Part 3 - Creating a wcf service

Suggested Videos
Part 1 - Introduction to WCF
Part 2 - Creating a remoting service and a web service

This is continuation to Part 2. Please watch Part 2 from WCF video tutorial before proceeding.



In this video, we will discuss 
1. Creating a WCF service
2. Hosting the WCF service using a console application
3. Exposing 2 service endpoints. 
4. Creating a windows and a web Client applications.



Let's take the scenario that we discussed in Part 2. 
We have 2 clients and we need to implement a service a for them. 
1. The first client is using a Java application to interact with our service, so for interoperability this client wants meesages to be in XML format and the protocl to be HTTP.
2. The second client uses .NET, so for better performance this client wants messages formmated in binary over TCP protocol.

In Part 2,
To meet the requirement of the first client, we implemented a web service and to meet the requirement of the second client we implemented a remoting service.

In this video, we will create a single WCF service, and configure 2 endpoints to meet the requirements of both the clients.

Creating the WCF Service:
1. Create a new Class Library Project and name it HelloService.
2. Delete Class1.cs file that is auto-generated.
3. Add a new WCF Service with name = HelloService. This should automatically generate 2 files (HelloService.cs & IHelloService.cs). Also a reference to System.ServiceModel assembly is added.
4. Copy and paste the following code in IHelloService.cs file
using System.ServiceModel;
namespace HelloService
{
    [ServiceContract(Namespace="http://PragimTech.com/ServiceVersion1")]
    public interface IHelloService
    {
        [OperationContract]
        string GetMessage(string name);
    }
}
5. Copy and paste the following code in HelloService.cs
namespace HelloService
{
    public class HelloService : IHelloService
    {
        public string GetMessage(string name)
        {
            return "Hello " + name;
        }
    }
}

That's it we are done implementing a WCF Service. The next step is to host the service using a console application. A WCF service can also be hosted in a Windows application, or Windows Service or IIS. We will discuss these hosting options in a later video session.

Hosting the WCF service using a console application.
1. Right click on HelloService solution in Solution Explorer and add a new Console Application project with name = HelloServiceHost
2. Add a reference to System.ServiceModel assembly and HelloService project
3. Right click on HelloServiceHost project and add Application Configuration File. This should add App.config file to the project. Copy and paste the following XML. Notice that we have specified 2 endpoints in the configuration. One endpoint uses basicHttpBinding, which communicates over HTTP protocol using XML messages. This endpoint will satisfy the requirement of the first client. The other endpoint uses netTcpBinding, which communicates over TCP protocol using binary messages. This endpoint will satisfy the requirement of the second client. 
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.serviceModel>
    <behaviors>
      <serviceBehaviors>
        <behavior name="mexBehaviour">
          <serviceMetadata httpGetEnabled="true" />
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <services>
      <service name="HelloService.HelloService" behaviorConfiguration="mexBehaviour">
        <endpoint address="HelloService" binding="basicHttpBinding" contract="HelloService.IHelloService">
        </endpoint>
        <endpoint address="HelloService" binding="netTcpBinding" contract="HelloService.IHelloService">
        </endpoint>
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:8080/" />
            <add baseAddress="net.tcp://localhost:8090"/>
          </baseAddresses>
        </host>
      </service>
    </services>
  </system.serviceModel>
</configuration>
4. Copy and paste the following code in Program.cs file
using System;
namespace HelloServiceHost
{
    class Program
    {
        static void Main()
        {
            using(System.ServiceModel.ServiceHost host = new 
                System.ServiceModel.ServiceHost(typeof(HelloService.HelloService)))
            {
                host.Open();
                Console.WriteLine("Host started @ " + DateTime.Now.ToString());
                Console.ReadLine();
            }
        }
    }
}

Build the solution. Set HelloServiceHost as startup project and run it by pressing CTRL + F5 keys.

Now let's build a web application that is going to consume the WCF service using the endpoint with basicHttpBinding. basicHttpBinding communicates over HTTP protocol using XML messages.
1. Create a new asp.net empty web application and name it HelloWebClient
2. Right click on References folder and select Add Service Reference option. In the address textbox type http://localhost:8080/ and click on GO button. In the namespace textbox type HelloService and click OK. This should generate a proxy class to communicate with the service.
3. Add a new webform. Copy and paste the following HTML in WebForm1.aspx
<div style="font-family:Arial">
    <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
    <asp:Button ID="Button1" runat="server" Text="Get Message" 
        onclick="Button1_Click" />
    <br />
    <asp:Label ID="Label1" runat="server" Font-Bold="true"></asp:Label>
</div>
4. Copy and paste the following code in WebForm1.aspx.cs file
protected void Button1_Click(object sender, EventArgs e)
{
    HelloService.HelloServiceClient client = new 
        HelloService.HelloServiceClient("BasicHttpBinding_IHelloService");
    Label1.Text = client.GetMessage(TextBox1.Text);
}

Now let's build a windows application that is going to consume the WCF service using the endpoint with netTcpBinding. netTcpBinding communicated over TCP protocol using binary messages.
1. Create a new Windows Forms application and name it HelloWindowsClient
2. Right click on References folder and select Add Service Reference option. In the address textbox type http://localhost:8080/ and click on GO button. In the namespace textbox type HelloService and click OK. This should generate a proxy class to communicate with the service.
3. On Form1, drag and drop a textbox, a button and a label control. Double click the button to generate the click event handler.
4. Copy and paste the following code in Form1.cs file
private void button1_Click(object sender, EventArgs e)
{
    HelloService.HelloServiceClient client = new 
        HelloService.HelloServiceClient("NetTcpBinding_IHelloService");
    label1.Text = client.GetMessage(textBox1.Text);
}