setting ack to client results in duplicate message delivery stomp-CodePudding

I have a stomp application and I set the ack mode to client during subscription from front-end. During the subscription the same client during a session would connect to the same queue in the message broker ActiveMQ Artemis because a session id is used for queue.But a different id is passed in the header every time the user reloads the page.

The subscription code is shown below.

            consumer.subscribe(
                '/queue.'  rscSessionId,
                function (response) {
                    console.log("resposne");
                },
                {
                    "subscription-type": "ANYCAST",
                    ack: "client",
                    id: generateId(),
                }
            );

Once I send message from client it gets send to frontend with following headers.

MESSAGE
subscription:1234
message-id:1543449
destination:/queue.sessionid
expires:1653914606725
redelivered:false
priority:4
persistent:true
timestamp:1653912806717
destination-type:ANYCAST
__AMQ_CID:30e64793-dd9b-11ec-8843-c238460c3152
_type:ResponseData
content-length:300

and afterwards on every reload.

MESSAGE
subscription:1235
message-id:1543449
destination:/queue.sessionid
expires:1653914606725
redelivered:true
priority:4
persistent:true
timestamp:1653912806717
destination-type:ANYCAST
__AMQ_CID:30e64793-dd9b-11ec-8843-c238460c3152
_type:ResponseData
content-length:300

You can see that redelivered is set to true after first delivery and after that every response has redelivered to false. the subscription value keeps getting changed though because of the id passed in header.

How can I make it deliver only once but with guarantee?

CodePudding user response：

Are you actually acknowledging the message once you receive it? If you don't acknowledge the message then once the client closes the connection and subscribes again it will receive the same message again. The different value you're seeing for the subscription header indicates this is what is happening.

To be clear, if you're using the client acknowledgement mode then once you receive the MESSAGE frame you need to send a corresponding ACK frame in order to acknowledge the message. Your client should have a way to do this since it is a standard part of the STOMP specification.

CodePudding user response：

I guess that Artemis is configured with publisher/subscriber messaging style. In this case, every new consumer/receiver/client will get the messages aka you write/read from a topic.

Changing to a point-to-point message style would fix the issue (would only be read once) aka a queue.

This is usually decided by the setup but I recall that ActiveMQ allowed producer to create those on the fly.

If you do need a topic, then you will have to handle the IDs on the client side.