I am developing a chat application in rails with the help of quickblox. I have created the application in quickblox and setup it in the rails app. With the help of API, I can get the list of registered users. But I need to get a list of online users. How to get it. Is there any API available to get the list of online users.
There is no way to get online/offline statuses of any user
You can use user.last_request_at for such purpose, but it's not 100% 'true' status
http://quickblox.com/developers/Users
What else you can do is to implement Chat Roster. It allows to manage a user's contact list. And you can track your contact list user online/offline status as you can see on Skype for example
There are a lots of Ruby XMPP libraries
http://xmpp.org/xmpp-software/libraries/
How to interact with QuickBlox Chat http://quickblox.com/developers/Chat