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Question

I need to write a application that can send push notifications at clients. But sometimes clients are disconnected, so I'd like to store notifications and send them to clients when they reconnect.

Is there a way to achieve this ? I need a way to know if client is present before sending, OR a way to know if a notification is well received. And my notifications are client specific.

I can't show off a lot of code, but I'd like to use something like this :

@Autowired
private SimpMessagingTemplate messagingTemplate;

public void sendPush(Long clientId) {

    messagingTemplate.convertAndSendToUser(clientId, "/queue/reply", myMessage);
    // -> how do I know if message is received ?
}

I use spring-websocket and stomp-endpoint.

Thank you !

Answer 1

Maybe you can expect to get an "ack" message from the user. You can keep all the message in a data structure and remove them from it only when you get the ack.