Enable sharing a rate limiter

Between multiple axios clients, sharing the rate limiting between them.

Author: leorochael

README.md

@@ -39,6 +39,27 @@ http.getMaxRPS() // 3
 http.setRateLimitOptions({ maxRequests: 6, perMilliseconds: 150 }) // same options as constructor
 ```
 
+You can also share a rate limiter between axios instances
+
+```javascript
+import axios from 'axios';
+import rateLimit, { getLimiter } from 'axios-rate-limit';
+
+const rateLimiter = getLimiter({ maxRPS: 2 })
+
+const http1 = rateLimiter.enabled(axios.create({baseUrl: 'http://example.com/api/v1/users/1'}))
+// another way of doing the same thing:
+const http2 = rateLimit(
+    axios.create({baseUrl: 'http://example.com/api/v1/users/2'}),
+    { rateLimiter: rateLimiter }
+)
+
+http1.get('/info.json') // will perform immediately
+http2.get('/info.json') // will perform immediately
+http1.get('/info.json') // will after one second from the first one
+
+```
+
 ## Alternatives
 
 Consider using Axios built-in [rate-limiting](https://www.npmjs.com/package/axios#user-content--rate-limiting) functionality.

__tests__/index.js

@@ -191,3 +191,31 @@ it('not delay requests if requests are cancelled', async function () {
   expect(end - start).toBeLessThan(perMilliseconds * 2)
   expect(end - start).toBeGreaterThan(perMilliseconds)
 })
+
+it('can share a limiter between multiple axios instances', async function () {
+  function adapter (config) { return Promise.resolve(config) }
+
+  var limiter = axiosRateLimit.getLimiter({
+    maxRequests: 2, perMilliseconds: 100
+  })
+
+  var http1 = limiter.enable(axios.create({ adapter: adapter }))
+  // another way of doing the same thing:
+  var http2 = axiosRateLimit(
+    axios.create({ adapter: adapter }), { rateLimiter: limiter }
+  )
+
+  var onSuccess = sinon.spy()
+
+  var requests = []
+  requests.push(http1.get('/users/1').then(onSuccess))
+  requests.push(http1.get('/users/2').then(onSuccess))
+
+  requests.push(http2.get('/users/3').then(onSuccess))
+  requests.push(http2.get('/users/4').then(onSuccess))
+
+  await delay(90)
+  expect(onSuccess.callCount).toEqual(2)
+  await Promise.all(requests)
+  expect(onSuccess.callCount).toEqual(4)
+})

src/index.js

@@ -1,16 +1,13 @@
-function AxiosRateLimit (axios) {
+function AxiosRateLimit (options) {
   this.queue = []
   this.timeslotRequests = 0
 
-  this.interceptors = {
-    request: null,
-    response: null
-  }
+  this.interceptors = []
 
   this.handleRequest = this.handleRequest.bind(this)
   this.handleResponse = this.handleResponse.bind(this)
 
-  this.enable(axios)
+  this.setRateLimitOptions(options)
 }
 
 AxiosRateLimit.prototype.getMaxRPS = function () {
@@ -43,14 +40,27 @@ AxiosRateLimit.prototype.enable = function (axios) {
     return Promise.reject(error)
   }
 
-  this.interceptors.request = axios.interceptors.request.use(
+  var requestInterceptor = axios.interceptors.request.use(
     this.handleRequest,
     handleError
   )
-  this.interceptors.response = axios.interceptors.response.use(
+  var responseInterceptor = axios.interceptors.response.use(
     this.handleResponse,
     handleError
   )
+
+  this.interceptors.push({
+    axios: axios,
+    request: requestInterceptor,
+    response: responseInterceptor
+  })
+
+  axios.getQueue = this.getQueue.bind(this)
+  axios.getMaxRPS = this.getMaxRPS.bind(this)
+  axios.setMaxRPS = this.setMaxRPS.bind(this)
+  axios.setRateLimitOptions = this.setRateLimitOptions.bind(this)
+
+  return axios
 }
 
 /*
@@ -156,16 +166,33 @@ AxiosRateLimit.prototype.shift = function () {
