axios是一个专业的ajax请求库，使用它无需考虑跨平台问题，并且可以对ajax请求进行更灵活的定制。
一、特点
- 浏览器端支持ajax
- node.js端支持http请求
- promise API
- 可以拦截请求和回复
- 可以对请求和回复的数据进行变形
- 可以取消请求
- 对JSON数据自动转换
- 安全性：防止跨域访问
二、基本用法
（1）GET请求参数在URL中指明
axios.get('/user?ID=12345')
.then(function (response) {
console.log(response);
})
.catch(function (error) {
console.log(error);
});
（2）GET请求参数在定制区域指明
axios.get('/user', {
params: {
ID: 12345
}
})
.then(function (response) {
console.log(response);
})
.catch(function (error) {
console.log(error);
});
（3）POST请求指明参数
axios.post('/user', {
firstName: 'Fred',
lastName: 'Flintstone'
})
.then(function (response) {
console.log(response);
})
.catch(function (error) {
console.log(error);
});
（4）等待多个请求结束再执行某个函数
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
}));
（5）使用完整版
//POST请求
axios({
method: 'post',
url: '/user/12345',
data: {
firstName: 'Fred',
lastName: 'Flintstone'
}
}).then(function(resp){
console.log(resp)
});
// 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'))
});
也可以使用另外一种写法，把url放在比较突出的位置
axios("http://bit.ly/2mTM3nY",{
method:'get',
responseType:'stream'
}).then(function(response) {
response.data.pipe(fs.createWriteStream('ada_lovelace.jpg'))
})
二、请求的别名列表
为了更加直观的把url和请求method显示出来，axios定义了一系列函数。
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]])
三、并发请求
axios.all(iterable)
axios.spread(callback)
四、创建axios实例
通过创建实例可以统一定制请求。
var instance = axios.create({
baseURL: 'https://some-domain.com/api/',
timeout: 1000,
headers: {'X-Custom-Header': 'foobar'}
});
instance这个变量拥有和axios一模一样的函数
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]])
五、axios详细配置列表
axios的配置中只有url参数是必需的。
axios的配置中method参数默认取值为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', and 'PATCH'
// 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'
},
// `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 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`.
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 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
// 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) {
})
}
六、axios resposne的格式
{
// `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 the browser
request: {}
}
七、多个请求共用配置
axios有三级配置：全局配置、实例配置、请求配置
（1）全局配置
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';
（2）实例配置
// Set config defaults when creating the instance
var instance = axios.create({
baseURL: 'https://api.example.com'
});
// Alter defaults after instance has been created
instance.defaults.headers.common['Authorization'] = AUTH_TOKEN;
（3）请求配置
在每次发起请求的时候可以进行更详细的配置。三级配置后面的会覆盖掉前面的。
八、拦截器
拦截器分为两种：
- 请求拦截器
对请求进行拦截 - 回复拦截器
对回复进行拦截
// Add a request interceptor
axios.interceptors.request.use(function (config) {
// Do something before request is sent
return config;
}, function (error) {
// Do something with request error
return Promise.reject(error);
});
// Add a response interceptor
axios.interceptors.response.use(function (response) {
// Do something with response data
return response;
}, function (error) {
// Do something with response error
return Promise.reject(error);
});
通过保留下来拦截器实例的名称，以后可以禁用掉该拦截器
var myInterceptor = axios.interceptors.request.use(function () {/*...*/});
axios.interceptors.request.eject(myInterceptor);
自定义实例也是可以使用拦截器的
var instance = axios.create();
instance.interceptors.request.use(function () {/*...*/});
九、错误处理
通过catch来捕捉错误，错误可以分为多种。
- 请求没有发出去
- 请求发出去了，但是服务器没能回复
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);
});
可以定制statusCode来确定是否交给catch来处理
axios.get('/user/12345', {
validateStatus: function (status) {
return status < 500; // Reject only if the status code is greater than or equal to 500
}
})