agile web development with ewd - m/gateway · vista web development • browser-based gui for vista...

Agile Web Development with EWD

Rob TweedM/Gateway Developments Ltd

http://www.mgateway.comTwitter: @rtweed

• My interpretation:

– Faster

– Faster development

– Faster maintenance

– Faster performance

• Days and weeks, not months and years

Faster development

– Faster Development

• Days and weeks, not months and years

– Therefore cheaper

• $10k’s, not $M’s or $10M’s

– Faster maintenance

Everyone forgets Maintenance

– Faster performance

– than what?

Agile Web Development?

• Web Applications

– Applications that make use of a web browser to provide the client “front-end” interface

– Dynamically-generated pages of HTML (& Javascript, CSS)

– Controlled by user input and database content

• Amazon.com, eBay.com, etc

• Quest’s Care360

Benefits of Web Applications

• Nothing to install or upgrade on client

– Just requires a “standard” web browser

– Business logic is on a remote server

• Ubiquitous User Interface

– Browser + HTML

• Make use of Internet and its protocols to allow broad reach to users

• Now the de facto standard for applications

How do web applications work?

How do Web Applications Work?

Web Browser

Web Server

Simple “static” web page retrieval

SimpleFile Store

Web Browser

Web Serverhttp

request(URL)

SimpleFile Store

Web Browser

Web Serverhttp

request(URL)

SimpleFile Store

Web Browser

Web Serverhttp

response(HTML)

SimpleFile Store

Web Browser

Web Server

SimpleFile Store

disconnected

Web Browser

Web Server

“Dynamic” web page retrieval

ScriptingEnvironment

Database

Web Browser

Web Server

Database

httprequest(URL)

Web Browser

Web Server

Run query

Database

httprequest(URL)

Web Browser

Web Server

ConstructPage (HTML)

Database

Web Browser

Web Server

ConstructPage (HTML)

Database

httpresponse(HTML)

Web Browser

Web Server

disconnected

Database

Further Benefit of web applications

• Much more efficient use of network

• Much more efficient use of back-end

• Massively scalable

Web Browser

Web Server

Mapping of incoming request toa corresponding query

Run query

Database

httprequest(URL)

Web Server doesn’t understand“dynamic” requests

And doesn’t remember you fromone request to the next

Forwarded by web serverdue to request structure

Web Browser

Web Server

PersistentSession Data

SessionManagement

ApplicationDatabase

httprequest(URL)

State management must beprovided within the scripting

environment

Web Browser

Web Server

SessionManagement

ApplicationDatabase

Incomingrequest

Web Browser

Web Server

SessionManagement

ApplicationDatabase

Incomingrequest

Web Browser

Web Server

SessionManagement

ApplicationDatabase

Incomingrequest

• Original user back again?• Different valid user?• Someone pretending to be

the original user?

URLs are all you’ve got

Uniform Resource Locators

http://www.mgateway.com/mgw/mgw2.ewd?a=123&user=rob

transport method

target system domain name/IP Address

directory/path

“page” orResource name

name/value pairs

Web Application Frameworks

• Look after:

– Session management

– Security management

– State management

• Creating the illusion of a stateful environment on top of the stateless web architecture

Interface

Script

Mainstream Web Application Mainstream Web Application ArchitectureArchitecture

Browser

ServerInternet/

Intranet

1. Request page

4. Send page

DBMSGateway SQL

2. Translate

request3. Build HTML

Interface

Script

egeg PHP ArchitecturePHP Architecture

Browser

ServerInternet/

Intranet

1. Request page

4. Send page

DBMSGateway SQL

2. Translate

Zend Engine

Interface

Script

.Net, Java (Tomcat), etc.Net, Java (Tomcat), etc

Browser

ServerInternet/

Intranet

1. Request page

4. Send page

DBMSGateway SQL

2. Translate

Web Middle Tier

Web-enabled VistA

• Modernise the UI

• Browser-based interface

• Get all those benefits of web applications

VistA Web Development

• Browser-based GUI for VistA

– Without any modification to VistA

• Desktop:

– As functional as CPRS without the downsides:• Nothing to install

• Nothing to update

• Mobile:

– As functional as Native Apps without the downsides:

• Cross-platform

• No App Store worries, delays or costs

How can it be done?

