ONC Mod Specs Provider Directories Initiative-related proposed changes to HPD Plus WSDL, and underlying XML message structure.

[Douglas Harley]

Hello IHE HPD Implementors Community,

As part of the Mod Specs Provider Directories initiative, under the auspices of the Office of the National Coordinator for Health Information Technology (ONC), we are proposing various changes to the HPD Plus web service WSDL, underlying data/object model, and a new HPD Plus message schema.  All of these proposed changes are intended to provide support for both multiple HPD Plus datasources (e.g., multiple LDAP servers) and HPD Plus federation, in terms of regular functionality and error handling.

Our proposed new WSDL web service definition, and an object model of the new HPD Plus message structure can be seen here: http://www.gliffy.com/go/publish/4571230.  A couple key features to be noted:

• A new HpdPlusRequest wrapper element, which contains exactly one DSML-based BatchRequest element, and optionally one HpdPlusRequestMetadata element, which is basically a set of properties that clients might want to pass-in to an HPD Plus service to control query flow (e.g., to tell the HPD Plus instance not to federate out queries to other known HPD Plus peers, or to specify a certain timeout length).
• A new HpdPlusResponse wrapper element will represent a response from an individual HPD Plus web service.  Data responses from datasources queried directly by that HPD Plus instance will be represented by one or more DSML BatchResponse nested child elements, and responses by other HPD Plus federation peer instances would each have their own nested HpdPlusResponse child elements.  Any errors which occur at the web service layer of HPD Plus would be represented with the optional HpdPlusError.  Errors encoutered at the datasource level would continue to be represented within the DSML BatchResponse via the ErrorResponse element.  Optionally, a HpdPlusResponseMetadata element might be present, and if there was HpdPlusRequestMetadata provided to the query, then it will be inside as a child of the HpdPlusResponseMetadata element.  With this proposed structure, we can support a rich contextual model of the query through the federation hierarchy, as well as abstract errors and results at the correct conceptual level of HPD Plus instance, HPD Plus federation peer, or underlying datasource.

Any feedback from the community on these proposals would be greatly appreciated.

Thanks,

Doug Harley

ONC Mod Specs Provider Directory HPD Plus Test Implementation Team