C# website screenshots

using UrlboxMain;
 
namespace Screenshot
{
  public class Screenshotter
  {
    Urlbox urlbox = new Urlbox("YOUR_URLBOX_API_KEY", "YOUR_URLBOX_API_SECRET");
 
    public void GetScreenshotUrl()
    {
      dynamic options = new ExpandoObject();
      options.Width = 1280;
      options.Thumb_Width = 500;
      options.Full_Page = true;
 
      var output = urlbox.GenerateUrl("bbc.co.uk", options);
      // output is now https://api.urlbox.io/v1/YOUR_URLBOX_API_KEY/d6b5068716c19ba4556648ad9df047d5847cda0c/png?url=bbc.co.uk&width=1280&thumb_width=500&full_page=true
      // to generate a screenshot image you would make a simple GET request to this URL, for example putting it inside an <img> tag.
    }
  }
}
  // ================================================================
// UrlboxMain project/package:
using System;
using System.Collections.Generic;
using System.Dynamic;
using System.Linq;
using System.Text;
using PCLCrypto;
 
namespace UrlboxMain
{
  public class Urlbox
  {
    String apiKey;
    String apiSecret;
    static List<String> encodedPropertyNames = new List<String> { "user_agent", "bg_color", "hide_selector", "click_selector", "highlight", "highlightbg", "highlightfg" };
    static List<String> booleanPropertyNames = new List<String> { "force", "retina", "full_page", "disable_js" };
 
    public Urlbox(String apiKey, String apiSecret)
    {
      if (String.IsNullOrEmpty(apiKey) || String.IsNullOrEmpty(apiSecret))
      {
        throw new ArgumentException("Please provide your Urlbox.io API Key and API Secret");
      }
      this.apiKey = apiKey;
      this.apiSecret = apiSecret;
    }
 
    public string GenerateUrl(string url)
    {
      return this.GenerateUrl(url, new ExpandoObject());
    }
 
    public string GenerateUrl(string url, ExpandoObject options)
    {
      if (String.IsNullOrEmpty(url))
      {
        throw new ArgumentException("Please provide a url in order to generate a screenshot URL");
      }
      var encodedUrl = urlEncode(url);
      var format = "png";
 
      byte[] key = Encoding.UTF8.GetBytes(this.apiSecret);
      var urlString = string.Format("url={0}", encodedUrl);
      StringBuilder sb = new StringBuilder(urlString);
 
      foreach (KeyValuePair<string, object> kvp in options)
      {
        var optionName = kvp.Key.ToLower();
        var optionValue = kvp.Value.ToString();
        if (String.IsNullOrEmpty(optionValue))
        {
          continue;
        }
        if (string.Equals(optionName, "format")){
          format = optionValue;
          continue;
        }
        if (encodedPropertyNames.Contains(optionName))
        {
          optionValue = urlEncode(optionValue);
        }
        if (booleanPropertyNames.Contains(optionName))
        {
          if (!(bool)kvp.Value) { continue; }
          optionValue = optionValue.ToLower();
        }
        sb.Append(string.Format("&{0}={1}", optionName, optionValue));
      }
 
      var queryString = sb.ToString();
      var uniqueToken = generateToken(queryString, key);
      return string.Format("https://api.urlbox.io/v1/{0}/{1}/{2}?{3}", this.apiKey, uniqueToken, format, queryString);
    }
 
    private static string generateToken(String data, byte[] key)
    {
      var algorithm = WinRTCrypto.MacAlgorithmProvider.OpenAlgorithm(MacAlgorithm.HmacSha256);
      CryptographicHash hasher = algorithm.CreateHash(key);
      hasher.Append(Encoding.UTF8.GetBytes(data));
      byte[] mac = hasher.GetValueAndReset();
      var macStr = byteArrayToString(mac);
      return macStr;
    }
 
    private static string byteArrayToString(byte[] ba)
    {
      string hex = BitConverter.ToString(ba).ToLower();
      return hex.Replace("-", "");
    }
 
    private static string urlEncode(string url)
    {
      // make it behave like javascript encodeURIComponent()
      var encoded = Uri.EscapeDataString(url);
      encoded = encoded.Replace("%28", "(");
      encoded = encoded.Replace("%29", ")");
      return encoded;
    }
 
  }
}