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 handleStart function sets up a WebSocket event listener for the connect event.

• 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 handleStartCommand function to accept input from the user through the console.

• To persist data between sessions, consider using a database or file storage.