Improve Csla.Channels.Http.HttpProxy

[ctescu]

HttpProxy uses WebClient for all sync call.
WebClient is marked like obsolete https://learn.microsoft.com/en-us/dotnet/api/system.net.webclient?view=net-8.0 and suggested to be replaced with sync calls from HttpClient.

[rockfordlhotka]

Thank you @ctescu, this will be a good enhancement for more modern versions of .NET.

We'll need to use compiler directives to continue using WebClient for netfx targets (4.6.2, 4.7.2, 4.8) I assume?

[StefanOssendorf]

I'm not so sure about that. Yeah there is a Send() method on HttpClient but no extension methods like PostAsync, GetAsync and so on as sync versions. And I'm not sure if we should implement such methods for our usage 🤔.

If we plan to implement that we should consider making this an opt-in feature. Currently some stuff for WebClient is configured via ServicePointManager which is not used in any way by HttpClient. So that might be more impactfull than just changing our implementation.

[ctescu]

Dear @StefanOssendorf now DefaultWebClient uses req.Timeout = timeout.Milliseconds; that will trigger the exception that timeout must be greater than 0 or infinite,.
I don't think the current implementation works as expected, for me to work with sync call I needed to create a new WebClient and use TotalMiliseconds.
For async call I had the problem from https://www.aspnetmonsters.com/2016/08/2016-08-27-httpclientwrong/ and changed the implementation to https://josef.codes/you-are-probably-still-using-httpclient-wrong-and-it-is-destabilizing-your-software/ with [IHttpClientFactory] .

[StefanOssendorf]

Thanks for pointing the bug out in our current sync calls. I've created an issue to fix that.

But I don't get the part with the async call problem. We have since v8 IIRC, this option for the HttpProxy:

csla/Source/Csla/DataPortalClient/HttpProxyOptions.cs

Lines 34 to 37 in 60bd0b3

	/// <summary>
	/// Gets or sets the factory to obtain an <see cref="HttpClient"/> to make server calls.
	/// </summary>
	public Func<IServiceProvider, HttpClient> HttpClientFactory { get; set; } = DefaultHttpFactory;

and we are using it to setup the HttpProxy

csla/Source/Csla/DataPortalClient/HttpProxyExtensions.cs

Lines 34 to 35 in 60bd0b3

	var client = proxyOptions.HttpClientFactory(sp);
	return new HttpProxy(applicationContext, client, proxyOptions, dataPortalOptions);

So if you want to use the IHttpClientFactory (which I do at work) you only have to configure it's usage in the registration and you are done.

[ctescu]

You are right about async call, was a misusage in my code.