How to fail installation if WebAppPool doesn't exist? - iis

Question

I use the following Wix code to create a WebApplication in IIS and assign it to a specific Application Pool.
<iis:WebAppPool Id="AppPool_Wcf" Name="$(var.WCF_APP_POOL)" />
<iis:WebSite Id="Web_site" Description="$(var.WEB_SITE_DESCRIPTION)" SiteId="[SITEID]">
<iis:WebAddress Id="Web_Address" Port="*"/>
</iis:WebSite>
<DirectoryRef Id="TARGETDIR">
<Directory Id="SITEPATH">
<Directory Id="WCF_VIRT_DIR" Name="$(var.WCF_VIRT_DIR)">
<Component Id="IIS_Wcf" Guid="$(var.deploy.wcf.guid)" KeyPath="yes">
<iis:WebVirtualDir Id="Wcf_VirtualDir" Alias="$(var.WCF_VIRT_DIR)" WebSite="Web_site" Directory="WCF_VIRT_DIR">
<iis:WebApplication Id="Wcf_Application" Name="$(var.WCF_VIRT_DIR)" WebAppPool="AppPool_Wcf" />
</iis:WebVirtualDir>
</Component>
</Directory>
</Directory>
</DirectoryRef>
App Pool should already exist, as it’s shared with some other applications.
If it doesn’t exist, setup succeeds, assigning Web Application to a mysterious <Invalid Application Pool> (can be seen in web app Properties).
The application even works!
How can I make installation fail if App Pool is not found?

Answer 1

You have to create an immediate custom action for this. For instance, in C#/DTF it could be implemented like this:
[CustomAction]
public static ActionResult FailIfAppPoolNotExist(Session session)
{
DirectoryEntry appPool = new DirectoryEntry(string.Format("IIS://localhost/w3svc/AppPools/{0}", session["APP_POOL_NAME"]));
if (appPool == null)
{
return ActionResult.Failure;
}
return ActionResult.Success;
}