A utility class that extracts the actual IP and port to which your remote executions are being routed to by Grid2

GridInfoExtracter.java

public class GridInfoExtracter{

	private static String[] getHostNameAndPort(String hostName, int port,
			SessionId session) {
		String[] hostAndPort = new String[2];
		String errorMsg = "Failed to acquire remote webdriver node and port info. Root cause: ";

		try {
			HttpHost host = new HttpHost(hostName, port);
			DefaultHttpClient client = new DefaultHttpClient();
			URL sessionURL = new URL("http://" + hostName + ":" + port + "/grid/api/testsession?session=" + session);
			BasicHttpEntityEnclosingRequest r = new BasicHttpEntityEnclosingRequest("POST", sessionURL.toExternalForm());
			HttpResponse response = client.execute(host, r);
			JSONObject object = extractObject(response);
			URL myURL = new URL(object.getString("proxyId"));
			if ((myURL.getHost() != null) && (myURL.getPort() != -1)) {
				hostAndPort[0] = myURL.getHost();
				hostAndPort[1] = Integer.toString(myURL.getPort());
			}
		} catch (Exception e) {
			logger.log(Level.SEVERE, errorMsg, e);
			throw new RuntimeException(errorMsg, e);
		}
		return hostAndPort;
	}

	private static JSONObject extractObject(HttpResponse resp) throws IOException, JSONException {
		BufferedReader rd = new BufferedReader(new InputStreamReader(resp.getEntity().getContent()));
		StringBuffer s = new StringBuffer();
		String line;
		while ((line = rd.readLine()) != null) {
			s.append(line);
		}
		rd.close();
		JSONObject objToReturn = new JSONObject(s.toString());
		return objToReturn;
	}
}

A typical call to this would be

GridInfoExtracter.getHostNameAndPort("localhost",4444,myRemoteWebDriver.getSessionId());

For those who don't use Java with Grid2, I still see value in this code. And rather than port it to another language, except where it is easy for one to port, one could just compile and execute the Java code to get the host and port via a command line / shell call from another language and then make use of that. That would mean of course the need to add to this class a main method that exposes a CLI interface.

Just for kicks a another more complicated method would be to load this class (or its methods) into an XML-RPC server, etc. making it possible to call the method over XML-RPC from any language.

Though of course, it would be nice if this code was ported to other WebDriver languages for native support (.NET/C#, Python, Ruby).

In c# I used this to get the hostname:

string url = "http://localhost:4444/grid/api/testsession?session=" + this.SessionId;
WebClient client = new WebClient();
Stream stream = client.OpenRead(url);
StreamReader reader = new StreamReader(stream);
Newtonsoft.Json.Linq.JObject jObject = Newtonsoft.Json.Linq.JObject.Parse(reader.ReadLine());
string host = new Uri(jObject.GetValue("proxyId").ToString()).Host;
stream.Close();

Console.WriteLine(host);

Note: You have to subclass RemoteWebDriver to get access to the SessionID.

And here's a snippet for Python 2.x, for getting hostname

import json
import urllib2 
from selenium import webdriver
from urlparse import urlparse
driver = webdriver.Remote( command_executor='http://localhost:4444/wd/hub',desired_capabilities={'browserName':'firefox'})
grid_node_extract_url = "http://localhost:4444/grid/api/testsession?session=%s" % driver.session_id
response = urllib2.urlopen(grid_node_extract_url).read()
node_host = urlparse(json.loads(response).get('proxyId')).hostname # use .port for port
print node_host
driver.quit()

For Python 3.x, making the following substitutions should work

import urllib.request
from urllib.parse import urlparse
from __future__ import print_function
response = urllib.request.urlopen(grid_node_extract_url).read()
print(node_host)

Here's the Ruby version (for v1.9+, for older versions, may have to resort to require 'net/http' and use that or something else instead of this REST client to make the HTTP request to get proxy URL with hostname)

#gem install rest-client & selenium as needed
require "selenium-webdriver"
require 'rest-client'
require 'json'
require 'uri'

caps = Selenium::WebDriver::Remote::Capabilities.firefox
driver = Selenium::WebDriver.for(:remote, :url => "http://localhost:4444/wd/hub", :desired_capabilities => caps)
grid_node_extract_url = "http://localhost:4444/grid/api/testsession?session=#{driver.session_id}"
response = RestClient.get grid_node_extract_url 
response = JSON.parse(response)
node_host = URI(response['proxyId']).host # use .port for port
puts node_host
driver.quit

getting lot of compilation error, can you please add the imported package as well, if possible? or are those still valid as this post is 10 years old?

@mdsapon - You should perhaps take a look at this library that I built as a follow up to this gist : https://github.com/RationaleEmotions/talk2grid

@mdsapon - You should perhaps take a look at this library that I built as a follow up to this gist : https://github.com/RationaleEmotions/talk2grid

Thanks a lot, this is amazing and works great with Selenium 3, but didn't work with Selenium 4. Do you have any plan to upgrade? Btw thanks a ton for creating this library

@mdsapon - I haven't yet delved into Grid4 completely. But its definitely on the cards. I didnt take this library so seriously because I didn't see many people even have a want to use it :D

I will work on sorting it out hopefully soon.