ble-server/ble/gdata-characteristic.js

const bleno = require('bleno')
const config = require('../config.json')
const localEvent = require('../localEvent')

var tmp = []
var idx = 0
var failFlag = false

const notifyDesciptor = new bleno.Descriptor({
  uuid: '8888',
  value: 0
})

class DataCharacteristic extends bleno.Characteristic {
  constructor () {
    super({
      uuid: config.ble.uuid.characteristic,
      properties: ['write', 'writeWithoutResponse', 'notify'],
      descriptors: [
        notifyDesciptor
      ]
    })
    this._notifyFunc = null
  }

  onWriteRequest (data, offset, withoutResponse, callback) {
    console.log(`offset :: ${offset} , withoutRes :: ${withoutResponse}`)
    console.log(`get data`, data)

    if (data.length === 1 && data[0] === 0x00) {
      tmp = []
      idx = 0
      failFlag = false
    } else if (data.length === 1 && data[0] === 0xff) {
      console.log(Buffer.from(tmp).toString())
      if (!failFlag) {
        localEvent.emit('print', Buffer.from(tmp).toString())
      }
    } else if (!failFlag) {
      let pidx = ((data[0] & 0xff) << 8) + (data[1] & 0xff)
      if (idx !== pidx) {
        // insert fail method
        failFlag = true
        this.sendNotidy('fail')
      }
      idx++
      tmp = [...tmp, ...data.slice(2, data.length)]
    }

    if (!withoutResponse) {
      console.log('send response')
      callback(this.RESULT_SUCCESS)
    }
  }

  sendNotidy (str) {
    if (!this._notifyFunc) return
    this._notifyFunc(Buffer.from(str))
  }

  onSubscribe (maxValueSize, cb) {
    console.log(maxValueSize)
    this._notifyFunc = cb
  }

  onUnsubscribe () {
    this._notifyFunc = null
  }
}

module.exports = DataCharacteristic