Building Large-Scale Data-Centric Applications with Silverlight

Building Large-Scale Data-Centric Applications with Silverlight

Ramya Parthasarathy Roman Rubin

About us

• Roman Rubin – Wolters Kluwerroman.rubin@wolterskluwer.com

• Ramya Parthasarathy – Wolters Kluwerramya.parthasarathy@wolterskluwer.com

• Wade Wegner – Microsoftwade.wegner@microsoft.com

CT Corporation is …• The leader for registered agent, corporate compliance and

governance solutions, CT Corporation's expertise defines every customer contact. Law firms and corporate legal departments turn to its reliable service organization and intelligent technology for the precision and speed they need.

About hCue

• CT’s hCue is a market-leading, web-based, secure entity management and board collaboration solution. It consolidates all your essential corporate data in one central repository, facilitates collaboration and information sharing across your organization and assists you to meet state and SEC Section 16 compliance requirements.

About hCue

• A large product in production for more than five years

• Currently approx 300+ active pages delivered using ASP.Net 2.0 platform with Oracle back-end (database)

• Multiple sub-sites (sub-domains and virtual directories)

• Approx 30 batches / Windows services

• Approx 200 tables moved to SQL Server, 400 SPs, 500 selects…

What to expect in this session

• How we packaged the application (XAPs/DLLs)• Overview of Application Building Blocks for

Silverlight Development (Instrumentation, Client Configuration, MVVM, Light-weight Web Services)

• How we deploy our Web Services (DX)

Packaging large Silverlight LOB Application

Application Packaging• Initial download time (XAP size)• Browser working set size• Impact of long running application• Maintainability

One large XAP model

One HUGE XAP

Module #1

HTML #1

Module #2

Module #3

Module #4 Application = One HUGE XAP

• Default model supported by tooling and default project templates

• Initial download time (XAP size) - Large• Browser working set size - Large• Impact of long running application - Impacted• Maintainability - Difficult

How does it stack up?

Primary XAP with DLLs model

One HUGE XAP

Module #1

HTML #1

Module #2

Module #3

Module #4

Primary XAP

Module #1

HTML #1

Module #2

Module #3

Module #4

Application = One HUGE XAP

Application = One Primary XAP + Multiple on-demand DLLs

• Initial download time (XAP size) – Can be controlled• Browser working set size – Increases over time• Impact of long running application – Impacted

How does it stack up?

Multi-XAP model

Primary XAP

Module #1

HTML #1

XAP #2

Module #2

HTML #2

XAP #3

Module #3

HTML #3

XAP #4

Module #4

HTML #4

Application = Multiple modules (XAPs) each with independent URI

Module #1

HTML #1

Module #2

Module #3

Module #4

Primary XAP

Module #1

HTML #1

Module #2

Module #3

Module #4

Application = One HUGE XAP

Application = One Primary XAP + Multiple on-demand DLLs

• Initial download time (XAP size) – Under control• Browser working set size – Under control• Impact of long running application – Mitigated• Maintainability – Under control

Multi-XAP model• Exercise care while partitioning to avoid constant switching

between modules• Data sharing between modules• Fits in existing project templates and tooling support

Application Packaging - Summary

• Establish design objective for max XAP size• Establish design objective for browser’s max-

working-set-size• Choose a model that fits your needs early in

development. • Start your application with at least two XAPs,

even if you are only prototyping.

Multi-XAP model: Wrapper generation

SLHost.axd

Primary XAP

Module #1

HTML

XAP #2

Module #2

HTML

XAP #3

Module #3

HTML

XAP #4

Module #4

HTMLxml

Silverlight Object Tag related options

Browser DOM

Multi-XAP model: Application Configuration

SLHost.axd

Primary XAP

Module #1

HTML

XAP #2

Module #2

HTML

XAP #3

Module #3

HTML

XAP #4

Module #4

HTML

Silverlight Client Config. Providers

Browser DOM

Silverlight App Domain

Client Config. API

Encrypted Client Config Data

blocks

Layout, Navigation

• Define a common Layout for our pages (MasterPage concept from ASP.NET world).

• Make Navigation between modules seamless• Make Navigation in a “use-case” seamless

YourModule : UxModule : Application

MasterPage : UxMasterFrame

Header : UserControl

LeftNavArea

MyOrders: UserControl

ContactUs: UserControl

UxPageFrame

EntitySearch : HCuePage

ViewFrame’s optional footer

UxViewFrame

CustPreview : UserControl

CustSearchResult : UserControl

CustSearch: UserControl

Re-inventing ASP.Net mind-set

• Horizontally scalable packaging model with no upper limit • Logical application that can span multiple XAPs• Modules (or XAPs or Silverlight applications)• Master Page • Silverlight PageFrame, Pages,ViewFrame,Views, Abstract UX

containers• Heavyweight (PageFrame) and lightweight (ViewFrame)

navigation scheme• Consistent declarative navigation controls with declarative

parameter bindings.• Extensible “logical-application-level” Client Configuration

Instrumentation

Instrumentation

• Server-side and client-side • Performance Log, Trace log and Error log• Monitor health of production application• Understand site-usage• Trouble-shoot issues during an outage• Defect fixing during development• Performance tuning during development• Server side: Stored to database• Client side: In memory logging

Client-side Instrumentation

• Stored in memory. Therefore lives as long as the Silverlight application lives

• A sparse tree of loggers arranged by namespace in a hierarchical manner.

