Pro WCF 4: Practical Microsoft SOA Implementation

458 Pages·2011·10.162 MB·English

by  Nishith Pathak

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Pro WCF 4: Practical Microsoft SOA Implementation is a complete guide to
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from the .NET 4.0 Framework – learn about service discovery, the routing ser-

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Nishith Pathak, Author of in understanding and implementing these important additions. C
Pro WCF: Practical Microsoft Inside, you’ll find coverage of the unified programming model, reliable mes-
SOA Implementation saging, security, and the peer-to-peer programming model. You'll also learn
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and how to integrate those applications with WCF 4. This book offers genuine
insight into solving real enterprise problems using WCF and .NET 4.0.

In Pro WCF 4, learn more about: 4

• New features of WCF with .NET 4.0
• A comprehensive WCF programming model
• How queue management and reliable messaging work in WCF
• Implementing transaction support in WCF
• Making WCF services interoperable with other SOA offerings
• Best practices in using WCF effectively
• Developing WCF applications with Visual Studio 2010 Practical Microsoft SOA Implementation
The release of .NET 4.0 brought a wide range of new functionality to WCF.
Developers and architects with experience using WCF 3.5 or earlier who want
to apply this new functionality to their application will benefit greatly from the
discussions and code samples in this book. Pro WCF 4 is also a great resource for
application developers and architects new to SOA or the core concepts of WCF.
Creating the next generation of secure, reliable,
and interoperable services
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Contents at a Glance
Contents ..................................................................................................................... v

About the Author ..................................................................................................... xiv

About the Technical Reviewer .................................................................................. xv(cid:1)
Acknowledgments ................................................................................................... xvi(cid:1)
Introduction ............................................................................................................ xvii(cid:1)

