React Native Bluechat

Simple one-on-one bluetooth chatting module using Bluetooth Low Energy (BLE)

This library was created as part of a learning exercise to explore and expose native Android events to JS using Turbo Modules.
Initial usage was meant for during-flight communication through Bluetooth.
It only supporst New Architecture and backward compatability will not be implemented.

Warning

Android only: This library currently supports Android only. There are no plans for iOS support at this time.
This library is not suitable for production use. It is intended as a refererence implementation.

Features

• Advertise your device
• Scan for nearby BLE devices
• Connect to a selected BLE device
• Send and receive messages between connected devices

Getting started

npm i react-native-bluechat

yarn add react-native-bluechat

bun add react-native-bluechat

Setup Android

Add required permission to your AndroidManifest.xml file.

    <!-- Request legacy Bluetooth permissions on older devices. -->
    <uses-permission android:name="android.permission.BLUETOOTH" android:maxSdkVersion="30"/>
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" android:maxSdkVersion="30" />
    <!-- For Android 12 (API 31) or higher -->
    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADVERTISE" />
    <uses-permission android:name="android.permission.BLUETOOTH_SCAN"/>

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

You can use react-native-permissions or similar for requesting permissions.

Usage

Server: Device that starts GATT Server. This is a device that calls startAdvertising() method.
Client: Device that connects to GATT Server. A devices that scans using startScan() method and connects to a scanned device using connectToDevice(address) method.

Usual flow consists of

• Device A that wants to act as GATT server calls startAdvertising() method. This method will make a device discoverable by others.
• Device B starts scanning for devices using startsScan() and onBluetoothScanListener start emitting devices on the same SERVICE_UUID.
• onConnectionChangedListener will emit GATT Connection change to determine connection state as well as role (client or server).
• Based on your role, devices call sendMessageToServer(message) for client or sendMessageToClient(messages) for server.
• onMessageReceivedListener listens for messages comming from other device. This means you are not receiving your own sent messages.
• Finally, disconnectFromDevice will disconnect both client and server, as well as trigger onConnectionChangedListener marking as STATE_DISCONNECTED.

You can read more about Bluetooth Low Energy on Android docs

//Hook
import { useBluechat } from 'react-native-bluechat';

// ...

const {
  startScan,
  stopScan,
  startAdvertising,
  stopAdvertising,
  connectToDevice,
  disconnectFromDevice,
  btEnabled,
  isScanning,
  sendMessage,
  scannedDevices,
  messages,
  connectionState,
  isAdvertising,
} = useBluechat();

// ...

See Example

Contributing

See the contributing guide to learn how to contribute to the repository and the development workflow.

License

MIT

---

Made as learning process by Aironas Kulvelis