Node.js For .Net Developers By WCF

This article illustrates how to use Node.js by WCF which is written in C# , and using node.js as real time communication technology, with the aid of C# code, to connect with MS Sql Server.

Introduction

Nowadays, having real time web applications as two way connections, is necessary in all kinds of fields. JavaScript is a good solution but it just works at client side while there are some scenarios where we really need to have solutions that work on server side too, for instance, storing data on database or processing data at server side. There are two popular technologies used for this - SignalR and Node.js.

Why do we use Node.js?

First and foremost, because we need real time solutions for our web application in two ways - client to server and server to client side so that the data can be shared between both sides. Another good advantage is that Node.js is cross platform and does not need complex preparation and installation before using it. It establishes well for I/O and last, but not least, the probability of missing data is too rare.


The architecture of Node.js is drawn in the following picture - flow of data can be seen between client and server. It is possible to have connection with database, by using some solutions which I have described below:


There are some situations when we need to stick to the .NET platform, and just take the benefits from node.js. In such a case, I have written this code, by the aid of WCF, to communicate with MS SQL Server instead of installing drivers, such as node-ts, node-sqlserver, mssqlhelper, mssqlx, edge.js.


Background

I strongly recommend you to read this article in order to learn how to trigger node.js on .NET platform.

Using the code

1. File -> New Project -> WebApplication.
   
   
2. Solution -> Right Click -> Add New Project -> Class Library -> DAL.
   
   
3. Add New Item-> Class -> DataAccess.cs.
   
   1. using System;
   2. using System.Collections.Generic;
   3. using System.Linq;
   4. using System.Text;
   5. using System.Threading.Tasks;
   6. using System.Configuration;
   7. using System.Data;
   8. using System.Data.Common;
   10. namespace DAL
   11. {
   12. public abstract class DataAccess
   13. {
   14. public string ConnectionString
   15. {
   16. get
   17. {
   18. return "Data Source =DESKTOP-EVM02NE\\MAHSA; Initial Catalog = NodeByWCF; Integrated Security=true ";
   19. //return ConfigurationSettings.AppSettings["ConnectionString"].ToString();
   20. }
   21. }
   23. protected Int32 ExecuteNonQuery(DbCommand cmd)
   24. {
   25. return cmd.ExecuteNonQuery();
   26. }
   28. protected IDataReader ExecuteReader(DbCommand cmd)
   29. {
   30. return ExecuteReader(cmd, CommandBehavior.Default);
   31. }
   33. protected IDataReader ExecuteReader(DbCommand cmd, CommandBehavior behavior)
   34. {
   35. return cmd.ExecuteReader(behavior);
   36. }
   38. protected object ExecuteScalar(DbCommand cmd)
   39. {
   40. return cmd.ExecuteScalar();
   41. }
   43. }
   44. }
4. Add New Item-> Class -> CustomerDAL.cs.
   
   1. using System;
   2. using System.Collections.Generic;
   3. using System.Data;
   4. using System.Data.SqlClient;
   5. using System.Linq;
   6. using System.Text;
   7. using System.Threading.Tasks;
   9. namespace DAL
   10. {
   11. public class CustomerDAL : DataAccess
   12. {
   13. public CustomerDAL()
   14. {
   16. }
   17. public IEnumerable<customer> Load()
   18. {
   19. SqlConnection conn = new SqlConnection(ConnectionString);
   20. SqlDataAdapter dAd = new SqlDataAdapter("select * from Customer", conn);
   21. dAd.SelectCommand.CommandType = CommandType.Text;
   22. DataTable dt = new DataTable();
   23. try
   24. {
   25. dAd.Fill(dt);
   27. foreach (DataRow row in dt.Rows)
   28. {
   29. yield return new Customer
   30. {
   31. ID = Convert.ToInt32(row["ID"]),
   32. Name = (row["Name"]).ToString()
   33. };
   34. }
   37. }
   39. finally
   40. {
   42. dAd.Dispose();
   43. conn.Close();
   44. conn.Dispose();
   45. }
   46. }
   47. }
   48. }
   50. </customer>
5. Add New Item-> Class -> Customer.cs.
   
   1. using System;
   2. using System.Collections.Generic;
   3. using System.Linq;
   4. using System.Text;
   5. using System.Threading.Tasks;
   7. namespace DAL
   8. {
   9. public class Customer
   10. {
   11. public int ID { get; set; }
   12. public string Name { get; set; }
   13. }
   14. }
6. Solution -> Right Click -> Add New Project -> Class Library -> BAL.
   