• Javascript frameworks

– Desktop

• ExtJS v4

• YUI, Dojo, jQuery etc

– Mobile

• Sencha Touch 2

• Dojo Mobile, jQTouch, jQuery Mobile etc

Javascript framework downsides

• Brutal learning curve

• Coding free-for-all

• Unlimited degrees of freedom

• Therefore maintenance nightmare

• Hardly a recipe for agile!

Interface

Script

Mainstream webMainstream web--enablement of enablement of VistAVistA

Browser

ServerInternet/

Intranet

1. Request page

4. Send page

DatabaseGateway

Web Middle Tier

Java.Netetc

Result:

• Logic now in .Net or Java + Mumps– Skills required

– Maintenance

– Version changes

• Extra tier– Performance bottleneck

– Scalability bottleneck

– Extra complexity to maintain

– Extra cost

Result:

• Logic now in .Net or Java + Mumps– Skills required

– Maintenance

– Version changes

• Extra tier– Performance bottleneck

– Scalability bottleneck

– Extra complexity to maintain

– Extra cost

• Hardly a recipe for agile!

• EWD

– Web Application Development framework

– Designed to work natively with Cache and GT.M

• Ideal for legacy applications such as VistA– Not actually specifically created for VistA

• EWD

– High performance, scalability

– High efficiency

Interface

Script

Mainstream webMainstream web--enablement of enablement of VistAVistA

Browser

ServerInternet/

Intranet

1. Request page

4. Send page

DatabaseGateway

Web Middle Tier

Java.Netetc

VistA Web Enablement

• The mainstream forget or don’t realise:

– Mumps (Cache or GT.M) isn’t just a database

– Has its own integrated scripting language

– Mumps is capable of doing everything required for:

• Parsing HTTP requests

• Creating HTTP responses (HTML, XML, JSON ..)

• Session, state and security management

– Tailor-made for the web

EWD runtime Architecture

Browser

WebServer

(Apache)

m_apache

http/https

xinetd – basedpersistent

connections

EWDRuntime

Yourscripts

Yourdata

EWDPage

routines

m_apache Architecture

Browser

Web Server

Internet/

Intranet

interface

Apache

processesm_apache

GT.M Server

EWD runtime Architecture: WebLink

Browser

WebServer

(Apache/IIS)

WebLink Caché

http/https

WebLin

Caché

Persistentconnections W

EWDRuntime

Yourscripts

Yourdata

EWDWeblinkroutines

EWD runtime Architecture: CSP

Browser

WebServer

(Apache/IIS)

CSP Caché

http/https

Caché

Persistentconnections

Yourscripts

Yourdata

EWDCSP

Handling stateless requests

Web Server

Apache

m_apache

1. Request arrives froma user

GT.M Server

User 1

User 2

Apache

m_apache

Web Server

GT.M Server

User 1

User 2

2. MGWSI establishesSocket and Session

Apache

m_apache

Web Server

GT.M Server

User 1

User 2

Processing...

3. User request isprocessed on GT.M server

Apache

m_apache

Web Server

GT.M Server

User 1

User 2

Processing...

4. Meanwhile a seconduser makes a request..

Apache

m_apache

Web Server

GT.M Server

User 1

User 2

Processing...

5. 2nd sessionEstablished by

Processing...

Web Server

GT.M Server

User 1

User 2

m_apache

Apache

6. User 2’s requestis completed.

Processing...

Write HTML

m_apache

Apache

Web Server

User 3

Caché Server

User 1

User 2

Processing...

Waiting….

7. User 2’s processingstops. Connectionis maintained...

Web Server

User 3

GT.M Server

User 1

User 2

Processing...