Part I: Introducing Windows Communication Foundation .......................................... 1(cid:1)
■Chapter 1: WCF and SOA Basics .............................................................................. 3(cid:1)
■Chapter 2: What’s New in WCF 4 ........................................................................... 25(cid:1)
■Chapter 3: Exploring the WCF Programming Model .............................................. 55(cid:1)
Part II: Programming with WCF ................................................................................ 99(cid:1)
■Chapter 4: Installing and Creating WCF Services ................................................ 101(cid:1)
■Chapter 5: Hosting and Consuming WCF Services .............................................. 145(cid:1)
■Chapter 6: Managing WCF Services .................................................................... 185(cid:1)
Part III: Advanced Topics in WCF ........................................................................... 217(cid:1)
■Chapter 7: Implementing WCF Security .............................................................. 219(cid:1)
■Chapter 8: Implementing Reliable Messaging and
Queue-Based Communications ......................................................... 253(cid:1)
■Chapter 9: Using Transactions in WCF ................................................................ 281(cid:1)
■Chapter 10: Integrating with COM+ .................................................................... 303(cid:1)
■Chapter 11: Working with Data ........................................................................... 337(cid:1)
■Chapter 12: Developing Peer-to-Peer Applications with WCF ............................. 371(cid:1)
■Chapter 13: Implementing SOA Interoperability ................................................. 399(cid:1)
■Appendix: QuickReturns Ltd. ............................................................................... 419(cid:1)
Index ....................................................................................................................... 425
iv
Introduction
This book is a complete guide to Windows Communication Foundation (WCF) from a service-oriented
architecture (SOA) perspective. With each new version of the .NET Framework, Microsoft has improved
many key areas of WCF. In .NET 4.0, Microsoft has given developers a better experience and enabled
them to become more productive. The book not only provides deep insight into the new WCF
functionality that ships with .NET 4.0—such as service discovery, routing services, and simplified
configuration—but also provides extensive examples to make it easier to put the new concepts into
practice. You'll learn how to move your current offerings to WCF, and how to integrate those
applications with WCF 4.0. This book offers genuine insight into solving real enterprise problems using
WCF and .NET 4.0. This books covers the following:
• The new features of WCF with .NET 4.0
• The WCF programming model
• Implementing WS-Discovery and routing services in WCF
• How queue management and reliable messaging work in WCF
• Implementing transaction support in WCF
• How to make WCF services interoperable with other SOA offerings
• Best practices for using WCF effectively
• Developing WCF applications with Visual Studio 2010
It will also address the business drivers that dictate the need for these WCF features, as well as the
industry best practices for applying them.
Who This Book Is For
The release of .NET 4.0 brought a wide range of new functionality to WCF. Developers and architects
with experience using WCF 3.5 or earlier who want to be able to apply this new functionality to their
applications will benefit greatly from the discussions and code samples in this book. This book is also a
great resource for application developers and architects new to SOA and/or the core concepts of WCF.
An Overview of This Book
This book specifically targets WCF in .NET 4.0. The text that you hold in your hands is a massive retelling
of this book’s first printing to account for all of the major changes that are found in .NET 4.0. Not only
will you find brand-new chapters, you will find that many of the previous chapters have been expanded
in great detail. This book divided into three parts, each of which contains related chapters. The following
xvii
■ INTRODUCTION
sections describe each part. The book also has one appendix, where you’ll find a description of the
sample application used throughout this book.
Part 1: Introducing Windows Communication Foundation
This part of the book explains the business motives and pain points of the various distributed
technologies developed by Microsoft. It explains how you can address these issues using WCF. Once you
understand some of these basic concepts of WCF, including the business and technological factors, you
can appreciate its simplicity and flexibility. Chapter 1 covers the service standards and introduces WCF.
Chapter 2 explains the new features of WCF that ship with .NET 4.0. Chapter 3 discusses the unified
programming model of WCF and how WCF provides the best tools for creating secure, interoperable
web services.
Part 2: Programming with WCF
This part covers the technical features of WCF in detail. You’ll concentrate on the programming aspects
of WCF with the assistance of a fictitious stock market application. Chapter 4 guides you through
installing and creating WCF services. Chapter 5 covers creating services, and the various hosting options
available in WCF services. Chapter 6 discusses how to manage WCF services to obtain the best return on
investment for your application.
Part 3: Advanced Topics in WCF
Real-world SOA applications will have many demanding features to implement. These complex real-world
web service implementations will address security issues (both client and service), reliable messaging,
transactions, COM+ integration, data integration issues, and peer-to-peer communications. In Chapters 7
through 12, you will concentrate on these topics. In addition, you’ll investigate the WCF interoperability
options available to seamlessly communicate with non-Microsoft platforms in Chapter 13.
Prerequisites
To get the most out of this book, you should install WCF and the .NET Framework 4.0. I recommend
using Microsoft Visual Studio 2010 as the development environment to experiment with the code
samples, which you can find in the Source Code section of the Apress web site (www.apress.com).
Obtaining Updates for This Book
As you read through this text, you may find the occasional grammatical or code error (although I sure
hope not). If this is the case my sincere apologies. Being human, I am sure that a glitch or two may be
present, regardless of my best efforts. If this is the case, you can obtain the current errata list from the
Apress web site (located once again on the home page for this book), as well as information on how to
notify me of any errors you might find.
xviii
■ INTRODUCTION
Contacting the Author
If you have any questions regarding this book’s source code, are in need of clarification for a given
example, or simply wish to offer your thoughts regarding WCF and .NET 4.0, feel free to drop me a line at
[email protected]. I will do my best to get back to you in a timely fashion; however, like yourself, I
get busy from time to time.
Thanks for buying this text. I hope you enjoy reading it and putting your newfound knowledge to
good use.

xix
P A R T I

■ ■ ■
Introducing Windows
Communication Foundation
Part 1 of this book introduces web service standards and the fundamental components of service-
oriented architecture (SOA). Once you have an understanding of some of these concepts, you can
appreciate the simplicity and flexibility of Windows Communication Foundation (WCF). This part also
discusses how SOA principles are applied in WCF. Chapter 1 covers the reasons SOA is needed, and
provides a brief introduction to WCF. Chapter 2 looks at some of the key new features of WCF that were
released with .NET 4.0. This is followed by a discussion of the WCF programming model in Chapter 3.
C H A P T E R 1

