Building Workflow Services in .NET 3.5CLAEYS Kurt, ORDINAwww.devitect.net

Agenda

Windows Communication Foundation Overview

ServiceClient

ABC

AddressWhere?

ContractWhat?

BindingHow?

CBA

CBA

CBA

WCF Contracts[ServiceContract] public interface IKBO{ [OperationContract] void RegisterCompany(CompanyFile data);}

[DataContract]public class CompanyFile{ [DataMember] public string companyName { get; set; } [DataMember] public string VATID { get; set; } }

Windows Workflow Foundation Overview

WorkflowActivities

Activity Library

Workflow Runtime

Persistence Service

WorkflowServiceHost - Workflow

WorkflowServiceHost

Workflow

WCF Endpoint

WCF Endpoint

ServiceHostClient

Service

WCF

CBAWCF

CBA

Start – More Input – Action !

Start

Action

WorfklowService

WaitMore Input

Service

Client 1

Client 2

ReceiveActivity

•Activity that implements an operation defined by a Windows Communication Foundation (WCF) service contract.•To implement service behavior : add child activities to the ReceiveActivity

Client

Binding an operation contract to a ReceiveActivity

•ServiceOperationInfo property•Add Contract = Workflow First•Import = Contract First

Contract First vs Workflow First approach

•Contract First• You have a WCF contract (=interface)• You map receiveActivities in workflows to the

operations in the contract• SOA

•Workflow First Approach• No WCF contract present• Create contract as you model the workflow• More agile

ContextExhange Protocol

Client 1

Client 2 More Input

instanceID

WorkflowPersistenc

eDB

“creates” instance

“follows” instancesome data + instanceIDEC969B-4239-427E-BB0A-9F7E5610A1F0

some data + instanceIDEC969B-4239-427E-BB0A-9F7E5610A1F0

some dataStart

CanCreateInstance

•CanCreateInstance (true/false)• Gets or sets whether the operation on a

ReceiveActivity causes a new workflow service instance to be created or to participate in an already instantiated workflow.

Persisting the instance

- Creates an InstanceID-Sends it to the Client

- Allows to persists WF instance

- Expects an InstanceID - Load persisted WF instance

CanCreateInstance = false

CanCreateInstance = trueStart

More Input

EC969B-4239-427E-BB0A-9F7E5610A1F0

SendActivity

•Activity that models the synchronous invocation of a service operation.•Use ChannelToken as reference to client endpoint

Service

ChannelToken - Endpoint

<client> <endpoint address="http://localhost:4321/Foo" binding="basicHttpBinding" bindingConfiguration="" contract=“IFOO" name=“TheEndpointForTheService" /></client>

WorkflowServiceHost

WorkflowServiceHost host;host = new WorkflowServiceHost(typeof(TheWorkflow));

host.Open();

Participating ClientDossierInterface.IDossier proxy;

System.ServiceModel.Channels.Binding b;b = new NetTcpContextBinding();EndpointAddress ea;ea = new EndpointAddress("net.tcp://localhost:9876/TheWorkflow");

proxy = ChannelFactory<DossierInterface.IDossier>. CreateChannel(b, ea);

System.ServiceModel.Channels.IContextManager cm;cm = ((System.ServiceModel.IContextChannel)proxy). GetProperty<System.ServiceModel.Channels.IContextManager>();

var d = cm.GetContext();

d["instanceId"] = textBox1.Text;

cm.SetContext(d);

proxy.PaymentReceived();

DEMO

Demo Scenario

Step 1User starts the process by filling in data in a webapplication

Step 2Process StartedGenerate paymentreferenceStep 3

User gets paymentreference Step 4Process waits for payment for amount of timeStep 5

User pays Step 6Process receives payments and continues

Step 7Process data is send to external service

Wrap-up

What to remember about workflow services

•Workflows Services is an easy technology to build processes that integrate WCF Services•Start with creating interfaces (= contract first approach)•Share interface to all participants •Importance of the instanceId•Database for persisting workflows makes the process long running !•Have a delay activity for every ‘waiting for input’ scenario•Have a look at WCF 4.0 and Dublin !

Links

Some links to get you started ...

•This Example •http://www.devitect.net/techdays09

•Workflow Services (Foundation)•http://msdn.microsoft.com/en-us/magazine/cc164251.aspx

•Context Exhange Protocol •http://msdn.microsoft.com/en-us/library/bb924468.aspx

•WF and WCF integration in .NET 3.5•http://channel9.msdn.com/shows/The+EndPoint/WF-and-WCF-integration-in-NET-35/

•Workflow Services Samples (WF)•http://msdn.microsoft.com/nl-be/library/bb943473(en-us).aspx

•Workflows, Services, and Models, A First Look at WF 4.0, “Dublin”, and “Oslo”•http://msdn.microsoft.com/en-us/library/dd200919.aspx

Q/A

Thankskurt.claeys@ordina.be