need to capture entire request/response?

I have a asp.net MVC 3 application and to get some data I'm hitting a web api.

I need to log all request that we sent to web api and the response that's come from the web api side with whatever the status code including 500.

How to log each request in a text file, what will be the best approach, specially we also need to log 500 status code response also.

Thanks!