Starting and Stopping a WebSocket Connection from a GUI Application using Binance Websocket
As a developer, you may have encountered situations where you need to control the flow of your program from within a user interface (GUI) application. In this article, we’ll explore how to create a simple GUI-based system that starts and stops a WebSocket connection using the Binance websocket library.
Prerequisites
- Install Node.js on your computer (
node.js.org).
- Ensure you have an existing Binance websocket library installed (
npm install binance-websocket).
- Create a new GUI application (e.g., using Electron or a framework like React, Angular, etc.).
- Set up the WebSocket connection with the Binance API.
Example Code
// Import required libraries
const { Websocket } = require('binance-websocket');
const { createInterface } = require('readline');
// Initialize the 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 the 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 the 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();
}
});
}
// Function to stop the WebSocket connection
function handleStopCommand() {
websocket.send({ command: 'close' });
}
// Main program loop
while (true) {
handleStart();
}
How it works
- The
handleStartfunction sets up a WebSocket event listener for theconnectevent.
- When the user presses Enter, the WebSocket connection is established and a new task starts when the user presses Ctrl+C.
- A simple text-based interface is created using Readline.js, 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.
- You can use a more advanced GUI library like Electron or React for a native desktop application.
- If you prefer a command-line interface, modify the
handleStartCommandfunction to accept input from the user through the console.
- To persist data between sessions, consider using a database or file storage.