9. Session 2 isre-used for incomingRequest from User 3

Processing...

m_apache

Apache

Web Server

User 3

GT.M Server

User 1

User 2

Waiting...

9. Session 1 has finishedHandling user 1's request

and is now free

Processing...

m_apache

Apache

Web Server

User 3

GT.M Server

User 1

User 2

Processing...

9. 2nd request fromUser 2 is handled

by process 1

Processing...

m_apache

Apache

• Each back-end GT.M process supports multiple browsers/users

– Perhaps 10:1 to 20:1 ratio of concurrent users to physical processes

– Highly scalable architecture

– Extremely high performance

• Unused back-end processes aren't shut down

• Process startup overhead only for the 1st request

• m_apache connects an incoming request to an existing waiting back-end process

Beware: CSP

• When a back-end process finishes sending its response

• CSP doesn’t release it immediately to the free pool– Is available for requests from the previous user

– Isn’t available for any other requests for a period of time:

• Grace period

• Result: artificially inflates the number of processes necessary for handling HTTP traffic– Easy to run out of licenses

• EWD

– High efficiency

• Its stateless architecture significantly reduces the resources needed to support large numbers of users

– Less memory

– Less CPU

– Far fewer processes (therefore licenses)

Compare using web apps

BrowserWeb Server

Web Server

Internet/

Intranet

interface

Apache

processesm_apache

GT.M Server

Browser

With current VistA usage

GT.M orCache

Statefullconnections

Broker connections

Terminal

PersistentProcesses

Browser

WebServer

(Apache)

m_apache

http/https

connections

EWDRuntime

Yourscripts

Yourdata

EWDPage

routines

Architectural responsibilities

• Web Server looks after the HTTP protocol handling

• Processing the meaning of requests and creating the response is done in Mumps

• EWD

– Everything happens in the Mumps domain

– We know that GT.M & Cache can scale massively

– Web server does nothing other than passively pass through requests and responses

– No additional technology layers needed or wanted

J2EE architecture:

Agile Web Applications?

• EWD

m_apache scaling

Browsers Apachehttp overTCP/IP

GT.M Server GT.M Server

Telnet overTCP/IP

Multiple servers

Components

Key:GT.M Server

m_apache scaling

Apache

GT.M Server GT.M Server

Components

Key:GT.M Server

Apache

• EWD

– High reliability & security

– Looks after security & session management automatically behind the scenes

Reliability & Security

• Last 5 years:

– EWD supports the world's largest Internet-

facing Caché-based web application

• Quest Diagnostics Care360 EziOrder

– 30,000+ concurrent users

– 500,000 test requests/day

– 24 X 7 operation with no breakdowns or incidents

– No security breaches

• EWD

– "If it can be automated, it is!“

– User extensible

• Custom tags

Agile development with EWD?

• Case Study, May 2012:

– 1 Clinician; 1 Developer

– Dr Tony Shannon

• Consultant in Emergency Medicine & Chief Clinical Information Officer, Leeds Teaching Hospitals, UK

• Fellowship in Informatics & MSc in IT Management

– Chris Casey

• Mumps, Cache, EWD developer

Project Objective

• Build a hospital clinical portal

– Based on clinical process patterns

– Clinically-led, user-centered design

– ie around the workflow and perspective of clinicians, and not:

• An IT technical developer's perspective

• A database expert's perspective

• Hospital management perspective

Agile focus

• 2-page high-level proposal

• Fast-paced development

• Rapid prototyping

– Build, review, change

• "storyboarding" as communication between clinician & developer

Open Source Focus

• GT.M

• ExtJS (GPL License)

• EWD + ExtJS v4 Tag Library

Clinical Focus

• Centered around key clinical processes– 5 key UI patterns

• 3 levels:– Strategic

• Overview across all patients in hospital– Different filters/stratification

– Tactical• Patients within a particular category

– Ward, department, specialty etc

– Operational• Individual patient

• Referral in, assessment, plan care, deliver care, referral out

Try it for yourself

• http://clinuip.wordpress.com/• http://ec2-184-73-102-27.compute-1.amazonaws.com/ewd/leeds/index.ewd

Total development time

• 10 days

This redefines agile!

