[🚀 Feature]: Allow setting the proxy/HttpClientHandler for DriverService

[Schnutzel]

Description

If the machine running Selenium is configured with a system proxy, and for some reason the proxy isn't bypassed for localhost, then the DriverService is unable to connect to the ChromeDriver because it uses the default HttpClient.

I want to be able to set the proxy (or the HttpClientHandler) in the DriverService's HttpClient, so that we can bypass the system proxy.

Edit for clarification: I'm using C#.

Have you considered any alternatives or workarounds?

A possible workaround is to set HttpClient.DefaultProxy, but this might cause a problem if other parts of the code rely on the system proxy settings.

[selenium-ci]

@Schnutzel, thank you for creating this issue. We will troubleshoot it as soon as we can.

Selenium Triage Team: remember to follow the Triage Guide

[diemol]

We have documented some of those, please check https://www.selenium.dev/documentation/webdriver/drivers/http_client/

[Schnutzel]

We have documented some of those, please check https://www.selenium.dev/documentation/webdriver/drivers/http_client/

Thanks, maybe I wasn't clear, I'm working with C#. It seems like ClientConfig isn't available there.

[diemol]

@nvborisenko do you know?

[nvborisenko]

AFAIK Selenium in .NET didn't consider to "modify" HttpClient/Handler by end-users. There is a possibility to "modify" it only by custom driver services, like Appium do: https://github.com/appium/dotnet-client/blob/main/src/Appium.Net/Appium/Service/AppiumHttpCommandExecutor.cs

For end-users there is a possibility to customize only for RemoteWebDriver, when user uses:

public RemoteWebDriver(ICommandExecutor commandExecutor, ICapabilities capabilities)

where ICommandExecutor is something custom defined/implemented by user.

I don't think everything above is for normal end-users.

My thoughts:

1. Apply workaround: disable proxy for localhost using NO_PROXY env variable: https://learn.microsoft.com/en-us/dotnet/api/system.net.http.httpclient.defaultproxy?view=net-9.0#remarks
2. Hmm, if Chrome/Edge/AnyDriver is really supposed to always interact with local driver service, then should we ignore proxy by default? So we can look at this feature request as a bug and just fix it.
3. Be more friendly for end-users and allow to modify HttpClient/Handler with friendly API (new feature). Like currently user is able to specify driver command timeout, which is directly applied to HttpClient/Handler options. So just review this approach and provide better mechanism (actually core API).