axios使用API

 背景：请求失败后，因跨域引起的不能传递statusCode问题，通过设置前后台选项解决，这里先总结一下axios的使用

一、安装与配置：

安装：

npm install axios

axios使用API:

1.默认使用的是get请求：

// Send a GET request (default method)
axios('/user/12345');

2.常用2种请求方式：

// GET ：获取图片
axios({
  method:'get',
  url:'http://bit.ly/2mTM3nY',
  responseType:'stream'
})
  .then(function (response) {
    response.data.pipe(fs.createWriteStream('ada_lovelace.jpg'))
  });

// Send a POST request
axios({
  method: 'post',
  url: '/user/12345',
  data: {
    firstName: 'Fred',
    lastName: 'Flintstone'
  }
});

3.自定义配置axios：

// 全局more设置
axios.defaults.baseURL = 'https://api.example.com';
axios.defaults.headers.common['Authorization'] = AUTH_TOKEN;
axios.defaults.headers.post['Content-Type'] = 'application/x-www-form-urlencoded';
//自定义设置
const instance = axios.create({
  baseURL: 'https://some-domain.com/api/',
  timeout: 1000,
  headers: {'X-Custom-Header': 'foobar'}
});

// 全局与个别请求设置
instance.defaults.timeout = 2500;

instance.get('/longRequest', {
  timeout: 5000
});

// 设置token
const CancelToken = axios.CancelToken;
const source = CancelToken.source();

axios.get('/user/12345', {
  cancelToken: source.token
}).catch(function (thrown) {
  if (axios.isCancel(thrown)) {
    console.log('Request canceled', thrown.message);
  } else {
    // handle error
  }
});

axios.post('/user/12345', {
  name: 'new name'
}, {
  cancelToken: source.token
})

// cancel the request (the message parameter is optional)
source.cancel('Operation canceled by the user.');

// 自定义取消token
const CancelToken = axios.CancelToken;
let cancel;

axios.get('/user/12345', {
  cancelToken: new CancelToken(function executor(c) {
    // An executor function receives a cancel function as a parameter
    cancel = c;
  })
});

// cancel the request
cancel();

4.请求配置：

{
  url: '/user',
  method: 'get', // default
  baseURL: 'https://some-domain.com/api/',
  transformRequest: [function (data, headers) {
    return data;
  }],
  transformResponse: [function (data) {
    return data;
  }],
  headers: {'X-Requested-With': 'XMLHttpRequest'},
  params: {
    ID: 12345
  },
  paramsSerializer: function (params) {
    return Qs.stringify(params, {arrayFormat: 'brackets'})
  },
  data: {
    firstName: 'Fred'
  },
  // 设置请求超时.
  timeout: 1000, // default is `0` (no timeout)
  // 【是否使用凭证】
  withCredentials: false, // default
  adapter: function (config) {
    /* ... */
  },
  auth: {
    username: 'janedoe',
    password: 's00pers3cret'
  },
  responseType: 'json', // default
  responseEncoding: 'utf8', // default
  xsrfCookieName: 'XSRF-TOKEN', // default
  xsrfHeaderName: 'X-XSRF-TOKEN', // default
  onUploadProgress: function (progressEvent) {
    // Do whatever you want with the native progress event
  },
  onDownloadProgress: function (progressEvent) {
    // Do whatever you want with the native progress event
  },
  maxContentLength: 2000,
  validateStatus: function (status) {
    return status >= 200 && status < 300; // default
  },
  maxRedirects: 5, // default
  socketPath: null, // default
  httpAgent: new http.Agent({ keepAlive: true }),
  httpsAgent: new https.Agent({ keepAlive: true }),
  proxy: {
    host: '127.0.0.1',
    port: 9000,
    auth: {
      username: 'mikeymike',
      password: 'rapunz3l'
    }
  },
  cancelToken: new CancelToken(function (cancel) {
  })
}

5.返回配置：

{
  // `data` is the response that was provided by the server
  data: {},

  // `status` is the HTTP status code from the server response
  status: 200,

  // `statusText` is the HTTP status message from the server response
  statusText: 'OK',

  // `headers` the headers that the server responded with
  // All header names are lower cased
  headers: {},

  // `config` is the config that was provided to `axios` for the request
  config: {},

  // `request` is the request that generated this response
  request: {}
}

6.拦截操作：返回正确后操作，返回错误操作

axios.get('/user/12345')
  .then(function (response) {
    console.log(response.data);
    console.log(response.status);
    console.log(response.statusText);
    console.log(response.headers);
    console.log(response.config);
  });

axios.get('/user/12345')
  .catch(function (error) {
    if (error.response) {
      // The request was made and the server responded with a status code
      // that falls out of the range of 2xx
      console.log(error.response.data);
      console.log(error.response.status);
      console.log(error.response.headers);
    } else if (error.request) {
      // The request was made but no response was received
      // `error.request` is an instance of XMLHttpRequest in the browser and an instance of
      // http.ClientRequest in node.js
      console.log(error.request);
    } else {
      // Something happened in setting up the request that triggered an Error
      console.log('Error', error.message);
    }
    console.log(error.config);
  });

在main.js导入:

// 引入axios，并加到原型链中
import axios from 'axios';
Vue.prototype.$axios = axios;
import QS from 'qs'
Vue.prototype.qs = QS;

设置代理解决跨域：

import axios from 'axios'
import qs from 'qs'

axios.defaults.timeout = 5000;                        //响应时间
axios.defaults.headers.post['Content-Type'] = 'application/x-www-form-urlencoded;charset=UTF-8';        //配置请求头
axios.defaults.baseURL = '';   //配置接口地址

