Calling WCF REST Service from ASP.Net does not return

Question

I have a WCF service implemented as windows service and I need to call this service from a ASP.Net application. The WCF service responds using a custom formatter.

I have tested the code below and it works if I run it from a console application or even from a unit testing project but it hangs if I call it from an ASP.Net application.

I have been able to debug the request in the WCF code and I see it responds, but the client does not receive the response.

Does anyone know any limitation that can impede the response to reach the ASP.NET client application?

public async Task<SomeDataToken> PostData()
{
    const string SomeMediaTypeName = "application/some-media-type";
    SomeDataToken request = new SomeDataToken();           

    using (var client = new HttpClient())
    {
        var formatter = new SomeMedyaTypeFormatter();
        client.BaseAddress = new Uri(@"http://localhost:8001/");
        client.DefaultRequestHeaders.Accept.Clear();
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue(SomeMediaTypeName));
        client.DefaultRequestHeaders.TryAddWithoutValidation("Content-Type", SomeMediaTypeName);

        try
        {
            var httpResponse = await client.PostAsync("SomeController/SomeAction", request, formatter);
            var result = await httpResponse.Content.ReadAsAsync<SomeDataToken>(new[] { formatter });
            return result;
        }
        catch
        {
            return null;
        }

    }
}

Answer 1

It seems the problem is not related to WCF but to the way ASP.Net / MVC manages async, as it creates its own threads.

When making async calls from any sincrhonous part of an ASP.NET / MVC application, pay attention to add .ConfigureAwait(false) to the PostAsync or GetAsync methods. Otherwise, the PostAsync or GetAsync call will hang.