Steve Graham WS-Notification Technical Overview OASIS WS-Notification TC F2F Thursday, April 29th, 2004

© 2004 IBM Corporation 2 WS-Notification  Family of documents and specifications  Brings enterprise quality publish and subscribe messaging to Web services Loosely coupled, asynchronous messaging in a Web services context  WS Notification exploits WS Resource framework and other Web services technologies  Direct and Brokered notification  Topics and Topic Spaces

© 2004 IBM Corporation 3 Requirements  Must support resource-constrained devices  Must support both direct and brokered Notification  Must permit transformation and aggregation of Topics  Must provide runtime metadata In addition, must allow for:  WS-Notification must be independent of binding-level details  Must allow for Message Oriented Middleware implementations  Must allow for federation of brokers  Relationship to other WS-* specifications

© 2004 IBM Corporation 4 Non Goals  Defining the format of notification payloads:  Defining any Events or NotificationMessages  Defining the mapping between Situations and NotificationMessages  Defining the means by which NotificationProducers and NotificationBrokers are discovered by subscribers  Defining the specific policy language to be used to govern specifics of the notification message exchange between the NotificationProducer and the NotificationConsumer

© 2004 IBM Corporation 5 WS-Notification Family of Documents  WS-Notification is a family of documents: Publish-Subscribe for Web services –Whitepaper describing roles, concepts, terms, etc. Base Notification –Basic interfaces: Producer, Consumer, Subscription Topics –Topics and TopicSpaces model in XML –Topic Expression Dialects Brokered Notification –Mechanisms of Publish and the Broker role  Authored by: CA, Fujitsu, Globus, HP, IBM + Akamai, SAP, Sonic, Tibco

© 2004 IBM Corporation 6 Status of WS-Notification  Specification announced on January 20,  Public feedback session February 24  Specifications updated March 5 Factored into 4 documents  OASIS TC call for participation March 9  Interoperability “fest” April 21  First meeting of OASIS TC April 29

© 2004 IBM Corporation 7 Terminology and Concepts  Situation  NotificationMessage  Notification  NotificationProducer  NotificationConsumer  Subscription  SubscriptionManager  Subscriber  Topic  Topic Space  Topic Tree  NotificationBroker  Publisher  PublisherRegistration  PublisherRegistrationMana ger  Demand-based Publisher

© 2004 IBM Corporation 8 Consumer Producer Subscriber WS-Notification: Base Notification subscribe S notify EPR  Defines the Basis for the family  Direct notification: Three primary roles  Subscriber deals directly with the producer of the Notifications indicates interest in a particular “Topic” by issuing a “subscribe” request  An EPR to the subscription is returned  Producer is responsible for detecting situation and creating the notification  Subscriptions that match receive the notification

© 2004 IBM Corporation 9 Base Message Exchange Pattern

© 2004 IBM Corporation 10 WS-Base Notification  Defines the Web services interfaces for NotificationProducers and NotificationConsumers It includes standard message exchanges along with operational requirements expected of them.  This is the base specification on which the other WS-Notification specification documents depend.  Direct, point to point, notification WS-Base Notification Publish-Subscribe Notification for Web Services

© 2004 IBM Corporation 11 WS-Base Notification Interfaces

© 2004 IBM Corporation 12 Notification Consumer: Notify {any} ? wsa:EndpointReference xsd:any +

© 2004 IBM Corporation 13 Notification Producer: Resource Properties  MUST support required WS-ResourceProperties message exchanges <xsd:element name=”Topics” type=”wsnt:TopicExpressionType” minOccurs=”0” maxOccurs=”unbounded” /> <xsd:element name=”FixedTopicSet” type=”xsd:boolean” minOccurs=”1” maxOccurs=”1” /> <xsd:element name=”TopicExpressionDialects” type=”xsd:anyURI” minOccurs=”1” maxOccurs=”unbounded” />

© 2004 IBM Corporation 14 Notification Producer:: Subscribe  More on Subscribe Request  Returns EPR to a Subscription WS-Resource EPR xsd:boolean ? wsrp:QueryExpression ? any ? xsd:dateTime ?

© 2004 IBM Corporation 15 NotificationProducer::GetCurrentMessage {any} {any}

© 2004 IBM Corporation 16 SubscriptionManager Resource Properties <xsd:element name=”ConsumerReference” type=”wsa:EndpointReferenceType” minOccurs=”1” maxOccurs=”1” /> <xsd:element name=”TopicExpression” type=”wsnt:TopicExpressionType” minOccurs=”1” maxOccurs=”1” /> <xsd:element name=”UseNotify” type=”xsd:boolean” minOccurs=”1” maxOccurs=”1” /> <xsd:element name=”Precondition” type=”wsrp:QueryExpressionType” minOccurs=”0” maxOccurs=”1” /> <xsd:element name=”Selector” type=”wsrp:QueryExpressionType” minOccurs=”0” maxOccurs=”1” /> <xsd:element name=”SubscriptionPolicy” type=”xsd:anyType” minOccurs=”0” maxOccurs=”1” /> <xsd:element name=”CreationTime” type=”xsd:dateTime” minOccurs=”0” maxOccurs=”1” />

© 2004 IBM Corporation 17 SubscriptionManager Operations  MUST support the required WS-ResourceProperties message exchanges  MUST support the message exchanges defined for immediate and scheduled destruction