WebSockets

The Nord application provides real-time data streaming via WebSocket connections. This allows for efficient updates of market data such as candle charts.

Chart Data Streaming

The application uses a dedicated WebSocket endpoint to stream real-time candle data for charts.

Nord API URLs:

• Mainnet: wss://zo-mainnet.n1.xyz
• Devnet: wss://zo-devnet.n1.xyz

Endpoint

The WebSocket URL is constructed using the base Nord URL extended with the specific symbol and resolution.

WS_URL = {NORD_API_URL}/ws/candle@{symbol}:{resolution}

• symbol: The trading pair symbol (e.g., SOLUSD, BTCUSD).
• resolution: The chart resolution timeframe (e.g., 1, 5, 60, 1D).

Connection Lifecycle

Each WebSocket connection is dedicated to a specific symbol and resolution pair.

1. Initialization: When a chart component mounts or the user changes the symbol/resolution, a new WebSocket connection is established.
2. Multiplexing: The client implementation (streaming.ts) handles multiplexing, allowing multiple subscribers (e.g., different UI components) to listen to the same data stream without opening duplicate sockets.
3. Cleanup: Connections are automatically closed when no subscribers remain for a specific channel or when switching symbols, ensuring efficient resource usage.

Message Format

The server sends JSON-formatted messages representing candle updates. The CandleUpdate interface is defined as follows:

interface CandleUpdate {
  res: string; // Resolution of the candle data (e.g., "1", "1D")
  mid: number; // Market identifier
  t: number;   // Timestamp in seconds
  o: number;   // Open price
  h: number;   // High price
  l: number;   // Low price
  c: number;   // Close price
  v?: number;  // Volume (optional)
}

Usage Example

The following example demonstrates how to establish a connection and handle incoming messages.

// Define the Nord API URLs for different environments
const NORD_URL_MAINNET = "wss://zo-mainnet.n1.xyz";
const NORD_URL_DEVNET = "wss://zo-devnet.n1.xyz";
 
// Select the environment
const nordUrl = NORD_URL_MAINNET;
 
const symbol = "SOLUSD";
const resolution = "1";
 
const url = `${nordUrl}/ws/candle@${symbol}:${resolution}`;
 
const socket = new WebSocket(url);
 
socket.onopen = () => {
    console.log(`Connected to ${symbol} ${resolution} stream`);
};
 
socket.onmessage = (event) => {
    const data: CandleUpdate = JSON.parse(event.data);
    console.log("New candle data:", data);
    // Process data (e.g., update chart)
};
 
socket.onclose = (event) => {
    console.log("Connection closed", event.code, event.reason);
};
 
socket.onerror = (event) => {
    console.error("WebSocket error", event);
};