Puppeteer - How to connect WSEndpoint using local IP address?

Question

I have two Node.js scripts for puppeteer automation.

1) launcher.js

This Puppeteer script launches a chrome browser and disconnects the chrome so that it can be connected by using WSEndpoint.

const puppeteer = require('puppeteer');

module.exports = async () => {
    try {
        const options = {
            headless: false,
            devtools: false,
            ignoreHTTPSErrors: true,
            args: [
                `--no-sandbox`,
                `--disable-setuid-sandbox`,
                `--ignore-certificate-errors`
            ]
        };
        const browser = await puppeteer.launch(options);
        let pagesCount = await browser.pages();
        const browserWSEndpoint = await browser.wsEndpoint();
        // console  WSEndPoint say : "ws://127.0.0.1:42207/devtools/browser/dbb2525b-ce44-43c2-a335-ff15d0306f36"
        console.log("browserWSEndpoint----- :> ", browserWSEndpoint);
        await browser.disconnect();
        return browserWSEndpoint;
    } catch (err) {
        console.error(err);
        process.exit(1);
        return false;
    }
};

2) connector.js

Launches headless chrome and tries to connect chrome by WSEndPoint by various hostnames. If I ran this script with run command as node connector.js localhost, it tries to connect WSEndpint with localhost as the hostname.

const puppeteer = require('puppeteer');
const launcher = require('./launcher');

(async (host) => {
    try {
        let WSEndPoint = await launcher();
        WSEndPoint = WSEndPoint.replace('127.0.0.1', host);
        console.log("WSENDPOINT :", WSEndPoint);
        const browser = await puppeteer.connect({
            browserWSEndpoint: WSEndPoint,
            ignoreHTTPSErrors: true
        });
        let pagesCount = await browser.pages();
        console.log("Pages available :> ", pagesCount.length);
        // const browserWSEndpoint = await browser.wsEndpoint();
        await browser.disconnect();
        process.exit(1);
        return true;
    } catch (err) {
        console.error(err);
        process.exit(1);
        return false;
    }
})(process.argv[2]);

But I can't connect the WSEndpint of the chrome using my local IP address ( say 192.168.1.36). Why?

The error message is

{ Error: connect ECONNREFUSED 192.168.1.33:36693
    at Object._errnoException (util.js:992:11)
    at _exceptionWithHostPort (util.js:1014:20)
    at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1186:14)
  code: 'ECONNREFUSED',
  errno: 'ECONNREFUSED',
  syscall: 'connect',
  address: '192.168.1.33',
  port: 36693 }

Answer 1

You can proxy the websocket and connect to the proxy instead. I tested it on my server and it ran successfully.

Here is how we create a websocket server using http-proxy,

Server

const httpProxy = require("http-proxy");
const host = "0.0.0.0";
const port = 8080;
async function createServer(WSEndPoint, host, port) {
  await httpProxy
    .createServer({
      target: WSEndPoint, // where we are connecting
      ws: true,
      localAddress: host // where to bind the proxy
    })
    .listen(port); // which port the proxy should listen to
  return `ws://${host}:${port}`; // ie: ws://123.123.123.123:8080
}

Then when we run it, we create a proxy server and listen to the ws endpoint instead. I am not exporting it to keep the explanation simpler.

// your other codes
const pagesCount = (await browser.pages()).length; // just to make sure we have the same stuff on both place
const browserWSEndpoint = await browser.wsEndpoint();
const customWSEndpoint = await createServer(browserWSEndpoint, host, port); // create the server here
console.log({ browserWSEndpoint, customWSEndpoint, pagesCount });
// your other code here

When I run on the server, we get the following,

On the droplet,

➜  node index.js 
{ browserWSEndpoint: 'ws://127.0.0.1:45722/devtools/browser/df0ca6a9-48ba-4962-9a20-a3a536d403fa',
  customWSEndpoint: 'ws://0.0.0.0:8080',
  pagesCount: 1 }

Client

Then we connect it like this,

const puppeteer = require("puppeteer-core");
(async serverAddr => {
  const browser = await puppeteer.connect({
    browserWSEndpoint: `ws://${serverAddr}`,
    ignoreHTTPSErrors: true
  });
  const pagesCount = (await browser.pages()).length;
  const browserWSEndpoint = await browser.wsEndpoint();
  console.log({ browserWSEndpoint, pagesCount });
})(process.argv[2]);

On my guest computer,

➜  node index.js "123.123.123.123:8080"
Pages available :>  1
{ browserWSEndpoint: 'ws://123.123.123.123:8080' }

This way we can host on multiple server and route between them, scale away and more if needed.

Peace!