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Example

What you'll build​

Build a WSO2 Integrator automation that publishes a topic update to a remote WebSub Hub using the ballerina/websubhub connector. The integration creates a connection to the hub, then calls the publishUpdate operation to deliver a JSON payload to a specified topic.

Operations used:

  • publishUpdate : Publishes a content update for a given topic to the configured WebSub Hub

Architecture​

Prerequisites​

  • A running WebSub Hub endpoint with a valid URL
  • A registered topic on the hub to publish updates to

Setting up the Websubhub Publisher integration​

New to WSO2 Integrator? Follow the Create a New Integration guide to set up your integration first, then return here to add the connector.

Adding the Websubhub Publisher connector​

Add the Websubhub Publisher connection to your integration project.

Step 1: Open the connector palette and select the Websubhub Publisher connector​

  1. In the WSO2 Integrator sidebar, select + Add Artifact.
  2. Search for websub in the artifact palette and select Websubhub Publisher (from ballerina/websubhub).

Websubhub Publisher connector palette open with search field before any selection

Configuring the Websubhub Publisher connection​

Step 2: Fill in the connection parameters​

In the Add Connection form, bind each parameter to a configurable variable:

  • Connection Name : A unique name for this connection instance
  • Hub URL : The URL of the remote WebSub Hub, bound to the websubHubUrl configurable variable

Websubhub Publisher connection form fully filled with all parameters before saving

Step 3: Save the connection​

Select Save to create the connection. The new connection appears in the Connections panel.

Websubhub Publisher Connections panel showing websubhubPublisherclient entry after saving

Step 4: Set actual values for your configurables​

  1. In the left panel, select Configurations.
  2. Set a value for each configurable listed below.
  • websubHubUrl (string) : The full URL of the remote WebSub Hub endpoint

Configuring the Websubhub Publisher publishUpdate operation​

Step 5: Add the Automation entry point​

  1. In the WSO2 Integrator sidebar, select + Add Artifact.
  2. Select Automation as the artifact type.
  3. Set the function name to main (default).
  4. Select Create; the Automation flow canvas opens.

Step 6: Select the publishUpdate operation and configure its parameters​

  1. In the Automation flow canvas, select the + drop zone between Start and Error Handler.
  2. Expand the websubhubPublisherclient section in the node panel.
  3. Select Publish Update to open the operation configuration panel.

Websubhub Publisher connection node expanded showing all available operations before selection

Fill in the operation fields:

  • Topic : The topic URL to publish the update to, bound to the websubTopic configurable variable
  • Payload : The JSON content to deliver to subscribers
  • Result : The variable name that receives the websubhub:Acknowledgement response

Websubhub Publisher publishUpdate operation configuration filled with all values

Select Save; the publishUpdate node appears on the flow canvas.

Completed Websubhub Publisher automation flow

Try it yourself​

Try this sample in WSO2 Integration Platform.

Deploy to Devant

View source on GitHub

More code examples​

The WebSub Hub connector provides practical examples illustrating usage in various scenarios. Explore these examples, covering WebSub hub implementations and publish-subscribe delivery patterns.

  1. In-memory hub: Implement a WebSub hub that stores subscription state in memory.

  2. JMS WebSub hub: Build a WebSub hub backed by JMS-based message delivery.

  3. Kafka hub: Implement a WebSub hub backed by Kafka-based event distribution.