New Features in WCF 4.0-Part 2

1. Simplified Configuration

In WCF 3.5 when we host  Service without  Endpoint we get  exception saying that we need to configure at least a single Endpoint.   But in WCF 4.0 this is not the case because Service Runtime will automatically adds default endpoints for us.

Lets see how this works –

Code for IService1-

[ServiceContract]
    public interface IService1
    {
        [OperationContract]
        string GetData(int value);
    }

Code for Service1 -

public string GetData(int value)
        {
            return string.Format("You entered: {0}", value);
        }


 

Now add ConsoleApplication1 in the Solution.

Add following in App.config.

<system.serviceModel>
    <behaviors>
      <serviceBehaviors>
        <behavior>
          <serviceMetadata httpGetEnabled ="true"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <protocolMapping>
      <add binding="wsHttpBinding" scheme ="http"/>
    </protocolMapping>
  </system.serviceModel>

Add the following code in Program.cs-

static void Main(string[] args)
        {
            ServiceHost Host = new ServiceHost(typeof(WcfSimpleService1.Service1), new Uri("http://localhost:7777/Services/Hello"));
            Host.Open();
            Console.WriteLine("Wow Started....");
            Console.ReadLine();
            Host.Close();
            Console.ReadLine(); 
        }
 

Put breakpoint on Host.Open and run ConsoleApplication.Since protocol mapping is set to wsHttpBinding it uses wsHttpBinding as shown in fig-

You can also download the attached project file.

2. Protocol bridging and Fault tolerance

Protocol bridging is basically used for transport. As in fig.  Client sends message to Routing Service via HTTP .Routing Service will send the message to Backend WCF Service via TCP/IP.Here we are using Protocol bridging between HTTP AND TCP/IP.

Fault tolerance is alternate endpoints (any no of endpoints) which will  be called when Exception occurs in the RoutingService while calling the original target endpoint.

We are  exposing  our RoutingService via an basicHttpBinding-based request-reply endpoint.

      <service behaviorConfiguration="routingData"
    name="System.ServiceModel.Routing.RoutingService">
        <host>
          <baseAddresses>
            <add  baseAddress="http://localhost:3562/Services/Hello"/>
          </baseAddresses>
        </host>
 
        <endpoint address=""
                  binding="basicHttpBinding"
                  name="requestReplyEndpoint"
                  contract="System.ServiceModel.Routing.IRequestReplyRouter" />
      </service>
 

We have actually two services TestService1 and TestService2.One is exposed via basicHttpBinding and other through netTcpBinding.

We have configured our router in such a way that it still accepts incoming messages via basicHttpBinding  but on need arising it  can route messages to the netTcpBinding-based service.

  <client>
        <endpoint name="TestService1"
                  address="net.tcp://localhost:3562/Services/Test"
                  binding="netTcpBinding"
                  contract="*" />
        <endpoint name="TestService2"
                  address="http://localhost:3562/Services/Test"
                  binding="basicHttpBinding"
                  contract="*" />
  </client>

Routing table to route to netTcpBinding-based service.

<routingTables>
        <table name="mainRoutingTable">
          <entries>
            <add filterName="xPath1" endpointName="TestService1" />
          </entries>
        </table>
</routingTables>
 

We can specify alternate endpoints (any no of endpoints) which will  be called when Exception occurs in the RoutingService while calling the original target endpoint.

<routingTables>
        <table name="mainRoutingTable">
          <entries>
            <add filterName="xPath1" endpointName="TestService1"                         alternateEndpoints="endpointsList" />
          </entries>
        </table>
  </routingTables>
  <alternateEndpoints>
        <list name="endpointsList">
          <endpoints>
            <add endpointName="TestService2" />
            </endpoints>
        </list>
  </alternateEndpoints>
 

Here we have TestService2 endpoint which is exposed via  basicHttpBinding endpoint.

3. Standard End Points

<system.serviceModel>
    <services>
      <service name="HelloService">
        <endpoint kind="udpDiscoveryEndpoint" />
      </service>
    </services>
    <behaviors>
      <behavior>
        <serviceDiscovery />
      </behavior>
    </behaviors>
  </system.serviceModel>
 
 

We can also  specify a reusable endpointConfiguration for the endpoint using the new standardEndpoints section in Web.config

 
<system.serviceModel>
    <services>
      <service name="TestService">
        <endpoint
            kind="udpDiscoveryEndpoint"
            endpointConfiguration="udpDiscoveryEndpointSettings"/>
      </service>
    </services>
    <standardEndpoints>
      <udpDiscoveryEndpoint>
        <standardEndpoint
          name="udpDiscoveryEndpointSettings"
          multicastAddress="soap.udp://239.255.255.252:5762"
          maxResponseDelay="00:00:07">
          <transportSettings
              duplicateMessageHistoryLength="2048"
              maxPendingMessageCount="5"
              maxReceivedMessageSize="8192"
              maxBufferPoolSize="262144"/>
        </standardEndpoint>
      </udpDiscoveryEndpoint>
    </standardEndpoints>
    <behaviors>
      <behavior>
        <serviceDiscovery />
      </behavior>
    </behaviors>
  </system.serviceModel>

4. .svc-less activation of REST services.

It is specially needed in  WAS-hosting WCF services.If we have to write  http://xyz/ CalulatorService.svc .svc at the end of url makes it user unfriendly. It also makes it Low REST service as it does not follows REST URI principle.

Till date developers have to overcome this limitation by implementing URL ReWrite module in IIS. WCF 4.0 has introduced a feature to access WCF services using attribute called as relativeAddress.

<system.serviceModel>
    <serviceHostingEnvironment>
      <serviceActivations>
        <add relativeAddress="/Calculator" service="CalulatorService.svc"/>
      </serviceActivations>
    </serviceHostingEnvironment>
  </system.serviceModel>
 

Now  we can write http://xyz/CalulatorService.  

Neat isn’t it.

Conclusion