ARC312 Smart Client Architecture Chris J.T. Auld Managing Director- Kognition Microsoft Regional Director & MVP [email protected]

ARC312ARC312Smart Client ArchitectureSmart Client Architecture

Chris J.T. AuldChris J.T. AuldManaging Director- Kognition Managing Director- Kognition Microsoft Regional Director & MVPMicrosoft Regional Director & [email protected]@kognition.co.nz

AgendaAgenda

Why smart clients?Why smart clients?

What is a smart client?What is a smart client?

How do you decide between How do you decide between browser-based and smart client UI?browser-based and smart client UI?

Changes in Changes in nn-tier architecture for smart -tier architecture for smart clientsclients

Drill down on client tier architectureDrill down on client tier architecture

Data transportData transport

Data containers Data containers (datasets vs. business objects)(datasets vs. business objects)

A Spiraling Evolution A Spiraling Evolution of Architecturesof Architectures

CentralizedMainframe

DecentralizedClient-Server

CentralizedWeb Server

DistributedSmart Client

Advent of networked PC – Intelligent interfaces improve

productivity

“Dumb” terminals allow minimal

support for user activities

Intelligent interfaces have no cost-effective Internet reach.

“Dumb” browsers have cheap deployment but limited

support for user activities.

Intelligent interfaces develop cost effective deployment and data

transport.

Browsers LimitationsBrowsers Limitations

HTML not designed as application HTML not designed as application interface technologyinterface technology

Minimal GUI elementsMinimal GUI elements

Limited control over user interaction Limited control over user interaction (keystrokes, drag and drop)(keystrokes, drag and drop)

Limited client-side data validationLimited client-side data validation

Costly to produce effective UICostly to produce effective UI

Immature security model (“Would you Immature security model (“Would you like to install this component from like to install this component from Gator Corp?”)Gator Corp?”)

What Is a Smart Client?What Is a Smart Client?

No agreement on general definitionNo agreement on general definition

Emphasizes intelligence in the UIEmphasizes intelligence in the UI

Takes full advantage of the client Takes full advantage of the client machinemachine

Typically means a true Windows interfaceTypically means a true Windows interface

Client UI has some level of detachment Client UI has some level of detachment from the rest of the applicationfrom the rest of the application

This may mean flexible ways to get and This may mean flexible ways to get and store datastore data

Often means offline capabilitiesOften means offline capabilities

Key Decision PointsKey Decision Points

Do you control the user’s operating environment? Do you control the user’s operating environment?

Are offline capabilities required?Are offline capabilities required?

Will a better UI translate to productivity gains and Will a better UI translate to productivity gains and resultant savings?resultant savings?

Is it important for your application to access local Is it important for your application to access local resources on user machines?resources on user machines?

Do you need (or would you benefit from) Do you need (or would you benefit from) alternative UI – handwriting or speech recognition?alternative UI – handwriting or speech recognition?

What security capabilities do you need?What security capabilities do you need?

Lesser factorsLesser factorsDistribution of processing overheadDistribution of processing overhead

Efficient utilization of bandwidth Efficient utilization of bandwidth

Peer-to-peer capabilitiesPeer-to-peer capabilities

Bottleneck: .NET Framework RequiredBottleneck: .NET Framework Required

Limiting factor: the .NET Framework must be Limiting factor: the .NET Framework must be on all client machineson all client machines

First candidates for distributed smart clients:First candidates for distributed smart clients:Corporate applications (control over desktop)Corporate applications (control over desktop)

Commercial or extranet applications where a Commercial or extranet applications where a minimum platform can be requiredminimum platform can be required

.NET Framework becoming ubiquitous.NET Framework becoming ubiquitous# of Framework installations growing rapidly# of Framework installations growing rapidly

Future O/S versionsFuture O/S versions

Service PacksService Packs

Other .NET applicationsOther .NET applications

Where are Smart Clients Where are Smart Clients Most Important?Most Important?

Corporate apps for distributed Corporate apps for distributed operationsoperations

Healthcare, transportation, supply chainHealthcare, transportation, supply chain

Etc.Etc.

Distributed data entry systemsDistributed data entry systems

Commercial packages of all kinds, Commercial packages of all kinds, especially vertical market packagesespecially vertical market packages

Applications that require offline Applications that require offline capabilitiescapabilities

Technologies RequiredTechnologies Required

Standard HTTP connection from Standard HTTP connection from each client machine to a web servereach client machine to a web server

A forms engine and execution A forms engine and execution environment running on the client environment running on the client machinemachine

A way to easily and cheaply deploy A way to easily and cheaply deploy the application to the client machinethe application to the client machine

One or more ways to transport data One or more ways to transport data to and from a central serverto and from a central server

A security model that limits the A security model that limits the ability to do damage to the client ability to do damage to the client machinemachine

A means to secure access to the A means to secure access to the system and the datasystem and the data

Windows Forms

Broadband

Copy and Run / ClickOnce / etc.

