How to send a broadcast message with SmackAPI?

Question

We're developing special devices that uses XMPP to talk to each other. A new API i am developing now, should talk to these devices too. The problem i am facing - all these devices are building little groups - for each customer we have... so we will have a chat-room for each group of devices, or, for each of our customer with his bunch of devices ;)

But now.. the api should be able to talk to every device that is connected. I don't need a real broadcast-mechanism - in the end, i will send a message only to one specific device..

But i don't want to login to each chat-room either - running a product with over 40k customers and much more devices, will end in a funny api, that is opening over 40k chat-rooms at startup... even if don't tried this yet, i can't imagine that an app like this will run well... even though we can have millions of customers in a few years.. i don't like solutions that will grow linear with the amount of customers, if you know what i mean :/

Now, basically i'm thinking of a solution, where i just can use the basic XMPPConnection to do my stuff.

MyCustomMessage msg = new MyCustomMessage();
msg.setTo("*"); // don't know what to address, i want to send it to "all"
msg.setFrom("ThatAPI"); // just a string telling that is sent from my java api ;)

msg.setEvent(event); // stuff that is coming through the parameters of the method where this code is inside
msg.setCustomStanza(data); // same here

connection.sendPacket(msg); // my try to send it to all till now..

Somewhere in the Ignite Realtime Forums i have read of one guy who "solved" it, but everything he says is "it's working now, i push my message through the sendPacket of Connection"... ok nice, my attempt of this seems not to work :(

Any better ideas/real implementations how this will work fine?

Basically i start to think that XMPP will not be the best technology to achieve something like this at all - i wish i could have a real/basic socket-implementation where something like this would be piece of cake.. But i can't choose - the third-party-system has implemented XMPP already... not enough time to change all of this... Just if you're wondering why we try this on XMPP..

Answer 1

You seem to have some conflicting requirements in that you want to send to all devices now, but only 1 specific device later. Are both models required at the same time, or do you plan on switching? How either is done would be different solutions.

As for your current approach, I think pubsub would make more sense than your chatroom approach, as that is oriented to generic message passing to subscribers.

• You could set up a pubsub node per customer to send messages to all of their devices.
• As for a broadcast to all, you can make all devices subscribe to a single pubsub node.

Thus you control broadcast and group messages by sending to the appropriate pubsub node.

For sending to a specific device, that is just a sendPacket to the specific entity, nothing really special there.