Habari Client for RabbitMQ is a library for Delphi and Free Pascal which provides access to the RabbitMQ open source message broker. Habarisoft offers example aplications for this client library including chat and performance tests, which need an installation of RabbitMQ. But while the RabbitMQ server installation itself is very simple, it also requires an installed Erlang run time environment, and so the preparing steps for client library evaluation take some time.
Fortunately, there is an easy way to avoid the RabbitMQ installation: CloudAMQP, a service which provides managed RabbitMQ servers in the cloud.
After a simple registration, clients can connect to the server using various standard protocols (AMQP, MQTT, STOMP). The CloudAMQ console page displays a connection URL for AMQP connections, which can be used with Habari Client for RabbitMQ chat application after small changes.
A valid URL for the Habari Chat demo application for CloudAMQP has the form stomp://<Server>?connect.host=<VHost>.
An article by Thomas Beyer (also available in German language) gives a short introduction into popular messaging solutions which are available as free open source projects.
“Newer architectures and the standardized AMQP protocol have led to a flood of message brokers. All brokers take claim to be fast, robust and reliable. But what really distinguish the broker? How do I choose the right broker? Should we continue to use established brokers such as the ActiveMQ or try a more modern one? This article attempts to answer these questions and help the reader in selecting a suitable broker.”
We use Rabbit MQ as our message passing system. Right now, the messages we handle are things like Breaking News Alerts and Live Video alerts. Our internal clients send the fabrik these messages over AMQP. We then send them around our stack, ensuring they are delivered.
We have Rabbit in all layers of our stack, with shovels connecting them. Our own internal code helps route the messages based on there services level. Some messages, like Breaking News, must go out as quickly as possible. So we spread these out over out clusters AND shovel them to clusters in other regions for processing. From there the messages get send to the front end for delivery.
We also use Rabbit for individual messages. If you are a registered NYTimes users, we can send you personally a message. Things like credit card expiring.
To configure ActiveMQ to use the statistics plugin add the following to the ActiveMQ XML configuration:
The statistics plugin looks for messages sent to particular destinations.
Query running broker statistics
To query the running statistics of the message broker, the client sends an empty message to a Destination named ActiveMQ.Statistics.Broker, and sets the replyto field with the Destination you want to receive the result on. The statistics plugin will send a MapMessage filled with the statistics for the running ActiveMQ broker.
Requires ActiveMQ 5.3 or higher
To configure ActiveMQ to use the statistics plugin, add the following to the ActiveMQ XML configuration:
If no destination is specified, the program returns the broker statistics
You can also use wildcards too, and receive a separate message for every destination matched.
BTJMSInterfaces, BTJMSConnection, BTSessionIntf, BTSerialIntf,
Destination, ReplyQueue: IQueue;
Connection := TBTJMSConnection.MakeConnection;
// Create and assign the message transformer
Session := Connection.CreateSession(False, amAutoAcknowledge);
// listen on reply queue
ReplyQueue := Session.CreateQueue('Habari' + '?' +
BTStompTypes.SH_TRANSFORMATION + '=' + TRANSFORMER_ID_MAP_XML);
Consumer := Session.CreateConsumer(ReplyQueue);
// create the pseudo destination
if ParamCount = 0 then
Destination := Session.CreateQueue('ActiveMQ.Statistics.Broker');
Destination := Session.CreateQueue('ActiveMQ.Statistics.Destination.' + ParamStr(1));
// display destination name
WriteLn('Request statistics for ' + Destination.QueueName + ' ...');
// create the message and set reply queue name
JMSMessage := Session.CreateTextMessage;
JMSMessage.JMSReplyTo := ReplyQueue;
Producer := Session.CreateProducer(Destination);
// read the result message
Reply := Consumer.Receive(1000) as IMapMessage;
// list the map key/values
while Assigned(Reply) do
MapNames := Reply.GetMapNames;
for I := 0 to Length(MapNames) - 1 do
Key := MapNames[I];
WriteLn(Key + '=' + Reply.GetString(Key));
Reply := Consumer.Receive(1000) as IMapMessage;
WriteLn('No more message on queue ' + ReplyQueue.QueueName);
on E: Exception do
WriteLn('Press any key');
The RabbitMQ team announced the release of RabbitMQ 3.3.1. This release fixes a number of bugs in 3.3.0 and earlier versions, including security bugs in the MQTT and shovel plugins. Binary and source distributions of the new release can be found on the download page.
For application integration in Delphi and Free Pascal, Habarisoft offers a commercial client library for RabbitMQ 3.2.4 and newer.