Vue.js—— axios（六）

￡神魔★判官ぃ 2022-11-19 11:27 48阅读 0赞

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

# axios安装 #

npm:

$ npm install axios

bower:

$ bower install axios

Using cdn:

# 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

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。

# 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。  
> 知乎链接：[https://www.zhihu.com/question/52418455/answer/130535375][https_www.zhihu.com_question_52418455_answer_130535375]

[axios]: https://github.com/mzabriskie/axios
[https_www.zhihu.com_question_52418455_answer_130535375]: https://www.zhihu.com/question/52418455/answer/130535375