跟踪客人历史互动的最佳方式是什么？

Question

Currently in development is a PHP site where anyone can reply to peoples listings. They do not require a login or account.

What I would like to achieve is to inform the users if they have already responded to a listing and when. Because they are not logged in I cannot simply save responses in a database mapped to a user.

My initial conception is to use cookies. Saving the listing IDs and timestamp. But this could result in numerous cookies being stored. The other option to store all in info in one cookes via a coded string. IE code the array into a string and save it in the cookies. But my concern here is the data in the cookies will become quite large.

Are there limits on the count of cookies and/or the data within a cookies. Are there any other better methods to achieve the same results. IP addresses are unreliable and I do not think will be accurate. If cookies are used they would need to be maintained when listing get deleted and the data is no longer relevant.

Answer 1

I would be concerned about the reliability of the cookies as well. Firstly, people tend to use several browsers on several devices, and cookies approach limit it to one. Or, what is worse, different results on different devices. Secondly, one could just delete cookies. Of course, it's not an often thing, but still - you won't achieve 100% working thing.

What I would suggest is to add an optional login/register system for those who DO NEED that function, and I think that if they need it, they will register.