JavaScript - open document only with a specific user roles from a server path

Can some one guide me on the below:

I have a repeater control which open a document on java script call from a shared folder where every user can access the path to download the file.

Now we have a scenario where we want to give access to particular user credentials/role using impersonation or any other approach.

Please suggest.

Use Active Directory permissions on the file.  Either by individual or by a group of people who are permitted to access a file.  It is easier if you manage this sort of thing by folder (if that is possible or makes sense in your app).