2

case REQUEST_FAILED:
      //Probably it can failed by 2 reason
      //1. 404 from server
      //2. network is down
      if (action.payload.response === undefined) {
        return {
          token: undefined,
          message: 'Network is down',
          isAuthenticated: false,
          statusCode: 406
        }
      } else {
        const tmp = action.payload.response.request.response;
        const tmp2 = JSON.parse(tmp);
        return {
          token: undefined,
          message: tmp2.non_field_errors[0],
          isAuthenticated: false,
          statusCode: action.payload.response.status
        };
      }