Get Session Attributes is a server side plug-in, and according to your description, it is executed after the view has already loaded, which means it's referrer is indeed the view.
What you really want is to catch the initial referal to your application which causes the view to load in the first place. For that you'll need to implement a <Welcome> callable service. When an application includes a <Welcome> callable service in its root system, it is automatically executed when the initial request to the application is received. The callable service should return (at a minimum) the html code for the application page, and in addition can implement other processing (such as finding out the referrer).
The attached demo: Referrer Demo.tersus demonstrates this. It includes the following:
To test this demo:
For best results, use the Firefox browser..