This API documentation is for Ballerina 1.2.0. View API documentation for the latest release.

Object - websub : Hub

Represents the Ballerina WebSub Hub.

Constructor

__init

(string subscriptionUrl, string publishUrl, Listener hubHttpListener)

  • subscriptionUrl string
  • publishUrl string

Methods

Stops the started up Ballerina WebSub Hub.

Publishes an update against the topic in the initialized Ballerina Hub.

Registers a topic in the Ballerina Hub.

Unregisters a topic in the Ballerina Hub.

Removes a subscription from the Ballerina Hub, without verifying intent.

Retrieves topics currently recognized by the Hub.

Retrieves details of subscribers registered to receive updates for a particular topic.

Fields

  • subscriptionUrl string
  • The URL for subscription changes

  • publishUrl string
  • The URL for publishing and topic registration

stop

()

returns error?

Stops the started up Ballerina WebSub Hub.

 error? registrationResponse = webSubHub.stop();
  • Return Type

    (error?)
  • An error if hub can't be stoped or else ()

publishUpdate

(string topic, string | xml | json | byte[] | ReadableByteChannel payload, string? contentType)

returns error?

Publishes an update against the topic in the initialized Ballerina Hub.

 error? publishResponse = webSubHub.publishUpdate("http://websubpubtopic.com",{"action": "publish",
 "mode": "internal-hub"});

Parameters

  • topic string
  • The topic for which the update should happen

  • contentType string? (default ())
  • The content type header to set for the request delivering the payload

  • Return Type

    (error?)
  • An error if the hub is not initialized or does not represent the internal hub or else ()

registerTopic

(string topic)

returns error?

Registers a topic in the Ballerina Hub.

 error? registrationResponse = webSubHub.registerTopic("http://websubpubtopic.com");

Parameters

  • topic string
  • The topic to register

  • Return Type

    (error?)
  • An error if an error occurred with registration or else ()

unregisterTopic

(string topic)

returns error?

Unregisters a topic in the Ballerina Hub.

 error? registrationResponse = webSubHub.unregisterTopic("http://websubpubtopic.com");

Parameters

  • topic string
  • The topic to unregister

  • Return Type

    (error?)
  • An error if an error occurred with unregistration or else ()

removeSubscription

(string topic, string callback)

returns error?

Removes a subscription from the Ballerina Hub, without verifying intent.

 error? registrationResponse = webSubHub.removeSubscription("http://websubpubtopic.com", "removeSubscriptioCallback");

Parameters

  • topic string
  • The topic for which the subscription should be removed

  • callback string
  • The callback for which the subscription should be removed

  • Return Type

    (error?)
  • An error if an error occurred with removal or else ()

getAvailableTopics

()

returns string[]

Retrieves topics currently recognized by the Hub.

 string[] topic = webSubHub.getAvailableTopics();
  • Return Type

    (string[])
  • An array of available topics

getSubscribers

(string topic)

returns SubscriberDetails[]

Retrieves details of subscribers registered to receive updates for a particular topic.

 string[] topic = webSubHub.getSubscribers("http://websubpubtopic.com");

Parameters

  • topic string
  • The topic for which details need to be retrieved