index.js

const express = require('express')
const app = express()
const server = require('http').createServer(app)
const io = require('socket.io')(server)

app.use(express.static('lib'))
app.use(express.static('node_modules/ace-builds/src-noconflict'))
app.use('/', express.static('public'))

io.on('connection', (socket) => {
  socket.on('join', (roomId, user_name) => {
    const roomClients = io.sockets.adapter.rooms[roomId] || { length: 0 }
    const numberOfClients = roomClients.length

    // These events are emitted only to the sender socket.
    if (numberOfClients == 0) {
      console.log(`Creating room ${roomId} and emitting room_created socket event`)
      socket.join(roomId)
      socket.emit('room_created', roomId)
      socket.emit('init', { id: roomId })
      // socket.on('message', op => { socket.broadcast.emit('message', op) })
    } else {
      console.log(`Joining room ${roomId} and emitting room_joined socket event`)
      socket.join(roomId)
      socket.emit('room_joined', roomId)
      socket.emit('init', { id: roomId })
      // socket.on('message', op => { socket.broadcast.emit('message', op) })
    }
  })

  // These events are emitted to all the sockets connected to the same room except the sender.
  socket.on('start_call', (roomId) => {
    console.log(`Broadcasting start_call event to peers in room ${roomId}`)
    socket.broadcast.to(roomId).emit('start_call')
  })
  socket.on('webrtc_offer', (event) => {
    console.log(`Broadcasting webrtc_offer event to peers in room ${event.roomId}`)
    socket.broadcast.to(event.roomId).emit('webrtc_offer', event.sdp)
  })
  socket.on('webrtc_answer', (event) => {
    console.log(`Broadcasting webrtc_answer event to peers in room ${event.roomId}`)
    socket.broadcast.to(event.roomId).emit('webrtc_answer', event.sdp)
  })
  socket.on('webrtc_ice_candidate', (event) => {
    console.log(`Broadcasting webrtc_ice_candidate event to peers in room ${event.roomId}`)
    socket.broadcast.to(event.roomId).emit('webrtc_ice_candidate', event)
  })
  socket.on('message', op => {console.log(op.id, op); socket.broadcast.to(op.id).emit('message', op) })
  socket.on('download-file', (event) => {
    socket.broadcast.to(event.roomId).emit('download-file', event.file_desc)
  })
  socket.on('text-message', (event) => {
    socket.broadcast.to(event.roomId).emit('text-message', event)
  })
})

// START THE SERVER =================================================================
const port = process.env.PORT || 3000
server.listen(port, () => {
  console.log(`Express server listening on port ${port}`)
})