noble-buffer-bug.js

var noble = require('noble');

noble.on('stateChange', (state)=>{
    console.log(state);
  
    if (state === 'poweredOn') {
        noble.startScanning();
    } else {
        noble.stopScanning();
    }
});

noble.on('warning', function(warning) {
    console.warn('Warning: ', warning);
});

noble.on('discover', function(peripheral) {
    console.log(
        "Found device with local name: ", peripheral.advertisement.localName,
        " address ", peripheral.addressType, peripheral.address, 
        " service UUIDS ", peripheral.advertisement.serviceUuids,
        " RSSI ", peripheral.rssi,
        "\n" );
    
    // If the device is advertising a Nordic Secure DFU (0xfe59) service...
//     if (peripheral.advertisement.serviceUuids.indexOf('fe59') !== 1){
    
    // Check if the device is advertiing a "DfuTest" name.
    if (peripheral.advertisement.localName === 'DfuTest'){
        noble.stopScanning();

        peripheral.connect(onConnect.bind(peripheral));
    }
});


function onConnect(err) {
    if (err) { throw err; }
    
    // Discover the DFU service
    this.discoverServices(['fe59'], onDiscoverServices);
}

function onDiscoverServices(err, services) {
    if (err) { throw err; }

    var dfuService = services[0];
    // Discover the two characteristics of the DFU service
    dfuService.discoverCharacteristics(null, onDiscoverCharacteristics);
}

function onDiscoverCharacteristics(err, characteristics) {
    if (err) { throw err; }
    
//     console.log(characteristics);
    
    var controlEndpoint = characteristics.filter(function(i){ 
        return i.uuid === '8ec90001f3154f609fb8838830daea50'
    })[0];
    
    var dataEndpoint = characteristics.filter(function(i){ 
        return i.uuid === '8ec90002f3154f609fb8838830daea50'
    })[0];
    
    // Change this value to receive notifications more/less often
    var prn = 0x10;

    controlEndpoint.subscribe(function() {
        sendBytes(controlEndpoint, false, [
            0x02,   // 0x02 = "Set PRN" command. We expect a notification through the
            prn, 0x00,   // control characteristic every PRN (little-endian) data packets
        ])
        .then(function(){
            return waitForBytes(controlEndpoint);  // Should receive 0x60 0x02 0x01.
        })
        .then(function(){
            return sendBytes(controlEndpoint, false, [
                0x01,   // 0x01 = "Create object". The target should allocate ...
                0x01,   // ...in the command region (0x01) a buffer...
                0xFF, 0x00, 0x00, 0x00 // ... of 0x000000FF (little-endian) bytes.
            ]);
        })
        .then(function(){
            return waitForBytes(controlEndpoint);  // Should receive 0x60 0x01 0x01.
        })
        .then(function(){ return sendDataBlock(controlEndpoint, dataEndpoint, prn); })
        .then(function(){ return sendDataBlock(controlEndpoint, dataEndpoint, prn); })
        .then(function(){ return sendDataBlock(controlEndpoint, dataEndpoint, prn); })
        .then(function(){ return process.exit(0); })
    });
}

// Returns a Promise
function sendBytes(endpoint, writeWithoutResponse, bytes) {
    bytes = new Buffer(bytes);
    
    // Uncomment the timeout to add a synthetic delay
    return new Promise(function(res, rej){
//         setTimeout(function() {
            endpoint.write(bytes, writeWithoutResponse, function(err) {
                if (writeWithoutResponse) {
                    console.log(' data --> ', bytes);
                } else {
                    console.log(' cmnd --> ', bytes);
                }

                if (err) rej(err); else res();
            });
//         }, 250);
    });
}

// Returns a Promise
function waitForBytes(endpoint) {
    return new Promise(function(res, rej){
        endpoint.once('data', function(bytes) {
            console.log(' recv <-- ', bytes);
            res(bytes);
        });
    });
}

// Sends a bunch of data blocks and then waits for a notification.
function sendDataBlock(controlEndpoint, dataEndpoint, prnLeft) {
    if (prnLeft <= 0) {
        return waitForBytes(controlEndpoint);   // Should receive 0x60 0x03 [offset] [crc]
    }
    return sendBytes(dataEndpoint, true, [1,2,3,4,5,6,7,8])
    .then(function(){
        return sendDataBlock(controlEndpoint, dataEndpoint, prnLeft - 1);
    })
}