WCF : An introduction

1. What is WCF?

ü  WCF stands for Windows Communication Foundation (WCF).

ü  This is considered as the Microsoft Service-Oriented Architecture (SOA) platform for building distributed and interoperable applications. 

ü  WCF unifies ASMX, Remoting, and Enterprise Services stacks and provides a single programming model.

ü  WCF services are interoperable and supports all the core Web services standards. 

ü  A WCF service also provide extension points to quickly adapt to new protocols and updates and integrates very easily with the earlier Microsoft technologies like Enterprise Services, COM and MSMQ.

2. Why should I use WCF?

ü  WCF is interoperable with other services when compared to .Net Remoting, where the client and service have to be .Net.

ü  WCF services provide better reliability and security in compared to ASMX web services.

ü  In WCF, there is no need to make much change in code for implementing the security model and changing the binding. Small changes in the configuration will make your requirements.

ü  WCF has integrated logging mechanism, changing the configuration file settings will provide this functionality. In other technology developer has to write the code.

3.    What is difference between WCF and Web Services?

ü  Protocol: Web services can only be invoked by HTTP (traditional web service with .asmx). While WCF Service or a WCF component can be invoked by any protocol (like http, tcp etc.) and any transport type. 

ü  Flexibility: web services are not flexible. However, WCF Services are flexible. If you make a new version of the service then you need to just expose a new end. Therefore, services are agile and which is a very practical approach looking at the current business trends. 

ü  Ease of Development: We develop WCF as contracts, interface, operations, and data contracts. As the developer we are more focused on the business logic services and need not worry about channel stack. WCF is a unified programming API for any kind of services so we create the service and use configuration information to set up the communication mechanism like HTTP/TCP/MSMQ etc 

ü  XmlSerializer and DataContractSerializer

That Web Services Use XmlSerializer But WCF Uses
DataContractSerializer which is better in Performance as Compared to XmlSerializer.
Key issues with XmlSerializer to serialize .NET types to XML

* Only Public fields or Properties of .NET types can be translated into XML.
* Only the classes which implement IEnumerable interface.
* Classes that implement the IDictionary interface, such as Hash table can not be serialized.

The DataContractAttribute can be applied to the class or a structure. DataMemberAttribute can be applied to field or a property and theses fields or properties can be either public or private. A practical benefit of the design of the DataContractSerializer is better performance over XmlSerializer. 

4. What is service and client in perspective of data communication?

ü  A service is a unit of functionality exposed to the world.
The client of a service is merely the party consuming the service.

5. What is SOA Service?

ü  SOA is Service Oriented Architecture. SOA service is the encapsulation of a high level business concept. A SOA service is composed of three parts.

Any Service that fulfills above three requirements is SOA

6. What are the core components of WCF?

ü  Like any other SOA Service the three core components of WCF are:

a.       A service class

b.       A hosting service

c.       Endpoints to expose the service

7. What is ABC in WCF?

8.    What is an endpoint?

ü  WCF Service is a program that exposes a collection of Endpoints. Each Endpoint is a portal for communicating with the world.

ü  All the WCF communications are take place through end point. End point consists of three components.

a.       Address

b.       Binding

c.       Contract

ü  The Endpoint is the fusion of Address, Contract and Binding.