How to implement a link that can get bonus for 5 times by different people on a Social Network?

Question

How can we generate a link that can be clicked on by 5 different people on a Social Network game, so that each of the five people can get a bonus? The link will be published as a "newsfeed" on the Social Network such as Facebook.

The link shouldn't be easily "generated" by any people as a cheating method.

Also, what database table(s) should be added to handle:

1) the bonus can be claimed up to 5 times
2) must be claimed by different people

(each person has a unique numeric ID on social network platform such as Facebook)

?

Answer 1

You create a table with current valid hashes, and the max count it is able to be claimed, and another table where you safe all ids that already clicked the link. By that you can check if the link still has clicks left, and that only different people have clicked it.