ApiLogHandler

gistfile1.cs

public class ApiLogHandler : DelegatingHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        var apiLogEntry = CreateApiLogEntryWithRequestData(request);
        if (request.Content != null)
        {
            await request.Content.ReadAsStringAsync()
                .ContinueWith(task =>
                {
                    apiLogEntry.RequestContentBody = task.Result;
                }, cancellationToken);
        }

        return await base.SendAsync(request, cancellationToken)
            .ContinueWith(task =>
            {
                var response = task.Result;

                // Update the API log entry with response info
                apiLogEntry.ResponseStatusCode = (int)response.StatusCode;
                apiLogEntry.ResponseTimestamp = DateTime.Now;

                if (response.Content != null)
                {
                    apiLogEntry.ResponseContentBody = response.Content.ReadAsStringAsync().Result;
                    apiLogEntry.ResponseContentType = response.Content.Headers.ContentType.MediaType;
                    apiLogEntry.ResponseHeaders = SerializeHeaders(response.Content.Headers);
                }

                // TODO: Save the API log entry to the database

                return response;
            }, cancellationToken);
    }

    private ApiLogEntry CreateApiLogEntryWithRequestData(HttpRequestMessage request)
    {
        var context = ((HttpContextBase)request.Properties["MS_HttpContext"]);
        var routeData = request.GetRouteData();

        return new ApiLogEntry
        {
            Application = "[insert-calling-app-here]",
            User = context.User.Identity.Name,
            Machine = Environment.MachineName,
            RequestContentType = context.Request.ContentType,
            RequestRouteTemplate = routeData.Route.RouteTemplate,
            RequestRouteData = SerializeRouteData(routeData),
            RequestIpAddress = context.Request.UserHostAddress,
            RequestMethod = request.Method.Method,
            RequestHeaders = SerializeHeaders(request.Headers),
            RequestTimestamp = DateTime.Now,
            RequestUri = request.RequestUri.ToString()
        };
    }

    private string SerializeRouteData(IHttpRouteData routeData)
    {
        return JsonConvert.SerializeObject(routeData, Formatting.Indented);
    }

    private string SerializeHeaders(HttpHeaders headers)
    {
        var dict = new Dictionary<string, string>();

        foreach (var item in headers.ToList())
        {
            if (item.Value != null)
            {
                var header = String.Empty;
                foreach (var value in item.Value)
                {
                    header += value + " ";
                }

                // Trim the trailing space and add item to the dictionary
                header = header.TrimEnd(" ".ToCharArray());
                dict.Add(item.Key, header);
            }
        }

        return JsonConvert.SerializeObject(dict, Formatting.Indented);
    }
}