■ ■ ■
WCF and SOA Basics
In today’s world, implementing distributed systems that provide business value in a reliable fashion
presents many challenges. We take many features for granted when developing nondistributed
systems—features that can become issues when working with disparate distributed systems. Although
some of these challenges are obvious (such as a loss of connectivity leading to data being lost or
corrupted), for other aspects—such as tightly coupled systems—the dependencies between various
system components make it cost prohibitive to make changes to meet the demands of the business.
Business processes are quite often supported by systems that run on different platforms and
technologies both within and outside of the organization. Service-oriented architecture (SOA) is a
mechanism that enables organizations to facilitate communication between systems running on
multiple platforms.
During the past decade, a lot of research has been done in the field of distributed computing.
Microsoft and other leading vendors have come up with various distributed technologies. Each of these
technologies reduces the convolution of building rich applications and lowers development costs. The
latest from Microsoft is Windows Communication Foundation (WCF), which provides a uniform way of
developing distributed applications by providing a service-oriented programming model.
WCF (formerly known as Indigo) handles the communication infrastructure of .NET 3.x and later,
which allows you to create a diverse range of applications through its simplified model. Based on the
notion of services, WCF contains the best features of today’s distributed technology stack for developing
the connected systems. This chapter not only introduces the fundamental concepts of SOA, but also
provides a brief discussion of WCF and its features. After completing this chapter, you will have learned
about the following:
• What SOA means, and what makes it the preferred approach to designing complex
heterogeneous IT systems
• The four tenets of SOA
• Existing distributed technologies and their pitfalls
• The key architectural concepts and features that underpin WCF
• How WCF unifies existing distributed technologies
Understanding SOA
It is not practical to build monolithic systems in current multinational enterprises. These systems often
take many years to implement and usually address a narrow set of objectives. Today a business needs to
be agile and adapt processes quickly, and SOA is a design principle that can help address this business
need. Although any kind of implementation can be an SOA implementation, unfortunately many
implementations using web services are marketed as SOA implementations when they are not.
3
CHAPTER 1 ■ WCF AND SOA BASICS
In reality, SOA is a collection of well-defined services. A service is an autonomous (business) system
that accepts one or more requests and returns one or more responses via a set of published and well-
defined interfaces. Each of these individual services can be modified independently of other services to
help respond to the ever-evolving market conditions of a business.
Unlike traditional, tightly coupled architectures, SOA implements a set of loosely coupled services
that collectively achieve the desired results; in addition, since the underlying implementation details are
hidden from the consumer, changes to the implementation won’t affect the service, as long as the
contract does not change. This allows systems based on SOA to respond more quickly and cost-
effectively for the business.
Although some of these aspects might be similar to component-based development (which is based
on strict interfaces), the key difference is that SOA provides an approach based on open standards and
generic messages that aren’t specific to any platform or programming language. As a result, you can
achieve a high degree of loose coupling and interoperability across platforms and technologies.
■
Note Although SOA might seem abstract, it marks a significant shift from procedural and object-oriented
languages to a more loosely coupled set of autonomous tasks. SOA is more than a collection of services. It’s a
methodology encompassing policies, procedures, and best practices that allow the services to be provided and
consumed effectively. SOA is not a product that can be bought off the shelf; however, many vendors have products
that can form the basis of an SOA implementation.
It is important that the services don’t get reduced to a set of interfaces, since they are the keys to
communication between the provider and the consumer of the service. In a traditional client-server
world, the provider will be a server and the consumer will be a client. When factoring in services, try to
model the flow and process on recognized business events and existing business processes. You also
need to answer a few questions to ensure a clean design for services:
• What services do you need?
• What services are available to consume?
• What services will operate together?
• What substitute services are available?
• What dependencies exist between various services and other applications?
• Does the application have components that qualify it for being a service?
Service orientation, as described earlier, is about services and messages. Figure 1–1 shows an
example of how service providers and consumers can coexist with a repository to form an SOA
implementation. Service providers are components that execute some business logic based on
predetermined inputs and outputs, and expose this functionality through an SOA implementation. A
consumer, on the other hand, is a set of components interested in using one or more of the services
offered by the providers. A repository contains a description of the services, where the providers register
their services and consumers find what services are provided.
4
CHAPTER 1 ■ WCF AND SOA BASICS

Figure 1–1. How SOA components interact with each other
What Is a Service?
The term service has been used to describe everything from web services (discussed later in the chapter)
to business processes. You should use services to represent the functions of the business and explicitly
define the boundaries of what the business does, which essentially will define what the service can and
cannot do. The key is that it is not a technology-driven approach, but rather a business-driven approach.
■
Note The term loose coupling refers to situations in which any two entities reduce the assumptions they make
about each other when they try to exchange information. Contrary to this, tight coupling increases the range of
assumptions made between two entities (such as when the communication protocol becomes more complex), as
well as the efficiency of their communication. However, the two entities also become less tolerant to changes in,
say, interruptions in the communication, because they are tightly bound (or coupled) to each other. Local method
invocation is an excellent example of tight coupling, because it requires many assumptions to be made between
the called and calling routines, since both need to be in the same process, use the same language, pass the same
number of parameters in the agreed data formats, and so on.
Service orientation is a business-driven modeling strategy that defines business functionality in
terms of loosely coupled autonomous business systems (or services) that exchange information based
on messages. The term services is used in many contexts, but in the context of service orientation, a
service is based on four fundamental tenets. We’ll discuss these four tenets, originally proposed by the
WCF team at Microsoft, in the following sections.
5