WCF - Transactions

 Transactions provide a way to perform one or more than one operations as single unit of work

Transaction characteristics

• Atomic (either all the operations of the transactions succeed or none of them succeed )
• Consistent (outcome is exactly what we expected it to be)
• Isolated (Isolated transactions are "private," meaning that no one else knows about the transaction until it is committed)
• Durable

Name space used : System.Transactions

 

WCF supports transaction on following bindings :

1.       WSHttpBinding

2.       NetTcpBinding

3.       NetNamedPipeBinding

4.       WSDualHttpBinding

5.       WSFederationHttpBinding

TransactionFlow Attribute :

It has three options:

• Allowed: Transaction may be flowed.
• Mandatory: Transaction must be flowed.
• NotAllowed (default): Transaction cannot be flowed

While developing a Service Contract we have to specify the TransactionFlow attribute on each
Operation Contracts that requires a Transaction to be handled

   [ServiceContract]

    public interface ITransectionService

    {

        [OperationContract]

        [TransactionFlow(TransactionFlowOption.Allowed)]

        void Displaydata();   

    }

ServiceBehavior Attribute

The [ServiceBehavior] attribute has three properties that deal with handling and managing transactions

TransactionAutoCompleteOnSessionClose: Specifies whether pending transactions are completed either commited or rollback  when the current session closes.

TransactionIsolationLevel: Determines the isolation level(hold locks on the data) of the transaction.

TransactionTimeout: Specifies the period in which a transaction has to complete.  If the transaction has not completed before the timeout value has been reached, the transaction is rolled back.

OperationBehavior Attribute :

The [OperationBehavior] also has followingof properties related to transactions.

TransactionAutoComplete: Specifies that transactions will be auto-completed if no exceptions occur.

TransactionScopeRequired: Specifies whether the associate method requires a transaction.

 [OperationBehavior(TransactionScopeRequired = true,TransactionAutoComplete=true)]

Enable transaction flow using WCF service config file

<bindings>

      <wsHttpBinding>

        <binding name="TransactionalBind" transactionFlow="true"/>

      </wsHttpBinding>

</bindings>

 

Example :

Database Table :

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

SET ANSI_PADDING ON

GO

CREATE TABLE [dbo].[Emp](

      [AutoID] [int] IDENTITY(1,1) NOT NULL,

      [Name] [varchar](50) NULL,

      [Designation] [varchar](50) NULL,

      [Salary] [int] NULL,

 CONSTRAINT [PK_Emp] PRIMARY KEY CLUSTERED

(

      [AutoID] ASC

)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]

) ON [PRIMARY]

GO

SET ANSI_PADDING OFF

Interface:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Runtime.Serialization;

using System.ServiceModel;

using System.Text;

using System.ServiceModel.Web;

namespace WcfService1

{  

    [ServiceContract]

    public interface ITransectionService

    {

        [OperationContract]

        [TransactionFlow(TransactionFlowOption.Mandatory)]

        int AddEmp(int Salary,string Name, string Designation);   

       

    }   

}

Service :

using System;

using System.Collections.Generic;

using System.Linq;

using System.Runtime.Serialization;

using System.ServiceModel;

using System.Text;

using System.ServiceModel.Transactions;

using System.Data.SqlClient;

using System.Configuration;

using System.Collections;

using System.Transactions;

namespace WcfService1

{

    

    public class TransectionService : ITransectionService

    {

     

        [OperationBehavior(TransactionScopeRequired = true)]

        public int AddEmp(int Salary, string Name, string Designation)

        {

            int retval = 0;

            Emp em = new Emp();         

            em.Name = Name;

            em.Designation = Designation;

            em.Salary = Salary ;                          

         

            using (Database1Entities ctx = new Database1Entities())

            {

              

                ctx.Emps.AddObject(em);

                retval=ctx.SaveChanges();

            }

           return retval;

        }

     

    }

}

Webconfig:

<?xml version="1.0" encoding="utf-8"?>

<configuration>

 

  <connectionStrings>

     <add name="Database1Entities" connectionString="metadata=res://*/Model1.csdl|res://*/Model1.ssdl|res://*/Model1.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=.\SQLEXPRESS;attachdbfilename=|DataDirectory|\Database1.mdf;integrated security=True;user instance=True;multipleactiveresultsets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />

  </connectionStrings>

 

  <system.web>

    <compilation debug="true" targetFramework="4.0">

      <assemblies>

        <add assembly="System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />

      </assemblies>

    </compilation>

  </system.web>

  <system.serviceModel>

    <behaviors>

      <serviceBehaviors>

        <behavior>

          <serviceMetadata httpGetEnabled="true" />         

          <serviceDebug includeExceptionDetailInFaults="false" />

        </behavior>

      </serviceBehaviors>

    </behaviors>

    <bindings>

      <wsHttpBinding>

        <binding name="transactionalWsatHttpBinding" transactionFlow="true" />

      </wsHttpBinding>

    </bindings>

    <serviceHostingEnvironment multipleSiteBindingsEnabled="false" />

    <services>

      <service name="WcfService1.TransectionService">

        <endpoint name="" address="http://localhost:56464/TransectionService.svc" bindingConfiguration="transactionalWsatHttpBinding" binding="wsHttpBinding" contract="WcfService1.ITransectionService" />

      </service>

    </services>

  </system.serviceModel>

  <system.webServer>

    <modules runAllManagedModulesForAllRequests="true" />

  </system.webServer>

</configuration>

Client :

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Transactions;

using System.Data.SqlClient;

using System.Configuration;

namespace WCF_Transaction

{

    class Program

    {

        static void Main(string[] args)

        {

            //We TransactionScope object to group the WCF services  operations in one transaction.

            //Here we are colling same service TWO times with different objects.

            using (TransactionScope ts = new TransactionScope(TransactionScopeOption.RequiresNew))

            {

                try

                {

                    // declare object 1 to call servic method

WCF_Transaction.TransectionServiceServiceref.TransectionServiceClient Obj1 = new WCF_Transaction.TransectionServiceServiceref.TransectionServiceClient();

                    int A = Obj1.AddEmp(10000,"Employee1", "Manager");

                    // declare object 1 to call servic method

WCF_Transaction.TransectionServiceServiceref.TransectionServiceClient Obj2 = new WCF_Transaction.TransectionServiceServiceref.TransectionServiceClient();

                    int B = Obj1.AddEmp(2000,"Employee2", "Director");

                    Console.WriteLine(" Done , press enter to exit  ");

                   

                    ts.Complete();

                }

                catch

                {

                    Console.WriteLine("Unable to process transaction,press enter to exit  ");

                    ts.Dispose();

                }

                Console.ReadLine();

            }

        }

    }

     

    

}

OutPut: