From ee1d4c53f2770b5e4748d0d7402dc0291f9f869e Mon Sep 17 00:00:00 2001
From: Gus Caplan <me@gus.host>
Date: Tue, 24 Oct 2017 15:07:21 -0500
Subject: [PATCH] Add rateLimit event (#2019)

* add ratelimited event

* add some useful props

* death

* more death

* Update tester1000.js

* Update RequestHandler.js
---
 src/rest/handlers/RequestHandler.js | 33 ++++++++++++++++++++++++++---
 src/rest/handlers/burst.js          |  2 +-
 src/rest/handlers/sequential.js     |  2 +-
 src/util/Constants.js               |  1 +
 test/tester1000.js                  |  1 +
 5 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/src/rest/handlers/RequestHandler.js b/src/rest/handlers/RequestHandler.js
index d1dea22e3..aaeed9d69 100644
--- a/src/rest/handlers/RequestHandler.js
+++ b/src/rest/handlers/RequestHandler.js
@@ -1,4 +1,5 @@
 const DiscordAPIError = require('../DiscordAPIError');
+const { Events: { RATE_LIMIT } } = require('../../util/Constants');
 
 class RequestHandler {
   constructor(manager, handler) {
@@ -29,9 +30,35 @@ class RequestHandler {
   execute(item) {
     return new Promise((resolve, reject) => {
       const finish = timeout => {
-        // eslint-disable-next-line prefer-promise-reject-errors
-        if (timeout || this.limited) reject({ timeout, limited: this.limited });
-        else resolve();
+        if (timeout || this.limited) {
+          if (!timeout) {
+            timeout = this.resetTime - Date.now() + this.timeDifference + this.client.options.restTimeOffset;
+          }
+          // eslint-disable-next-line prefer-promise-reject-errors
+          reject({ timeout });
+          if (this.client.listenerCount(RATE_LIMIT)) {
+            /**
+             * Emitted when the client hits a rate limit while making a request
+             * @event Client#rateLimit
+             * @prop {number} timeout Timeout in ms
+             * @prop {number} limit Number of requests that can be made to this endpoint
+             * @prop {number} timeDifference Delta-T in ms between your system and Discord servers
+             * @prop {string} method HTTP method used for request that triggered this event
+             * @prop {string} path Path used for request that triggered this event
+             * @prop {string} route Route used for request that triggered this event
+             */
+            this.client.emit(RATE_LIMIT, {
+              timeout,
+              limit: this.limit,
+              timeDifference: this.timeDifference,
+              method: item.request.method,
+              path: item.request.path,
+              route: item.request.route,
+            });
+          }
+        } else {
+          resolve();
+        }
       };
       item.request.gen().end((err, res) => {
         if (res && res.headers) {
diff --git a/src/rest/handlers/burst.js b/src/rest/handlers/burst.js
index 8184d1037..fe35d20ae 100644
--- a/src/rest/handlers/burst.js
+++ b/src/rest/handlers/burst.js
@@ -6,7 +6,7 @@ module.exports = function burst() {
       this.client.setTimeout(() => {
         this.reset();
         this.handle();
-      }, timeout || (this.resetTime - Date.now() + this.timeDifference + this.client.options.restTimeOffset));
+      }, timeout);
     });
   this.remaining--;
   this.handle();
diff --git a/src/rest/handlers/sequential.js b/src/rest/handlers/sequential.js
index efc10b058..17e368036 100644
--- a/src/rest/handlers/sequential.js
+++ b/src/rest/handlers/sequential.js
@@ -11,6 +11,6 @@ module.exports = function sequential() {
         this.reset();
         this.busy = false;
         this.handle();
-      }, timeout || (this.resetTime - Date.now() + this.timeDifference + this.client.options.restTimeOffset));
+      }, timeout);
     });
 };
diff --git a/src/util/Constants.js b/src/util/Constants.js
index 07273a130..3c54dd638 100644
--- a/src/util/Constants.js
+++ b/src/util/Constants.js
@@ -194,6 +194,7 @@ exports.VoiceOPCodes = {
 };
 
 exports.Events = {
+  RATE_LIMIT: 'rateLimit',
   READY: 'ready',
   RESUMED: 'resumed',
   GUILD_CREATE: 'guildCreate',
diff --git a/test/tester1000.js b/test/tester1000.js
index e884324b4..99209c71a 100644
--- a/test/tester1000.js
+++ b/test/tester1000.js
@@ -10,6 +10,7 @@ client.on('debug', log);
 client.on('ready', () => {
   log('READY', client.user.tag, client.user.id);
 });
+client.on('rateLimit', log);
 
 const commands = {
   eval: message => {