• 1 Clinician + 1 Developer

• 10 days

• Entire Clinical Portal

– Including a database designed and built from scratch to support it!

• Orders of magnitude better than normal industry expectations

Implications

• Makes the timescales and costs associated with government procurements look ridiculous– Years of development

– Millions of dollars

• Total cost of Tony Shannon's project was less than $10,000

• 10 days

Not just sheer development speed

• Chris's application is highly maintainable– Clear and rigorous split between UI/Design

and back-end database programming

• Easily adaptable into mobile version:– EWD's Sencha Touch 2 tags are very similar

in use and syntax

– Able to share most of the back-end code

• Easily adaptable to use different database– Levels 1 & 2 grafted onto VistA in 3 days

How does EWD make this possible?

• Exploiting the best Javascript frameworks

– ExtJS, Sencha Touch etc

• But abstracting them into XML tags and integrating them with EWD Session

– Massively reduces learning curve

– Simplifies their use

– Standardises their use

• Maintainability!

Container Page & Fragments

• EWD breaks down complex UI into many small "fragments"

– Each is a discrete EWD "page"

• onBeforeRender method

• Markup or JSON

• Optional Javascript and/or "listeners"

– Fragments get injected into the container page

ExtJS tags

• Very high-level tags

– Describe a great deal of functionality in just one tag

• Data array

• Implied event (eg click a cell)

• Implied action (eg fetch another fragment)

Example

<ext4:container rootPath="/ext-4" onBeforeRender="getGridData^MyDemo" ><ext4:gridPanel title="Simpsons" frame="true" height="200" width="550“

sessionName="simpsons"><ext4:gridcolumn text="Name" width="100" sortable="false" hideable="false"

dataIndex="name" /><ext4:gridcolumn text="Email Address" width="150" dataIndex="email" /><ext4:gridcolumn text="Phone Number" flex="1" dataIndex="phone" />

</ext4:gridPanel></ext4:container>

EWD Page

Example

<ext4:container rootPath="/ext-4" onBeforeRender="getGridData^MyDemo" ><ext4:gridPanel title="Simpsons" frame="true" height="200" width="550“

sessionName="simpsons"><ext4:gridcolumn text="Name" width="100" sortable="false" hideable="false"

dataIndex="name" /><ext4:gridcolumn text="Email Address" width="150" dataIndex="email" /><ext4:gridcolumn text="Phone Number" flex="1" dataIndex="phone" />

</ext4:gridPanel></ext4:container>

OnBeforeRender Method:• Mumps function• Executed before page renders

ExamplegetGridData(sessid);n data;s data(1,"name")="Lisa"s data(1,"email")="lisa@simpsons.com"s data(1,"phone")="555-111-1224"s data(2,"name")="Bart"s data(2,"email")="bart@simpsons.com"s data(2,"phone")="555-111-1234"s data(3,"name")="Homer"s data(3,"email")="homer@simpsons.com"s data(3,"phone")="555-111-1244"s data(4,"name")="Marge"s data(4,"email")="marge@simpsons.com"s data(4,"phone")="555-111-1245"d mergeArrayToSession^%zewdAPI(.data,"simpsons",sessid);QUIT ""

Example

“Mumps mindset” integration

• EWD’s integration and use of Mumps (GT.M & Cache):

– Designed by someone who understands:

• Mumps technology and mindset

• Web technologies

– Intuitive back-end coding

• Compare with Java, .Net and “mainstream” web frameworks

EWD: Design-Centric

• Design, not programming, is what makes great applications

• Clear separation of Design from Programming

• Reduce programming to trivial levels

Clear separation of presentation & programming

• EWD Session as middle ground

– Front-end decoupled from back-end

Middle Tier

• UI and Back-end are deliberately de-coupled, with "EWD Session" as middle ground

