Tag: web usb api

The Source Code

Init The Project

Creating a new project and running the npm create script

mkdir web-iot && cd web-iot
npm init

The package.json looks like this:

{
  "name": "@mastashake08/web-iot",
  "version": "1.0.0",
  "description": "Connect to your IoT devices via usb, serial, NFC or Bluetooth",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "repository": {
    "type": "git",
    "url": "git+https://github.com/mastashake08/web-iot.git"
  },
  "keywords": [
    "iot",
    "webserial",
    "bluetooth",
    "webusb",
    "nfc"
  ],
  "author": "Mastashake",
  "license": "MIT",
  "bugs": {
    "url": "https://github.com/mastashake08/web-iot/issues"
  },
  "homepage": "https://github.com/mastashake08/web-iot#readme"
}

The index.js file

This is the entry point for the package and it simply exports our classes

import { WebIOT } from './classes/WebIOT'
import { NFCManager } from './classes/NFCManager'
import { BluetoothManager } from './classes/BluetoothManager'
import { SerialManager } from './classes/SerialManager'
import { USBManager } from './classes/USBManager'
export {
  WebIOT,
  NFCManager,
  BluetoothManager,
  SerialManager,
  USBManager
}

The WebIOT Class

This is the base class for all our managers. It contains some functions for sending data to a remote server, a functionality that’s usually needed when dealing with IoT devices.

export class WebIOT {
  debug = false
  constructor(debug = false) {
    this.debug = debug
  }
  sendData (url, options = {}, type='fetch') {
      try {
        switch (type) {
          case 'fetch':
            return this.sendFetch(url, options)
            break;
          case 'beacon':
            return this.sendBeacon(url, options)
            break;
          default:
            return this.sendFetch(url, options)
        }
      } catch (e) {
        this.handleError(e)
      }
  }

  sendBeacon (url, data) {
    try {
      navigator.sendBeacon(url, data)
    } catch (e) {
      this.handleError(e)
    }
  }

  async sendFetch(url, options) {
    try {
      const res = await fetch(url, options)
      if (res.status != 200) {
        throw new Error(`HTTP error! Status: ${res.status}`)
      } else {
        return res
      }
    } catch (e) {
      this.handleError(e)
    }
  }

  handleError (e) {
    if(this.debug) {
      alert(e.message)
      console.log(e.message)
    } else {
      throw e
    }
  }
}

The USBManager

The USBManager is responsible for working with USB devices.

import { WebIOT } from './WebIOT'
export class USBManager extends WebIOT{
  #devices = {}
  #selectedDevice = {}
  constructor (debug = false) {
    super(debug)
  }

  async getDevices () {
    this.devices = await navigator.usb.getDevices()
    return this.devices
  }

  async requestDevice(options = {}) {
    this.selectedDevice = this.selectedDevice = await navigator.usb.requestDevice(options)
    return this.selectedDevice
  }

  async openDevice() {
    await this.connectDevice()
  }

  async closeDevice(options) {
    await this.selectedDevice.close()
  }

  async connectDevice() {
    await this.selectedDevice.open();
    if (this.selectedDevice.configuration === null)
      await this.selectedDevice.selectConfiguration(1);
    await this.selectedDevice.claimInterface(0);
    return this.selectedDevice

  }

  async writeData(endpointNumber, data) {
    return await this.selectedDevice.transferOut(endpointNumber, data)
  }
  async readData(endpointNumber, data) {
    return await this.selectedDevice.transferIn(endpointNumber, data)
  }
}

}

The SerialManager

The SerialManager class manages serial connections.

import { WebIOT } from './WebIOT'
export class SerialManager extends WebIOT {
  #ports = {}
  #selectedPort = {}
  constructor (debug = false) {
    super(debug)
  }

  async getPorts () {
    this.ports = await navigator.serial.getPorts()
    return this.ports
  }

  async requestPort(options = {}) {
    this.selectedPort = this.selectedPort = await navigator.serial.requestPort(options)
    return this.selectedPort
  }

  async openPort(options) {
    await this.selectedPort.open(options)
  }

  async closePort(options) {
    await this.selectedPort.close()
  }

  async getInfo() {
    await this.selectedPort.getInfo()
  }

  async setSignals(options) {
    await this.selectedPort.setSignals(options)
  }

  async getSignals() {
    return await this.selectedPort.getSignals()
  }

  async readData () {
    const reader = this.selectedPort.readable.getReader();

    // Listen to data coming from the serial device.
    while (true) {
      const { value, done } = await reader.read();
      if (done) {
        // Allow the serial port to be closed later.
        reader.releaseLock();
        break;
      }
      // value is a Uint8Array.
      return value
    }
  }

  async writeData(data) {
    const writer = port.writable.getWriter();

    await writer.write(data);
    // Allow the serial port to be closed later.
    writer.releaseLock();
  }
}

The BluetoothManager

The BluetoothManager is responsible for managing Bluetooth devices

import { WebIOT } from './WebIOT'
export class BluetoothManager extends WebIOT {
  #bluetooth = {}
  #device = {}
  #server = {}
  #selectedService = {}
  #services = {}
  #characteristic = {}
  #currentValue = null
  constructor (debug = false) {
    super(debug)
    navigator.bluetooth.getAvailability().then((available) => {
      if (available) {
        this.bluetooth = navigator.bluetooth
      } else {
        alert("Doh! Bluetooth is not supported");
      }
    });

  }

  async getDevices (options = {acceptAllDevices: true}) {
    return await this.requestDevice(options)
  }

  async requestDevice (options) {
    try {
      this.device = await navigator.bluetooth.requestDevice(options)
      return this.device
    } catch(e) {
      alert(e.message)
    }
  }

  async connectToServer () {
    this.server = await this.device.gatt.connect()
  }

  async getService (service) {
    this.selectedService = await this.server.getPrimaryService(service)
    return this.selectedService
  }

  async getServices () {
    this.services = await this.server.getPrimaryServices()
    return this.services
  }

  async getCharacteristic (char) {
    this.characteristic = await this.selectedService.getCharacteristic(char)
    return this.characteristic
  }

  async getCharacteristics () {
    return await this.selectedService.getCharacteristics()
  }

  async getValue () {
    this.currentValue = await this.characteristic.readValue()
    return this.currentValue
  }

  async writeValue(data) {
    await this.characteristic.writeValue(data)
  }
}

The NFCManager

Work with NFC tags with the NFCManager

import { WebIOT } from './WebIOT'
export class NFCManager extends WebIOT {
  #nfc = {}
  constructor (debug = false) {
    super(debug)
    if ('NDEFReader' in window) { /* Scan and write NFC tags */
      this.nfc = new NDEFReader()
    } else {
      alert('NFC is not supported in your browser')
    }

  }

  startNFC () {

    this.nfc = new NDEFReader()
  }
  async readNFCData (readCb, errorCb = (event) => console.log(event)) {
    this.nfc.onreading = readCb()
    await this.nfc.scan()
  }
  async writeNFCData (records, errorCb = (event) => console.log(event)) {
    try {
      await this.nfc.write(records)
    } catch (e) {
      errorCb(e)
    }
  }
  async lockNFCTag(errorCb = (event) => console.log(event)) {
    try {
      await this.nfc.makeReadOnly()
    } catch(e) {
      errorCb(e)
    }
  }
  static generateNFC () {
    return new NDEFReader()
  }
}

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