MSDN Webcast- Windows Communication Foundation Top to Bottom (Part 02 of 15)- Contracts (Level 200)

7/27/2019 MSDN Webcast- Windows Communication Foundation Top to Bottom (Part 02 of 15)- Contracts (Level 200)

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Windows CommunicationFoundation Top to Bottom

(Part 02 of 15): Contracts

Michele Leroux Bustamante

Chief ArchitectIDesign Inc.


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About Michele LerouxBustamante

IDesign Inc., www.idesign.net

Microsoft regional director

MVP Connected Systems

BEA technical directorIASA - board member

Published MSDN, CoDe, TheServerSide

International speaker, International .NET

Association (INETA)Program advisor, UCSD Extension

Track chair, SD Expo

www.dasblonde.net, www.thatindigogirl.com
http://www.idesign.net/http://www.dasblonde.net/http://www.thatindigogirl.com/http://www.thatindigogirl.com/http://www.dasblonde.net/http://www.idesign.net/


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Session Prerequisites

Experience building Microsoft .NETFramework applications

Basic understanding of WCF clients and

services

Level 100


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Agenda

Contractsand metadata

Service contracts

Complex type serializationSerializable types, data contracts, known types,IXmlSerializable

Message contracts

Summary of approaches


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Host Process

ServiceHost

Endpoint

EndpointService

Clients and Services


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Client Process Host Process

Client App ServiceHost

Endpoint

EndpointService

Proxy


Endpoint


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Client Process Host Process

Client App ServiceHost

Endpoint

EndpointService

Proxy


Endpoint


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Demonstration One

Contracts and metadata


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WCF Contracts

Service contracts

Data contracts and other serializable types

Message contracts


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Agenda


Service contracts

Complex type serializationSerializable types, data contracts, known types,IXmlSerializable

Message contracts



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Service Contracts

ServiceContractAttribute

Define service operations

OperationContractAttribute

Methods exposed as part of the public servicecontract

[ServiceContract]

publicinterfaceIContentManagerService{[OperationContract]void SaveLink(LinkItem item);

}


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ServiceContractAttribute

Applied to interfaces or classes

Prefer interface

Remove coupling to service implementation

Services may implement >1 contract

Always provide meaningful Namespace

Can provide explicit Name

[ServiceContract(Name="ContentManagerContract",Namespace=

"http://www.thatindigogirl.com /samples/2007/07")]publicinterfaceIContentManagerService{}


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OperationContractAttribute

All methods in a service contract should haveOperationContractAttribute

Can provide explicit Name, Action, ReplyAction

[ServiceContract(Name="ContentManagerContract", Namespace ="http://www.thatindigogirl.com/samples/2007/07")]publicinterfaceIContentManagerService{[OperationContract(Name="SaveLink", Action=

"http://www.thatindigogirl.com/samples/2007/07/

ContentManagerContract/SaveLink",ReplyAction="http://www.thatindigogirl.com/samples/2007/07/ContentManagerContract/SaveLink")]void SaveLink(LinkItem item);

}


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MessageParameterAttribute

UseMessageParameterAttribute tocontrol parameter or return naming

[ServiceContract(Name="ContentManagerContract,

Namespace="http://www.thatindigogirl.com/samples/2007/07")]publicinterfaceIContentManagerService{[OperationContract]void SaveLink([MessageParameter(Name="LinkItem")]

LinkItem item);

[OperationContract][return:MessageParameter(Name="LinkItem")]

LinkItem GetLink(string id);}


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Agenda


Service contracts

Complex type serialization

Serializable types, data contracts, known types,IXmlSerializable

Message contracts



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Complex Type Serialization

Serializable types

Data contracts

Known types

IXmlSerializable


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DataContractSerializer

WSDL

XSD

XML DataContractSerializer

DataContractAttribute

IXmlSerializable

SerializableAttribute


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SerializableAttribute

SerializableAttribute, Serializable

Many CLR types are serializable

All fields are serialized

Regardless of accessibility

No control over naming conventions or data types[Serializable]publicclassLinkItem{

privatelong m_id;privatestring m_title;privatestring m_description;privateDateTime m_dateStart;privateDateTime m_dateEnd;privatestring m_url;

