在學(xué)習(xí)了之前的路由vue-router和狀態(tài)管理vuex之后妆够，就應(yīng)該是網(wǎng)絡(luò)交互了炭臭。就學(xué)習(xí)尤大推薦的axios了晤郑。剛好本人對(duì)網(wǎng)絡(luò)請(qǐng)求這塊除了會(huì)get敌呈、put、post和delete這四個(gè)方法之外知之甚少造寝，剛好補(bǔ)全上磕洪。

注意：Vue官方推薦的網(wǎng)絡(luò)通信庫(kù)不再是vue-resource了，推薦使用axios诫龙。

image.png

axios安裝

npm:

$ npm install axios

bower:

$ bower install axios

Using cdn:

<script src="https://unpkg.com/axios/dist/axios.min.js"></script>

基本使用方法

GET請(qǐng)求

// Make a request for a user with a given ID
axios.get('/user?ID=12345')
  .then(function (response) {
    console.log(response);
  })
  .catch(function (error) {
    console.log(error);
  });

// Optionally the request above could also be done as
axios.get('/user', {
    params: {
      ID: 12345
    }
  })
  .then(function (response) {
    console.log(response);
  })
  .catch(function (error) {
    console.log(error);
  });

POST請(qǐng)求

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

同時(shí)執(zhí)行多個(gè)請(qǐng)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
  }));

其實(shí)和其他的ajax庫(kù)一樣析显，基本用法都是差不多的。大家一看就知道怎么用签赃。

axios API

可以直接通過(guò)config來(lái)完成請(qǐng)求
axios(config)

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

axios(url, [config])

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

請(qǐng)求方法別名

下面是axios支持的所有請(qǐng)求方法別名谷异，便于各種請(qǐng)求。
注：[...]中的數(shù)據(jù)表示可以為空锦聊。url是ajax請(qǐng)求地址歹嘹；data是提交的數(shù)據(jù)對(duì)象；config是配置對(duì)象括丁，所有ajax配置都可以在config中實(shí)現(xiàn)荞下。

• axios.request(config)
• axios.get(url[, config])
• axios.delete(url[, config])
• axios.head(url[, config])
• axios.post(url[, data[, config]])
• axios.put(url[, data[, config]])
• axios.patch(url[, data[, config]])

并發(fā)性

下列接口用于處理并發(fā)請(qǐng)求(同時(shí)處理多個(gè)多個(gè)request)

• axios.all(iterable)
• axios.spread(callback)

axios實(shí)例

可以用自定義的config創(chuàng)建一個(gè)axios實(shí)例
axios.create([config])

var instance = axios.create({
  baseURL: 'https://some-domain.com/api/',
  timeout: 1000,
  headers: {'X-Custom-Header': 'foobar'}
});

實(shí)例方法

下面是實(shí)例的所有可用方法，方法中的config會(huì)與axios實(shí)例中的config合并。（實(shí)例可以將一些通用的config先配置好）

• axios#request(config)
• axios#get(url, [config])
• axios#delete(url, [config])
• axios#head(url, [config])
• axios#post(url[, data[, config]])
• axios#put(url[, data[, config]])
• axios#patch(url[, data[, config]])

Config

重點(diǎn)來(lái)了尖昏，來(lái)看看Config仰税。
下面列出了config的所有配置項(xiàng)，其中之后url是必填的抽诉。當(dāng)method沒(méi)有指定方法陨簇，默認(rèn)為GET。

{
  // `url` is the server URL that will be used for the request
  // 用來(lái)向服務(wù)器發(fā)送請(qǐng)求的url
  url: '/user',

  // `method` is the request method to be used when making the request
 // 請(qǐng)求方法
  method: 'get', // default

  // `baseURL` will be prepended to `url` unless `url` is absolute.
  // It can be convenient to set `baseURL` for an instance of axios to pass relative URLs
  // to methods of that instance.
  // 假如`url`不是絕對(duì)路徑迹淌，那么向服務(wù)器發(fā)送請(qǐng)求的URL將是`baseURL + url`
  baseURL: 'https://some-domain.com/api/',

  // `transformRequest` allows changes to the request data before it is sent to the server
  // This is only applicable for request methods 'PUT', 'POST', and 'PATCH'
  // The last function in the array must return a string, an ArrayBuffer, or a Stream
  transformRequest: [function (data) {
    // Do whatever you want to transform the data

    return data;
  }],

  // `transformResponse` allows changes to the response data to be made before
  // it is passed to then/catch
  transformResponse: [function (data) {
    // Do whatever you want to transform the data

    return data;
  }],

  // `headers` are custom headers to be sent
  headers: {'X-Requested-With': 'XMLHttpRequest'},

