Detect client connection drop using Jersey/Java

I have created Restful Web Services using Jersey over Java. My client is an iOS app which sends user data after every minute. What would be the best way to detect that client has stopped sending the data due to either network lost or app killed by the user. I want to detect it on my API server.

I am able to do it using Redis event notification mechanism. For reference I used

• basrikahveci.com/a-simple-jedis-publish-subscribe-example
• Redis Key expire notification with Jedis