using System;

using System.IO;

using System.Net;

using System.Threading.Tasks;

using System.Text.RegularExpressions;

​

class MainClass {

  static void Main() {  

            string uri = "https://coderbyte.com/api/challenges/json/json-cleaning";

            string response = GetAsync(uri).Result;

            string filtered = FilterJsonResponse("{\"name\":{\"first\":\"Daniel\",\"middle\":\"\",\"last\":\"Smith\"},\"age\":45,\"DOB\":\"-\"}");

            Console.WriteLine(filtered);

    }

    private static async Task<string> GetAsync(string uri)

    {

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);

        request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;

​

        using (HttpWebResponse response = (HttpWebResponse)await request.GetResponseAsync())

            using (Stream stream = response.GetResponseStream())

            using (StreamReader reader = new StreamReader(stream))

        {

            return await reader.ReadToEndAsync();

        }

    }

​

    private static string FilterJsonResponse(string jsonString)

    {

        string originalEmptyValues = "(\"\"|\"[-]\"|\"N\\/A\")";

        string emptyPlaceholder = "#empty#";

        string emptyKeyValues = "(\"[a-zA-Z]+\":#empty#,|,\"[a-zA-Z]+\":#empty#)";

        string emptyArrayValues = "(#empty#,|,#empty#)";

        string result = Regex.Replace(jsonString, originalEmptyValues, emptyPlaceholder);

        result = Regex.Replace(result, emptyKeyValues, "");

        result = Regex.Replace(result, emptyArrayValues, "");            

​

        return result;

​

    }

}