Build DLLs that call a REST API to return the latest price of bitcoin in US dollars and Euros.

1. Compile the code that is used to test the methods.

   using System;
   using System.Collections.Generic;
   using System.Linq;
   using System.Text;
   using System.Threading.Tasks;
   using MyApp4Lib;
   
   namespace MyApp4Test
   {
       class Program  // Test program for the classes 
       {
           static void Main(string[] args)
           {
               VisibleBotMethods vbm = new VisibleBotMethods();
               String UsdPrice = vbm.GetPriceOfBitcoin("usd");
               Console.WriteLine("\nPrice of Bitcoin in USD: " + UsdPrice);
               Console.ReadKey();
           }
       }
   }
   

2. Compile the code that orchestrates the REST call and retrieves the bitcoin price.

   using System;
   using System.Collections.Generic;
   using System.Linq;
   using System.Text;
   using System.Threading.Tasks;
   namespace MyApp4Lib
   {
       public class VisibleBotMethods
       {
           public String GetPriceOfBitcoin(String Currency)
           {
               // Make GET call -- the Currency is the variable:  
               // usd for $Dollars, eur for Euros
               String URL = "https://api.cryptonator.com/api/ticker/btc-" + Currency;
   
               // Instantiate objects
               RestUtils ru = new RestUtils();  
               JsonUtils ju = new JsonUtils();
   
               // Make the REST call and return the JSON response
               String JsonResp = ru.CallRestGETNoAuth(URL);  
   
               // Retrieve just the price from the JSON as a String
               String BCPrice = ju.GetDataFromJsonResponse(JsonResp);
               return BCPrice;
           }
       }
   }
   

3. Compile the methods to make REST calls.

   using System;
   using System.Collections.Generic;
   using System.Linq;
   using System.Net;
   using System.Text;
   using System.Threading.Tasks;
   
   namespace MyApp4Lib
   {
       public class RestUtils      
       {
           public String CallRestGETNoAuth(String URL)
           {
           // Setting up a web request on the URL that we pass as a parameter, 
   	 // specifying a GET request for a JSON response
               System.Net.HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(URL);
               httpWebRequest.ContentType = "text/json";
               httpWebRequest.Method = "GET";
   
               // Submitting the request, getting the response, turning it into a string, 
   	     // and returning the response
               try
               {
                   var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
                   using (var streamReader = new System.IO.StreamReader(httpResponse.GetResponseStream()))
                   {
                       var result = streamReader.ReadToEnd();
                       return result;
                   }
               }
               catch (System.Net.WebException e)  // Catch error if URL is not valid
               {
                   return "Error:" + e.Message;
               }
           }
       }
   }
   

4. Compile the code that processes the JSON response and returns the bitcoin price.

   using System;
   using System.Collections.Generic;
   using System.Linq;
   using System.Text;
   using System.Threading.Tasks;
   
   namespace MyApp4Lib
   {
       class JsonUtils  // Includes methods to process JSON
       {
           public String GetDataFromJsonResponse(String JsonResp)
           {
               RestSharp.RestResponse response = new RestSharp.RestResponse();
               response.Content = JsonResp;
   
               // Turning JSON structure into object / class structure 
               JsonDeserializer deserial = new JsonDeserializer();
               StdJsonResponseForCurrCheck x = deserial.Deserialize<StdJsonResponseForCurrCheck>(response);
               String Resp = "";
   
               // Identifying price within the class structure, and then return it
               Resp = x.ticker.price;
               return Resp;
           }
       }
       // Taking JSON response and turning it into classes
       public class Ticker
       {
           public string @base { get; set; }
           public string target { get; set; }
           public string price { get; set; }
           public string volume { get; set; }
           public string change { get; set; }
       }
       public class StdJsonResponseForCurrCheck
       {
           public Ticker ticker { get; set; }
           public int timestamp { get; set; }
           public bool success { get; set; }
           public string error { get; set; }
       }
   }