51工具盒子
研究过vue.js的童鞋，对于axios肯定会有些了解，它基于Promise的HTTP客户端，用于浏览器和node.js。那如何去应用它呢？我们一起从最基础的学习起吧。
特征
首先了解下axios的一些主要特征应用：
1、从浏览器发出XMLHttpRequests
2、从node.js发出HTTP请求
3、支持Promise API
4、拦截请求和响应
5、转换请求和响应数据
6、取消请求
7、JSON数据的自动转换
8、客户端支持以防止XSRF
如何安装anios
使用npm：
$ npm install axios
使用bower:
$ bower install axios
使用yarn：
$ yarn add axios
使用cdn：
<script src =“ https://unpkg.com/axios/dist/axios.min.js”> </ script>
安装很简单的，接下来我们来看些如何在实际项目中的应用。
实例应用
注意：CommonJS用法
为了在将CommonJS导入与require（）一起使用时获得TypeScript类型（用于智能/自动完成），请使用以下方法：
const axios = require('axios').default;
// axios。<method>现在将提供自动完成和参数输入
执行GET请求
const axios = require('axios');
// Make a request for a user with a given ID
axios.get('/user?ID=12345')
.then(function (response) {
// handle success
console.log(response);
})
.catch(function (error) {
// handle error
console.log(error);
})
.finally(function () {
// always executed
});
// 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);
})
.finally(function () {
// always executed
});
// Want to use async/await? Add the `async` keyword to your outer function/method.
async function getUser() {
try {
const response = await axios.get('/user?ID=12345');
console.log(response);
} catch (error) {
console.error(error);
}
}
注意：async / await是ECMAScript 2017的一部分，并且Internet Explorer和旧版浏览器不支持async / await，因此请谨慎使用。
执行POST请求
axios.post('/user', {
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
}));
axios API
可以通过将相关配置传递给axios来发出请求。
axios（配置）
// Send a POST request
axios({
method: 'post',
url: '/user/12345',
data: {
firstName: 'Fred',
lastName: 'Flintstone'
}
});
// GET request for remote image
axios({
method: 'get',
url: 'http://bit.ly/2mTM3nY',
responseType: 'stream'
})
.then(function (response) {
response.data.pipe(fs.createWriteStream('ada_lovelace.jpg'))
});
axios（URL [，config]）
// Send a GET request (default method)
axios('/user/12345');
Request method aliases
为了方便起见，aliases已为所有受支持的请求方法。
axios.request（配置）
axios.get（URL [，config]）
axios.delete（url [，config]）
axios.head（url [，config]）
axios.options（url [，config]）
axios.post（URL [，data [，config]]）
axios.put（URL [，data [，config]]）
axios.patch（url [，data [，config]]）
注意
使用别名方法时，无需在config中指定url，method和data属性。
并发
帮助程序功能，用于处理并发请求。
axios.all（可迭代）
axios.spread（回调）
创建一个实例
您可以使用自定义配置创建axios的新实例。
axios.create（[config]）
const instance = axios.create({
baseURL: 'https://some-domain.com/api/',
timeout: 1000,
headers: {'X-Custom-Header': 'foobar'}
});
实例方法
可用的实例方法在下面列出。指定的配置将与实例配置合并。
axios＃request（config）
axios＃get（URL [，config]）
axios＃delete（url [，config]）
axios＃head（url [，config]）
axios＃options（url [，config]）
axios＃post（url [，data [，config]]）
axios＃put（url [，data [，config]]）
axios＃patch（url [，data [，config]]）
axios＃getUri（[config]）
请求配置
这些是发出请求的可用配置选项。仅URL是必需的。如果未指定method，则请求将默认为GET。
{
// `url` is the server URL that will be used for the request
url: '/user',
// `method` is the request method to be used when making the request
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.
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', 'PATCH' and 'DELETE'
// The last function in the array must return a string or an instance of Buffer, ArrayBuffer,
// FormData or Stream
// You may modify the headers object.
transformRequest: [function (data, headers) {
// 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, Buffer
data: {
firstName: 'Fred'
},
// syntax alternative to send data into the body
// method post
// only the value is sent, not the key
data: 'Country=Brasil&City=Belo Horizonte',
// `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, // default is `0` (no timeout)
// `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 lib/adapters/README.md).
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`.
// Please note that only HTTP Basic auth is configurable through this parameter.
// For Bearer tokens and such, use `Authorization` custom headers instead.
auth: {
username: 'janedoe',
password: 's00pers3cret'
},
// `responseType` indicates the type of data that the server will respond with
// options are: 'arraybuffer', 'document', 'json', 'text', 'stream'
// browser only: 'blob'
responseType: 'json', // default
// `responseEncoding` indicates encoding to use for decoding responses
// Note: Ignored for `responseType` of 'stream' or client-side requests
responseEncoding: 'utf8', // 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 in bytes 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
// `socketPath` defines a UNIX Socket to be used in node.js.
// e.g. '/var/run/docker.sock' to send requests to the docker daemon.
// Only either `socketPath` or `proxy` can be specified.
// If both are specified, `socketPath` is used.
socketPath: null, // default
// `httpAgent` and `httpsAgent` define a custom agent to be used when performing http
// and https requests, respectively, in node.js. This allows options to be added 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.
// You can also define your proxy using the conventional `http_proxy` and
// `https_proxy` environment variables. If you are using environment variables
// for your proxy configuration, you can also define a `no_proxy` environment
// variable as a comma-separated list of domains that should not be proxied.
