I'm looking at using FB login to my MySQL DB via PHP API using Xamarin.Forms rather than setting up login/registration myself in MySQL.
I can do the FB login part, check for success and get the FB_ID. Once that done, I can check the FB_ID if exists in my DB and populate DB etc.
I don't understand the process how to securely check for FB login pass/fail and use that flag to access MySQL. The process checking the FB login pass/fail is within the app itself (IF FB_login_ok then fetch the data from MYSQL based on FB_ID), so one can easily edit the app.
I'm passing all the data to PHP API using JWT/HTTPS and I'm planning to use JWE if xamarin.forms has support for it.
Can someone please direct/explain to me how to achieve using the FB login to authorize MySQL DB login?