WCF- Notes 3 Hosting

Selecting a Host

·         A WCF service class is typically compiled into a library. By definition, all libraries need a host Windows process to run in. WCF provides two main options for hosting libraries that implement services. One is to use a host process created by either:

ü  Internet Information Services (IIS) or a

ü  Related technology called the Windows Activation Service (WAS).

ü  The other allows a service to be hosted in an arbitrary process. 

Hosting a Service Using IIS or WAS

·         The simplest way to host a WCF service is to rely on IIS or WAS. Both rely on the notion of a virtual directory, which is just a shorter alias for an actual directory path in the Windows file system.

·         IIS-hosted WCF services can only be accessed using SOAP over HTTP. No other transport protocols are supported.

·         Although WAS doesn’t require a Web server to be installed on the system, WCF services hosted in IIS obviously do.

·         Whatever choice is made, both WAS and IIS provide WCF services with a range of support, such as the ability to configure automatic process recycling.

·         To allow a WCF service to take requests from its clients, the process that hosts it must remain running. With WAS-hosted services, the standard process ensures the host remains running, but a hosting application must solve this problem on its own. A WCF service hosted console would be running in a Windows service, allowing it to be started when a system boots, or be hosted in a GUI application, such as one built with Windows Presentation Foundation.