Archive for November, 2013

 As I’ve worked building the Cartera OfferLink app on iOS, I’ve learned a little about Apple’s Push Notification service. One thing that I wanted to do from the start was avoid sending a notification when someone might be sleeping! Every once in a while, I’ll get a text message early, like 6am. I’m a late sleeper, and the BUZZ! that my phone makes will always wake me.

I really don’t like that.

So I decided early on that I’d do the best I could to avoid sending messages at inappropriate times. I know you can change your phone settings to avoid notifications at certain times, but the default – and most folks devices are set to the default – is to just deliver the message when it arrives, buzzing and binging and waking you up.

What I did with OfferLink is send the current time, local to the phone, to the server, along with its data requests. Then I calculate the seconds offset from the server and the phone’s time. This gives me the current time zone of the phone as of that request.

It’s not a perfect system – the user could fly around the world to a different time zone, and get a notification before the app refreshed its data and told the server its new time zone. But it should be a good 80/20 solution – solving for 80% of users.

// (pseudo code for handling the time zone)
localTime = time();
remoteTime = localTime + tzOffset;
if (hourOf(remoteTime) > 8 && hourOf(remoteTime) < 22) doNotify();

Please be kind to your users – handle push notifications in such a way that you don’t annoy them.

Or wake them up.