Implement Sequential Rate Limiting

package.json

@@ -30,7 +30,7 @@
     "object.values": "^1.0.3",
     "superagent": "^1.5.0",
     "unpipe": "^1.0.0",
-    "ws": "^0.8.1"
+    "ws": "^1.1.1"
   },
   "devDependencies": {
     "babel-preset-es2015": "^6.6.0",
@@ -40,15 +40,15 @@
     "eslint-plugin-import": "^1.13.0",
     "eslint-plugin-jsx-a11y": "^2.1.0",
     "eslint-plugin-react": "^6.0.0",
+    "fs-extra": "^0.30.0",
     "grunt": "^0.4.5",
     "grunt-babel": "^6.0.0",
     "grunt-browserify": "^4.0.1",
     "grunt-contrib-uglify": "^0.11.0",
     "grunt-jscs": "^2.8.0",
     "jscs": "^2.11.0",
-    "load-grunt-tasks": "^3.3.0",
-    "fs-extra": "^0.30.0",
-    "jsdoc-parse": "^1.2.7"
+    "jsdoc-parse": "^1.2.7",
+    "load-grunt-tasks": "^3.3.0"
   },
   "optionalDependencies": {
     "node-opus": "^0.1.11"

src/client/rest/APIRequest.js

@@ -11,7 +11,7 @@ class APIRequest {
     this.file = file;
   }
 
-  getBucketName() {
+  getEndpoint() {
     return `${this.method} ${this.url}`;
   }
 

src/client/rest/Bucket.js

@@ -1,62 +0,0 @@
-class Bucket {
-  constructor(rest, limit, remainingRequests = 1, resetTime) {
-    this.rest = rest;
-    this.limit = limit;
-    this.remainingRequests = remainingRequests;
-    this.resetTime = resetTime;
-    this.locked = false;
-    this.queue = [];
-    this.nextCheck = null;
-  }
-
-  setCheck(time) {
-    clearTimeout(this.nextCheck);
-    console.log('going to iterate in', time, 'remaining:', this.queue.length);
-    this.nextCheck = setTimeout(() => {
-      this.remainingRequests = this.limit - 1;
-      this.locked = false;
-      this.process();
-    }, time);
-  }
-
-  process() {
-    if (this.locked) {
-      return;
-    }
-
-    this.locked = true;
-
-    if (this.queue.length === 0) {
-      return;
-    }
-
-    if (this.remainingRequests === 0) {
-      return;
-    }
-    console.log('bucket is going to iterate', Math.min(this.remainingRequests, this.queue.length), 'items with max', this.limit, 'and remaining', this.remainingRequests);
-    while (Math.min(this.remainingRequests, this.queue.length) > 0) {
-      const item = this.queue.shift();
-      item.request.gen().end((err, res) => {
-        if (res && res.headers) {
-          this.limit = res.headers['x-ratelimit-limit'];
-          this.resetTime = Number(res.headers['x-ratelimit-reset']) * 1000;
-          this.setCheck((Math.max(500, this.resetTime - Date.now())) + 1000);
-        }
-        if (err) {
-          console.log(err.status, this.remainingRequests);
-          item.reject(err);
-        } else {
-          item.resolve(res && res.body ? res.body : {});
-        }
-      });
-      this.remainingRequests--;
-    }
-  }
-
-  add(method) {
-    this.queue.push(method);
-    this.process();
-  }
-}
-
-module.exports = Bucket;

src/client/rest/RESTManager.js

@@ -1,23 +1,21 @@
-const request = require('superagent');
-const Constants = require('../../util/Constants');
 const UserAgentManager = require('./UserAgentManager');
 const RESTMethods = require('./RESTMethods');
-const Bucket = require('./Bucket');
+const SequentialRequestHandler = require('./RequestHandlers/Sequential');
 const APIRequest = require('./APIRequest');
 
 class RESTManager {
 
   constructor(client) {
     this.client = client;
-    this.buckets = {};
+    this.handlers = {};
     this.userAgentManager = new UserAgentManager(this);
     this.methods = new RESTMethods(this);
     this.rateLimitedEndpoints = {};
   }
 
-  addToBucket(bucket, apiRequest) {
+  push(handler, apiRequest) {
     return new Promise((resolve, reject) => {
-      bucket.add({
+      handler.push({
         request: apiRequest,
         resolve,
         reject,
@@ -26,17 +24,13 @@ class RESTManager {
   }
 
   makeRequest(method, url, auth, data, file) {
-    /*
-    	file is {file, name}
-     */
     const apiRequest = new APIRequest(this, method, url, auth, data, file);
 
