Towards a Service Oriented Architecture

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Towards a Service Oriented Architecture

• Geoff StockhamDevelopment WebmasterScotlands
  Health On the Web (SHOW)http//www.show.scot.nhs.
  uk

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Current SHOW service
SHOW Servers
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SHOW Applications

• Current
• Vacancies
• Media Monitoring
• Publications
• Find Nearest
• Search (?)
• Mapping

Planned UMLS Search Publications Consultations Pre
ss Releases News
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SHOW Applications

• Lots of independent applications using duplicate
  information
• Organisations
• Locations and addresses
• Reference files
• Login information

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Service Oriented Architecture

• SOA new buzzword!
• Separate common information
• Provide services that expose this information
• Services can be consumed by
• Other services
• Other applications
• External organisations

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Conceptual Diagram
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What is a (web) service?

• A black box with a well-defined interface
• Implementation not important to consumer
• May consume other services
• Uses XML for messaging
• May be located anywhere
• May take time to call

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What is a (web) service?

• Services are autonomous
• Independently managed
• May be out of your control
• Should be prepared for failures when calling

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What is a (web) service?

• Interact using messages
• XML, described using schema
• Many message patterns
• HTTP means request/response most common
• Described using XML
• Web Service Description Language

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What is a (web) service?

• In the future
• Services share policies on
• Security
• Reliable messaging
• Transactions
• etc.

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SOA for SHOW

• Common services
• e.g. Reference files (GPs, Organisations)
• Applications become services
• Vacancies, publications etc.
• Use standard schemas where possible
• e-GIF, NHSScotland

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First steps

• RSS Feeds
• http//www.show.scot.nhs.uk/rss
• Presentation at last DevDay
• XML over HTTP
• Simple
• No schemas
• Difficult for complicated applications

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Mapping software

• Next talk
• Not XML based!
• Attachments are difficult
• Could still be considered as a service

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Where next?

• Need common services first
• Reference files
• National reference files
• Postcode information
• Build services on top (next talk)
• Find Nearest
• Addressing

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Example

• Vacancies database
• Fraser next talk
• Import and Export XML
• Current job site
• Better to change to web services
• Perhaps InfoPath back end?

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Where next?

• Problems?
• Versioning
• Need to let people know about changes
• How do we know who is using system?
• Adoption
• People need to know about these services

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Where next?

• Add developer tokens
• Anyone calling service needs to supply token
• Can track usage
• Can let developers know of changes
• Education
• XML Steering Group runs XML web service workshops

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More Information

• http//news.nhsscotland.com/Geoffs
• http//www.stockham.co.uk/
• http//www.show.scot.nhs.uk/rss