test.js

const net = require('net')

const port = 15740
const host = '192.168.1.132'

const PTPPacketType = {
  Invalid:            0,
  InitCommandRequest: 1,
  InitCommandAck:     2,
  InitEventRequest:   3,
  InitEventAck:       4,
  InitFail:           5,
  OperationRequest:   6,
  OperationResponse:  7,
  Event:              8,
  StartDataPacket:    9,
  DataPacket:         10,
  CancelTransaction:  11,
  EndDataPacket:      12,
  Ping:               13,
  Pong:               14,
}

const PTPVersion = Buffer.from([0x00, 0x00, 0x01, 0x00])

const PTPPacketGenerator = {
  initCommandRequest (guid, hostname) {
    // allocate buffer with space for length, type, guid, hostname, and version
    const payload = Buffer.alloc(4 + 4 + 16 + (hostname.length * 2 + 2) + 4)
    payload.writeInt32LE(payload.length, 0)
    payload.writeInt32LE(PTPPacketType.InitCommandRequest, 4)
    payload.fill(guid, 8, 24, 'hex')
    payload.fill(hostname, 24, 24 + hostname.length * 2, 'utf16le')
    payload.fill(PTPVersion, 24 + hostname.length * 2 + 2) // +2 leaves null reference character to indicate end of hostname
    return payload
  },

  InitEventRequest (connectionNumber) {
    // allocate buffer with length, type, and command connection number
    const payload = Buffer.alloc(12)
    payload.writeInt32LE(payload.length, 0)
    payload.writeInt32LE(PTPPacketType.InitEventRequest, 4)
    payload.writeInt32LE(connectionNumber, 8)
    return payload
  }
}

const commandClient = new net.Socket()
const eventClient = new net.Socket()

commandClient.connect(port, host, function () {
  console.log('Command Connected')
  const payload = PTPPacketGenerator.initCommandRequest('ffffffffffffffffffffffffffffffff', 'PTPIP Test')
  commandClient.write(payload)
})

commandClient.on('data', function (data) {
  const typeInt = data.readUInt16LE(4)
  const type = Object.keys(PTPPacketType).find(key => PTPPacketType[key] === typeInt)
  console.log(`Received Command Packet of type ${type}`)

  switch (typeInt) {
    case PTPPacketType.InitCommandAck:
      const connectionNumber = data.readUInt16LE(8)
      const guid = data.toString('hex', 12, 28)
      const hostname = data.toString('utf16le', 28, data.length - 6)
      console.log(`Received: ${type} | Connection #: ${connectionNumber} | ${guid} | ${hostname}`)
      eventClient.connect(port, host, function () {
        console.log('Event Connected')
        const payload = PTPPacketGenerator.InitEventRequest(connectionNumber)
        eventClient.write(payload)
      })
      break
  }
})

commandClient.on('close', function () {
  console.log('Command Connection Closed')
  eventClient.destroy() // kill client on close..?
  commandClient.destroy() // kill client on close..?
})

eventClient.on('data', function (data) {
  const typeInt = data.readUInt16LE(4)

  const type = Object.keys(PTPPacketType).find(key => PTPPacketType[key] === typeInt)
  console.log(`Received Event Packet of type ${type}`)

  switch (typeInt) {

    // If the init was successful then extend the lens and start the intervalometer
    case PTPPacketType.InitEventAck:

      // OpenSession (not sure what this is or if needed... taken from wireshark)
      commandClient.write(Buffer.from('16000000060000000100000002100000000041000000', 'hex'))

      // Needed to prevent camera connection timeout
      setTimeout(function () {
        // Operation Code: CANON_EOS_SetRemoteMode (0x9114)
        commandClient.write(Buffer.from('16000000060000000100000014910100000015000000', 'hex'))
      }, 1000)

      setTimeout(function () {

        // G7X extend lens. From what I can tell this is a non-standard PTP packet, and
        // there is some additional data in the "End Data Packet" that wireshark doesn't
        // recognize (the data starting at c000000b0d1000008000000).
        commandClient.write(Buffer.from('120000000600000002000000109101000000', 'hex')) //Operation Code: CANON_EOS_SetDevicePropValueEx (0x9110)
        commandClient.write(Buffer.from('1400000009000000010000000c00000000000000', 'hex')) //Packet Type: Start Data Packet (0x00000009)
        commandClient.write(Buffer.from('180000000c000000930000000c000000b0d1000008000000', 'hex')) //Packet Type: End Data Packet (0x0000000c)

        // Trigger shutter & release every X sec
        setInterval(function () {
          commandClient.write(Buffer.from('1a000000060000000100000028919a0100000300000001000000', 'hex')) // trigger shutter [Operation Code: CANON_EOS_RemoteReleaseOn (0x9128)]
          commandClient.write(Buffer.from('16000000060000000100000029919c01000003000000', 'hex')) // release shutter [Operation Code: CANON_EOS_RemoteReleaseOff (0x9129)]
        }, 3000)

        // Send keepalive packet X sec
        setInterval(function () {
          commandClient.write(Buffer.from('1200000006000000010000002f9013000000', 'hex')) // keepalive?
        }, 5000)

      }, 2000)

      break
  }
})

eventClient.on('close', function () {
  console.log('Event Connection Closed')
  eventClient.destroy() // kill client on close..?
  commandClient.destroy() // kill client on close..?
})