How to make authorization on the site for certain users and the ability to add new ones?

Question

JavaScript

Hello, since I'm not really familiar with the Steam API, could you tell me how to authorize the site for certain users (steamid) and so that it would be possible to add new users.

Example: https://a.csgorun.pro/welcome

Answer 1

If the user is in a certain list - let him in, if not - do not let him in. The simplest if-check.
The Steam API returns data about the account that has been authorized, respectively, there is also a steam id there.