[🚀 Feature]: [dotnet] Expose HttpClient initialization in HttpCommandExecutor to make it possible for overriding

[nvborisenko]

Feature and motivation

HttpCommandExecutor entirely closed for any overriding to create HttpClient:

selenium/dotnet/src/webdriver/Remote/HttpCommandExecutor.cs

Line 224 in 6836d0a

private HttpClient CreateHttpClient()

It will be good to make it protected virtual. Proposed API:

protected virtual HttpClientHandler CreateHttpClientHandler()
protected virtual HttpClient CreateHttpClient()

It also exposes initialization of HttpClientHandler to make it possible to customize it, like ignoring certificate validation (appium/dotnet-client#455).

Usage example

class MyHttpCommandExecutor : HttpCommandExecutor
{
  override CreateHttpClientHandler()
  {
    var handler = base.CreateHttpClientHandler();
    handler.SomeProperty = "abc";
    return handler;
  }
}

[github-actions]

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

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Thank you!

[nvborisenko]

It will be amazing to implement it and include into upcoming release for our Appium friends. @RenderMichael do you have any objections about proposed API?

[RenderMichael]

I think the goal is a good one.

An alternative API would be to modify the existing HttpClient and HttpClientHandler:

public class MyHttpCommandExecutor : HttpCommandExecutor
{
  protected override void ModifyHttpClientHandler(HttpClientHandler handler)
  {
    httpHandler.ServerCertificateCustomValidationCallback = 
        HttpClientHandler.DangerousAcceptAnyServerCertificateValidator;
  }

  protected override void ModifyHttpClient(HttpClient client)
  {
    // anything else here
  }
}

This helps ensure nobody misses calling var handler = base.CreateHttpClientHandler();, prevents any null returns, and leaves things in a safer state overall.

[nvborisenko]

ModifyHttpClientHandler wants to be an Action, like ConfigureServices(container). I prefer more Create*, then user is able to return new * he wants, not only modified. So more flexibility for advanced users.

[nvborisenko]

Done, thanks team.