I've added StompClientLib in my project and I'm facing problem while unsubscribing a destination topic.
Unsubscription of destination gives following error: "org.apache.activemq.transport.stomp.ProtocolException: No subscription matched.\r\tat org.apache.activemq.transport.stomp.ProtocolConverter.onStompUnsubscribe(ProtocolConverter.java:734)\r\tat org.apache.activemq.transport.stomp.ProtocolConverter.onStompCommand(ProtocolConverter.java:262)\r\tat org.apache.activemq.transport.ws.AbstractStompSocket.processStompFrame(AbstractStompSocket.java:151)\r\tat org.apache.activemq.transport.ws.jetty9.StompSocket.onWebSocketText(StompSocket.java:96)\r\tat org.eclipse.jetty.websocket.common.events.JettyListenerEventDriver.onTextMessage(JettyListenerEventDriver.java:128)\r\tat org.eclipse.jetty.websocket.common.message.SimpleTextMessage.messageComplete(SimpleTextMessage.java:69)\r\tat org.eclipse.jetty.websocket.common.events.AbstractEventDriver.appendMessage(AbstractEventDriver.java:64)\r\tat org.eclipse.jetty.websocket.common.events.JettyListenerEventDriver.onTextFrame(JettyListenerEventDriver.java:122)\r\tat org.eclipse.jetty.websocket.common.events.AbstractEventDriver.incomingFrame(AbstractEventDriver.java:160)\r\tat org.eclipse.jetty.websocket.common.WebSocketSession.incomingFrame(WebSocketSession.java:309)\r\tat org.eclipse.jetty.websocket.common.extensions.ExtensionStack.incomingFrame(ExtensionStack.java:214)\r\tat org.eclipse.jetty.websocket.common.Parser.notifyFrame(Parser.java:220)\r\tat org.eclipse.jetty.websocket.common.Parser.parse(Parser.java:258)\r\tat org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.readParse(AbstractWebSocketConnection.java:628)\r\tat org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.onFillable(AbstractWebSocketConnection.java:476)\r\tat org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:540)\r\tat org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:635)\r\tat org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:555)\r\tat java.lang.Thread.run(Unknown Source)\r")
Yes, It's an issue with subscription name but It doesn't accept the same string I used to subscribe specific channel.
For example:
```
// destination
let destinationChannelTopic = "/topic/channel_1234"
// subscribe successful
socketClient?.subscribe(destination: destinationChannelTopic)
// unsubscribe not successful with same destination
socketClient?.unsubscribe(destination: destinationChannelTopic)
```
Here unsubscribe replies me with an error: No subscription matched
Can anyone help me to understand, what is wrong? What am I doing wrong?
As I analyzed from Subscribe and receive messages, subscription (a subscribe method) returns a string (subscription channel id) from the server, that we need to store somewhere at client side (in our project/code) and we need to use the same string to unsubscribe.
This is javcScript (not an iOS - swift) code, a sample that available in this link (Subscribe and receive messages) and we implemented similar way it in web application:
```
// subscribe
var subscription = client.subscribe("/queue/test", callback);
```
The subscribe() methods return a JavaScript object with 1 attribute, id, that correspond to the client subscription ID and one method unsubscribe() that can be used later on to unsubscribe the client from this destination.
```
// unsubscribe
subscription.unsubscribe();
```
So, is this only the method/possible way, for subscription and unsubscription. If yes, then we do not have any value returning to subscribe(...) that I can use to unsubscribe. I don't get any value (destination subscription id) from subscription socketClient?.subscribe(destination: destinationChannelTopic) method
As an alternate solution to this issue, I disconnect the client from the server and reconnect again + subscribe to all other destinations again. And this is not a proper way to handle but I have only this solution at this time.
Please help to find out the solution for this problem.
Here is reference link about the issue: unsubscribe socketclient #14
Subscription methodology approach for subscribe and unsubscribe are very different.
Subscribe uses unique destination (id) to connect with server as a destination but links and remembers it with reference of subscription-id and uses subscription-id to identify itself on server while unsubcribe.
Here is code, you are looking for. Try it.
let destination = "/topic/channel_1234"
let ack = "ack_\(destination)" // It can be any unique string
let subsId = "subscription_\(destination)" // It can be any unique string
let header = ["destination": destination, "ack": ack, "id": subsId]
// subscribe
socketClient?.subscribeWithHeader(destination: destination, withHeader: header)
// unsubscribe
socketClient?.unsubscribe(destination: subsId)
The subscribe func in this StompClientLib library is not returning the subscription ID that the server will generate and return to the client. You can see the code here:
So you will have to specify a subscription ID by using this other func from the library, and provide a stomp header that includes a subscription ID of your choosing:
public func subscribeWithHeader(destination: String, withHeader header: [String: String])
For example:
var destination = "mytopic"
var ack = StompCommands.ackAuto
var subsId = "12345"
let header = [StompCommands.commandHeaderDestination: destination, StompCommands.commandHeaderAck: ack, StompCommands.commandHeaderDestinationId: subsId]
socketClient?.subscribeWithHeader(destination, header)
...
socketClient?.unsubscribe(subsId)
来源：https://stackoverflow.com/questions/48472473/stompclientlib-unsubscribe-socketclient