Difference between Proxy and Channel Factory in WCF

Introduction

In this article I will show you the difference betweens a WCF Channel factory and Proxy and when to use a Proxy and when to use a Channel Factory.

Background

There are three ways to create a WCF client:

• Proxy
• WCF Channel Factory
• REST services, using HttpClient or WebClient

Using the code

Before going into the differences, I will explain what a WCF channel factory is and what a proxy is in WCF and when to use a Proxy and when to use a channel factory.

What is Proxy

Proxy is a CLR class that exposes a single CLR interface representing the service contract.

A proxy is the same as a service contract, but also has additional methods for managing the proxy life cycle and the connection to the service. The proxy gives the following details: its location, its implementation technology, and run time platform and communication transport.

A proxy can be generated in two ways:

1. By using Visual Studio: by right clicking References and clicking on Add Service Reference. Then open the Add Service Reference dialog box where you have to specify the base address of the service and the namespace that contains the proxy.

This auto generates proxy code that connects to the service by reading the WSDL (Web Service Descriptive language). If the service address changes for any reason you have to regenerate it. The big advantage of this is that it is easy to set up - Visual Studio has a wizard and it's all automatic. The disadvantage is that you're relying on Visual Studio to do all the hard work for you, and so you lose control.

2. Using the SvcUtil.exe command-line utility. We have to provide SvcUtil with the HTTP-GET address or the metadata exchange endpoint address and, optionally, using svcutil.exe, it creates a proxy that derives from System.ServiceModel.ClientBase<TChannel>.

2. What is Channel Factory

Use the ChannelFactory class with a known interface. This depends on you having local interfaces that describe the service contract. The big advantage is that you can change more easily. But you still have to recompile and fix changes, but now you're not regenerating code, you're only referencing the new interfaces. Channel factory is commonly used when you have control of both the server and the client.

In ChannelFactory<T> you must share contract assemblies between the service and the client. That's why ChannelFactory<T> can save you time.

When your project shares a common service contract DLL between the client and the server, you have to use the ChannelFactory class.

For using channel factory, the following steps are necessary:

1. Create a binding in WCF
2. Create a ChannelFactory class
3. Create a Channel
4. Send-Receive messages over that channel

Example:

In the below example, we use the ChannelFactory class and we send messages back and forth to the service.

using System;
using System.ServiceModel;
using ClientConsole.ServiceReference;

namespace ClientConsole
{
    internal class Program
    {
        private static void Main()
        {
            var channelFactory =
                new ChannelFactory<IEchoService>(
                    "WSHttpBinding_IService" // endpoint name
                    ); 

            IService channel = channelFactory.CreateChannel();
            Message result = channel.Echo(
                new Message
                    {
                        Text = "Hey "  
                    });

            Console.WriteLine("Service given respond at {0}: {1}",
                              result.Invoked,
                              result.Text);
            Console.ReadLine();

            ((IClientChannel)channel).Close();
        }
    }
}

Difference between proxy and channel factory

Good luck and please let me know your feedback! In this way you can learn the difference between a proxy and a channel factory.

If you have any queries, mail me at Sujeet.bhujbal@gmail.com.