I am looking into building an app that has chat as one of its core components. Now I am looking into Real Time Services like Pusher, Firebase, Pubnub, etc. While all these support real time messaging, I want a solution where I can send a message to the subscribed users and if the app isn't online (open), we fall back to Push Notification.
Is there any service that offers this? Or how do I go about achieving this? I would have gone for a traditional server approach but I need real time performance for chat.
PubNub do offer this functionality. In particular PubNub advertise "Seamless fallback to Push Notifications (Realtime socket connection attempted first)": http://www.pubnub.com/how-it-works/mobile-push/
As do Realtime.co: http://messaging-public.realtime.co/documentation/starting-guide/mobilepush.html