//POST传参序列化(添加请求拦截器)
axios.interceptors.request.use((config) => {
    //在发送请求之前做某件事
    if(config.method  === 'post'){
        config.data = qs.stringify(config.data);
    }
    return config;
},(error) =>{
    console.log('错误的传参')
    return Promise.reject(error);
});

//返回状态判断(添加响应拦截器)
axios.interceptors.response.use((res) =>{
    //对响应数据做些事
    if(!res.data.success){
        return Promise.resolve(res);
    }
    return res;
}, (error) => {
    console.log('网络异常')
    return Promise.reject(error);
});

//返回一个Promise(发送post请求)
export function fetchPost(url, params) {
    return new Promise((resolve, reject) => {
        axios.post(url, params)
            .then(response => {
                resolve(response);
            }, err => {
                reject(err);
            })
            .catch((error) => {
                reject(error)
            })
    })
}
////返回一个Promise(发送get请求)
export function fetchGet(url, param) {
    return new Promise((resolve, reject) => {
        axios.get(url, {params: param})
            .then(response => {
                resolve(response)
            }, err => {
                reject(err)
            })
            .catch((error) => {
                reject(error)
            })
    })
}
export default {
    fetchPost,
    fetchGet,
}

vue-cli 3.0的在 package.json  同级目录新建一个 vue.config.js 文件，加入下面代码，其他版本找到配置文件的devServer加入代码，如下：

module.exports = {
    //axios域代理，解决axios跨域问题
    baseUrl: '/',
    devServer: {
        proxy: {
            '': {
                target: 'http://192.168.0.108:8090',
                changeOrigin: true,
                ws: true,
                pathRewrite: {

                }
            }
        }
    }
}

实例：get/post

const axios = require('axios');

// 1.在url中携带
axios.get('/user?ID=12345') // get
  .then(function (response) {
    // handle success
    console.log(response);
  })
  .catch(function (error) {
    // handle error
    console.log(error);
  })
  .then(function () {
    // always executed
  });

// 2.通过对象params传递
axios.get('/user', {
    params: {
      ID: 12345
    }
  })
  .then(function (response) {
    console.log(response);
  })
  .catch(function (error) {
    console.log(error);
  })
  .then(function () {
    // always executed
  });  

// 3.异步请求
async function getUser() {
  try {
    const response = await axios.get('/user?ID=12345');
    console.log(response);
  } catch (error) {
    console.error(error);
  }
}

axios.post('/user', { // post
    firstName: 'Fred',
    lastName: 'Flintstone'
  })
  .then(function (response) {
    console.log(response);
  })
  .catch(function (error) {
    console.log(error);
  });

执行多个并发请求：

function getUserAccount() {
  return axios.get('/user/12345');
}

function getUserPermissions() {
  return axios.get('/user/12345/permissions');
}

axios.all([getUserAccount(), getUserPermissions()])
  .then(axios.spread(function (acct, perms) {
    // Both requests are now complete
  }));

使用封装请求https.js，简化操作：

import https from '../https.js' 　　// 注意用自己的路径

loginPost: function () {
    let params ={'username': 'admin', 'password': 'admin123'}
    https.fetchPost('/login',params ).then((data) => {
        // console.log('fetchPost',data)
    }).catch(err=>{
            console.log(err)
        }
    )
},
indexPost2:function (date) {
  // ...
},

补：默认情况下，axios将JavaScript对象序列化为JSON。要以application/x-www-form-urlencoded格式

1.Json对象转字符串：用JSON.stringify()将对象a变成了字符串c，那么我就可以用JSON.parse()将字符串c还原成对象a

let arr = [1,2,3];
JSON.stringify(arr);//'[1,2,3]'
typeof JSON.stringify(arr);//string

let string = '[1,2,3]';
console.log(JSON.parse(string))//[1,2,3]
console.log(typeof JSON.parse(string))//object

作用1：判断是否包含、相等、

//判断数组是否包含某对象
let data = [
    {name:'echo'},
    {name:'听风是风'},
    {name:'天子笑'},
    ],
    val = {name:'天子笑'};
JSON.stringify(data).indexOf(JSON.stringify(val)) !== -1;//true

//判断两数组/对象是否相等
let a = [1,2,3],
    b = [1,2,3];
JSON.stringify(a) === JSON.stringify(b);//true

作用2：本地数据缓存

//存
function setLocalStorage(key,val){
    window.localStorage.setItem(key,JSON.stringify(val));
};
//取
function getLocalStorage(key){
    let val = JSON.parse(window.localStorage.getItem(key));
    return val;
};
//测试
setLocalStorage('demo',[1,2,3]);
let  a = getLocalStorage('demo');//[1,2,3]

作用3：深拷贝

//深拷贝
function deepClone(data) {
    let _data = JSON.stringify(data),
        dataClone = JSON.parse(_data);
    return dataClone;
};
//测试
let arr = [1,2,3],
    _arr = deepClone(arr);
arr[0] = 2;
console.log(arr,_arr)//[2,2,3]  [1,2,3]

区分：toString()虽然可以将数组转为字符串，但并不能对{name:'天子笑'}这类对象实现你想要的操作，它的受众更多是数字。

2.node,js：

const querystring = require('querystring'); // node.js内
axios.post('http://something.com/', querystring.stringify({ foo: 'bar' }));

3.使用“qs”工具转换：

// const qs = require('qs');
import qs from 'qs'; // 推荐使用es6

axios.post('/foo', qs.stringify({ 'bar': 123 })); // 方式1

const data = { 'bar': 123 };
const options = {
  method: 'POST',
  headers: { 'content-type': 'application/x-www-form-urlencoded' },
  data: qs.stringify(data),
  url,
};

axios(options); // 方式2