• Enforces upper limits on memory usage• Provides embedded UI for reviewing logs, configuring

logs, and exporting logs• Can be configured to enable / disable logging at a

node-level• Can be configured to log only messages that meet a

defined message level threshold

Instrumentation – Performance Log

Instrumentation – Trace Log

Instrumentation – Error Log

MV-VM Extensions

Visual Hierarchy – Perceived vs Actual

An Use-case container…

Transactions

Review Search Result

Search

An Use-case container… Review Search ResultXAML + Code-behind

SearchXAML + Code-behind

TransactionsXAML + Code-behind

Perceived

Actual

VM

VM

MV-VM Flexibility – Partitioning ViewModel

An Use-case container…

Transactions

Review Search Result

Search

An Use-case container… Review Search ResultXAML + Code-behind

SearchXAML + Code-behind

TransactionsXAML + Code-behind

Perceived

Actual

VM

VM

VM

VM

MV-VM - Questions

As our use-case complexity increased we were struggling with many fundamental questions, some ‘philosophical’…

• What is the definition/scope/boundary of a ‘View’?• How does composite Views fit in to the larger pattern?• Who is responsible for ‘provisioning’ ViewModel?• Is DataContext a good choice for attaching ViewModel to View?• If we do not use DataContext, how can we do data-binding to

substance of ViewModel?• Can we provision ViewModel using Dependency Injection pattern

(MEF for example…)• Are we abusing the MV-VM pattern?

MV-VM FlexibilitiesAn Use-case container…

Transactions

Review Search Result

Search

An Use-case container… Review Search ResultXAML + Code-behind

SearchXAML + Code-behind

TransactionsXAML + Code-behind

Perceived

Actual

VM

VM

VM

VM?

?

Our MV-VM Extended Implementation

• Can split / merge ViewModel with minimal impact• Provisioning ViewModel

– Can be provisioned declaratively (XAML) or using code– Not a static resource, can be attached to any FrameworkElement– Can attach multiple-view-models to parent UI container– Can be provisioned at any level of UI hierarchy– Strongly typed Connector model to declaratively bind to a ViewModel– Recycled when parent FrameworkElement goes out of scope

• Expression Trigger/Action/Behavior extensions for– Declarative binding to ViewModel substance– Route actions to ViewModel with parameter bindings.

Web Services Deployment

Service deployment

UX

www.wk.com

• One website for both UX and Services• Easily set up by default templates• Config file size and proxy count increase when more web services

are added.

Service deployment

UXapi.wk.com

ux.wk.com

• UX (passive) and Services are segregated• Requires more complex setup than first model

Service deployment

UX

api1.wk.com

api2.wk.com

api3.wk.com

• Services are partitioned to distinct end-points• Tolerant UI can improve perceived availability• Ease of service maintenance, enhancement and deployment

ux.wk.com

Service deployment

UXhttps://ux.wk.com

• Services are partitioned to distinct end-points• Enables partial DR capability

PRIM

ARYapi3.wk.com

api1.wk.com

DRapi3.wk.com

Service deployment

Content Delivery

Networks

• CDN used to push passive UI closer to end-user

UXapi1.wk.com

api2.wk.com

ux.wk.com

Light weight proxy

• Generic service contracts– IDxService<TRequest, TResponse>– Light-weight-strongly-typed proxy – Zero web.config entries (Convention over

configuration)

• Sharing data contracts - Issues– Runtime parity between Silverlight and core .Net– Bindable data contracts

Service Deployment – Takeaways

• Consider partitioning UX from web-service• Consider partitioning the services • Consider writing UI that tolerates service

unavailability• Consider writing light-weight universal proxy

and universal contracts. • Consider these aspects from day #1

More…

More foundation challenges

• DataSource With client-side caching, paging, sorting and not tied to type-of-source

• Runtime discovery of composite parts• Messaging• Extending role-based security to Silverlight client• Client side state management• Client side cache management• To-use or not-to-use Isolated storage• What-if-out-of-browser?

Why Silverlight…

Why Silverlight?

• Compressed budget Under tight economy, the budget that we could afford was lower than our comfort zone.

• Compressed timelineBusiness wanted to have the product out much sooner than we were comfortable.

• Dense and interactive experienceCompressed user-flow and dense screens that are highly interactive.

• Size was overwhelmingWe had to deliver many complex screens.

• Questions? Need Answers?– Ramya Parthasarathy (

ramya.parthasarathy@wolterskluwer.com)– Roman Rubin (

roman.rubin@wolterskluwer.com)

Don’t forget to fill out evaluation forms.