Contents
To get an overall idea about
the fundamentals of WCF, and help those readers who want to learn the basics of WCF from scratch
1.2.SCOPE
WCF is one of the latest technologies
of Microsoft that is used to build service-oriented applications. Based on the
concept of message-based communication, in which an HTTP request is represented
uniformly, WCF makes it possible to have a unified API irrespective of diverse
transport mechanisms.
WCF-Windows Communication Foundation
SOAP - Simple Object Access
Protocol
<This section should list all the applicable and reference
documents>
What is
WCF ???
Ø WCF is one of the latest service
oriented technology developed by Microsoft
Ø Released for the first time in 2006
as a part of the .NET framework, and then got updated several times. WCF 4.5 is
the most recent version that is now widely used
Ø WCF is a programming platform and
runtime system for building, configuring and deploying network-distributed
services
Ø The elementary feature of WCF is
interoperability
Ø WCF is a set of .NET technologies
(Web services ,.Net Remoting and enterprises services) for building and running
connected systems
Why WCF
???
Ø It is interoperable with respect to
other services
Ø Provides a varying array of
communication across several platforms: HTTP, HTTPS, TCP, MSMQ, and Etc
Ø It provides additional Security
Ø It provides more code reusability
Ø Different forms of hosting
Ø WCF has integrated AJAX and support
for JSON (JavaScript object notation)
Ø It offers scalability and support for
up-coming web service standards
When
WCF???
Ø When your business logic has to
interact with a variety of client applications
Ø When client apps, which are going to
use your service, may be written in Java or .Net.
Ø You are targeting a distributed
computing architecture
Difference
between WCF & Web Services
WCF
Ø [ServiceContract] attribute has to be
added to the class
Ø [OperationContract] attribute
represents the method exposed to client
Ø One-Way, Request-Response, Duplex are
different type of operations supported in WCF
Ø System.Runtime.Serialization
namespace is used for serialization
Ø XML 1.0, MTOM, Binary, Custom
Ø Can be accessed through HTTP, TCP,
Named pipes, MSMQ,P2P, Custom
Web
Services
Ø [WebService] attribute has to be
added to the class
Ø [WebMethod] attribute represents the
method exposed to client
Ø One-way, Request- Response are the
different operations supported in web service
Ø System.Xml.serialization name space
is used for serialization
Ø XML 1.0, MTOM(Message Transmission
Optimization Mechanism), DIME, Custom
Ø Can be accessed through HTTP, TCP,
Custom
WCF – key
terms to remember
- WCF Service
- Addresses
- Contracts
- Host Environment
- End point
- WCF Client
- Channel
- SOAP
WCF
Service
A WCF
service is based on an interface that defines a contract between the service
and the client. It is marked with a ServiceContractAttribute attribute
Example:
[ServiceContract]
public interface
ICalculatorService
We define
functions or methods that are exposed by a WCF service by marking them with an
OperationContractAttribute
Example :
[OperationContract]
string
GetData(string value);
Address
Description:
In WCF,
every service is associated with a unique address. The address provides two
important elements: the location of the service and the transport protocol or
transport schema used to communicate with the service. The location portion of
the address indicates the name of the target machine, site, or network; a
communication port, pipe, or queue; and an optional specific path or URI.
a) TCP
Addresses
Ex.
net.tcp://localhost:8002/MyService.
b) HTTP
Addresses
c) IPC
Addresses
Ex.
net.pipe://localhost/MyPipe
d) MSMQ
Addresses
Ex.
net.msmq://localhost/MyService
e) Peer
Network Addresses
Peer
network addresses use net.p2p for transport, to indicate the use of the Windows
peer network transport. You must specify the peer network name as well as a
unique path and port.
Contracts
Description:
In WCF,
all services expose contracts. The contract is a platform-neutral and standard
way of describing what the service does. WCF defines four types of contracts.
a)
Service Contracts
Describe
which operations the client can perform on the service.
b) Data
Contracts
Define
which data types are passed to and from the service. WCF defines implicit
contracts for built-in types such as int and string, but you can easily define
explicit opt-in data contracts for custom types
c) Fault
Contracts
Define
which errors are raised by the service, and how the service handles and
propagates errors to its clients
d)
Message Contracts
Allow the
service to interact directly with messages. Message contracts can be typed or
untyped, and are useful in interoperability cases and when there is an existing
message format you have to comply with.