Web Services / Remoting

Code Access Security

Authentication / Authorization

Class Three Tier Architecture for Class Three Tier Architecture for Client/Server and WebClient/Server and Web

Must be refined for distributed smart clientsMust be refined for distributed smart clientsIncreased processing power on the clientIncreased processing power on the client

Ability for client to store state informationAbility for client to store state information

Data transport options must be handled – both Data transport options must be handled – both for now and the futurefor now and the future

Presentation TierPresentation TierUser interfaceUser interface

Middle TierMiddle TierComponents, RulesComponents, Rules

Data TierData TierRelational DatabaseRelational Database

Many Many nn-Tier Principles Still Apply-Tier Principles Still Apply

Data tier is mostly unchangedData tier is mostly unchangedStored procs may need to support new paging Stored procs may need to support new paging designs, more robust batch updating, etc.designs, more robust batch updating, etc.

Middle tier still isolates all database Middle tier still isolates all database interactioninteraction

Controls connection to RDB with its own Controls connection to RDB with its own credentialscredentials

Parts exposed to web outside firewall, rest of Parts exposed to web outside firewall, rest of middle tier insidemiddle tier inside

Entry points to business tier can include Entry points to business tier can include technologies such as message queuetechnologies such as message queue

Data tier (database)Data tier (database)

Data access layerData access layer

Business rules, etc.Business rules, etc.

Channel Adapter (data façade)Channel Adapter (data façade)

Common componentsCommon componentsand controlsand controls

UI – Forms and controlsUI – Forms and controls

A Tiered Architecture for Distributed A Tiered Architecture for Distributed Smart ClientsSmart Clients

Client machine

Application server

Database server

Port 2Port 2e.g. Web Servicese.g. Web Services

Port 1Port 1e.g. Remotinge.g. Remoting

Local storageLocal storagefor cachingfor caching

Web server

Client Layer Drill-DownClient Layer Drill-Down

UI – Forms and controlsUI – Forms and controls

Channel Adapter (data facade)Channel Adapter (data facade)

CustomerCustomer OrderOrder ProductProduct VendorVendor Etc.Etc.

Standard interfaceStandard interfacefor Get / Update / etc.for Get / Update / etc.

Common components and controlsCommon components and controls

Data validationData validation SecuritySecurity Base formsBase forms Etc.Etc.

Form AForm A Form BForm B Form CForm C Form DForm D Form EForm E Etc.Etc.

Local store forLocal store forcachingcaching Data transport Data transport

channelschannels

Building the Client TierBuilding the Client Tier

Componentize as much logic as possibleComponentize as much logic as possible

Minimize repeated code patterns in routine Minimize repeated code patterns in routine forms with frameworks or toolkitsforms with frameworks or toolkits

Data validationData validation

Data managementData management

SecuritySecurity

Use high level controller as app-entry pointUse high level controller as app-entry pointIsolates security checking, menu building, etc.Isolates security checking, menu building, etc.

If possible, get data validation rules from If possible, get data validation rules from databasedatabase

Key TechnologiesKey Technologies

Extender Providers in Windows Forms Extender Providers in Windows Forms

Dynamic loading of .NET assembliesDynamic loading of .NET assembliesNeed location of assembly, and name of Need location of assembly, and name of type to get instancetype to get instance

Allows apps to have dynamic construction Allows apps to have dynamic construction and single entry pointand single entry point

An Example of Extender Providers An Example of Extender Providers for “Dirty Checking”for “Dirty Checking”

Drag and drop checking to see if data Drag and drop checking to see if data has changedhas changed

DemonstrationDemonstration

Note that this is an implementation of Note that this is an implementation of the Observer patternthe Observer pattern

Application “Portals”Application “Portals”

Complex applications need an Complex applications need an “application shell” or “portal” to “application shell” or “portal” to coordinate sub-systemscoordinate sub-systems

Flexible plug-in pieces for menuing, Flexible plug-in pieces for menuing, authorization/authenticationauthorization/authentication

Data driven list of user options, with Data driven list of user options, with screens loaded on demandscreens loaded on demand

Process uses dynamic loading of Process uses dynamic loading of assembliesassemblies

Typical Code to Load a Typical Code to Load a Dynamic FormDynamic Form

Dim sLocation As String = {set assembly location}Dim sType As String = {set class name of form}Dim formAsm As [Assembly] = _ [Assembly].LoadFrom(sLocation)Dim ClassType As Type = formAsm.GetType(sType)Dim Classobj As ObjectClassobj = Activator.CreateInstance(ClassType)

Dim FormToShow As Form = CType(Classobj, Form)FormToShow.MdiParent = MeFormToShow.Show()

A Composite A Composite Application ShellApplication Shell

Data TransportData Transport

`

XML

UIUI

Business LogicBusiness Logic

Data Storage and ManagementData Storage and Management

Data AccessData Access

PresentationPresentation

?

