Skip to main content

STOMP API

STOMP stack​

The included STOMP stack supports only version 1.2 of STOMP, with the following exceptions:

  • There is no support for transactions, so frames BEGIN, COMMIT and ABORT are not supported
  • On SUBSCRIBE, ack type client is not supported; you'd need to use client-individual and emit ack/nack for each message. Also, client-individual is also not supported on queues lacking reserve support (type redis:list)
  • Any type of body is allowed, not just string; for non-string bodies it is recommended to pass a content-length header to ensire bodies are read complete; also, the header content-type is kept and stored alongside the body (as keuss element headers)
  • On NACK frames:
    • A NACKed message will be delayed by 5 secs; that is, a NACKed message will not be reserved again (by any keuss client) until at least 5 secs have elapsed
    • There is no limit of retries

There are also a few additions on top of the standard STOMP:

  • Support for parallel consumers on subscriptions: more than one consumer can be used on any given subscription to pop/reserve elements from the underlying queue, just pass an extra header x-parallel on the SUBSCRIBE frame with the desired number of parallel consumers (defaults to 1)
  • Support for window size to limit the number of in flight messages on subscriptions: in flight messages are messages waiting to be acked/nacked, but also consumers waiting for a pop-from-queue. Default window size is 1000, but it can be specified by passing a header x-wsize on the SUBSCRIBE frame
  • Delay/Scheduling in SEND/NACK: messages can be delayed or scheduled for later on SEND frames, but also when NACKing a message. Simply use one of those headers (if none used, it will assume x-delta-t: 0):
    • x-next-t: UNIX time in milliseconds, to set an absolute time
    • x-delta-t: a delta in milliseconds from now, for a relative time
  • Extra info in MESSAGE: some extra info is included on each MESSAGE frame returned, to ease retries and/or better management:
    • x-mature: ISO timestamp when the message became eligible for pop/reserve (mature)
    • x-tries: number of tries of this message. Each NACK increments this value, so this can be used in conjunction with x-delta-t to implement custom delays on failing elements, or limiting the number of retries
    • any header with name starting with x-ks-hdr- is stored alongside the body (as keuss element headers) and therefore passed along it
  • support for streams by means of these headers:
    • x-ks-groups: set of potential consumer groups, in the insert operations
    • x-ks-group: consumer group to use, in get, reserve, commit and rollback operations
  • There is no support for auth yet. User and password are simply ignored