Alternate solution for handling the badge omitempty problem.

[justinrosenthal]

This implementation makes Payload.Badge a *int instead of an int so omitempty can easily tell between empty (nil) and zero (0).

Inspiration taken from: https://willnorris.com/2014/05/go-rest-apis-and-pointers

Note: this is not a backward-compatible change!

[joekarl]

Yeah, this is definitely a viable way to handle this. This lib isn't the only one having to tackle that issue (see Coccodrillo/apns#22 and Coccodrillo/apns#23).
Over there they decided to just leave it the way it was and not break the interface.
I'm kind of with them in trying to avoid non-backward compatible interface changes.

As it stands right now, I'm ok with the current way of specifying badge < 0 for 0 and badge == 0 for omit.
That being said, the output json does need to be cleaned up so that badge: -1 doesn't get sent to Apple (perhaps an internal representation that uses a pointer?)

[justinrosenthal]

Alrighty, it's your library 😁
Personally I think it's too easy for someone to accidentally screw it up as is... for instance:

func handleMarkRoomAsRead(roomID int) {
    previousCount := db.GetUnreadRoomCount()
    payload := &apns.Payload {
        Token: "some_token",
        Badge: (previousCount - 1),    // if previousCount == 1, whoops
    }
    apnsConn.SendChannel <- payload
}

[joekarl]

Okay, you've swayed me.

The PR looks good, give it a rebase and add a test to show that the serialization omits the badge key and another to show that Badge: Int(0) outputs badge 0 and I'll get it merged in.

Curious, I assume that you're using the lib? (or looking into using it)

[themartorana]

You could also remove Badge and replace it with badge, which can be a *int and add functions SetBadgeNumber(int) and BadgeNumber() int.

This way you can call SetBadgeNumber(0) and have it work appropriately.

Sometimes when you have edge-cases to deal with in Go, albeit slightly non-idiomatic, I've found the idea of setters/getters works well.

[themartorana]

Alternatively you could add a struct field SendBadge bool...

[joekarl]

Closed in favor of #9