Transport vs. HostTransport vs. Host

TransportTransportRPC, Queues, etc.RPC, Queues, etc.

HostHostIIS, Enterprise Services, etc.IIS, Enterprise Services, etc.

Separate but dependant issues Separate but dependant issues

Competing TechnologiesCompeting Technologies

RPCRPCDCOM, RMI, Remoting, Web servicesDCOM, RMI, Remoting, Web services

Async MessagingAsync MessagingMSMQ, MQ Series, JMS, Async RPCMSMQ, MQ Series, JMS, Async RPC

Services (SO)Services (SO)Web services, Indigo, other transportsWeb services, Indigo, other transports

Today’s OptionsToday’s Options

Web SvcWeb Svc Ent SvcsEnt Svcs RemoteRemote

Data-centricData-centric

Object-orientedObject-oriented

XML/SOAPXML/SOAP

BinaryBinary

Pass thru firewallPass thru firewall

IDE supportIDE support

Code controlledCode controlled

Peer to peerPeer to peer

Events/callbacksEvents/callbacks

Stateful objectsStateful objects

nn-Tier-Tier

Application 2Application 2

UIUI


Service Façade (Data Access)Service Façade (Data Access)


External ServiceExternal Service

Application 1Application 1

UIUI



Data Storage and ManagementData Storage and Management


DataPortalDataPortal

UIUI



DataPortal FaçadeDataPortal Façade







Client facadeClient facadeAbstracts the server/transport/hostAbstracts the server/transport/host

Acts as a channel adapterActs as a channel adapter

Server portalServer portalAbstracts server (transactions, etc.)Abstracts server (transactions, etc.)

Acts as a broker or message routerActs as a broker or message router

Channel Adapter / Ports Channel Adapter / Ports Drill DownDrill Down

Channel Adapter (data façade)Channel Adapter (data façade)

CustomerCustomer OrderOrder ProductProduct VendorVendor Etc.Etc.

On

the clien

tO

n th

e client

Data access layerData access layer

Business rules, etc.Business rules, etc.Data validation requiring connected accessData validation requiring connected access

Aggregation / disaggregation of dataAggregation / disaggregation of data

Web Services

Remoting listener In th

e mid

dle tier

In th

e mid

dle tier

MSMQ Etc.PortsPorts

ChannelsChannels

Data-Centric (Fat UI)Data-Centric (Fat UI)

UIUI



Logic

E.g. Traditional VB3/4/5/6 Client ServerE.g. Traditional VB3/4/5/6 Client ServerNo way to put logic in datasetNo way to put logic in datasetNeed to use a function library or;Need to use a function library or;Put logic in UIPut logic in UI

How Do We Push Data Around?How Do We Push Data Around?

ObjectsObjectsDatasets/DTOs (per Martin Fowler)Datasets/DTOs (per Martin Fowler)

Data-Centric (“thin” UI)Data-Centric (“thin” UI)

UIUI



Logic

Logic

Put logic on separate machine so you can’t cheat.Put logic on separate machine so you can’t cheat.

You will cheat.You will cheat.You still need to get data to the UIYou still need to get data to the UI

Distributed Data-CentricDistributed Data-Centric

UIUI



Logic

Same flaw as original model- just now have network Same flaw as original model- just now have network connection.connection.

Distributed ObjectsDistributed Objects

UIUI



Logic

Logic

Objects really just pumping data in and out at both ends.Objects really just pumping data in and out at both ends.

Client-side ObjectsClient-side Objects

UIUI



Logic

Not bad approach.Not bad approach.

Populate local intelligent objects on client from DTOsPopulate local intelligent objects on client from DTOs

Mobile Objects/AgentsMobile Objects/Agents

Fully mobile objects serialized and de-serialized.Fully mobile objects serialized and de-serialized.

Can be useful but has higher overhead at development timeCan be useful but has higher overhead at development time

DemonstrationDemonstration

A multi-transport DataPortalA multi-transport DataPortal

ResourcesResources

More Information:

[email protected]

www.syringe.net.nz

http://www.syringe.net.nz/

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© 2005 Microsoft Corporation. All rights reserved.This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

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ARC312 Smart Client Architecture Chris J.T. Auld Managing Director- Kognition Microsoft Regional Director & MVP [email protected]