  // `params` are the URL parameters to be sent with the request
  // Must be a plain object or a URLSearchParams object
  params: {
    ID: 12345
  },

  // `paramsSerializer` is an optional function in charge of serializing `params`
  // (e.g. https://www.npmjs.com/package/qs, http://api.jquery.com/jquery.param/)
  paramsSerializer: function(params) {
    return Qs.stringify(params, {arrayFormat: 'brackets'})
  },

  // `data` is the data to be sent as the request body
  // Only applicable for request methods 'PUT', 'POST', and 'PATCH'
  // When no `transformRequest` is set, must be of one of the following types:
  // - string, plain object, ArrayBuffer, ArrayBufferView, URLSearchParams
  // - Browser only: FormData, File, Blob
  // - Node only: Stream
  data: {
    firstName: 'Fred'
  },

  // `timeout` specifies the number of milliseconds before the request times out.
  // If the request takes longer than `timeout`, the request will be aborted.
  timeout: 1000,

  // `withCredentials` indicates whether or not cross-site Access-Control requests
  // should be made using credentials
  withCredentials: false, // default

  // `adapter` allows custom handling of requests which makes testing easier.
  // Return a promise and supply a valid response (see [response docs](#response-api)).
  adapter: function (config) {
    /* ... */
  },

  // `auth` indicates that HTTP Basic auth should be used, and supplies credentials.
  // This will set an `Authorization` header, overwriting any existing
  // `Authorization` custom headers you have set using `headers`.
  auth: {
    username: 'janedoe',
    password: 's00pers3cret'
  },

  // `responseType` indicates the type of data that the server will respond with
  // options are 'arraybuffer', 'blob', 'document', 'json', 'text', 'stream'
  responseType: 'json', // default

  // `xsrfCookieName` is the name of the cookie to use as a value for xsrf token
  xsrfCookieName: 'XSRF-TOKEN', // default

  // `xsrfHeaderName` is the name of the http header that carries the xsrf token value
  xsrfHeaderName: 'X-XSRF-TOKEN', // default

  // `onUploadProgress` allows handling of progress events for uploads
  onUploadProgress: function (progressEvent) {
    // Do whatever you want with the native progress event
  },

  // `onDownloadProgress` allows handling of progress events for downloads
  onDownloadProgress: function (progressEvent) {
    // Do whatever you want with the native progress event
  },

  // `maxContentLength` defines the max size of the http response content allowed
  maxContentLength: 2000,

  // `validateStatus` defines whether to resolve or reject the promise for a given
  // HTTP response status code. If `validateStatus` returns `true` (or is set to `null`
  // or `undefined`), the promise will be resolved; otherwise, the promise will be
  // rejected.
  validateStatus: function (status) {
    return status >= 200 && status < 300; // default
  },

  // `maxRedirects` defines the maximum number of redirects to follow in node.js.
  // If set to 0, no redirects will be followed.
  maxRedirects: 5, // default

  // `httpAgent` and `httpsAgent` define a custom agent to be used when performing http
  // and https requests, respectively, in node.js. This allows to configure options like
  // `keepAlive` that are not enabled by default.
  httpAgent: new http.Agent({ keepAlive: true }),
  httpsAgent: new https.Agent({ keepAlive: true }),

  // 'proxy' defines the hostname and port of the proxy server
  // `auth` indicates that HTTP Basic auth should be used to connect to the proxy, and supplies credentials.
  // This will set an `Proxy-Authorization` header, overwriting any existing `Proxy-Authorization` custom headers you have set using `headers`.
  proxy: {
    host: '127.0.0.1',
    port: 9000,
    auth: : {
      username: 'mikeymike',
      password: 'rapunz3l'
    }
  },

  // `cancelToken` specifies a cancel token that can be used to cancel the request
  // (see Cancellation section below for details)
  cancelToken: new CancelToken(function (cancel) {
  })
}