   
7. Add New Item-> Class -> CustomerBAL.cs.
   
1. using DAL;
2. using System;
3. using System.Collections.Generic;
4. using System.Data;
5. using System.Linq;
6. using System.Text;
7. using System.Threading.Tasks;
9. namespace BAL
10. {
11. public class CustomerBAL
12. {
13. public IEnumerable<dal.customer> Load()
14. {
15. CustomerDAL customer = new CustomerDAL();
16. try
17. {
19. return customer.Load();
21. }
23. catch
24. {
25. throw;
26. }
27. finally
28. {
29. customer = null;
30. }
31. }
32. }
33. }
35. </dal.customer>
8. Solution -> Right Click -> Add New Project -> WebApplication.
   
   
9. Add New Item-> WCF Service (Ajax-enabled)-> MyService.svc.
   
   1. using System;
   2. using System.Collections.Generic;
   3. using System.Data;
   4. using System.Linq;
   5. using System.Runtime.Serialization;
   6. using System.ServiceModel;
   7. using System.ServiceModel.Activation;
   8. using System.ServiceModel.Web;
   9. using System.Text;
   10. using BAL;
   11. using DAL;
   12. using System.Web.Script.Serialization;
   15. namespace WebApplication
   16. {
   17. [ServiceContract(Namespace = "")]
   18. [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
   19. public class MyService
   20. {
   21. [OperationContract]
   22. [WebGet()]
   23. public string GetCustomer()
   24. {
   25. CustomerBAL _Cust = new CustomerBAL();
   26. try
   27. {
   28. var customers = _Cust.Load();
   29. string json = new JavaScriptSerializer().Serialize(customers);
   32. return json;
   33. }
   34. catch (Exception)
   35. {
   36. throw;
   37. }
   38. finally
   39. {
   41. }
   43. }
   45. }
   46. }
   
   
   
10. Solution -> Right Click -> Add New Project ->Javascript -> Blank Node.js Web Application.
    
    
    
    
11. Server.js,
    
1. var http = require("http");
2. var url = require('url');
3. var fs = require('fs');
4. var io = require('socket.io');
5. var port = process.env.port || 1337;
7. var server = http.createServer(function (request, response) {
8. var path = url.parse(request.url).pathname;
10. switch (path) {
11. case '/':
12. response.writeHead(200, { 'Content-Type': 'text/html' });
13. response.write('hello world');
14. response.end();
15. break;
16. case '/Index.html':
17. fs.readFile(__dirname + path, function (error, data) {
18. if (error) {
19. response.writeHead(404);
20. response.write("page doesn't exist - 404");
21. response.end();
22. }
23. else {
24. response.writeHead(200, { "Content-Type": "text/html" });
25. response.write(data, "utf8");
26. response.end();
27. }
28. });
29. break;
30. default:
31. response.writeHead(404);
32. response.write("page this doesn't exist - 404");
33. response.end();
34. break;
35. }
36. });
38. server.listen(port);
42. var listener = io.listen(server);
43. listener.sockets.on('connection', function (socket) {
44. //Send Data From Server To Client
45. socket.emit('message', { 'message': 'Hello this message is from Server' });
47. //Receive Data From Client
48. socket.on('client_data', function (data) {
50. socket.emit('message', { 'message': data.name });
51. socket.broadcast.emit('message', { 'message': data.name });
53. process.stdout.write(data.name);
54. console.log(data.name);
55. });
56. });
12. Index.html.
    
    1. <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
    2. <script src="/socket.io/socket.io.js"></script>
    4. <script src="https://cdn.socket.io/socket.io-1.4.5.js"></script>
    5. <script src="http://localhost:8080/server.js"></script>
    6. <script src="/server.js"></script>
    7. <script>
    8. var socket = io.connect();
    10. socket.on('message', function (data) {
    11. $('#conversation').append('</br>' + data.message);
    12. });
    15. $(document).ready(function () {
    16. $('#send').click(function () {
    18. $.ajax({
    19. type: "GET", //GET or POST or PUT or DELETE verb
    20. url: "http://localhost:28448/MyService.svc/GetCustomer", // Location of the service
    21. //data: Data, //Data sent to server
    22. contentType: "application/json; charset=utf-8", // content type sent to server
    23. dataType: "text", //Expected data format from server
    24. processdata: true, //True or False
    25. success: function (msg) {//On Successfull service call
    26. var obj = JSON.parse(msg);
    27. var t = obj.d.length;
    29. var completeMsg = "";
    30. for (var i = 0; i < t; i++) {
    31. completeMsgcompleteMsg = completeMsg + " " + obj.d[i].Name;
    32. }
    33. alert(completeMsg);
    34. socket.emit('client_data', { 'name': completeMsg });
    36. }
    38. });
    40. })
    41. });
    43. </script>
    <input id="text" type="text" /><button id="send">send</button>
    
    Test and Rrun
    
    Type: Localhost:1337/Index.html
    
    Click on "send" button. The data will start coming from DB on Node.js.
    
    
    

References

• Calling WCF Services using jQuery
• Dealing with Node.js and Microsoft SQL Server: Part-1

History

1. First Version 4th July 2016