I've built a PHP based site that requires a user to log in to view certain pages. I want my users to be able to share these pages (and their custom open graph tags) on Facebook, however when I added my share button, Facebook could not share the correct open graph tags because the page requires you to be logged in. Does anyone know a way around this other than creating a page with the correct open graph tags that doesn't require a login?

I tested the Facebook sharing debugger and it shows the 'canonical URL' as the page you get re-directed to if you are not logged in.