Ethereum: Starting a websocket in a function (Binance Websocket)

February 5, 2025 By CRYPTOCURRENCY No Comments

Starting and stopping a WebSocket connection from a GUI application using Binance Websocket

As a developer, you may have come across situations where you need to control the flow of an application from a user interface (GUI) application. In this article, we will explore how to create a simple GUI-based system that starts and stops a WebSocket connection using the Binance Websocket library.

Prerequisites

Ethereum: Starting a websocket in a function (Binance Websocket)

  • Install Node.js on your computer (node.js.org).
  • Make sure you have installed the existing Binance Websocket library (npm install binance-websocket).
  • Create a new GUI application (e.g. using Electron or a framework like React, Angular, etc.).
  • Set up a WebSocket connection using the Binance API.

Code example

// Import the required libraries
const { Websocket } = require('binance-websocket');
const { CreateInterface } = require('readline');
// Initiate a WebSocket connection
const websocket = new Websocket({
host: 'your-binance-exchange.com',
port: 3000,
});
// Set up the GUI event loop
const gui = CreateInterface({
input: process.stdin,
output: process.stdout,
});
// Function to start/stop WebSocket connection
function handleStart() {
websocket.on('connect', () => {
console.log('WebSocket connection established. Starting...');
// Start a new task when the user presses Enter
gui.once('line', line => {
if (line === 'START') {
websocket.send({ command: 'start' });
setTimeout(() => {
console.log('Stopping WebSocket connection...');
websocket.close();
}, 5000);
}
});
// Start a new task when the user presses Ctrl+C
process.on('SIGINT', () => {
gui.kill();
});
});
}
// Function to start/stop a WebSocket connection from the command line
function handleStartCommand() {
const readline = require('readline');
const rl = readline.createInterface({
input: process.stdin,
output: process.stdout,
});
rl.question('Start (type "STOP" to stop)', answer => {
if (answer.toLowerCase() === 'start') {
websocket.send({ command: 'start' });
setTimeout(() => {
console.log('Stopping WebSocket connection...');
websocket.close();
handleStopCommand();
}, 5000);
} else if (answer.toLowerCase() === 'stop') {
handleStopCommand();
} else {
console.error('Invalid input. Exiting...');
handleStartCommand();
}
});
}
// WebSocket connection stop function
function handleStopCommand() {
websocket.send({ command: 'close' });
}
// Main program loop
o (true) {
handleStart();
}

How ​​it works

  • The handleStart function sets up a WebSocket event listener for the connect event.
  • When the user presses Enter, the WebSocket connection is established and the user presses Ctrl+C to start a new task.
  • Using Readline.js, a simple text interface is created where users can type “START” to start the WebSocket connection or “STOP” to stop it.

Tips and Variations

  • To make the GUI more interactive, consider adding buttons to start/stop the WebSocket connection.
  • For a native desktop application, you can use a more advanced GUI library such as Electron or React.
  • If you prefer a command-line interface, modify the handleStartCommand function to accept input from the user via the console.
  • To persist data between sessions, consider using a database or file storage.

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