Messaging & Web Services an Architectural View John Arnett, MSc Standards Modeller Information and Statistics Division NHSScotland Tel: (x2073)

Contents XML Usage XML Applications Messaging and Web Services Interaction Models Message Construction

XML Usage Key features –Human readable –Structured and searchable –Separates data from presentation –Self-describing –Extensible – any number of tags allowed –Meta-markup language

XML Usage Open standard, promoted by many vendor-neutral organisations, incl. –W3C –OASIS (Organization for Structured Information Standards) –HL7 (Health Level 7) –OMG (Object Management Group) –UK Government

XML Usage Widely supported by software vendors and open source groups, incl.

XML Applications Data Storage & Content Management Messaging & Web Services Presentation Application Logic

XML Messages –Ideal for data interchange Text based Open Self describing Extensible –Exchanged between applications on the same network or over the Internet/Extranet Messaging and Web Services

Web Services –Set of emerging standards, incl. SOAP, WSDL and UDDI –Allow systems to communicate over the internet using XML messages –Used for remote service requests/calls enterprise application integration business process integration

Messaging and Web Services SOAP –Lightweight, XML-based protocol for exchanging information over the internet –Language, platform and transport independent –v1.2 W3C Recommendation

Messaging and Web Services WSDL (Web Services Definition Language) –XML-based language for describing services available on the internet UDDI (Universal Description, Discovery and Integration) directory services –Information Services –Operations

Sender Interaction Models Channel Message Receiver Message Channel

Interaction Models One-way (“fire-and-forget”) –non-blocking, asynchronous model Consumer Provider Message

Interaction Models Synchronous Request/Response –RPC Consumer Provider Request Response

Interaction Models Call Back –Asynchronous conversations Consumer Provider Request with correlation id Acknowledgement Response Acknowledgement

Interaction Models Telephone-like Post Office-like Synchronous Asynchronous Tighter coupling Loose coupling Strongly typed Document-based Fast feedback Slower feedback - call-return - queuing and routing RPCMessage-oriented

Interaction Models Point-to-Point –One input channel to one output channel –Message sent to 1 receiver only –Message sent directly or via router/queue

Interaction Models Multi-Point –One input channel to many output channels or subscribers –Copy of message sent to each subscriber –Message published via router / topic

Message Construction Message Types –Document - transmits structured or unstructured data –Command - specifies a function or method to invoke on the receiver –Event - notifies receiver of some event of interest, e.g. an acknowledgement

Message Construction High Level Information Model –HL7 v3 RIM –CEN (European) Standards –e-GIF (UK Government)

Message Construction Message Content –Clinical guidelines, e.g. SIGN –National Data Definitions, e.g. SMR –Consultation with user groups, professional bodies and manufacturers –Other sources, e.g. existing EDIFACT messages

Message Construction Standard XML Vocabularies –Health Care NHSS architectural schemas Health Level 7 (HL7) v3 –Government UK GovTalk schemas –International UNeDocs Code Lists XML - units of measurement, etc

Message Construction Message Schemas –Messages Referral Waiting Times –Message Structures NHSS HL7 CDA Government Gateway

Message Construction SOAP Envelope SOAP Header SOAP Body Message Structure Message Content

Find Out More Scottish Health and Community Care XML Steering Group – SCI XML Standards – GovTalk Schemas and Standards – Health Level 7 –

Messaging and Web Sevices W3C Web Services Activity – Web Services Interoperability –

Communication Models WS-I Usage Scenarios – SupplyChainManagement/ / UsageScenarios-1.01-BdAD.doc Enterprise Integration Patterns –