// property accessors

}


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Data Contracts


Translation between CLR types and schema

DataMemberAttribute

Opt-in members for serialization

Applied to fields or properties

Preferred way for DataContractSerializer towork with complex types


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Demonstration Two

Data contracts


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Always provide a Namespace

Web service conventions use schemas prefix toservice target namespace

Can provide explicit Name

[DataContract(Name="LinkItem,Namespace="http://schemas.thatindigogirl.com/samples/2007/07")]publicclassLinkItem{}

[ServiceContract(Name="ContentManagerContract,Namespace="http://www.thatindigogirl.com/samples/2007/07")]publicinterfaceIContentManagerService{}


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DataMemberAttribute

Applied to fields or properties

Always provide Order

Default order is alphabetical

Can provide explicit Name, IsRequired

[DataMember(Name = "Id", IsRequired = false, Order = 0)]publiclong Id{get { return m_id; }set { m_id = value; }

}

[DataMember(Name = "Id", IsRequired = false, Order = 0)]privatelong m_id;


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Data Contract SchemaAlphabetical Ordering (Default)


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[DataContract(Name="LinkItem",Namespace="http://schemas.thatindigogirl.com/samples/2007/07")]publicclassLinkItem{// fields

[DataMember(Name="DateStart", IsRequired = true, Order = 3)]publicDateTime DateStart{get { return m_dateStart; }set { m_dateStart = value; }

}

[DataMember(Name="Description", IsRequired = true, Order = 2)]publicstring Description{}

[DataMember(Name="Id", IsRequired = false, Order = 0)]publiclong Id

{

}

[DataMember(Name="Title", IsRequired = true, Order = 1)]publicstring Title{}

// other properties}


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Data Contract SchemaExplicit Ordering, Required Elements


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Known Types

Known types enable polymorphic behavior inservice contracts

Expose base types in service operations

Associate known types

To the base types themselves

To particular operations

To the service contract as a whole

Use declarative attributes or configurationsettings


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KnownTypeAttribute

[DataContract(Namespace ="http://schemas.thatindigogirl.com/samples/2007/07" )][KnownType(typeof(GigInfo))][KnownType(typeof(PhotoLink))][KnownType(typeof(MP3Link))]publicclassLinkItem

[DataContract(Namespace ="http://schemas.thatindigogirl.com/samples/2007/07" )]publicclassGigInfo: LinkItem

[DataContract(Namespace ="http://schemas.thatindigogirl.com/samples/2007/07" )]publicclassPhotoLink: LinkItem

[DataContract(Namespace ="http://schemas.thatindigogirl.com/samples/2007/07" )]publicclassMP3Link: LinkItem


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Demonstration Three

Known types


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ServiceKnownTypeAttribute

[ServiceContract(Name = "GigManagerContract", Namespace ="http://www.thatindigogirl.com/samples/2007/07")][ServiceKnownType(typeof(GigInfo))][ServiceKnownType(typeof(PhotoLink))][ServiceKnownType(typeof(MP3Link))]publicinterfaceIGigManagerService

{[OperationContract]void SaveLink(LinkItem item);

[OperationContract]LinkItem GetLink(string id);

}

S


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ServiceKnownTypeAttribute

[ServiceContract(Name = "GigManagerContract", Namespace ="http://www.thatindigogirl.com/samples/2007/07")]publicinterfaceIGigManagerService{

[OperationContract][ServiceKnownType(typeof(GigInfo))]

void SaveGig(LinkItem item);

[OperationContract][ServiceKnownType(typeof(GigInfo))]LinkItem GetGig(string id);

}

d l dT


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C d Fi t C t t Fi t


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Code-First vs. Contract-First

In a perfect WCF world:

Create data contracts that also function asbusiness objects

Expose in service contracts

In reality:

May not own objects (cant make serializable)

Business object serialization may not beappropriate

May need to support pre-existing schemas

IX lS i li bl


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IXmlSerializable

IXmlSerializable types provide XSD schema toWeb Services Description Language (WSDL) andmetadata exchange (MEX)

Contract-first support

You handle mapping between XML and businessobjects

Requires knowledge of XML

Provide appropriate validationLess overhead than using interim data contracts

IX lS i li bl


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IXmlSerializable

IXmlSerializable

Valid in service contract (like data contract)

