From e75dd2638c2e479b5756b38986fe980582beda6d Mon Sep 17 00:00:00 2001
From: Amish Shah <amishshah.2k@gmail.com>
Date: Sat, 10 Sep 2016 22:12:03 +0100
Subject: [PATCH] Add Burst requests - addresses #656

---
 src/client/rest/RESTManager.js           |  3 +
 src/client/rest/RequestHandlers/Batch.js |  0
 src/client/rest/RequestHandlers/Burst.js | 73 ++++++++++++++++++++++++
 src/util/Constants.js                    |  2 +-
 test/random.js                           |  4 +-
 5 files changed, 79 insertions(+), 3 deletions(-)
 delete mode 100644 src/client/rest/RequestHandlers/Batch.js
 create mode 100644 src/client/rest/RequestHandlers/Burst.js

diff --git a/src/client/rest/RESTManager.js b/src/client/rest/RESTManager.js
index a2c11dd94..a56118a8e 100644
--- a/src/client/rest/RESTManager.js
+++ b/src/client/rest/RESTManager.js
@@ -1,6 +1,7 @@
 const UserAgentManager = require('./UserAgentManager');
 const RESTMethods = require('./RESTMethods');
 const SequentialRequestHandler = require('./RequestHandlers/Sequential');
+const BurstRequestHandler = require('./RequestHandlers/Burst');
 const APIRequest = require('./APIRequest');
 const Constants = require('../../util/Constants');
 
@@ -28,6 +29,8 @@ class RESTManager {
     switch (this.client.options.api_request_method) {
       case 'sequential':
         return SequentialRequestHandler;
+      case 'burst':
+        return BurstRequestHandler;
       default:
         throw new Error(Constants.Errors.INVALID_RATE_LIMIT_METHOD);
     }
diff --git a/src/client/rest/RequestHandlers/Batch.js b/src/client/rest/RequestHandlers/Batch.js
deleted file mode 100644
index e69de29bb..000000000
diff --git a/src/client/rest/RequestHandlers/Burst.js b/src/client/rest/RequestHandlers/Burst.js
new file mode 100644
index 000000000..0793cc00b
--- /dev/null
+++ b/src/client/rest/RequestHandlers/Burst.js
@@ -0,0 +1,73 @@
+const RequestHandler = require('./RequestHandler');
+
+class BurstRequestHandler extends RequestHandler {
+
+  constructor(restManager, endpoint) {
+    super(restManager, endpoint);
+    this.requestRemaining = 1;
+    this.first = true;
+  }
+
+  push(request) {
+    super.push(request);
+    this.handle();
+  }
+
+  handleNext(time) {
+    if (this.waiting) return;
+    this.waiting = true;
+    this.restManager.client.setTimeout(() => {
+      this.requestRemaining = this.requestLimit;
+      this.waiting = false;
+      this.handle();
+    }, time);
+  }
+
+  execute(item) {
+    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']);
+        this.timeDifference = Date.now() - new Date(res.headers.date).getTime();
+        this.handleNext((this.requestResetTime - Date.now()) + this.timeDifference + 1000);
+      }
+      if (err) {
+        if (err.status === 429) {
+          this.requestRemaining = 0;
+          this.queue.unshift(item);
+          this.restManager.client.setTimeout(() => {
+            this.globalLimit = false;
+            this.handle();
+          }, Number(res.headers['retry-after']) + 500);
+          if (res.headers['x-ratelimit-global']) {
+            this.globalLimit = true;
+          }
+        } else {
+          item.reject(err);
+        }
+      } else {
+        this.globalLimit = false;
+        const data = res && res.body ? res.body : {};
+        item.resolve(data);
+        if (this.first) {
+          this.first = false;
+          this.handle();
+        }
+      }
+    });
+  }
+
+
+  handle() {
+    super.handle();
+    if (this.requestRemaining < 1 || this.queue.length === 0 || this.globalLimit) return;
+    while (this.queue.length > 0 && this.requestRemaining > 0) {
+      this.execute(this.queue.shift());
+      this.requestRemaining--;
+    }
+  }
+
+}
+
+module.exports = BurstRequestHandler;
diff --git a/src/util/Constants.js b/src/util/Constants.js
index 911f8bad0..14a8a8ca7 100644
--- a/src/util/Constants.js
+++ b/src/util/Constants.js
@@ -16,7 +16,7 @@
  *   protocol_version: 6,
  *   max_message_cache: 200,
  *   rest_ws_bridge_timeout: 5000,
- *   api_request_method: 'sequential',
+ *   api_request_method: 'sequential', // can be sequential or burst
  *   shard_id: 0,
  *   shard_count: 0,
  *   fetch_all_members: false,
diff --git a/test/random.js b/test/random.js
index d1bf6a914..f487eb6b9 100644
--- a/test/random.js
+++ b/test/random.js
@@ -4,7 +4,7 @@ const Discord = require('../');
 const request = require('superagent');
 const fs = require('fs');
 
-const client = new Discord.Client({ fetch_all_members: false });
+const client = new Discord.Client({ fetch_all_members: false, api_request_method: 'burst' });
 
 const { email, password, token } = require('./auth.json');
 
@@ -134,7 +134,7 @@ client.on('message', msg => {
     msg.channel.guild.channels.get(chan).join()
       .then(conn => {
         msg.reply('done');
-        disp = conn.player.playStream(ytdl('https://www.youtube.com/watch?v=nbXgHAzUWB0', {filter : 'audioonly'}));
+        disp = conn.player.playStream(ytdl('https://www.youtube.com/watch?v=dc-nyGo0aC8', {filter : 'audioonly'}));
         conn.player.on('debug', console.log);
         conn.player.on('error', err => console.log(123, err));
         disp.on('error', err => console.log(123, err));