I think there are some places like IsSteemLink where you could use a regex to see if it's valid, and then split it by groups to get the information you need

Yeah that's probably how I'm going to handle this

In some places there are magic numbers, like for example $hasaccess == 2. What is 2? I personally would define some constants and use those instead, which should improve the readability of the code.

I know it is a bad way to do this, but those magic numbers are access levels, and I'm still designing the whole concept in my mind, so I'll fix it soon.

Thank you for all the suggestions @amosbastian, I really enjoyed your review, and I'll do my best to make this software as great as possible, as it will be a great help to use it! :)