Add to social network before downloading a file, how to do it?

Question

PHP

How to make it so that the user is shown the buttons of social networks and when, for example, he adds a link from Google + or Twitter or Facebook, then it becomes possible to download the file? like here

Answer 1

sociallocker.ru

Answer 2

IMHO, I would not use my acc in this form, but for fake use it will be 0, so you need to leave the opportunity to "unblock" in a different way