1. VistA on Douglas K. Martin, MD dkmartin@regenstrief.org
Regenstrief Center for Biomedical Informatics
Indiana University School of Medicine

2. Introducing Fast Healthcare Interoperability Resources
Defines a common clinical domain model
Resources
Normative attributes by 80% rule
Remaining 20% covered via extensions
Defines standard operations (API)
CRUDS (create, read, update, delete, search)
Resource-specific operations ($expand)
RESTful interface (easy to implement)
Current specification is STU-3

3. RESTful Web Service
Henry"

4. Patient Resource
<Patient xmlns=" <id value=”1234"/> <identifier> <use value="usual"/> <type> <coding> <system value=" <code value="MRN"/> </coding> </type> <system value="urn:oid: "/> <value value="12345"/> </identifier> <name> <family value="Levin"/> <given value="Henry"/> </name> <gender value="male"/> <birthDate value=" "/> <managingOrganization> <reference value="Organization/ "/> <display value="Good Health Clinic"/> </managingOrganization> <active value="true"/> </Patient>

5. NETSERV Unified TCP Connection Services
TCP Connection Manager
WEB Server
RPC Broker
OAuth2 Service*

6. NETSERV TCP Connection Manager
Handles socket allocation and hand-off
Protocol independent
Single place to define listeners
Single set of tools for managing listeners
Caché and GT.M support
API’s for I/O (handles caching of output)

7. NETSERV TCP Listener File
Field
Datatype
Example
NAME
Free Text
HTTP Endpoint
PORT
Number
9030
UCI
FOIA
DISABLE
Yes/No NO
MAXIMUM
100
HANDLER
M Entry Point
NETSERV^RGNETWWW

8. NETSERV Web Server Serve web pages Service REST requests
Authentication/authorization
Customizable handlers

9. NETSERV HTTP Endpoint File
Field
Datatype
Example
URL
Free Text
DSTU#/*
METHOD
Http Method
GET
AUTH
BASIC/BEARER/BOTH
BOTH
HANDLER
M Entry Point
MGET^RGSER
ACCESS CONTROL
Access Control Expression
K.XUPROG!P.RGCWENCX PROVIDER
DESCRIPTION
Word Processing
FHIR service endpoint

10. URL Pattern Examples / CWF/* DSTU#/* UTILITY/RPC UTILITY/RTN
oauth2/authorize
oauth2/token

11. Access Control Expression
An access control expression allows you to constrain access to an endpoint based upon security keys, parameters, and options held (or not held) by a user. An expression can consist of:
Operands
K.<name> Security key of the specified name
O.<name> Option of the specified name
P.<name> Parameter of the specified name
Operators
& Logical AND of two results
! Logical OR of two results
’ Negate a logical result
Parentheses to control the order of sub-expression evaluation

12. VistA Serialization Framework
Originally developed to serialize VistA objects to JSON via RPC broker
Expanded to support multiple formats
XML and JSON
FHIR DSTU1, DSTU2, and STU3?
Added REST interface via NETSERV
via HTTP
via RPC broker

13. Serialization Control File
(#.01) NAME [F] ^ (#1) CONTENT TYPE [F] ^ (#2) SERIALIZER [F] ^ (#3) VERSION [F] (#10) RESOURCE (#.01) RESOURCE [F] ^ (#1) INTERNAL [YN] ^ (#2) SOURCE [N] (#10) CUSTOM SERIALIZER [M] ^ (#20) PREFETCH LOGIC [M] ^ (#21) POSTFETCH LOGIC [M] (#30) PROPERTY (#.01) PROPERTY [F] ^ (#1) FIELD [F] ^ (#2) TYPE [S] ^ (#3) SEQUENCE [N] (#10) CONTROL [F] (#40) PARAMETER (#.01) PARAMETER [F] ^ (#1) FIELD [F] ^ (#2) TYPE [S] ^ (#3) SEQUENCE [N] (#10) CONTROL [M] (#20) COHORT [M] (#50) TEMPLATE (#.01) TEMPLATE [F] ^ (#1) CONTENT [W] ^ (#99) DESCRIPTION [F] (#20) HEADER FIELDS [1W] (#99) DESCRIPTION [1W]

14. http://acme. org/DSTU2/Patient/1. _format=xml http://acme
NAME: DSTU2 CONTENT TYPE: application/xml+fhir,application/xml,text/xml,xml SERIALIZER: RGSEFHIX VERSION: RESOURCE: Patient INTERNAL: N SOURCE: 2 (PATIENT) PROPERTY: name FIELD: .01 TYPE: CUSTOM SEQUENCE: 10 CONTROL: D NAME(VL("I")) PROPERTY: birthdate FIELD: .03 TYPE: DATE SEQUENCE: 30 CONTROL: PARAMETER: family TYPE: STRING SEQUENCE: 20 CONTROL: D OPRNAME(VL("E"),1) K PVAL COHORT: S X="$$NAMEITER^RGSERPAT"

15. Supported Formats CWF application/json,text/json
DSTU1 application/xml+fhir,application/xml,text/xml,xml
DSTU1 application/json+fhir,application/json,text/json,json
DSTU2 application/xml+fhir,application/xml,text/xml,xml
DSTU2 application/json+fhir,application/json,text/json,json
STU3* application/fhir+xml,application/xml,text/xml,xml
STU3* application/fhir+json,application/json,text/json,json

16. Questions?