-    if (!this.buckets[apiRequest.getBucketName()]) {
-      console.log('new bucket', apiRequest.getBucketName());
-      this.buckets[apiRequest.getBucketName()] = new Bucket(this, 1, 1);
+    if (!this.handlers[apiRequest.getEndpoint()]) {
+      this.handlers[apiRequest.getEndpoint()] = new SequentialRequestHandler(this);
     }
 
-    return this.addToBucket(this.buckets[apiRequest.getBucketName()], apiRequest);
+    return this.push(this.handlers[apiRequest.getEndpoint()], apiRequest);
   }
 }
 

src/client/rest/RequestHandlers/RequestHandler.js

@@ -0,0 +1,34 @@
+/**
+ * A base class for different types of rate limiting handlers for the REST API.
+ * @private
+ */
+module.exports = class RequestHandler {
+  constructor(restManager) {
+    /**
+     * The RESTManager that instantiated this RequestHandler
+     * @type {RESTManager}
+     */
+    this.restManager = restManager;
+
+    /**
+     * A list of requests that have yet to be processed.
+     * @type {Array<APIRequest>}
+     */
+    this.queue = [];
+  }
+
+  /**
+   * Push a new API request into this bucket
+   * @param {APIRequest} request the new request to push into the queue
+   */
+  push(request) {
+    this.queue.push(request);
+  }
+
+  /**
+   * Attempts to get this RequestHandler to process its current queue
+   */
+  handle() {
+
+  }
+};

src/client/rest/RequestHandlers/Sequential.js

@@ -0,0 +1,71 @@
+const RequestHandler = require('./RequestHandler');
+
+/**
+ * Handles API Requests sequentially, i.e. we wait until the current request is finished before moving onto
+ * the next. This plays a _lot_ nicer in terms of avoiding 429's when there is more than one session of the account,
+ * but it can be slower.
+ * @extends {RequestHandler}
+ */
+module.exports = class SequentialRequestHandler extends RequestHandler {
+
+  constructor(restManager) {
+    super(restManager);
+
+    /**
+     * Whether this rate limiter is waiting for a response from a request
+     * @type {Boolean}
+     */
+    this.waiting = false;
+  }
+
+  push(request) {
+    super.push(request);
+    this.handle();
+  }
+
+  /**
+   * Performs a request then resolves a promise to indicate its readiness for a new request
+   * @param {APIRequest} item the item to execute
+   * @returns {Promise<Object, Error>}
+   */
+  execute(item) {
+    return new Promise((resolve, reject) => {
+      item.request.gen().end((err, res) => {
+        if (res && res.headers) {
+          this.requestLimit = res.headers['x-ratelimit-limit'];
+          this.requestResetTime = Number(res.headers['x-ratelimit-reset']) * 1000;
+          this.requestRemaining = Number(res.headers['x-ratelimit-remaining']);
+        }
+        if (err) {
+          this.waiting = false;
+          item.reject(err);
+          reject(err);
+        } else {
+          this.queue.shift();
+          const data = res && res.body ? res.body : {};
+          item.resolve(data);
+          if (this.requestRemaining === 0) {
+            setTimeout(() => {
+              this.waiting = false;
+              resolve(data);
+            }, (this.requestResetTime - Date.now()) + 4000);
+          } else {
+            this.waiting = false;
+            resolve(data);
+          }
+        }
+      });
+    });
+  }
+
+  handle() {
+    super.handle();
+    if (this.waiting || this.queue.length === 0) {
+      return;
+    }
+    this.waiting = true;
+
+    const item = this.queue[0];
+    this.execute(item).then(() => this.handle()).catch(console.log);
+  }
+};

src/client/websocket/WebSocketManager.js

@@ -151,7 +151,8 @@ class WebSocketManager {
    * Run whenever an error occurs with the WebSocket connection. Tries to reconnect
    * @returns {null}
    */
-  eventError() {
+  eventError(e) {
+    console.log(e);
     this.tryReconnect();
   }
 

test/random.js

@@ -142,8 +142,8 @@ client.on('message', message => {
     }
 
     if (message.content === 'ratelimittest') {
-      let i = 0;
-      while (i < 20) {
+      let i = 1;
+      while (i <= 20) {
         message.channel.sendMessage(`Testing my rates, item ${i} of 20`);
         i++;
       }