React Native

Once you've started receiving data from a device into your app, you can start sending this data to Terra's websocket server.

Prerequisite

Before following the steps below, make sure you've followed the guide to stream data from a wearable device to your app

Streaming to Terra's Server

You'll have previously set up a local stream using startRealtime without a token. To also send data to Terra's server, pass a streaming token as the third argument:

import { getUserId, startRealtime, Connections, DataTypes } from 'react-native-terra-rt-react';

const startServerStreaming = async () => {
  // 1. Get the Terra user ID
  const { userId } = await getUserId();
  if (!userId) return;

  // 2. Get a streaming token from your backend
  const tokenResponse = await fetch('YOUR_BACKEND_URL/streaming-token', {
    method: 'POST',
    body: JSON.stringify({ userId }),
  });
  const { token } = await tokenResponse.json();

  // 3. Start streaming with the token — data goes to BOTH your app and Terra's server
  const dataTypes = [DataTypes.HEART_RATE, DataTypes.STEPS];
  await startRealtime(Connections.BLE, dataTypes, token);
};

The token parameter is the only difference from local-only streaming. When provided, the SDK opens a websocket connection to Terra and relays data in real time.

Listen for websocket connection status via the ConnectionUpdate event:

import { NativeEventEmitter, NativeModules } from 'react-native';

const connectionEmitter = new NativeEventEmitter(NativeModules.ConnectionHandler);
connectionEmitter.addListener('ConnectionUpdate', (connected: boolean) => {
  console.log('Websocket connected:', connected);
});

Your backend should generate the streaming token by calling:

Stream - Generate user token

post

Endpoint for generation of a token for a user (producer) connection

Authorizations

apiKeyAuth & devIdAuth

x-api-keystringRequired

dev-idstringRequired

Query parameters

idstringOptional

The ID of the user to generate a token for

Header parameters

dev-idstringRequired

your developer ID

x-api-keystringRequired

your API key

Responses

200

Successful response

application/json

tokenstringOptionalExample: OTYwNWFi5ZWQMTAxMjg0Y2Qw.gzrPzZcS3Gy8QDOxbiPRwu30PTB3VxW0eE

403

Forbidden

text/plain

post

/auth/user

HTTPcURLJavaScriptPython

POST /auth/user HTTP/1.1
Host: ws.tryterra.co
x-api-key: text
dev-id: text
Accept: */*

{
  "token": "OTYwNWFi5ZWQMTAxMjg0Y2Qw.gzrPzZcS3Gy8QDOxbiPRwu30PTB3VxW0eE"
}