Hosting
Hosting from
the viewpoint of WCF refers to the WCF service hosting which can be done
through many available options like
self-hosting
IIS hosting
and WAS
hosting.
End point
All
communications with the WCF service will happen via the endpoints.
It defines
the address where a message is to be sent or received. It also specifies the
communication mechanism to describe how the messages will be sent along with
defining the set of messages. A structure of an endpoint comprises of the
following parts:
Address - Address specifies the exact
location to receive the messages and is specified as a Uniform Resource
Identifier (URI). It is expressed as scheme://domain[:port]/[path]. Take a look
at the address mentioned below:
net.tcp://localhost:9000/ServiceA
Here,
'net.tcp' is the scheme for the TCP protocol. The domain is 'localhost' which
can be the name of a machine or a web domain, and the path is 'ServiceA'.
Binding - It defines the way an
endpoint communicates. It comprises of some binding elements that make the
infrastructure for communication. For example, a binding states the protocols
used for transport like TCP, HTTP, etc., the format of message encoding, and
the protocols related to security as well as reliability.
Contracts - It is a collection of
operations that specifies what functionality the endpoint exposes to the
client. It generally consists of an interface name.
WCF
Client
A WCF client
consists of a proxy that
enables an application to communicate
with a WCF
service, and an endpoint that matches an endpoint defined for the service. The
proxy is generated on the client side in the app.config file and includes
information about the types and methods that are exposed by the service. For
services that expose multiple endpoints, the client can select the one that
best fits its needs, for example, to communicate over HTTP and use Windows
Authentication.
Channel
Channels are
the responsible component of WCF for
Ø Creation of consistent message
Ø Transport of consistent message
Ø Conversion of Message in wire format
The main
goal of Channel is to transform message to format understandable by the
communication wire and compatible to both server and client and then transport
the message over the wire in between client and server.
Soap(Simple
Object Access Protocol)
SOAP is an
open-standard, XML-based messaging protocol for exchanging information among
computers.
Although
SOAP can be used in a variety of messaging systems and can be delivered via a
variety of transport protocols, the initial focus of SOAP is remote procedure
calls transported via HTTP.
Our First
WCF!!!
First open
Visual Studio and click file --> New ->Project
-->WCF
->WCF Service Library
Given the
name of WCF Service Library and click ok
Now we are
successfully created a WCF Service Library. Now In our solution Explorer we can
see default class files including Service.cs and IService.cs.
Ø IService.cs is an interface it does contain
Service contracts and Data Contracts
Ø Service.cs is a
normal class inherited by IService where you can all the
methods and other stuff.
Ø Change the file names like below
screenshot.
Now open ICalculator.cs and replace with following code.
using System;
using System.Runtime.Serialization;
using System.ServiceModel;
namespace Calculator
{
[ServiceContract]
public interface ICalculatorService
{
[OperationContract]
ResultSet
PerformCalculatorOperations(double firstInput,double secondInput,string operationType);
}
[DataContract]
public class ResultSet
{
[DataMember]
public double Result { get; set; }
[DataMember]
public string Staus { get; set; }
}
}
Then open Calculator.cs file and replace the content with
below code.
namespace Calculator
{
public class CalculatorService : ICalculatorService
{
ResultSet result = new ResultSet();
public ResultSet
PerformCalculatorOperations(double firstInput, double secondInput, string operationType)
{
switch (operationType)
{
case "Addition":
Addition(firstInput,
secondInput);
break;
case "Subtraction":
Subtraction(firstInput,
secondInput);
break;
case "Multiplication":
Multiplication(firstInput,
secondInput);
break;
case "Division":
Division(firstInput,
secondInput);
break;
default:
result.Staus = "Error";
break;
}
return result;
}
public void Addition(double firstInput, double secondInput)
{
result.Result = firstInput +
secondInput;
result.Staus = "Sucess";
}
public void Subtraction(double firstInput, double secondInput)
{
result.Result = firstInput -
secondInput;
result.Staus = "Sucess";
}
public void Multiplication(double firstInput, double secondInput)
{
result.Result = firstInput
* secondInput;
result.Staus = "Sucess";
}
public void Division(double firstInput, double secondInput)
{
result.Result = firstInput /
secondInput;
result.Staus = "Sucess";
}
}
}
Build the application. Now our WFC Service Library is ready
to use. Run the project this will open a WCF test client.
In test client click on service name
(PerformCalcultorOperations). And fill the inputs to the service
Now you can see the output of our application in WCF Test
client
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