// Use `false` to disable proxies, ignoring environment variables.
// `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) {
})
}
响应模式
请求的响应包含以下信息。
{
// `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
// It is the last ClientRequest instance in node.js (in redirects)
// and an XMLHttpRequest instance in the browser
request: {}
}
使用then时，您将收到如下响应：
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);
});
当使用catch或将拒绝回调作为then的第二个参数传递时，响应将通过错误对象提供，如"处理错误"部分所述。
配置默认值
您可以指定将应用于每个请求的配置默认值。
全局axios默认值
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';
自定义实例默认值
//创建实例时设置默认配置
const instance = axios.create（{
baseURL：“ https://api.example.com”
}）;
//创建实例后更改默认值
instance.defaults.headers.common ['Authorization'] = AUTH_TOKEN;
配置优先顺序
Config将以优先顺序合并。顺序是在lib / defaults.js中找到库默认值，然后是实例的defaults属性，最后是请求的config参数。后者将优先于前者。这是一个例子。
//使用库提供的配置默认值创建实例
//此时，超时配置值为0，这是库的默认值
const instance = axios.create（）;
//默认情况下，库的超时超时
//现在使用此实例的所有请求将等待2.5秒，然后再超时
instance.defaults.timeout = 2500;
//覆盖此请求的超时时间，因为它需要花费很长时间
instance.get（'/ longRequest'，{
timeout：5000
}）;
拦截器
您可以先拦截请求或响应，然后再进行捕获或捕获。
//添加请求拦截器
axios.interceptors.request.use(function (config) {
//在发送请求之前先做点事
return config;
}, function (error) {
//发生请求错误
return Promise.reject(error);
});
//添加响应拦截器
axios.interceptors.response.use(function (response) {
//处于2xx范围内的任何状态代码都会导致此函数触发
//对响应数据进行处理
return response;
}, function (error) {
//任何超出2xx范围的状态代码都会触发此函数
//做一些响应错误
return Promise.reject(error);
});
如果以后需要删除拦截器，则可以。
const myInterceptor = axios.interceptors.request.use（function（）{/*...*/}）;
axios.interceptors.request.eject（myInterceptor）;
您可以将拦截器添加到axios的自定义实例中。
const instance = axios.create（）;
instance.interceptors.request.use（function（）{/*...*/}）;
处理错误
axios.get('/user/12345')
.catch(function (error) {
if (error.response) {
//发出了请求，服务器返回了状态码
//不在2xx范围内
console.log(error.response.data);
console.log(error.response.status);
console.log(error.response.headers);
} else if (error.request) {
//已发出请求，但未收到响应
//`error.request`是浏览器中XMLHttpRequest的实例，也是
// node.js中的http.ClientRequest
console.log(error.request);
} else {
//设置触发错误的请求时发生了什么
console.log('Error', error.message);
}
console.log(error.config);
});
使用validateStatus config选项，您可以定义应该引发错误的HTTP代码。
axios.get('/user/12345', {
validateStatus: function (status) {
return status < 500; //仅在状态码大于或等于500时拒绝
}
})
使用toJSON，您将获得一个对象，其中包含有关HTTP错误的更多信息。
axios.get('/user/12345')
.catch(function (error) {
console.log(error.toJSON());
});
Cancellation
您可以使用cancel token取消请求。
axios取消tokenAPI基于撤回的可取消承诺提议。
您可以使用CancelToken.source工厂创建一个cancel token，如下所示：
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
})
//取消请求（message参数是可选的）
source.cancel('Operation canceled by the user.');
您还可以通过将执行程序函数传递给CancelToken构造函数来创建cancel 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();
注意：您可以使用相同的cancel token取消多个请求。
使用application / x-www-form-urlencoded格式
默认情况下，axios将JavaScript对象序列化为JSON。要改为以application / x-www-form-urlencoded格式发送数据，可以使用以下选项之一。
浏览器
在浏览器中，可以如下使用URLSearchParams API：
const params = new URLSearchParams();
params.append('param1', 'value1');
params.append('param2', 'value2');
axios.post('/foo', params);
请注意，并非所有浏览器都支持URLSearchParams（请参见caniuse.com），但是有可用的polyfill（确保对全局环境进行polyfill）。
另外，您可以使用qs库对数据进行编码：
const qs = require（'qs'）;
axios.post（'/ foo'，qs.stringify（{'bar'：123}））;
或以另一种方式（ES6），
import qs from 'qs';
const data = { 'bar': 123 };
const options = {
method: 'POST',
headers: { 'content-type': 'application/x-www-form-urlencoded' },
data: qs.stringify(data),
url,
};
axios(options);
Node.js
在node.js中，可以按以下方式使用querystring模块：
const querystring = require（'querystring'）;
axios.post（'http://something.com/'，querystring.stringify（{foo：'bar'}）））;
您也可以使用qs库。
**注意:**如果需要对嵌套对象进行字符串化处理，则最好使用qs库，因为querystring方法存在该用例的已知问题（https://github.com/nodejs/node-v0.x-archive/issues/1665）。
Promises
axios取决于要支持的本机ES6 Promise实现。如果您的环境不支持ES6 Promises，则可以进行polyfill。
TypeScript
axios包括TypeScript定义。
import axios from 'axios';
axios.get('/user?ID=12345');
