Web Services and HL7v3 in IHE profiles

Vassil Peytchev Vassil Peytchev Epic

Introduction

Web Services OverviewWeb Services in IHE – Why and HowHL7 Version 3HL7 Version 3 in IHE – Why and HowFirst Steps

Web Services Overview

• In the beginning there was the Internet (TCP/UDP + IP)– Then came the Web (http + html)– Then XML + DTD– Then XML Namespaces + XML Schema– Then SOAP + UDDI + WSDL– … and there were Web Services!

What are Web Services

• (W3C) The programmatic interfaces used for application to application communication over the World Wide Web

• (W3C) Web Services provide a standard means of interoperating between different software applications

• SOAP-based messaging infrastructure and transport mechanism

Web Services Building Blocks

• A number of standards– SOAP (1.1, 1.2)– WSDL (1.1)– WS-Addressing– WS-Security– WS-Secure Conversation– WS-Policy– WS-Reliable Messaging– XOP– MTOM

• How do we navigate?

Web Services Building Blocks

Metadata

Foundation

Messaging

Assurances

Infrastructureand Profiles

WS-Transfer WS-Enumeration WS-Eventing

SOAP WS-Addressing MTOM

XML Infoset

XML 1.0 XMLNamespaces MIME SOAP/HTTP

SOAP/UDP

XML Schema

WS-Security

WS-Trust

WS-SecureConversation

WSDL

WS-Policy

WS-SecurityPolicy

WS-Discovery

WS-MetadataExchange

WS-ReliableMessaging

WS-Coordination

WS-AtomicTransaction

WS-BusinessActivity

WS-Federation

WS-Management

WS-DevicesProfile

Communitywork

StandardsTrack StandardColor Code:

Web Services-Interoperability Organization (WS-I)

• An open industry organization chartered to promote Web services interoperability across platforms, operating systems, and programming languages.

• Delivers practical guidance, best practices and resources for developing interoperable Web services solutions.

WS-I Profiles

• Current:– Basic Profile 1.1 + Simple Soap Binding Profile 1.0

(SOAP 1.1 + WSDL 1.1 + UDDI 2.x)– Basic Security Profile 1.0 (WS-Security 1.0)

• Working on:– Basic Profile 1.2 (WS-Addressing)– Basic Security Profile 1.1 (WS-Security 1.1)– Basic Profile 2.0 (MTOM, XOP, SOAP 1.2)– Reliable Secure Profile (WS-Reliable Messaging, WS-

Secure Conversation)• Interoperability Testing Tools (C# and Java

versions)

Why Web Services in IHE

• Original focus: Interoperability in the enterprise• Expanded focus: Cross-enterprise

interoperability• Web Services can provide interoperable transport

and messaging infrastructure for IHE transactions– Improve ease of implementation– Common transaction infrastructure– Layered security and reliability– Extensibility– Scalability

Ease of Implementation

• Web Services support in major development frameworks– Apache Axis2– Eclipse Web Standard Tools subproject– IBM WebSphere Business Integration Adapter

for Web services – Microsoft Communication Foundation (.NET

3.0)– Sun JAX-WS and WSIT

Using Web Services In IHE Transactions

• Appendix V– Explains how to specify web services

for IHE transactions– Compatible with the HL7 V3 WS Profile– Refined based on last year’s

experiences– Out for 2nd public comment

HL7 Version 3

• The Next Generation of HL7 Specifications– Based on a Reference Information

Model (RIM)– Message design on an abstract level –

independent of interchange format– Current interchange format is XML

Why HL7 Version 3

• Clinical Content– CDA– CCD– Patient Care Messages

• XML Formatting Well Suited for Web Services

• Local Mandates/Investment in HL7 V3 Infrastructure

Using HL7 Version 3 in IHE Transactions

• Follow HL7 Development Model– Constrain existing messages– Express constraints via models– Use existing HL7 schemas and artifacts

Implementing HL7 V3 Transactions

• Model Structure– Need to retain link to underlying model

(XML schema is not enough)

• XML– XML Schema validation is necessary,

but no sufficient– XPath or Schematron rules can enforce

IHE compliance

First Steps

• Profiles Using HL7 Messages and Web Services– PIX/PDQ HL7 V3– Query for Existing Data (QED)

• Other Profiles Using Web Services– XDS.b– RFD– XCA

• Feedback– All profiles are about to be published for public

comments– Please send comments

• Questions?

Vassil Peytchev

vassil@epicsystems.com