Developer who has worked with ASP.NET Web Services (ASMX) and WCF always feels that using predecessor was much more easier. It just because WCF configuration is much more complex as compare to ASP.NET Web Service.

WHY ??????

With ASMX, you were able to define a [WebMethod] operation and the runtime automatically provided a default configuration for the underlying communications. When moving to WCF 3.x, on the other hand, developers have to know enough about the various WCF configuration options to define at least one endpoint.

In an effort to make the overall WCF experience just as easy as ASMX, WCF 4 comes with a new “default configuration” model that completely removes the need for any WCF configuration. If you don’t provide any WCF configuration for a particular service, the WCF 4 runtime automatically configures your service with some standard endpoints and default binding/behavior configurations. This makes it much easier to get a WCF service up and running, especially for those who aren’t familiar with the various WCF configuration options.

Let’s discuss some of the standard configuration options that WCF 4 support :

1) Default Endpoints
2) Default Protocol Mapping
3) Default Binding Configurations
4) Default Behavior Configurations

1) Default Endpoints

With WCF 3.X, if you try to host a service without configured endpoints, ServiceHost instance will throw an exception informing you that you need to configure at least one endpoint. With WCF 4, this is no longer the case because the runtime automatically adds one or more ‘default endpoints’ for you.

Now question comes in mind, How this is done by WCF 4?

Answer to Question is like : When Host application calls Open method on ServiceHost instance, it build internal service description from the application configuration file. Than it check the count of configured endpoints. if it is still zero than it will call “AddDefaultEndpoints” public method and method will adds one default endpoint per base address for each service contract implemented by the service.

Clear or Confused ??

Lets take one example to be more clear on it.

If the service implements two service contracts and you configure the host with a single base address, AddDefaultEndpoints will configure the service with two default endpoints (one for each service contract). However, if the service implements two service contracts and the host is configured with two base addresses (one for HTTP and one for TCP), AddDefaultEndpoints will configure the service with four default endpoints.

I Hope now its clear….if still not…please go thru the link provided for more details on it.

-> New Features in WCF 4 that Will Instantly Make You More Productive
(http://www.code-magazine.com/Article.aspx?quickid=1006061)

2) Default Protocol Mapping

In .Net 4.0 framework, default protocol mapping between transport protocol schemes and the built in WCF bindings are as follows :

   <protocolMapping>
      <add scheme="http" binding="basicHttpBinding" bindingConfiguration="" />
      <add scheme="net.tcp" binding="netTcpBinding" bindingConfiguration=""/>
      <add scheme="net.pipe" binding="netNamedPipeBinding" bindingConfiguration=""/>
      <add scheme="net.msmq" binding="netMsmqBinding" bindingConfiguration=""/>
   </protocolMapping>

You can override these mappings at machine level by adding this section to machine.config file and modify the bindings as per your needs.

If you want to override this mappings at application level than you can override the above section in application/web configfile.

3) Default Binding Configurations

In WCF 3.x , binding can be done like this :

<configuration>
  <system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <binding name="BasicBindingMtom" messageEncoding="Mtom"/>
      </basicHttpBinding>
    </bindings>
    <services>
      <service name="HelloService">
        <endpoint address="mtom" binding="basicHttpBinding"
                  bindingConfiguration="BasicBindingMtom"
                  contract="IHello"/>
      </service>
    </services>
  </system.serviceModel>
</configuration>

Here “BasicBindingMtom” binding configuration overrides the defaults for BasicHttpBinding by changing the message encoding to “Mtom”. However this binding will effect only when you apply it to a specific endpoint thru “bindingConfiguration” attribute.

With WCF 4, binding can be done like this :

      <basicHttpBinding>
        <binding messageEncoding="Mtom"/>
      </basicHttpBinding>

No name attribute required. This feature gives you a simple mechanism to define a standard set of binding defaults that you can use across all your services without imposing any complexities of binding configurations.

4) Default Behavior Configurations

With WCF 4, it is possible to define default behavior configurations for services and endpoints.

    <behaviors>
      <serviceBehaviors>
        <behavior>
          <serviceMetadata httpGetEnabled="true"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>

Above configuration turns on the metadata for any service that doesn’t come with explicit behavior configuration.

In WCF 4, Behavior configuration also support inheritance model. It means that if application defines a behavior using same name as one already defined in machine.config, the application specific behavior configuration will get merged with machine configuration.

With these new additions in the WCF 4, it will be easier for developers to configure the services. I am sure that many developers will feel relaxed by having these new features in WCF and also start using it. Thats all from my side for this post.

Hope this will help !!!

Jay Ganesh ……