XMPP PubSub Workbench

Step through XEP-0060 nodes, subscriptions, item publishing, access models, persistence, and notification fan-out

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Learner-ready XMPP PubSub animation with scenario controls, step/play interaction, node access diagnosis, subscriber fan-out, XML stanza inspector, and mobile-ready reference support.
Animation XMPP XEP-0060 PubSub

XMPP PubSub Workbench

Follow one published item as an XMPP PubSub service checks the node, applies its access model, optionally stores the item, and sends event notifications only to matching subscribers.

Selected node /building/1/temperature
Access model open
Subscribers reached 3 of 5
Item storage persistent
Core object

The node is the server-managed channel. It is more than a topic string because it can have access control, affiliations, and storage policy.

Watch first

The item starts at a publisher, reaches the pubsub service by IQ stanza, and fans out as message event notifications.

Common mistake

XMPP PubSub is not MQTT transport. It is an XMPP extension that uses XML stanzas and XMPP identity, routing, and policy.

1. Select nodeService locates the target PubSub node.
2. Check accessSubscription and publish policy are evaluated.
3. Publish itemPublisher sends an IQ set with a node item.
4. Store if enabledPersistent nodes retain the latest item.
5. Notify subscribersOnly eligible subscribers receive events.

Temperature fan-out

A room sensor publishes one reading to the temperature node. The pubsub service notifies dashboard, HVAC, and analytics subscribers.

Stage 1 of 5: select node
XMPP PubSub item flow A publisher sends an item to a pubsub service, the service checks node policy, stores the item when configured, and sends notifications to eligible subscribers. Publishers PubSub service and nodes Subscribers Room sensor sensor-east@devices.iot 22.4 C item PubSub service pubsub.iot.local Checks open access Subscriptions: 3 allowed Selected node /building/1/temperature persistent, 3 subscribers Dashboard dashboard@ops.iot HVAC controller hvac-controller@building.iot Security console security-console@building.iot Analytics analytics@cloud.example Pending or denied subscriber guest-panel@visitor.iot waits IQ set enters service publish node=temperature item id=item-204 XML stanza payload
Delivery diagnosis

The node is open and persistent. Dashboard, HVAC, and Analytics are subscribed, so each receives an event message for the new temperature item.

Concept in focus

Publishers do not send directly to every consumer. The PubSub service owns node policy and notification fan-out.

Stanza Inspector

Read the XML associated with the current stage and scenario. The examples are shortened for learning, but keep the important XEP-0060 structure.


          

            Publish IQ
            
A publisher sends an IQ set to the pubsub service. The publish element names the target node and wraps the item payload.

            
    
          
    
        
    
      
    
    
    
  
    

  
    
    
    
      Technical Quick Reference
      
    
        
    
          
    PubSub service
    
          
    An XMPP entity such as pubsub.example.org that manages nodes, validates requests, stores items when configured, and sends notifications.
    
        
    
        
    
          
    Node
    
          
    A named collection point for items. It can have configuration such as access model, notification behavior, max items, and persistence.
    
        
    
        
    
          
    Item
    
          
    The published payload, usually wrapped in <item id="...">. Notifications deliver the item to subscribers as an event message.
    
        
    
        
    
          
    Subscription
    
          
    The relationship saying a JID wants notifications from a node. Subscriptions answer "who receives events?"
    
        
    
        
    
          
    Affiliation
    
          
    The longer-lived permission role on a node, such as owner, publisher, member, or outcast. Affiliations answer "who may manage or publish?"
    
        
    
        
    
          
    Access model
    
          
    Common models include open, authorize, whitelist, roster, and presence. Exact support and defaults depend on the XMPP server.
    
        
    
      
    
    
    

    
    
      Use The Workbench To Check Understanding
      
    
        
    
          
    Who receives the event?
    
          
    Change the selected node and subscriber. If a JID is not subscribed or is blocked by policy, the publish still reaches the service but no event is delivered to that JID.
    
        
    
        
    
          
    What changes with persistence?
    
          
    Turn persistence off and replay a stored item. Without storage, late subscribers cannot learn the last value from the PubSub node itself.
    
        
    
        
    
          
    What is not MQTT?
    
          
    MQTT brokers route PUBLISH packets by topic filters. XMPP PubSub routes XML stanzas by service, node, JID, subscription, and server policy.
    
        
    
      
    
    
    

    
    
      Model Boundaries And Sources
      
    
        
    
          
    Simplified here
    
          
      
            
    • TLS, SASL, stream negotiation, service discovery, and error codes are not animated.
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    • Only one publisher item is shown at a time.
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    • Server-specific policy and persistence details are summarized.
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    Technical basis
    
          
      
            
    • XEP-0060 defines the XMPP publish-subscribe extension.
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    • RFC 6120 defines XMPP core streams, stanzas, and routing foundations.
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    • RFC 6121 defines instant messaging and presence behavior around rosters and presence.
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    Accuracy notes
    
          
    Event notifications are shown as <message type="headline"> examples. Real deployments may use different message types, payload namespaces, node options, and authorization workflows.
    
        
    
      
    
      
    
        XEP-0060 Publish-Subscribe extension specification.
        RFC 6120 XMPP core protocol foundation.
        IoTClass XMPP chapter Local chapter context for XMPP in IoT systems.