Spring-Websocket: Send Updates to Subscribers when condition is met

Question

I have the following method on a Spring @Controller:

@MessageMapping("/comment/{id}")
@SendTo("/topic/conversation/{id}")
public OperationResult<Comment> comment(Comment comment) throws Exception {

    //call @Service to add comment
    OperationResult<Comment> operationResult = commentService.comment(comment);

    return operationResult;}

This will send updates to all the subscribers even if the operation was not successful (operationResult.success == false).

NB: OperationResult has a boolean field called 'success' to indicate whether the operation was successful or not.

Question: I want to find out how can I only send updates to subscribers if the operation was successful (without throwing an exception) and ensure that the client that sent the comment always gets the operationResult

FourtyTwo · Answer 1 · 2015-11-13T05:25:12.383

I managed to find a way to only send updates based on a condition

@Autowired
private SimpMessagingTemplate simpMessagingTemplate;

@MessageMapping("/comment/{id}" )
public OperationResult<Comment> comment(Comment comment) throws Exception {

    OperationResult<Comment> operationResult = new OperationResult<>();
    conversationService.comment(operationResult, comment);

    if (operationResult.isSuccess()) {
        simpMessagingTemplate.convertAndSend("/topic/conversation/"+operationResult.getReturnedObject().getConversation().getId(), operationResult);
    }
    return operationResult;
}

This however does not allow me to return the operationResult to the client.

UPDATE:

To allow the client to get the operationResult I replaced the @MessageMapping with @RequestMapping. So the client has to make a normal ajax call to submit a comment.

@Autowired
private SimpMessagingTemplate simpMessagingTemplate;

@RequestMapping("/comment" )
public OperationResult<Comment> comment(@RequestBody Comment comment) throws Exception {

    OperationResult<Comment> operationResult = new OperationResult<>();
    conversationService.comment(operationResult, comment);

    if (operationResult.isSuccess()) {
        simpMessagingTemplate.convertAndSend("/topic/conversation/"+operationResult.getReturnedObject().getConversation().getId(), operationResult);
    }
    return operationResult;
}

Spring-Websocket: Send Updates to Subscribers when condition is met

1 Answers1