Log message Request and Response in ASP.NET WebAPI

There are multiple approaches to generically handle Request/Response logging for every WebAPI method calls:

1.    ActionFilterAttribute: One can write custom ActionFilterAttribute and decorate the controller/action methods to enable logging.

Con: You need to decorate every controller/methods (still you can do it on base controller, but still it doesn't address cross cutting concerns.

2.    Override BaseController and handle logging there.

Con: We are expecting/forcing the controllers to inherit from a custom base controller.

3.    Using DelegatingHandler.

Advantage: We are not touching controller/method here with this approach. Delegating handler sits in isolation and gracefully handles the request/response logging.

I would recommend using a DelegatingHandler. Then you will not need to worry about any logging code in your controllers.

public class LogRequestAndResponseHandler : DelegatingHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(
        HttpRequestMessage request, CancellationToken cancellationToken)
    {
        if (request.Content != null)
        {
            // log request body
            string requestBody = await request.Content.ReadAsStringAsync();
            Trace.WriteLine(requestBody);
        }
        // let other handlers process the request
        var result = await base.SendAsync(request, cancellationToken);

        if (result.Content != null)
        {
            // once response body is ready, log it
            var responseBody = await result.Content.ReadAsStringAsync();
            Trace.WriteLine(responseBody);
        }

        return result;
    }
}

Just replace Trace.WriteLine with your logging code and register the handler in WebApiConfig like this:

For more indepth article, refer this http://weblogs.asp.net/fredriknormen/log-message-request-and-response-in-asp-net-webapi