Hi,
 
You get the users Role with the below REST API
 
<#assign restStr = "/users/id/${user.id}/roles">
 
Please refer this post. 
http://lithosphere.lithium.com/t5/developers-discussion/Only-Group-creators-can-see-Groups/m-p/118993/highlight/false#M4438
 
Also refer the below Lithium article to refer all the details related to user, page, node, etc
http://lithosphere.lithium.com/t5/developers-knowledge-base/Writing-custom-components-in-Lithium-Studio/ta-p/9217
 
Hope this helps, if it ansewers your question please accept this as a solution. 
 
Thanks,
Premkumar