Need to log asp.net webapi 2 request and response body to a database

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:

config.MessageHandlers.Add(new LogRequestAndResponseHandler());

Here is the full Microsoft documentation for Message Handlers.