分析Config

配置參數(shù)很多河绽，我們一個(gè)一個(gè)來(lái)了解它們

• url —— 用來(lái)向服務(wù)器發(fā)送請(qǐng)求的url
• method —— 請(qǐng)求方法，默認(rèn)是GET方法
• baseURL —— 基礎(chǔ)URL路徑唉窃，假如url不是絕對(duì)路徑耙饰，如https://some-domain.com/api/v1/login?name=jack,那么向服務(wù)器發(fā)送請(qǐng)求的URL將會(huì)是baseURL + url。
• transformRequest —— transformRequest方法允許在請(qǐng)求發(fā)送到服務(wù)器之前修改該請(qǐng)求纹份，此方法只適用于PUT苟跪、POST和PATCH方法中。而且蔓涧，此方法最后必須返回一個(gè)string件已、ArrayBuffer或者Stream。
• transformResponse —— transformResponse方法允許在數(shù)據(jù)傳遞到then/catch之前修改response數(shù)據(jù)元暴。此方法最后也要返回?cái)?shù)據(jù)篷扩。
• headers —— 發(fā)送自定義Headers頭文件，頭文件中包含了http請(qǐng)求的各種信息茉盏。
• params —— params是發(fā)送請(qǐng)求的查詢參數(shù)對(duì)象鉴未，對(duì)象中的數(shù)據(jù)會(huì)被拼接成url?param1=value1&param2=value2。
• paramsSerializer —— params參數(shù)序列化器援岩。
• data —— data是在發(fā)送POST歼狼、PUT或者PATCH請(qǐng)求的數(shù)據(jù)對(duì)象。
• timeout —— 請(qǐng)求超時(shí)設(shè)置享怀，單位為毫秒
• withCredentials —— 表明是否有跨域請(qǐng)求需要用到證書
• adapter —— adapter允許用戶處理更易于測(cè)試的請(qǐng)求羽峰。返回一個(gè)Promise和一個(gè)有效的response
• auth —— auth表明提供憑證用于完成http的身份驗(yàn)證。這將會(huì)在headers中設(shè)置一個(gè)Authorization授權(quán)信息添瓷。自定義Authorization授權(quán)要設(shè)置在headers中梅屉。
• responseType —— 表示服務(wù)器將返回響應(yīng)的數(shù)據(jù)類型，有arraybuffer鳞贷、blob坯汤、document、json搀愧、text惰聂、stream這6個(gè)類型疆偿，默認(rèn)是json類似數(shù)據(jù)。
• xsrfCookieName —— 用作 xsrf token 值的 cookie 名稱
• xsrfHeaderName —— 帶有 xsrf token 值 http head 名稱
• onUploadProgress —— 允許在上傳過(guò)程中的做一些操作
• onDownloadProgress —— 允許在下載過(guò)程中的做一些操作
• maxContentLength —— 定義了接收到的response響應(yīng)數(shù)據(jù)的最大長(zhǎng)度搓幌。
• validateStatus —— validateStatus定義了根據(jù)HTTP響應(yīng)狀態(tài)碼決定是否接收或拒絕獲取到的promise杆故。如果 validateStatus 返回 true (或設(shè)置為 null 或 undefined ),promise將被接收;否則,promise將被拒絕。
• maxRedirects —— maxRedirects定義了在node.js中redirect的最大值溉愁，如果設(shè)置為0处铛，則沒(méi)有redirect。
• httpAgent —— 定義在使用http請(qǐng)求時(shí)的代理
• httpsAgent —— 定義在使用https請(qǐng)求時(shí)的代理
• proxy —— proxy定義代理服務(wù)器的主機(jī)名和端口拐揭，auth
• cancelToken —— cancelToken定義一個(gè) cancel token 用于取消請(qǐng)求

Response

當(dāng)我們ajax獲取數(shù)據(jù)成功后會(huì)返回一個(gè)response對(duì)象撤蟆，它包含了以下內(nèi)容：

{
  // `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
  headers: {},

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

response是通過(guò)promise的then方法來(lái)獲取,具體使用方法如下：

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);
  });

相對(duì)的，我們有時(shí)也會(huì)出現(xiàn)ajax報(bào)錯(cuò)堂污，此時(shí)就會(huì)到我們的catch中去捕獲異常error對(duì)象家肯。

為何放棄vue-resource

尤大的原話：

最近團(tuán)隊(duì)討論了一下，Ajax 本身跟 Vue 并沒(méi)有什么需要特別整合的地方盟猖，使用 fetch polyfill 或是 axios息楔、superagent 等等都可以起到同等的效果，vue-resource 提供的價(jià)值和其維護(hù)成本相比并不劃算扒披，所以決定在不久以后取消對(duì) vue-resource 的官方推薦。已有的用戶可以繼續(xù)使用圃泡，但以后不再把 vue-resource 作為官方的 ajax 方案碟案。
知乎鏈接：https://www.zhihu.com/question/52418455/answer/130535375