safetwitch-backend/routes/proxyRoute.ts

import { Router, Response, Request, NextFunction } from 'express'
import { TwitchAPI } from '../util/scraping/extractor';
import ws, { WebSocket } from 'ws';
import { TwitchChatServer } from './chatIrcProxy'

const proxyRouter = Router();
const twitch = new TwitchAPI()

proxyRouter.get('/img/:base64Url', async (req: Request, res: Response, next: NextFunction) => {
  const imageUrl = Buffer.from(req.params.base64Url, 'base64url').toString('utf-8')
  if (!imageUrl) return;

  const imageRes = await fetch(imageUrl)
    .catch(next)

  if (!imageRes) return;

  if (imageRes.status !== 200) {
    res.status(imageRes.status).send()
  }

  const arrayBuffer = await imageRes.arrayBuffer()
  const buf = Buffer.from(arrayBuffer)

  res.send(buf)
})


proxyRouter.get('/stream/:username/hls.m3u8', async (req: Request, res: Response, next: NextFunction) => {
  let m3u8Data = await twitch.getStream(req.params.username)
    .catch((reason: Error) => {
      console.log(reason.message)
      if (reason.message === `Streamer ${req.params.username} is not live`) {
        res.status(400).send({
          status: 'error',
          message: 'Streamer is not live'
        })
        return false
      } else {
        next(reason)
      }
    })

  if (!m3u8Data) return;

  const urlRegex = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;
  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, `${process.env.URL}/proxy/stream/sub/${base64data}`)
  }


  res.setHeader('Content-type', 'application/vnd.apple.mpegurl')
  res.send(m3u8Data)
})

proxyRouter.get('/stream/sub/:encodedUrl', async (req: Request, res: Response, next: NextFunction) => {
  const unencodedUrl = Buffer.from(req.params.encodedUrl, 'base64url').toString()
  const m3u8Fetch = await fetch(unencodedUrl)
  let m3u8Data = await m3u8Fetch.text()
  const urlRegex = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;
  const matches = m3u8Data.match(urlRegex)
  if (!matches) return;

  for (let url of matches) {
    const base64data = Buffer.from(url).toString('base64url')
    m3u8Data = m3u8Data.replace(url, `${process.env.URL}/proxy/stream/segment/${base64data}`)
  }

  res.setHeader('Content-type', 'application/vnd.apple.mpegurl')
  res.send(m3u8Data)
})

proxyRouter.get('/stream/segment/:encodedUrl', async (req: Request, res: Response) => {
  const unencodedUrl = Buffer.from(req.params.encodedUrl, 'base64url').toString()
  const data = await fetch(unencodedUrl)
  const arrayBuffer = await data.arrayBuffer()
  const buf = Buffer.from(arrayBuffer)
  res.send(buf)
})

const twitchChatServer = new TwitchChatServer();
export const wsServer = new ws.Server({ noServer: true });
twitchChatServer.startWebSocketServer(wsServer);

export default proxyRouter