A logging handler for the HttpClient in ASP.NET Web API. It logs the body content to a file. That code can be replaced for some other stream.

gistfile1.cs

public class LogginHandler : DelegatingHandler
{
    public LogginHandler(HttpMessageHandler inner)
        : base(inner)
    {
    }

    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
    {
            using (var fs = new FileStream("c:\\temp\\log.txt", FileMode.Create, FileAccess.Write))
            {
                await request.Content.CopyToAsync(fs);
            }

            return await base.SendAsync(request, cancellationToken);

    }
}

// It's invoked as follow,

HttpClient client = new HttpClient(new LogginHandler(new HttpClientHandler()));