From 3a09ec51120b9246d1147b68f2628a9d8771cc1e Mon Sep 17 00:00:00 2001
From: dragongoose <19649813+dragongoose@users.noreply.github.com>
Date: Mon, 13 Mar 2023 21:07:25 -0400
Subject: [PATCH] Create twitch IRC client and begin to implement a HLS proxy

---
 server/routes/proxy/proxyRoute.ts  | 50 +++++++++++++++++++++++
 server/types/scraping/Chat.ts      | 17 ++++++++
 server/util/scraping/chat/chat.ts  | 65 ++++++++++++++++++++++++++++++
 server/util/scraping/chat/utils.ts |  4 ++
 4 files changed, 136 insertions(+)
 create mode 100644 server/types/scraping/Chat.ts
 create mode 100644 server/util/scraping/chat/chat.ts
 create mode 100644 server/util/scraping/chat/utils.ts

diff --git a/server/routes/proxy/proxyRoute.ts b/server/routes/proxy/proxyRoute.ts
index 959839f..054a6ab 100644
--- a/server/routes/proxy/proxyRoute.ts
+++ b/server/routes/proxy/proxyRoute.ts
@@ -1,3 +1,4 @@
+import { Streamlink } from '@dragongoose/streamlink';
 import { Router, Response, Request, NextFunction } from 'express'
 
 const proxyRouter = Router();
@@ -24,4 +25,53 @@ proxyRouter.get('/img', async (req: Request, res: Response, next: NextFunction)
       .catch((err) => next(err))
 })
 
+proxyRouter.get('/stream/:username/hls.m3u8', (req: Request, res: Response, next: NextFunction) => {
+  console.log(req.params.username)
+  const streamlink = new Streamlink(`https://twitch.tv/${req.params.username}`, {
+    otherArgs: ['--stream-url']
+  })
+
+  streamlink.begin()
+
+
+  streamlink.on('log', async (data) => {
+    // m3u8 url
+    let twitchM3u8url = data.toString()
+
+    const urlRegex =/(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;
+    const twitchRes = await fetch(twitchM3u8url)
+    let m3u8Data = await twitchRes.text()
+    const matches = m3u8Data.match(urlRegex)
+    if (!matches) return next(new Error('Error proxying HLS'));
+
+    for (let url of matches) {
+      const base64data = Buffer.from(url).toString('base64url')
+      //m3u8Data = m3u8Data.replace(url, `${process.env.URL}/proxy/hls/${base64data}`)
+    }
+
+    res.setHeader('Content-type','application/vnd.apple.mpegurl')
+    res.send(m3u8Data)
+  })
+})
+
+proxyRouter.get('/hls/:encodedUrl' , (req: Request, res: Response, next: NextFunction) => {
+  const unencodedUrl = Buffer.from(req.params.encodedUrl, 'base64url').toString()
+  fetch(unencodedUrl).then((response) => {
+    response.body!.pipeTo(
+      new WritableStream({
+        start() {
+          response.headers.forEach((v, n) => res.setHeader(n, v));
+        },
+        write(chunk) {
+          res.write(chunk);
+        },
+        close() {
+          res.end();
+        },
+      })
+    );
+  })
+  .catch((err) => next(err))
+})
+
 export default proxyRouter
\ No newline at end of file
diff --git a/server/types/scraping/Chat.ts b/server/types/scraping/Chat.ts
new file mode 100644
index 0000000..6d2fbdb
--- /dev/null
+++ b/server/types/scraping/Chat.ts
@@ -0,0 +1,17 @@
+export interface TwitchChatOptions {
+    login: { 
+        username: string,
+        password: string
+    },
+    channels: string[]
+}
+
+export const MessageTypes = ['PRIVMSG', 'WHISPER']
+export type MessageType = typeof MessageTypes[number];
+
+export interface Metadata {
+    username: string
+    messageType: MessageType
+    channel: string
+    message: string
+}
diff --git a/server/util/scraping/chat/chat.ts b/server/util/scraping/chat/chat.ts
new file mode 100644
index 0000000..8b8e021
--- /dev/null
+++ b/server/util/scraping/chat/chat.ts
@@ -0,0 +1,65 @@
+import { EventEmitter } from 'stream';
+import WebSocket from 'ws'
+import { TwitchChatOptions, Metadata, MessageType, MessageTypes } from '../../../types/scraping/Chat'
+import { parseUsername } from './utils';
+
+export declare interface TwitchChat {
+    on(event: 'PRIVMSG', listener: (username: string, messageType: MessageType, channel: string, message: string) => void): this
+}
+
+export class TwitchChat extends EventEmitter{
+    public channels: string[]
+    private url = 'wss://irc-ws.chat.twitch.tv:443'
+    private ws: WebSocket | null;
+
+    constructor(options: TwitchChatOptions) {
+        super()
+        this.channels = options.channels
+        this.ws = null
+    }
+
+    private parser() {
+        this.ws?.on('message', (data) => {
+            let normalData = data.toString()
+            let splitted = normalData.split(":")
+            
+            let metadata = splitted[1].split(' ')
+            let message = splitted[2]
+
+            if(!MessageTypes.includes(metadata[1])) return;
+
+            let parsedMetadata: Metadata = {
+                username: parseUsername(metadata[0]),
+                messageType: metadata[1],
+                channel: metadata[2],
+                message: message
+            }
+
+            this.createEmit(parsedMetadata)
+        })
+    }
+
+    private createEmit(data: Metadata) {
+        this.emit(data.messageType, ...Object.values(data))
+    }
+
+    public async connect() {
+        this.ws = new WebSocket(this.url)
+        
+        this.ws.on('open', () => {
+            if(this.ws) {
+                this.ws.send('PASS none')
+                this.ws.send('NICK justinfan333333333333')
+                
+                for(let channel of this.channels) {
+                    this.ws.send(`JOIN #${channel}`)
+                }
+
+                this.parser()
+                return Promise.resolve()
+            }
+        })
+
+    }
+
+}
diff --git a/server/util/scraping/chat/utils.ts b/server/util/scraping/chat/utils.ts
new file mode 100644
index 0000000..cadfcd0
--- /dev/null
+++ b/server/util/scraping/chat/utils.ts
@@ -0,0 +1,4 @@
+export const parseUsername = (rawUsername: String) => {
+    const splitted = rawUsername.split('!')
+    return splitted[0]
+}
\ No newline at end of file