Sunday, November 27, 2011

Extending ClientBase to Create a WCF Service Proxy

I was trying to explore different ways of creating a proxy to use the service. I knew 3 ways to doing it
1.using SVCUtil.exe
2.using Add Service Reference
3.using ChannelFactory<T> and DuplexChannelFactory<T> classes
As and when I explored that we could also create a proxy by using a wonderful class ClientBase<T>
Here are the steps I followed to create a Proxy using ClientBase<T>
1.Created a Sample service and Hosted in IIS
2.Copy the Service Interface to Client Code
3.Extend the ClientBase<T>
4. Create the proxy in the client and use

1.The Service Interface is as follows
[ServiceContract]
    public interface IService1
    {

        [OperationContract]
        string GetData(int value);


        // TODO: Add your service operations here
    }


The Implementation is as follows
  public class Service1 : IService1
    {
        public string GetData(int value)
        {
            return string.Format("You entered: {0}", value);
        }

    
    }


2. I copied the Service interface  to the Client Code
3. Extended the ClientBase<T> as Follow
    
    class ServiceClient:ClientBase<IService1>,IService1
    {

        public ServiceClient(BasicHttpBinding binding, EndpointAddress address
            ):base(binding,address)
        {

        }
        protected override IService1  CreateChannel()
{
        return base.CreateChannel();
}
   
public string  GetData(int value)
{
       return base.Channel.GetData(value); 
}
}
}


4.We can Invoke the custom handcoded proxy as follows
class Program
    {
        static void Main(string[] args)
        {
            ServiceClient client = new ServiceClient(new BasicHttpBinding(BasicHttpSecurityMode.None), new EndpointAddress("http://mycomputer:61468/Service1.svc"));
            Console.WriteLine(client.GetData(10));
            Console.ReadLine();
        }
    }



Saturday, November 5, 2011

using Microsoft Message Queuing and System.Messaging

Microsoft has provided a wonderful Queuing framework .It is known as Microsoft message Queuing .This can used for data storage during failure at the same time send message between two processes in the same machine or  2 different machine

In case of 2 processes in a local machine we use Private Queue
In case of 2 processes in  2 remote machines we use public  Queues

The message Queue Installation is available in Add remove Windows Components Message Queuing

After installing the same .you will able to  create an use Message Queues
The Queues can be created by following  the steps

1.       Start CompMgmt.msc
2.       You get MessageQueing Sub menu
3.       You can Select  Private and Public Queues and Select  New
4.       Enter the Queue Name
5.       Select  Transactional and Non-Transactional 

6.       The public queue name format is  machine-name\public$\Queue-Name
7.       The private queue name format is machine-name\private$\Queue-Name

I have written an article in this blog that demonstrates a QueueServer and a QueueClient.
The Queue Server pushes the message to a private Queue with name test Queue
The Queue Client Recieves the message and displays it on the console

The Queue stores the messages that is Enqueued and Dequeued in the first in first out order

Messages contain 3  important parts  which I have used
Label –unique id for the message

Formatter – the way in which message is stored it may be binary,text,xml or custom .

Body – The field which stores the message .
The message can be retrieved by the client in Synchronous and Asynchronous fashion
I have used asynchronous mechanism to retrieve the messages in the message queue client side
Following is the example 

Queue Server

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Messaging;

namespace MessageQueueServer
{
    class Program
    {
        static void Main(string[] args)
        {
            //create a Queue if it doesnot exists
            if (!MessageQueue.Exists(@"mycomputer\private$\testQueue"))
            {
                //create a message queue
                MessageQueue.Create(@"mycomputer\private$\testQueue");

            }
           
            //instance representing the Queue
            MessageQueue Queue = new MessageQueue(@"mycomputer\private$\testQueue");
           
            int messagecount = int.MaxValue;
            int messageindex = 0;


            while (messageindex < messagecount)
            {
                //create messages
                Message QueMessage = new Message();
             
                //unique id for the message
                QueMessage.Label = messageindex.ToString();

                //can be any information
                QueMessage.Body ="m"+ messageindex;

                QueMessage.Formatter = new BinaryMessageFormatter();

                //send the message to the Queue
                Console.WriteLine("pushing message no " + messageindex + "to " + Queue.QueueName);
                Queue.Send(QueMessage);
                messageindex++;          
            }


            Console.ReadLine();

        }
    }
}

The code above pushes the messages to the Queue

Queue Client

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Messaging;

namespace MessageQueueClient
{
    class Program
    {
        static MessageQueue queue;
        static void Main(string[] args)
        {
            //access the queue
             queue = new MessageQueue(@"mycomputer\private$\testQueue");
            queue.ReceiveCompleted += new ReceiveCompletedEventHandler(queue_ReceiveCompleted);
         
            //start recieving the message
            queue.BeginReceive();
            Console.ReadLine(); 
        }

        static void queue_ReceiveCompleted(object sender, ReceiveCompletedEventArgs e)
        {
            //recieve the message from the Queue and close it until one message is processed
            Message message = queue.EndReceive (e.AsyncResult);
            Console.WriteLine("Message recieved with id:" + e.Message.Label);
         
            //format the message to retrieve the data
            e.Message.Formatter = new BinaryMessageFormatter();
            Console.WriteLine("Content in the Queue:" + e.Message.Body);
            Console.WriteLine("--------------------------------");

            //open the queue for recieving
            queue.BeginReceive();


        }
    }
}

The code above is a Queue Client  and receives the messages from the Queue Server      
   
Run the Queue Server and then the Queue Client and enjoy the example.