Please see the Stomp site for more details
ActiveMQ v5.6 implements the Stomp v1.1 spec except for allowing spaces at the beginning or end of message header keys, they are preserved in the header values however. In future releases this will not be the case, clients should be updated and user code checked to ensure that spaces in the headers are there intentionally and not as a accident or a client "feature".
Enabling the ActiveMQ Broker for Stomp
To enable STOMP protocol support in the broker add a transport connector definition whose URI scheme is
To see a full example, try this XML. If you save that XML as
foo.xml then you can run stomp via the command line as
For more help see Run Broker.
The Stomp Wire Format
Stomp uses a text based wire format that can be configured with the following options. All options can be configured on a Brokers transport bind URI.
Maximum size of the message body (content) that can be sent.
From ActiveMQ 5.12.0: maximum frame size that can be sent. A Stomp frame includes a command, optional headers, and an optional body. Can help help prevent OOM DOS attacks
Use the Correct Prefix!
Wire format options must have the prefix
wireFormat. to take effect, e.g.,
wireFormat.. Options missing this prefix will be ignored.
From ActiveMQ 5.1: Stomp fully supports ActiveMQ's security mechanism. This means that the
CONNECT command will return an
ERROR STOMP frame on unsuccessful authentication. Also, the authorization policies will be applied when you try to access (read/write) certain destinations. If you use synchronous operations (by using receipts), you can expect an
ERROR frame in case of unauthorized access attempt. In other case, operations will be discarded but the client will not be informed of errors. This applies to all errors that can occur broker-side.
For additional security, you can use Stomp over SSL as described in the following section.
Enabling Stomp over NIO
From ActiveMQ 5.3: for better scalability and performance the Stomp protocol can be configured to be run over the NIO transport. The NIO transport will use far fewer threads than the corresponding TCP connector. This can help when support for a large number of queues is required. To use NIO change the URI scheme of the transport connector to
Enabling Stomp over SSL
To configure ActiveMQ to use Stomp over an SSL connection change the URI scheme to
Heart-Beat Grace Period
The STOMP protocol (version 1.1 or greater) defines the concept of heart beats as a method by which a client and broker can determine the health of the underlying TCP connection between them. ActiveMQ supports STOMP heart beating provided the client is using version 1.1 (or greater) of the protocol.
Before ActiveMQ 5.9.0: enforcement of the 'read' heart-beat timeout (that is, a heart-beat sent from the client to the broker) was strict. In other words, the broker was intolerant of late arriving read heart-beats from the client. This resulted in the broker concluding that the client was no longer present causing it to close its side of the client's connection when the client failed to honor it's configured heart-beat settings.
From ActiveMQ 5.9.0: the timeout enforcement for read heart-beats is now configurable via a new transport option
This multiplier is used to calculate the effective read heart-beat timeout the broker will enforce for each client's connection. The multiplier is applied to the read-timeout interval the client specifies in its
<client specified read heart-beat interval> * <grace periodmultiplier> == <broker enforced read heart-beat timeout interval>
For backward compatibility, if the grace period multiplier is not configured the default enforcement mode remains strict, e.g.,
transport.hbGracePeriodMultiplier=1.0. Attempts to configure the grace period multiplier to a value less than, or equal to
1.0 will be silently ignored.
STOMP clients that wish to be tolerant of late arriving heart-beats from the broker must implement their own solution for doing so.
Please check the STOMP specification for the details on heart-beating
The JIRA that implemented this: ActiveMQ 5.x does not support the notion of a grace-period for heart beats as supported by the STOMP protocol
Working with Destinations with Stomp
Note that the prefix in stomp
/topic/ is removed from the string before passing it to ActiveMQ as a JMS destination. Also note that the default separator in MOM systems is
. (dot). Whilst
FOO.BAR is the normal syntax to identify a queue type destination the Stomp equivalent is
Be careful about starting destinations with /
If in Stomp world you use
/queue/foo/bar then in a JMS world the queue would be called
Persistent Messaging in STOMP
STOMP messages are non-persistent by default. To use persistent messaging add the following STOMP header to all
persistent:true. This default is the opposite of that for JMS messages.
