From 03caddb4b5e0d01035da53470e288215274f0018 Mon Sep 17 00:00:00 2001
From: hydrabolt <amishshah.2k@gmail.com>
Date: Thu, 21 Apr 2016 18:24:08 +0100
Subject: [PATCH] Add Rate Limiting, see hammerandchisel/discord-api-docs#20

---
 src/client/rest/RESTManager.js | 55 +++++++++++++++++++++++++++++++++-
 test/random.js                 |  2 +-
 2 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/src/client/rest/RESTManager.js b/src/client/rest/RESTManager.js
index 5cda94ccd..926a4de82 100644
--- a/src/client/rest/RESTManager.js
+++ b/src/client/rest/RESTManager.js
@@ -12,14 +12,57 @@ class RESTManager{
 		this.queue = [];
 		this.userAgentManager = new UserAgentManager(this);
 		this.methods = new RESTMethods(this);
+		this.rateLimitedEndpoints = {};
 	}
 
-	makeRequest(method, url, auth, data, file) {
+	addRequestToQueue(method, url, auth, data, file, resolve, reject) {
+		let endpoint = url.replace(/\/[0-9]+/g, '/:id');
+
+		let rateLimitedEndpoint = this.rateLimitedEndpoints[endpoint];
+
+		rateLimitedEndpoint.queue = rateLimitedEndpoint.queue || [];
+
+		rateLimitedEndpoint.queue.push({
+			method, url, auth, data, file, resolve, reject,
+		});
+	}
+
+	processQueue(endpoint) {
+		let rateLimitedEndpoint = this.rateLimitedEndpoints[endpoint];
+
+		// prevent multiple queue processes
+		if (!rateLimitedEndpoint.timeout) {
+			return;
+		}
+
+		// lock the queue
+		clearTimeout(rateLimitedEndpoint.timeout);
+		rateLimitedEndpoint.timeout = null;
+
+		for (let item of rateLimitedEndpoint.queue) {
+			this.makeRequest(item.method, item.url, item.auth, item.data, item.file)
+				.then(item.resolve)
+				.catch(item.reject);
+		}
+
+		rateLimitedEndpoint.queue = [];
+	}
+
+	makeRequest(method, url, auth, data, file, fromQueue) {
 		/*
 			file is {file, name}
 		 */
 		let apiRequest = request[method](url);
 
+		let endpoint = url.replace(/\/[0-9]+/g, '/:id');
+
+		if (this.rateLimitedEndpoints[endpoint] && this.rateLimitedEndpoints[endpoint].timeout) {
+			console.log('adding to queue');
+			return new Promise((resolve, reject) => {
+				this.addRequestToQueue(method, url, auth, data, file, resolve, reject);
+			});
+		}
+
 		if (auth) {
 			if (this.client.store.token) {
 				apiRequest.set('authorization', this.client.store.token);
@@ -41,6 +84,16 @@ class RESTManager{
 		return new Promise((resolve, reject) => {
 			apiRequest.end((err, res) => {
 				if (err) {
+					let retry = res.headers['retry-after'] || res.headers['Retry-After'];
+					if (retry) {
+						this.rateLimitedEndpoints[endpoint] = {};
+						this.addRequestToQueue(method, url, auth, data, file, resolve, reject);
+						this.rateLimitedEndpoints[endpoint].timeout = setTimeout(() => {
+							this.processQueue(endpoint);
+						}, retry);
+						return;
+					}
+
 					reject(err);
 				} else {
 					resolve(res ? res.body || {} : {});
diff --git a/test/random.js b/test/random.js
index 87633f281..8bc302fdd 100644
--- a/test/random.js
+++ b/test/random.js
@@ -70,7 +70,7 @@ client.on('typingStop.', (channel, user, data) => {
 
 client.on('message', message => {
 	if (message.author.username === 'hydrabolt')
-	message.channel.sendMessage('hydrabolt said: ' + message.content).then(console.log).catch(console.log);
+	message.channel.sendMessage('hydrabolt said: ' + message.content).then(m => console.log(m.content)).catch(console.log);
 });
 
 client.on('messageDelete', message => {