Debugging Executables for Push Notifications

I am implementing Push Notifications in one of my apps. Doing so may be a bit tricky in terms of debugging since you cannot actually debug incoming Push Notifications appropriately while the app is running, so I wanted to share this tip. Also, I am writing this post on my iPad on an airplane, so pretty excited about that :)

Xcode allows you to debug applications that are running locally on your device. You can even set breakpoints in your code and print out any information you may need from the console in order to debug your app and fix whatever issue you’re experiencing, should you not be able to fix it via “live” debugging.

This feature is especially useful if you’re doing Push Notifications (a great way to easily communicate information to your user with their permission, such as notifications, reminders, marketing (be careful with this one), etc.).

With Push Notifications, your app receives data from Apple Push Notification servers in a dictionary in the UIApplication delegate application:didFinishLaunchingWithOptions: that you’ll need to parse and do in your app whatever is appropriate for the implementation you’ve chosen (launching with specific views in front, etc.). Since your app cannot be running while receiving Push Notifications (it actually does receive notifications while running, but you’re required to deal with that through another delegate method), you’ll need to use the “debug executables” with “Wait for next launch/push notifications” ticked. Once you run the debugger and launch your app (for example directly via a Push Notifications UIAlertView) you can set breakpoints anywhere in your code and use the console to print out (po) any objects you may wish to inspect.

As your app launches immediately when you debug, it’s a problem if you’re debugging Push Notification (which, by the way, does not work in Simulator). So here’s the hidden treasure in Xcode: In the Groups & Folder pane, find Executables, expand and select your app executable. Hit command+option+i to “Get Info” and select the Debugging tab. From here, tick “Wait for next launch/push notification”.

Now, when you Run & Debug your app it will not launch, but instead wait until you tap the app icon to launch it or the app is launched via a Push Notification UIAlertView (this of course requires you have not set the “action-loc-key” to null in your Push Notification JSON dictionary).

Once your app launches via a Push Notification, it will stop at the breakpoint you set and you can now print out any information you need to debug your app, such as the NSDictionary your app receives, whether the appropriate view will be displayed and any other issue you may have.