Consuming and Publishing XML messages with Orkes Conductor

This project contains a Worker and documentation which are part of a DEMO that shows how to consume and publish messages in XML format using an Event Handler and an Event Task respectively.

The input and output of Workflows and Tasks in Orkes Conductor is always a JSON. However, if a message is received that's not in JSON format, that message will be available as a string in the Workflow's input. To publish a string (XML or any other text format) you can use the special key __payload in the input of the Event task.

Consuming

If the following XML is sent to a queue and is read by an event handler:

<user>
    <name>John Doe</name>
    <age>20</age>
    <email>[email protected]</email>
    <created>2024-06-03 19:22:00</created>
</user>

The workflow input might look like this. As you can see ['conductor.event.eventPayload'].message is set to the XML string:

{
  "conductor.event.messageId": "BE1C55D1-F456-4279-945E-522DF9BABAA5",
  "conductor.event.name": "amqp:amqptest:new-user-queue",
  "conductor.event.eventPayload": {
    "_amqpMessageId": "BE1C55D1-F456-4279-945E-522DF9BABAA5",
    "_amqpType": null,
    "_amqpPriority": null,
    "_amqpUserId": null,
    "_amqpCorrelationId": null,
    "name": "amqp-event-handler-test",
    "_amqpConsumerTag": "amq.ctag-YFYBrKjnBFM88KvI47_7rw",
    "id": "BE1C55D1-F456-4279-945E-522DF9BABAA5",
    "message": "<user>\r\n    <name>John Doe</name>\r\n    <age>20</age>\r\n    <email>[email protected]</email>\r\n    <created>2024-06-03 19:22:00</created>\r\n</user>\r\n",
    "event": "amqp:amqptest:new-user-queue"
  }
}

That message can be used like in the workflow definition as an input to a Task, e.g.:

{
  "name": "approval_task",
  "taskReferenceName": "approval_ref",
  "inputParameters": {
    "data": "${workflow.input['conductor.event.eventPayload'].message}"
  },
  ...
}

Publishing

To send an XML message to a queue you can use an Event task with the special key __payload just like in the workflow definition used in the demo.

 {
  "name": "event",
  "taskReferenceName": "event_ref",
  "inputParameters": {
    "__payload": "${approval_ref.output.notification}"
  },
  "type": "EVENT",
  "decisionCases": {},
  "defaultCase": [],
  "forkTasks": [],
  "startDelay": 0,
  "joinOn": [],
  "sink": "amqp:amqptest:notification-queue",
  "optional": false,
  "defaultExclusiveJoinTask": [],
  "asyncComplete": false,
  "loopOver": [],
  "onStateChange": {}
}

Data flow

In this sequence diagram you can visualize the data flow which starts when an XML message is sent to a queue and ends when an Event Task is used to publish another XML message to a different queue.

Notes

• This is available since Orkes Conductor 3.3.54.
• In the demo "data": "${workflow.input.payload.__payload}" is used instead of "data": "${workflow.input['conductor.event.eventPayload'].message}". That was only available during initial development of this feature (custom payload support) and ended up being deprecated to avoid increasing the size of the task payload unnecessarily.