EWD“Back-end”

GT.M / Caché

EWDSession

Programmer

myVarPre-page

script

EWD Page

<?= #myVar ?>

Designer

setSessionValue^%zewdAPI

Page designer

EWD PageEWD

Session

Display Data

myVar<?= #myVar ?>

- UI Designer doesn't need back-end skills- UI can be initially designed with a simple, spoofed back-end

Programmer

EWD“Back-end”

GT.M / Caché

EWDSession

Fetch Data

myVarPre-page

script

setSessionValue^%zewdAPI

- Back-end developer doesn't need UI skills- Back-end can be changed without any impact on UI

Prototyping

• Back-end scripts initially hard-coded to generate test values for Session

• When design agreed, programmer can replace back-end scripts to use real queries, validation etc

– No change needed to front end

• Back-end logic can be completely replaced

– Just needs to maintain Session in the same way

– eg logic replaced to access VistA

Agile VistA Web Development

• Integration of EWD with VistA?

– What VistA logic to use?

– How to use that code?

Integrating EWD with VistA

• Zach Gonzales

– Oroville Hospital

Integrating EWD & VistA

• What RPCs to use?

• How to interface them with EWD?

• Agile:

– Don’t want everyone reinventing this wheel

RPC wrappering

• Creating EWD-aware APIs around core clinical RPCs

– Automatically map to EWD Session

– Just call the RPC

– Define UI to visualise the Session Data

Browser

WebServer

(Apache)

m_apache

connections

EWDRuntime

Yourscripts

Yourdata

EWDPage

routines

Accessing VistA Information

EWDRuntime

Yourscripts

EWDPage

routines

EWDRuntime

Yourscripts

EWDPage

routines

EWD-aware VistA APIs

RPC RPC

EWD Session

API, eg VitalsCreate / UsePredeterminedEWD Session data

Know which RPCsetc to call in VistA

RPC integration: the old waygetCurrentVitals.....n vitalList d FASTVIT^ORQQVI(.vitalList,DFN)n count s count=""f d q:'count. s count=$O(vitalsList(count)). q:'count. n vitalType s vitalType=$p($g(vitalsList(count)),U,2). n vitalDate s vitalDate=$$FMTE^XLFDT($p($g(vitalsList(count)),U,4)). n USMeasurement s USMeasurement=$p($g(vitalsList(count)),U,5). n metricMeasurement s metricMeasurement=$p($g(vitalsList(count)),U,6). n vitalMeasurement s vitalMeasurement=USMeasurement_" "_metricMeasurement. s vitals(count,"vitalMeas")=vitalType_": "_vitalMeasurement_" "_vitalDated deleteFromSession^%zewdAPI("vista_currVitals",sessid)d mergeArrayToSession^%zewdAPI(.vitals,"vista_currVitals",sessid)

RPC integration: the new way

getCurrentVitals(sessid)n oks ok=$$getCurrentVitals^RPCLibrary(sessid)QUIT ""

Scale of the Wrapering Task

• Approx 2,400 RPCs

EWDRuntime

Yourscripts

EWDPage

routines

Agile VistA Web Development

Agile Web Development using EWD

• Faster development

• Faster maintenance

• Faster performance

No excuses for not using EWD

• Free, Open Source for GT.M

• Free for Caché

• Cross-compilation

• Applications work on both Caché & GT.M

• Easy cross development on mobile and desktop

EWD Simplicity

• No need for extra layers or additional technologies

• Fastest, most efficient, most scalable architecture you can use

– Nothing else will come close

Agile Development

• Orders of magnitude faster than anything else

• EWD redefines agility

Agile Web Development with EWD

Rob TweedM/Gateway Developments Ltd

http://www.mgateway.comTwitter: @rtweed

agile web development with ewd - m/gateway · vista web development • browser-based gui for vista...

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