axios-observable

axios-observable

Observable (as opposed to Promise) based HTTP client for the browser and node.js

Want to use axios in a rxjs (observable) way? There we go!

This API of axios-observable is almost same as API of axios, giving you smooth transition. So the documentation mirrors the one of axios (A few exceptions will be cleared pointed out).

Features

• Make XMLHttpRequests from the browser
• Make http requests from node.js
• Supports the Observable API
• Intercept request and response
• Transform request and response data
• (NEW in v1.1.0) Cancel requests through unsubscribe
• Automatic transforms for JSON data
• Client side support for protecting against XSRF

Installing

Using npm: note: axios and rxjs are peer dependencies.

$ npm install axios rxjs axios-observable

Example

Performing a GET request

import Axios from  'axios-observable';
// or const Axios = require('axios-observable').Axios;

// Make a request for a user with a given ID
Axios.get('/user?ID=12345')
  .subscribe(
    response => console.log(response),
    error => console.log(error)
  );

// Optionally the request above could also be done as
Axios.get('/user?ID=12345'), {
    params: {
      ID: 12345
    }
  })
  .subscribe(
    response => console.log(response),
    error => console.log(error)
  );

Performing a POST request

Axios.post('/user', {
    firstName: 'Fred',
    lastName: 'Flintstone'
  })
   .subscribe(
    response => console.log(response),
    error => console.log(error)
  );

Why observable is better than Promise?

You can do much more! rxjs provides tons of operators to let you gracefully control your request.

Example, retry 3 times after failures.

Axios.post('/user', {
    firstName: 'Fred',
    lastName: 'Flintstone'
  })
  .pipe(
  	retry(3)
  )
   .subscribe(
    response => console.log(response),
    error => console.log(error)
  );

axios-observable API

Yeah! We use the exact same config object as axios.

Axios.request(config) (We don't support using Axios as a function as opposed to axios library)

The example below is wrong!

// Send a POST request
Axios({
  method: 'post',
  url: '/user/12345',
  data: {
    firstName: 'Fred',
    lastName: 'Flintstone'
  }
});

use Axios.request(config) instead

// Send a POST request
Axios.request({
  method: 'post',
  url: '/user/12345',
  data: {
    firstName: 'Fred',
    lastName: 'Flintstone'
  }
});

// GET request for remote image
Axios.request({
  method:'get',
  url:'http://bit.ly/2mTM3nY',
  responseType:'stream'
})
  .subscribe(response => {
  response.data.pipe(fs.createWriteStream('ada_lovelace.jpg'))
});

Request method aliases

For convenience aliases have been provided for all supported request methods.

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]])

NOTE

When using the alias methods url, method, and data properties don't need to be specified in config.

Concurrency

as opposed to axios using all and spread, rxjs has a much better way of handling concurrency.

Creating an instance

You can create a new instance of Axios with a custom config.

Axios.create([config])

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

Instance methods

The available instance methods are listed below. The specified config will be merged with the instance config.

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]])

Request Config (same as axios, typed with AxiosRequestConfig if using TypeScript)

These are the available config options for making requests. Only the url is required. Requests will default to GET if method is not specified.

{
  // `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

  // `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
  // 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) {
  })
}

Response Schema (same as axios, typed with AxiosResponse<T> if using TypeScript)

The response for a request contains the following information.

{
  // `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: {}
}

Config Defaults

You can specify config defaults that will be applied to every request.

Global axios defaults

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';

Custom instance defaults

// Set config defaults when creating the instance
const instance = Axios.create({
  baseURL: 'https://api.example.com'
});

// Alter defaults after instance has been created
instance.defaults.headers.common['Authorization'] = AUTH_TOKEN;

Config order of precedence

Config will be merged with an order of precedence. The order is library defaults found in lib/defaults.js, then defaults property of the instance, and finally config argument for the request. The latter will take precedence over the former. Here's an example.

// Create an instance using the config defaults provided by the library
// At this point the timeout config value is `0` as is the default for the library
const instance = Axios.create();

// Override timeout default for the library
// Now all requests using this instance will wait 2.5 seconds before timing out
instance.defaults.timeout = 2500;

// Override timeout for this request as it's known to take a long time
instance.get('/longRequest', {
  timeout: 5000
});

Interceptors

You can intercept requests or responses before they are handled by then or catch.

// 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);
  });

If you may need to remove an interceptor later you can.

const myInterceptor = Axios.interceptors.request.use(function () {/*...*/});
Axios.interceptors.request.eject(myInterceptor);

You can add interceptors to a custom instance of axios.

const instance = Axios.create();
instance.interceptors.request.use(function () {/*...*/});

You can define a custom HTTP status code error range using the validateStatus config option.

Axios.get('/user/12345', {
  validateStatus: function (status) {
    return status < 500; // Reject only if the status code is greater than or equal to 500
  }
})

Cancellation (Big win for axios-observable)

As opposed to axios which using cancel token, rxjs comes with a more natural way - unsubscribe

const subscription = Axios.get('/user/12345').subscribe(response => console.log(response));

subscription.unsubscribe();

Using application/x-www-form-urlencoded format

By default, axios serializes JavaScript objects to JSON. To send data in the application/x-www-form-urlencoded format instead, you can use one of the following options.

Browser

In a browser, you can use the URLSearchParams API as follows:

const params = new URLSearchParams();
params.append('param1', 'value1');
params.append('param2', 'value2');
Axios.post('/foo', params);

Note that URLSearchParams is not supported by all browsers (see caniuse.com), but there is a polyfill available (make sure to polyfill the global environment).

Alternatively, you can encode data using the qs library:

const qs = require('qs');
Axios.post('/foo', qs.stringify({ 'bar': 123 }));

Or in another way (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.request(options);

Node.js

In node.js, you can use the querystring module as follows:

const querystring = require('querystring');
Axios.post('http://something.com/', querystring.stringify({ foo: 'bar' }));

You can also use the qs library.

TypeScript

axios-observable includes TypeScript definitions.

import Axios from 'axios-observable';
// or import {Axios} from 'axios-observable';
Axios.get('/user?ID=12345');

License

MIT