Hook serialization process:

IXmlSerializable.ReadXml()

IXmlSerializable.WriteXml()

XmlSchemaProviderAttribute

Improvement onIXmlSerializable.GetSchema()

Return schema for WSDL and MEX


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Demonstration Four

IXmlSerializable

A d


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Agenda


Service contracts



Message contracts


M C t t


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Message Contracts

MessageContractAttribute

Greater control over message headers and bodyelements

Supporting attributes:MessageHeaderAttribute

MessageBodyMemberAttribute

Useful for:

Add custom headers

Control message wrapping

Control signing and encryption

M C t tAtt ib t


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MessageContractAttribute

Converts a type to a SOAP message

Type can contain header and body elements

Can set IsWrapped, ProtectionLevel

May set explicit Name, Namespace

[MessageContract(IsWrapped=true,ProtectionLevel=ProtectionLevel.Sign)]

publicclassSaveLinkRequest

{}

[MessageContract]

publicclassSaveLinkResponse{}

M H d Att ib t


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MessageHeaderAttribute

Apply to fields or properties of messagecontract

Simple technique for creating custom headers

Can provide Name, Namespace,ProtectionLevel

May set SOAP protocol settings: Relay,

Actor, MustUnderstand

M B d M b Att ib t


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MessageBodyMemberAttribute

Apply to fields or properties of messagecontract

Can have several body elements

Equivalent to multiple parameters in operation

Only way to return multiple complex types

Always supply Order

Can set Name, Namespace, ProtectionLevel

[MessageContract(IsWrapped=true,


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[MessageContract(IsWrapped true,ProtectionLevel=ProtectionLevel.Sign)]publicclassSaveEventRequest{privatestring m_licenseKey;privateLinkItem m_linkItem;

[MessageHeader(ProtectionLevel =ProtectionLevel.EncryptAndSign)]publicstring LicenseKey{get { return m_licenseKey; }

set { m_licenseKey = value; }}

[MessageBodyMember]publicLinkItem LinkItem{get { return m_linkItem; }

set { m_linkItem = value; }}

}

[MessageContract]publicclassSaveEventResponse

{}

A l i M C t t


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Applying Message Contracts

Message contracts are supplied as operationparameter or return value

Must contain serializable members

Data contracts or serializable types

[ServiceContract(Name = "ContentManagerContract",Namespace="http://www.thatindigogirl.com/samples/2007/07")]publicinterfaceIContentManagerService{

[OperationContract]SaveLinkResponse SaveLink(SaveLinkRequestmessage);

[OperationContract]GetLinkResponse GetLink(GetLinkRequest message);

}

Appl ing Message Contracts


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In the generated client proxy, custommessage headers are added as parametersto operations

Not optionalLinkItem item = newLinkItem();

// initialize item

string licenseKey = "XXX";m_proxy.SaveLink(licenseKey, item);



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At the service, message headers areprocessed as member of the messagecontract

Message body elements also availablethrough message contract

publicSaveLinkResponse SaveEvent(SaveLinkRequest message)

{ if (message.LicenseKey != "XXX") thrownewFaultException("Invalid license key.");

m_linkItem = message.LinkItem;returnnewSaveLinkResponse();

}

Agenda


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Agenda


Service contracts



Message contracts


WCF Contracts Summary


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WCF Contracts Summary

Service contracts define available operationsand signatures

Data contracts and other serializable types

can be included in service contractKnown types enable polymorphic contracts

Message contracts are useful for custom

headers and other advanced requirements

For More Information


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For More Information

My blog: www.dasblonde.net

IDesign resources: www.idesign.net

Learning WCF: A Hands-on Guideby Michele Bustamante (O'ReillyMedia, Inc., 2007)

Book blog: www.thatindigogirl.com

Questions and Answers
http://www.dasblonde.net/http://www.idesign.net/http://www.thatindigogirl.com/http://www.thatindigogirl.com/http://www.idesign.net/http://www.dasblonde.net/


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Questions and Answers

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Documents

MSDN Webcast- Windows Communication Foundation Top to Bottom (Part 02 of 15)- Contracts (Level 200)