Vue.js教程之axios与网络传输的学习实践

前言

在学习了之前的路由vue-router和状态管理vuex之后,就应该是网络交互了。就学习尤大推荐的axios了。刚好本人对网络请求这块除了会get、put、post和delete这四个方法之外知之甚少,刚好补全上。

注意:Vue官方推荐的网络通信库不再是vue-resource了,推荐使用axios

为何放弃vue-resource?

尤大的原话:

最近团队讨论了一下,Ajax 本身跟 Vue 并没有什么需要特别整合的地方,使用 fetch polyfill 或是 axios、superagent 等等都可以起到同等的效果,vue-resource 提供的价值和其维护成本相比并不划算,所以决定在不久以后取消对 vue-resource 的官方推荐。已有的用户可以继续使用,但以后不再把 vue-resource 作为官方的 ajax 方案。

axios安装

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请求

// 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请求

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

同时执行多个请求

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
 }));

其实和其他的ajax库一样,基本用法都是差不多的。大家一看就知道怎么用。

axios API

可以直接通过config来完成请求

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');

请求方法别名

下面是axios支持的所有请求方法别名,便于各种请求。

注: [...]中的数据表示可以为空。url是ajax请求地址;data是提交的数据对象;config是配置对象,所有ajax配置都可以在config中实现。

  • 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]])

并发性

下列接口用于处理并发请求(同时处理多个多个request)

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

axios实例

可以用自定义的config创建一个axios实例

axios.create([config])

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

实例方法

下面是实例的所有可用方法,方法中的config会与axios实例中的config合并。(实例可以将一些通用的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

重点来了,来看看Config。

下面列出了config的所有配置项,其中之后url是必填的。当method没有指定方法,默认为GET。

{
 // `url` is the server URL that will be used for the request
 // 用来向服务器发送请求的url
 url: '/user',

 // `method` is the request method to be used when making the request
 // 请求方法
 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`不是绝对路径,那么向服务器发送请求的URL将是`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

配置参数很多,我们一个一个来了解它们

  • url —— 用来向服务器发送请求的url
  • method —— 请求方法,默认是GET方法
  • baseURL —— 基础URL路径,假如url不是绝对路径,如https://some-domain.com/api/v1/login?name=jack,那么向服务器发送请求的URL将会是baseURL + url。
  • transformRequest —— transformRequest方法允许在请求发送到服务器之前修改该请求,此方法只适用于PUT、POST和PATCH方法中。而且,此方法最后必须返回一个string、ArrayBuffer或者Stream。
  • transformResponse —— transformResponse方法允许在数据传递到then/catch之前修改response数据。此方法最后也要返回数据。
  • headers —— 发送自定义Headers头文件,头文件中包含了http请求的各种信息。
  • params —— params是发送请求的查询参数对象,对象中的数据会被拼接成url?param1=value1&param2=value2。
  • paramsSerializer —— params参数序列化器。
  • data —— data是在发送POST、PUT或者PATCH请求的数据对象。
  • timeout —— 请求超时设置,单位为毫秒
  • withCredentials —— 表明是否有跨域请求需要用到证书
  • adapter —— adapter允许用户处理更易于测试的请求。返回一个Promise和一个有效的response
  • auth —— auth表明提供凭证用于完成http的身份验证。这将会在headers中设置一个Authorization授权信息。自定义Authorization授权要设置在headers中。
  • responseType —— 表示服务器将返回响应的数据类型,有arraybuffer、blob、document、json、text、stream这6个类型,默认是json类似数据。
  • xsrfCookieName —— 用作 xsrf token 值的 cookie 名称
  • xsrfHeaderName —— 带有 xsrf token 值 http head 名称
  • onUploadProgress —— 允许在上传过程中的做一些操作
  • onDownloadProgress —— 允许在下载过程中的做一些操作
  • maxContentLength —— 定义了接收到的response响应数据的最大长度。
  • validateStatus —— validateStatus定义了根据HTTP响应状态码决定是否接收或拒绝获取到的promise。如果 validateStatus 返回 true (或设置为 null 或 undefined ),promise将被接收;否则,promise将被拒绝。
  • maxRedirects —— maxRedirects定义了在node.js中redirect的最大值,如果设置为0,则没有redirect。
  • httpAgent —— 定义在使用http请求时的代理
  • httpsAgent —— 定义在使用https请求时的代理
  • proxy —— proxy定义代理服务器的主机名和端口,auth
  • cancelToken —— cancelToken定义一个 cancel token 用于取消请求

Response

当我们ajax获取数据成功后会返回一个response对象,它包含了以下内容:

{
 // `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是通过promise的then方法来获取,具体使用方法如下:

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);
 });

相对的,我们有时也会出现ajax报错,此时就会到我们的catch中去捕获异常error对象。

总结

以上就是这篇文章的全部内容了,希望本文的内容对大家的学习或者工作能带来一定的帮助,如果有疑问大家可以留言交流,谢谢大家对菜鸟教程(cainiaojc.com)的支持。

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