Service Contract
Service contract describes the operation that service provide. A Service can have more than one service contract but it should have at least one Service contract.
Service Contract can be define using [ServiceContract] and [OperationContract] attribute. [ServiceContract] attribute is similar to the [WebServcie] attribute in the WebService and [OpeartionContract] is similar to the [WebMethod] in WebService.
- It describes the client-callable operations (functions) exposed by the service
- It maps the interface and methods of your service to a platform-independent description
- It describes message exchange patterns that the service can have with another party. Some service operations might be one-way; others might require a request-reply pattern
- It is analogous to the element in WSDL
To create a service contract you define an interface with related methods representative of a collection of service operations, and then decorate the interface with the ServiceContract Attribute to indicate it is a service contract. Methods in the interface that should be included in the service contract are decorated with the OperationContract Attribute.
[ServiceContract()]
public interface ISimpleCalculator
{
[OperationContract()]
int Add(int num1, int num2);
}
Once we define Service contract in the interface, we can create implement class for this interface.
public class SimpleCalculator : ISimpleCalculator
{
public int Add(int num1, int num2)
{
return num1 + num2;
}
}
With out creating the interface, we can also directly created the service by placing Contract in the implemented class. But it is not good practice of creating the service
[ServiceContract()]
public class SimpleCalculator
{
[OperationContract()]
public int Add(int num1, int num2)
{
return num1 + num2;
}
}
Now you have some fundamental idea on Service contract. Next we will look into Data Contract.
Tips!
- Always create the service with Interface->Implementation format, mention the contract in Interface.
- Define the service in Class library and refer the class library in Host project. Don’t use service class in host project.
- Change the instance mode to per call as default.
- Always catch exception using try/catch block and throw exception using FaultException < T >.
- Logging and Include exception should be enable while compiling the project in debug mode. While in production deployment disable the logging and Include exception details.
|