1. NETSERV Network Services for VistA
Doug Martin, MD
The Regenstrief Institute, a pioneer in physician order entry and clinical decision support systems, is currently in the midst of deploying a new platform built on open-source technologies. The centerpiece of this effort is G3, a CPOE designed to support advanced research in clinical decision support, usability, physician workflow, and patient safety. We will be demonstrating this new system, with a focus on its interface design, CDS architecture, natural language processing capabilities, and provider communications. We will also be discussing our user-centered design process, opportunities for collaboration, and future development plans.

2. VistA TCP-based Packages
RPC Brokers
XWB broker (VA)
CIA broker (Medsphere)
BMX broker (IHS)
BGU broker (IHS)
Web Servers
WebMan (CAIRO)
M Web Server (VA)
VistAWeb (VA)
M2Web (UC Davis)
Other
VistALink

3. The Problem Each package does its own TCP connection management
Some do it better than others
Each package provides different tools for starting/stopping listeners
All of this is redundant

4. One Possible Solution 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)

5. 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

6. Listener Modes Mode Listener Type Description Primary
Primary
Dispatches connections 1
Secondary
Dispatched by primary 2
Dispatched by OS 3
Debug
Foreground listener for debugging

7. Common Listener Management (Mode 0 only)
D STARTALL^RGNETTCP HTTP ENDPOINT (9080): waiting for start signal.... started. RPC BROKER (9300): waiting for start signal.... started. D STOPALL^RGNETTCP HTTP ENDPOINT (9080): waiting for stop signal stopped. RPC BROKER (9300): waiting for stop signal stopped.

8. NETSERV RPC Broker Modeled after CIA broker Asynchronous calls
Event propagation
Java-based client

9. NETSERV Web Server Modeled after WEBMAN/M Web Server REST support
Basic and OAUTH2 authentication
API’s for accessing request data and constructing response
Request handler dispatch by URL pattern match

10. 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

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

12. 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

13. Questions?