I have a get request like "site.com/admin/fs/download?filename=blahblah.pdf", where fs is my custom view. How can I check in my custom view if user have access to express admin? Because now everyone can execute this query without login.
Yes, and you can have multiple users registered to use the admin - check out this comment
Also if you are POSTing data to the server don't forget to add a CSRF token in your web forms, just check out how this is done in the editview template.
I have a get request like "site.com/admin/fs/download?filename=blahblah.pdf", where fs is my custom view. How can I check in my custom view if user have access to express admin? Because now everyone can execute this query without login.