a first look at wcf and wf in .net 4.0

8/8/2019 A First Look at WCF and WF in .NET 4.0

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Aaron SkonnardCofounderPluralsight

SOA201


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About Aaron Skonnard

Cofounder of Pluralsight

Industry think-tank focused on developer training

Recently released Pluralsight On-Demand!

Active in the community

Microsoft MVP for Connected Systems

Author & 10-year columnist for MSDN Magazine

Contact information

Email: [email protected]

Blog: http://pluralsight.com/aaron

Twitter: http://twitter.com/skonnard


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WCF &WF 4.0

Primary focus on bringingWCF +WF together

WF 4.0WF 4.0WCF 4.0WCF 4.0

Enables new scenarios/features

Fairly minor in terms of impactto your applications

Enables some key new features

Major shift in direction

Redesign ofWF runtime andprogramming model

Likely to break today's apps


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NewWCF 4.0 Features

Workflow services (major focus)

Simplified configuration

Discovery

Router service

Improved REST support

Misc advanced features


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Simplified Configuration

New support for default service configurations

Default binding & behavior configurations

Implicit endpoint configurations

Much easier to get services up and runningRemoves the need for configuration

Also enables .svc-less activation


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Simplified Configuration & Discovery


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Service Discovery

WCF 4.0 provides two types of service discovery

Clients can discoverClients can discoverservices on a localservices on a local

subnet (UDPsubnet (UDP--based)based)

Clients can discoverClients can discoverservices on a largerservices on a larger

"managed" network"managed" network

(beyond the local(beyond the local

subnet) through asubnet) through a

discovery proxydiscovery proxy

AdhocAdhoc ManagedManaged

Enabled via the serviceDiscoverybehavior,clients "discover" services using a DynamicEndpoint


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Router Service

First-class "router" service

Content-based routing, protocol bridging, etc

Error handling support

You host it like any otherWCF serviceConfigure with routing "filters"

Client

Service

Service

Router

"filters"


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Improved REST Support

Many features from theWCF REST Starter Kitwill be part ofWCF 4.0

Automatichelp page

HTTP cachingsupport

Responseformatting

Default endpoint Web exceptions


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Improved REST Support


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AdvancedWCF Features

DataContractResolver for type resolution

Allows you to override known type resolution

Support for queues with competing consumers

Added a "receive context" featureHigh-performance ETW-based tracing

Blob encoder


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WF 3.x Challenges Today

Limited support for XAML-only workflows

Versioning is problematic

Limited base activity library (no work activities)

Writing custom activities is hard

Managing data flow is reallyhard

LimitedWCF integration and activity support


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Moving TowardsWF 4.0

Major themes inWF 4.0 include

XAML-only model More activities WorkflowServices

Simplifyingcustom activities

Simplifyingdata flow

Runtime/designerimprovements


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XAML-onlyWorkflows

A declarative workflowis fully described withina XAML file (no code-behind)

Has always been the ultimateWF vision

Possible in .NET 3.x but not easy.NET 4.0 makes them first-class citizens

Enhancements to programming model remove theneed for code-behind files altogether

Full designer support in Visual Studio 2010


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Benefits of DeclarativeWorkflows

C#

DSL

VisioVisio

Increases hosting & deployment flexibility

It can be represented in different formatsXAML, C#, Visio, custom DSL, etc.

The program definition isjust dataIt's typically an XML file that's easy to processSimplifies tool support and designersIt can be stored anywhere (file, DB, cloud, etc.)


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Extended Base Activity Library

.NET 4.0 comes with several new activities

FlowchartFlowchart

ForEachForEach

ParallelParallel

ParallelForEachParallelForEach

DoWhileDoWhile

PickPick

AddToCollectionAddToCollection

RemoveFromCollectionRemoveFromCollection

ExistsInCollectionExistsInCollection

ClearCollectionClearCollection

......

AssignAssign

InvokeMethodInvokeMethod

PersistPersist

InteropInterop

......

