By adding this method to your SysSingleton and marking it with Eco.ExternalLateBound=anyvalue you can get access to the running turnkey system's url address:

SysSingleton.GetSystemUrl():string

x

Making the method "IsQuery" makes it available in ocl (not only action language) - and you can write things like this:

SysSingleton.oclSingleton.GetSystemUrl()+ '/SiteAssets/ProjectReportTemplate.odt'

...this will fully qualify the address to a report template found in SiteAssets.

Or maybe you need an QRImage with a fully qualified url back to your system:

ZXing.QRImage(300,300,SysSingleton.oclSingleton.GetSystemUrl()+
     '/Turnkey/AngularApp#/ToolInfo/'+self.Guid.asstring)

Please note that this is the URL of the TurnKeyserver. Thus is an action originating from TurnKey needed to set the URL, this if needed for server-side jobs or similar.