NodeJS Websocket Test Client

ws-client.js

let WebSocketClient = require('websocket').client;
let uuid = require('uuid');

function runClient(clientIndex) {
    const port = process.argv[2] || 9160;
    const id = `${uuid.v4()}-${port}-${clientIndex.toString().padStart(3, '-')}`;

    let timeoutId = null;

    const client = new WebSocketClient();

    client.on('connectFailed', function (error) {
        console.info(`[${clientIndex}] Connect failed: ` + error.toString());
    });

    client.on('connect', function (connection) {
        console.info(`[${clientIndex}] Client connected`);

        connection.on('error', function (error) {
            console.error(`[${clientIndex}] Connection error: ` + error.toString());
        });

        connection.on('close', function () {
            console.info(`[${clientIndex}] Connection closed`);

            if (timeoutId !== null) {
                clearTimeout(timeoutId);
            }
        });

        connection.on('message', function (message) {
            if (message.type === 'utf8' && clientIndex === 0) {
                console.info(`[${clientIndex}] Received: "${message.utf8Data}"`);
            }
        });

        function sendAnnouncement() {
            connection.sendUTF("Hi! I am " + id)
        }

        function sendNumbers() {
            timeoutId = null;
            if (connection.connected) {
                const number = Math.round(Math.random() * 0xFFFFFF);
                console.info(`[${clientIndex}] Sending: ${number}`)
                connection.sendUTF(number.toString());

                const time = 10000 + Math.round(Math.random() * 1000) * 1000;
                console.info(`[${clientIndex}] Pausing for: ${time / 1000}s`);
                timeoutId = setTimeout(sendNumbers, time);
            }
        }

        sendAnnouncement();
        sendNumbers();
    });

    client.connect(`ws://localhost:${port}/`);
}

for (let i = 0; i < 1000; i++) {
    runClient(i);
}

This is an extremely simple test program.

• It starts 1,000 websocket connections (clients) - see line 61.
• For each connection, it generates a random identifier as "uuid-port-index"
• It announces itself to the server after connecting using "Hi! I am [identifier]"
• It then sends a random number
• And then enters a timeout-based loop, sending another number at a random interval

The program detects application close and cancels the timeout, so it will shut down immediately if all connections fail. The connections are terminated "brutally" from the server, not cleanly (i.e. no "goodbye" sequence is sent to the server.)