Bleno Gist

message.js

import bleno from 'bleno-mac';

class MessageCharacteristic extends bleno.Characteristic {
  constructor(config) {
    const props = Object.assign(config, {
      uuid: '13333333-3333-3333-3333-800000000001',
      properties: ['read', 'write', 'notify'],
      value: null,
    });
    super(props);
  }
}

export default MessageCharacteristic;

service.js

import blenoMac from 'bleno-mac';
import MessageCharacteristic from './characteristics/message';

const messageStartDelimeter = '<m$g>';
const messageEndDelimeter = '</m$g>';

function chunkData(str, size) {
  const chunks = new Array(Math.ceil(str.length / size));
  let newo = 0;
  for (let i = 0, o = 0; i < chunks.length; i += 1, o = newo) {
    newo += size;
    chunks[i] = str.substr(o, size);
  }

  return chunks;
}

function wait(ms) {
  const waitTill = new Date(new Date().getTime() + ms);
  while (waitTill > new Date()) { /* Don nothing */ }
}

function sendData(data, callback, maxValueSize) {
  const totalMessage = `${messageStartDelimeter}${data}${messageEndDelimeter}`;
  const chunks = chunkData(totalMessage, maxValueSize);
  console.log(chunks.length);
  chunks.forEach((chunk) => {
    const dataAsBuffer = Buffer.from(chunk, 'utf-8');
    console.log(chunk);
    callback(dataAsBuffer);
    wait(10);  // Comment this out to fail
  });
}

class TestService extends blenoMac.PrimaryService {
  constructor() {
    const message = new MessageCharacteristic(
      {
        onWriteRequest: (data, offset, withoutResponse, callback) => {
          console.log(`MessageCharacteristic - onWriteRequest: value = ${data.toString('utf8')}`);
          callback(MessageCharacteristic.RESULT_SUCCESS, data);
        },
        onSubscribe: (maxValueSize, updateValueCallback) => {
          sendData('Really Long Text That Needs Chunking due to OSX max valuesize', updateValueCallback, maxValueSize);
        },
      },
    );
    const props = {
      uuid: '13333333-3333-3333-3333-800000000000',
      characteristics: [
        message,
      ],
    };
    super(props);
  }
}

export default TestService;