检查用户是否在最近24小时内登录

Question

I'm currently developing a "user rewarding" system in my website to reward the active users with a given virtual currency (points for example)

I'm having a problem thinking of a way to acomplish that.

I know that I would have to compare timestamps, but I have no idea when I should create the base timestamp, which I would use as the base for my calculations. I think I may not be explaining my question properly, so I will say it in a short manner: How can I check if the user has logged in the last 24 hours. When to create to create the timestamps that I will use for my calculations.

Thank you in advance for all of your answers.

I have a last_activity column in my users table

Answer 1

Well you'd just have to store the timestamps each times your users log in. But if you want to check if they were online no matter if they had to login or not, you'd have implement an update to the timestamp on every page. You should also store the last update time in the cookie of the user so that you don't update at each page load but every ten minutes or what not.

Answer 2

Without knowing your application structure, it's hard to be specific, but update a 'last_activity' (or similar) field in your user table on occasion. Then check if that last_activity value is older than 24 hours.

Add some logic so the last_activity only gets updated every 15 minutes or so, and you won't be doing an extra DB write every page load.

Answer 3

I'm just going to use some short-hand for this one:

OnRegister (to void giving instant points on first login):

user->lastPoints = now();

OnLogin:

if (user->lastPoints - now > 24h)
{
    if (user->lastPoints - now < 48h)
    {
        user->rewardPoints();
    }
    user->lastPoints = now();
}

Hope this is what you're searching for.