Flow ControlFlow Control CollectionCollection OthersOthers

Microsoft is planning to ship more activities via CodePlexover time


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New Flow Chart Model

Simple step-by-step model,

with decisions and switches

Allows you to return to previous

activities in the workflow

Flowcharts offer a middle ground betweenthe sequential and state machine models


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SimplifiedWF Programming Model

WF 4.0 makes it much easier to:

Host workflows and run workflow instances

Manage workflow bookmarks

Create custom activitiesPass data into activities and store


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WorkflowElement

Activity CodeActivity NativeActivity

Creating Custom Activities

New programming model for custom activities

Plus the newDynamicActivityfor dynamic activity composition


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WF 4.0 Data Flow Constructs

ArgumentsArguments

VariablesVariables

ExpressionsExpressions

Used to define the way data flows in and out of an activity;

each argument has a binding direction:

input, output, or input/output.

Used to declare named storage for data within an activity;

variables can be defined at different scopes within a workflow.

Takes one or more input arguments, performs some operationon those input arguments, and then returns a value.


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Arguments and Variables

State MachineState Machine

Parallel

Sequence

SendSendMessageMessage

DelayDelayReceiveReceive

MessageMessage

GenerateGenerateOrderOrder

InArgument

OutArgument

InArgument

OutArgument

r cessr cessOrderOrder

SendSendRep rtRep rt

Variables

Variables

Variables

Activities are the primitive abstraction for behaviorActivities defineArguments to declare the type of datathat can flow into or out of an Activity

Activities are composable with other ActivitiesActivities have user-defined Variables for data storageActivities bind Arguments to in-scope Variables


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WF 4.0 Programming Model


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WCFWorkflow Services

WCF ServiceWCF Service

WFWorkflowWFWorkflow

ClientClientExternalExternalServiceService

ExternalExternalServiceService

WCF endpointWCF endpoint

WCF endpointWCF endpoint


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Workflow Services

New messaging activities

Add service reference (Visual Studio)

XAML authoring (contracts, bindings, etc)

Workflow service host


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WCF Activities in .NET 4.0

WF 4.0 comes with new-and-improvedWCF activities

SendSend

ReceiveReceive

SendAndReceiveReplySendAndReceiveReply

ReceiveAndSendReplyReceiveAndSendReply

SendSend

ReceiveReceive

.NET 4.0.NET 4.0.NET 3.5.NET 3.5

All 4.0 messaging activities come with improved

WCF support including correlation


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Message Correlation

When sending and receivingWCF messages,correlation is a common need

.NET 4.0 adds correlation support toWCF

WF makes correlation easy to use via activities


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Workflow Services


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The NewWF Designer

Improved usabilityImproved usabilityImproved designerImproved designer

performanceperformance

Major rehostingMajor rehosting

improvementsimprovements

Unified debuggingUnified debugging

experienceexperience


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WF Runtime Improvements

Full controlFull controlover persistenceover persistence

1010--100x Performance100x PerformanceImprovementsImprovements

FlowFlow--in Transactionsin Transactions Partial Trust SupportPartial Trust Support


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Preparing forWF 4.0

Your 3.x workflows will continue to work

Using theWF 3.0 runtime

You can use 3.x activities in a 4.0 workflow

Use the Interop activityMore guidance coming from Microsoft


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Summary

WCF/WF 4.0 offers many improvements:

WCF +WF integration:Workflow Services

NewWCF features & messaging improvements

NewWF runtime, programming model, & designerLays a solid foundation for building connectedsystems on the .NET platform


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Additional Resources

WCF andWF Services in the .NET Framework4.0 and "Dublin"

http://msdn.microsoft.com/en-us/magazine/2009.01.net40.aspx

TheWorkflowWay (new whitepaper)

Screencasts onWCF/WF 4.0:

http://www.pluralsight.com/main/screencasts/

Follow Pluralsight in real-time on Twitter:

http://twitter.com/pluralsight


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a first look at wcf and wf in .net 4.0

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