Configuring Image Service

This article describes the options for hosting the Image Service outside the Episerver CMS application. By default, the Episerver CMS Image Service runs in the same application domain as the Episerver CMS site. For performance and scalability reasons, you can host the Episerver CMS Image Service in another process and use Windows Communication Foundation to access it. This could be an ASP.NET Web Application, a Console Application or even a WinForms Application.  

Hosting with IIS HTTP / WAS

If you host using IIS and the HTTP protocol, or with Windows Activation Services (Windows Server 2008 / Windows Vista only), then you should create a file with the SVC extension somewhere in the website. The SVC file should contain the following line of code:

<%@ ServiceHost Language="C#" Debug="true" Service="EPiServer.ImageLibrary.ImageService" %>

You can configure the Windows Communication Foundation client and service from both code and configuration files. Configuration files are the most flexible because you can change endpoint addresses and binding types without having to touch the code.

Image Service host application configuration

The following configuration example shows an Image Service hosting application that uses the NET.TCP protocol. Place the <system.serviceModel> section in the application’s app/web.config file as a child of the <configuration> section.

<system.serviceModel>
   <services>
      <service name="EPiServer.ImageLibrary.ImageService">
         <endpoint address="net.tcp://serverxyz:8000/ImageService"
                   binding="netTcpBinding"
                   bindingConfiguration="ImageServiceBinding"
                   contract="EPiServer.ImageLibrary.IImageService" />
   </service>
   </services>
   <bindings>
      <netTcpBinding>
         <binding name="ImageServiceBinding"
                  maxReceivedMessageSize="20000000">
            <readerQuotas maxArrayLength="20000000" />
         </binding>
      </netTcpBinding >
   </bindings>

<add name="ImageServiceModule" type="EPiServer.ImageLibrary.ImageServiceModule, EPiServer.ImageLibrary" />

Configuring the Episerver CMS website

To use the remote Image Service on an Episerver CMS website, you also need to configure WCF in its web.config file. Assuming that the Image Service was configured to use the NET.TCP protocol and is listening on port 8000/ImageService on serverxyz, the following configuration is required:

<system.serviceModel>
   <client>
      <endpoint name="ImageServiceClientEndPoint"
                address="net.tcp://serverxyz:8000/ImageService"
                binding="netTcpBinding"
                bindingConfiguration="ImageServiceBinding"
                contract="EPiServer.ImageLibrary.IImageService" />
   </client>
   <bindings>
      <netTcpBinding >
         <binding name="ImageServiceBinding" maxReceivedMessageSize="20000000">
            <readerQuotas maxArrayLength="20000000" />
            <security mode="None">
            </security>
         </binding>
      </netTcpBinding >

Note: The client endpoints name MUST be ImageServiceClientEndPoint because this is the name that Episerver CMS looks for when deciding if the Image Service should be accessed using Windows Communication Foundation. If there is no client endpoint with the name ImageServiceClientEndPoint, then a local version of the Image Service is instantiated by Episerver CMS in the same application domain.

Hosting with a Console / WinForms application

In the startup code for the application, create a System.ServiceModel.ServiceHost instance passing in the ImageService type:

//Create a service of for the type EPiServer.ImageLibrary.ImageService
ServiceHost serviceHost = new ServiceHost(typeof(ImageService));

Open the service host to start the listening operation:

//Start the service
serviceHost.Open();

Note:  The call to Open is non-blocking. Therefore, in a console application you should have code to stop the application exiting immediately:

Console.WriteLine("Press any key to stop the service");
Console.ReadLine();

Always close the service host before the application exits, either with an explicit call to Close() or by employing the C# using statement:

//Close the service
serviceHost.Close();

Hosting with IIS and a Non-HTTP Protocol on Windows Server 2003 / XP

Microsoft does not support hosting a WCF service in IIS on Windows Server 2003 / Windows XP using a non-HTTP protocol (for example, NET.TCP, NET.PIPE), but you can do it and it works using the help of an HTTP module.

The EPiServer.ImageLibrary assembly actually supplies such a module to support this hosting option. No user code is required for this, only configuration.

The main disadvantage with this hosting method is that the requests to the WCF service do not go through the IIS HTTP pipeline and therefore have no effect on the lifetime of the web application. This means that you must activate the web application hosting the service via a normal web request to call the HTTP module and open the service host.

Related topics

• WCF Hosting Options (MSDN.com) 
• How to Host a WCF Service in IIS (MSDN.com) 
• How to Host a WCF Service with Windows Activation Services on Windows Server 2008 / Windows Vista (WAS) (MSDN.com)
• Configuration describes the syntax used in the description of the configuration elements.