Working with JMS Text/Bytes Messages and Stomp
Stomp is a very simple protocol - that's part of the beauty of it! As such, it does not have knowledge of JMS messages such as
BytesMessage's. The protocol does however support a
content-length header. To provide more robust interaction between STOMP and JMS clients, ActiveMQ keys off of the inclusion of this header to determine what message type to create when sending from Stomp to JMS. The logic is simple:
Inclusion of content-length header
This same logic can be followed when going from JMS to Stomp, as well. A Stomp client could be written to key off of the inclusion of the
content-length header to determine what type of message structure to provide to the user.
transformation message header on
SUBSCRIBE messages could be used to instruct ActiveMQ to transform messages from text to the format of your desire. Currently, ActiveMQ comes with a transformer that can transform XML/JSON text to Java objects, but you can add your own transformers as well.
Here's a quick example of how to use built-in transformer (taken from test cases)
In order to create your own transformer, you have to do the following:
Build your transformer by implementing a FrameTranslator interface
Associate it with the appropriate header value by creating a file named as a value you want to use in the
META-INF/services/org/apache/activemq/transport/frametranslator/folder of your JAR which will contain the value
class=fully qualified classname of your transformer
For example the built-in transformer contains the following value:
In case you want to debug Stomp communication between broker and clients you should configure the Stomp connector with the
trace parameter, like this:
This will instruct the broker to trace all packets it sends and receives.
Furthermore, you have to enable tracing for the appropriate log. You can achieve that by adding the following to your
Finally, you will probably want to keep these messages in the separate file instead of polluting the standard broker's log. You can achieve that with the following log4j configuration:
After this, all your Stomp packets will be logged to the
From ActiveMQ 5.2: there is a simple Java Stomp API distributed with ActiveMQ. Note that this API is provided purely for testing purposes and you should always consider using standard JMS API from Java instead of this one. The following code snippet provides a simple example of using this API:
This example is part of the standard ActiveMQ distribution. You can run it from the
./example folder with:
Stomp Extensions for JMS Message Semantics
Note that STOMP is designed to be as simple as possible - so any scripting language/platform can message any other with minimal effort. STOMP allows pluggable headers on each request such as sending & receiving messages. ActiveMQ has several extensions to the Stomp protocol, so that JMS semantics can be supported by Stomp clients. An OpenWire JMS producer can send messages to a Stomp consumer, and a Stomp producer can send messages to an OpenWire JMS consumer. And Stomp to Stomp configurations, can use the richer JMS message control.
STOMP supports the following standard JMS properties on
Good consumers will add this header to any responses they send.
Expiration time of the message.
Specifies the Message Groups.
Optional header that specifies the sequence number in the Message Groups.
Whether or not the message is persistent.
Priority on the message.
Destination you should send replies to.
Type of the message.
ActiveMQ Extensions to STOMP
You can add custom headers to STOMP commands to configure the ActiveMQ protocol. Here are some examples:
Specifies the JMS clientID which is used in combination with the
Should messages be dispatched synchronously or asynchronously from the producer thread for non-durable topics in the broker?
For fast consumers set this to
For slow consumers set it to
I would like to be an Exclusive Consumer on the queue.
For Slow Consumer Handling on non-durable topics by dropping old messages - we can set a maximum-pending limit, such that once a slow consumer backs up to this high water mark we begin to discard old messages.
Specifies whether or not locally sent messages should be ignored for subscriptions.
Specifies the maximum number of pending messages that will be dispatched to the client. Once this maximum is reached no more messages are dispatched until the client acknowledges a message.
Set to a low value > 1 for fair distribution of messages across consumers when processing messages can be slow
Note: if your STOMP client is implemented using a dynamic scripting language like Ruby, say, then this parameter must be set to
STOMP does not support a value of
Sets the priority of the consumer so that dispatching can be weighted in priority order.
For non-durable topics make this subscription retroactive.
For durable topic subscriptions you must specify the same
Note: the spelling
For the 5.0 release of ActiveMQ, both
Specifies a JMS Selector using SQL 92 syntax as specified in the JMS 1.1 specification. This allows a filter to be applied to each message as part of the subscription.