Network emulation with Chrome DevTools

Question

I'm currently using version 4.0.0-alpha5 of the Selenium Webdriver NuGet package. So this code only works when the DevTools are open in Chrome Version 98, but I don't understand why. As far as I know, should this always work, but the only thing that always works is the offline state.

devTools = driver as IDevTools;
session = devTools.CreateDevToolsSession();
EmulateNetworkConditionsCommandSettings command = new EmulateNetworkConditionsCommandSettings();

command.Latency = latencyInMilliseconds;
command.DownloadThroughput = downloadLimitKbps * 1024; // Kilobytes to bytes per second
command.UploadThroughput = uploadLimitKbps * 1024; // Kilobytes to bytes per second
command.Offline = false;

session.Network.EmulateNetworkConditions(command);
//session.SendCommand(command);

You will also find this code on this site, so I don't know what I'm doing wrong. Maybe this is a bug.

A solution would be to just open the DevTools during the test, but pressing a hotkey with selenium like F12 or any other Devtools hotkey doesn't work for me. I tried it with Actions and also with sending keys on an object like it is described here.

Another solution would maybe be to directly execute a CDP command, but I only found examples in Java and didn't find out how to do this. This is how you do it in Java:

driver.executeCdpCommand(commandString);

Thank you for reading, any help would be really appreciated.

score 1 · Accepted Answer · answered Apr 05 '22 at 12:39

My issue was that I forgot to add the Network.Enable command, so don't forget to call it before you do the other stuff. This is the code I use now, without being version specific. (works until Selenium 4.0 alpha 5)

public void LimitNetwork(int latencyInMilliseconds, long downloadLimitMbps, long uploadLimitMbps)
{
    IDevTools devTools = driver as IDevTools;
    session = devTools.CreateDevToolsSession();
    session.Network.Enable(new EnableCommandSettings());

    EmulateNetworkConditionsCommandSettings command = new EmulateNetworkConditionsCommandSettings();

    command.Latency = latencyInMilliseconds;
    command.DownloadThroughput = downloadLimitMbps * 125000; // Mbps to bytes per second
    command.UploadThroughput = uploadLimitMbps * 125000; // Mbps to bytes per second
    command.Offline = false;

    session.Network.EmulateNetworkConditions(command);
}

If session.Network.EmulateNetworkConditions doesn't work you can also try session.SendCommand(command);

score 1 · Answer 2 · answered Jul 21 '23 at 13:50

1

Selenium 4.10.0 Chrome 114

        var devTools = driver as IDevTools;

        var session = devTools.GetDevToolsSession();

        session.Domains.Network.EnableNetwork();

        session.SendCommand(new EmulateNetworkConditionsCommandSettings()
        {
            Offline = false,
            UploadThroughput = 500 * 1024 / 8, // 500 Kbps
            ConnectionType = ConnectionType.Cellular3g
        });

Needed usings:

using OpenQA.Selenium.DevTools;
using OpenQA.Selenium.DevTools.V114.Network;

answered Jul 21 '23 at 13:50

Denis Koreyba

3,144
1
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This works for me, thank you. I am new to Selenium/Chrome. Why do we have to specify a specific version number in the using statements, such as V114? – Sabuncu Aug 30 '23 at 11:58
@Sabuncu this same question doesn't allow me to sleep at night:) I screem WHYYYYY???? – Denis Koreyba Aug 30 '23 at 12:18
:) Since posting my comment above, I learned about the BiDi API. Maybe that'll fix things. – Sabuncu Aug 30 '23 at 12:20
@Sabuncu would you like to tell more? – Denis Koreyba Aug 31 '23 at 11:53
Here's the page that warns about using devtools, and recommends using BiDi instead: https://www.selenium.dev/documentation/webdriver/bidirectional/chrome_devtools/ – Sabuncu Aug 31 '23 at 15:15

score 0 · Answer 3 · answered Mar 09 '22 at 18:39

    public class ChromeNetworkConditionsContext : IDisposable
    {
        private readonly ChromeDriver _chromeDriver;
        private readonly ILogger _logger;

        public ChromeNetworkConditionsContext(ChromeDriver chromeDriver, ILogger logger)
        {
            _chromeDriver = chromeDriver;
            _logger = logger;
        }

        public void Dispose()
        {
            _logger.Information("Resetting network conditions");
            _chromeDriver.NetworkConditions = new();
        }
    }

        public IDisposable SetRequestsLatency(TimeSpan latency)
        {
            _log.Information($"Enabling {latency} requests latency");
            var driver = _driverProvider.GetDriver();
            if (driver is ChromeDriver chromeDriver)
            {
                chromeDriver.NetworkConditions = new()
                {
                    Latency = latency
                };
                return new ChromeNetworkConditionsContext(chromeDriver, _log);
            }

            throw new WebDriverException($"NetworkConditions is not handled for {driver.GetType().Name}");
        }

That works for me. It adds a delay before each API call from UI.

Chrome version 99.

<PackageReference Include="Selenium.WebDriver" Version="4.1.0" />

Thank you for sharing your solution, I found my mistake. :) – Schmebi Apr 05 '22 at 12:42 — Schmebi, Apr 05 '22 at 12:42

Network emulation with Chrome DevTools

3 Answers3