  * @returns {Object} axios instance with interceptors added
  */
 function axiosRateLimit (axios, options) {
-  var rateLimitInstance = new AxiosRateLimit(axios)
-  rateLimitInstance.setRateLimitOptions(options)
+  var rateLimitInstance = options.rateLimiter || new AxiosRateLimit(options)
 
-  axios.getQueue = AxiosRateLimit.prototype.getQueue.bind(rateLimitInstance)
-  axios.getMaxRPS = AxiosRateLimit.prototype.getMaxRPS.bind(rateLimitInstance)
-  axios.setMaxRPS = AxiosRateLimit.prototype.setMaxRPS.bind(rateLimitInstance)
-  axios.setRateLimitOptions = AxiosRateLimit.prototype.setRateLimitOptions
-    .bind(rateLimitInstance)
+  rateLimitInstance.enable(axios)
 
   return axios
 }
 
+/**
+ * Create a new rate limiter instance. It can be shared between multiple axios instances.
+ * The rate-limiting is shared between axios instances that are enabled with this rate limiter.
+ *
+ * @example
+ *   import rateLimit, { getLimiter } from 'axios-rate-limit';
+ *
+ *   const limiter = getLimiter({ maxRequests: 2, perMilliseconds: 1000 })
+ *   // limit an axios instance with this rate limiter:
+ *   const http1 = limiter.enable(axios.create())
+ *   // another way of doing the same thing:
+ *   const http2 = rateLimit(axios.create(), { rateLimiter: limiter })
+ *
+ * @param {Object} options options for rate limit, same as for rateLimit()
+ * @returns {Object} rate limiter instance
+ */
+function getLimiter (options) {
+  return new AxiosRateLimit(options)
+}
+
 module.exports = axiosRateLimit
+module.exports.AxiosRateLimiter = AxiosRateLimit
+module.exports.getLimiter = getLimiter

typings/index.d.ts

@@ -4,7 +4,7 @@ export type RateLimitRequestHandler = {
   resolve: () => boolean
 }
 
-export interface RateLimitedAxiosInstance extends AxiosInstance {
+export interface RateLimiter {
     getQueue: () => RateLimitRequestHandler[],
     getMaxRPS: () => number,
     setMaxRPS: (rps: number) => void,
@@ -17,12 +17,38 @@ export interface RateLimitedAxiosInstance extends AxiosInstance {
     // shift():any
 }
 
+export interface RateLimitedAxiosInstance extends AxiosInstance, RateLimiter {};
+
 export type rateLimitOptions = {
     maxRequests?: number,
     perMilliseconds?: number,
     maxRPS?: number
 };
 
+export interface AxiosRateLimiter extends RateLimiter {};
+
+export class AxiosRateLimiter implements RateLimiter {
+  constructor(options: rateLimitOptions);
+}
+
+/**
+ * Create a new rate limiter instance. It can be shared between multiple axios instances.
+ * The rate-limiting is shared between axios instances that are enabled with this rate limiter.
+ *
+ * @example
+ *   import rateLimit, { getLimiter } from 'axios-rate-limit';
+ *
+ *   const limiter = getLimiter({ maxRequests: 2, perMilliseconds: 1000 })
+ *   // limit an axios instance with this rate limiter:
+ *   const http1 = limiter.enable(axios.create())
+ *   // another way of doing the same thing:
+ *   const http2 = rateLimit(axios.create(), { rateLimiter: limiter })
+ *
+ * @param {Object} options options for rate limit, same as for rateLimit()
+ * @returns {Object} rate limiter instance
+ */
+export function getLimiter (options: rateLimitOptions): AxiosRateLimiter;
+
  /**
   * Apply rate limit to axios instance.
   *
@@ -50,5 +76,5 @@ export type rateLimitOptions = {
   */
 export default function axiosRateLimit(
     axiosInstance: AxiosInstance,
-    options: rateLimitOptions
+    options: rateLimitOptions & { rateLimiter?: AxiosRateLimiter }
 ): RateLimitedAxiosInstance;