ble-server/gdata-characteristic.js

const bleno = require('bleno')
const config = require('./config.json')
const escpos = require('escpos')
const device = escpos.Serial(config.printer.serial)
const printer = escpos.Printer(device)
let isOpen = false

device.open(()=>{
  isOpen = true
})

var tmp = []

class DataCharacteristic extends bleno.Characteristic {
  constructor() {
    super({
      uuid: config.uuid.service.func.data,
      properties: ['write', 'writeWithoutResponse'],
      descriptors: [
        new bleno.Descriptor({
          uuid: '8888',
          value: 'Now'
        })
      ]
    })
  }

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

    if (data.length == 1 && data[0] == 0x00) {
      tmp = []
      console.log(data[0])
    } else if (data.length == 1 && data[0] == 0xff) {
      //console.log(tmp)
      console.log(Buffer.from(tmp).toString())
      printString(Buffer.from(tmp).toString())
    } else {
      tmp = [...tmp, ...data.slice(2, data.length)]
    }
    if (!withoutResponse) {
      console.log('send response')
      callback(this.RESULT_SUCCESS)
    }
  }
}


function printString(str){
  if(!isOpen) return 
  let strs = str.split(/\n/)
  printer.font('a')
    .align('ct')
    .size(1,1)
  for(let i in strs){
    printer.text(strs[i])
  }
  printer.cut(true, 8)
}

module.exports = DataCharacteristic