Defining Address in WCF Service

Address is a way of letting client know that where a service is located. In WCF, every service is associated with a unique address. This contains the location of the service and transport schemas. 

WCF supports following transport schemas :

HTTP 
TCP 
Peer network 
IPC (Inter-Process Communication over named pipes) 
MSMQ 

Definition of an Address For a Service

The endpoint address for a service can be specified either imperatively using code or declaratively through configuration. Defining endpoints in code is usually not practical because the bindings and addresses for a deployed service are typically different from those used while the service is being developed. Generally, it is more practical to define service endpoints using configuration rather than code. Keeping the binding and addressing information out of the code allows them to change without having to recompile or redeploy the application.

Defining an Address in Configuration

In configuration file endpoint is defined as : 

<configuration>
  <system.serviceModel>
    <services>
      <service name="UE.Samples.HelloService"
               behaviorConfiguration="HelloServiceBehavior">
        <endpoint address="/Address1"
                  binding="basicHttpBinding" 
                  contract="UE.Samples.IHello"/>

        <endpoint address="mex"
                  binding="mexHttpBinding"
                  contract="IMetadataExchange" />
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="HelloServiceBehavior">
          <serviceMetadata httpGetEnabled="true" />
        </behavior>
      </serviceBehaviors>
    </behaviors>
  </system.serviceModel>
</configuration>

When the Open method is called (that is, when the hosting application attempts to start the service), the system looks for a <service> element with a name attribute that specifies "UE.Samples.HelloService". If the <service> element is found, the system loads the specified class and creates endpoints using the endpoint definitions provided in the configuration file. This mechanism allows you to load and start a service with two lines of code while keeping binding and addressing information out of your code. The advantage of this approach is that these changes can be made without having to recompile or redeploy the application.

Defining Endpoint Addresses in Code

An endpoint address can be created in code with the EndpointAddress class. The URI specified for the endpoint address can be a fully-qualified path or a path that is relative to the service's base address. The following code illustrates how to create an instance of the EndpointAddress class and add it to the ServiceHostinstance that is hosting the service.

Uri baseAddress = new Uri("http://localhost:8000/HelloService");
string address = "http://localhost:8000/HelloService/MyService";

using (ServiceHost serviceHost = new ServiceHost(typeof(HelloService), baseAddress))
{
    serviceHost.AddServiceEndpoint(typeof(IHello), new BasicHttpBinding(), address);
    serviceHost.Open();
    Console.WriteLine("Press <enter> to terminate service");
    Console.ReadLine();
    serviceHost.Close();
}

Using Default Endpoints

If no endpoints are specified in code or in configuration then the runtime provides default endpoints by adding one default endpoint on each base address for each service contract implemented by the service. The base address can be specified in code or in configuration, and the default endpoints are added when Open is       called on the ServiceHost.




If endpoints are explicitly provided, the default endpoints can still be added by calling AddDefaultEndPoints on the ServiceHost before calling Open