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Developing ASP Components

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Developing ASP Components

Second Edition

Shelley Powers

Beijing• Cambridge• Farnham• Köln• Paris• Sebastopol• Taipei• Tokyo

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Developing ASP Components, Second Edition

by Shelley Powers

Printed in the United States of America.

Published by O’Reilly & Associates, Inc., 101 Morris Street, Sebastopol, CA 95472.

Editor: Ron Petrusha

Production Editor: Leanne Clarke Soylemez

Cover Designer: Hanna Dyer

Printing History:

April 1999: First Edition.

March 2001: Second Edition.

Nutshell Handbook, the Nutshell Handbook logo, and the O’Reilly logo are registered trademarks of O’Reilly & Associates, Inc ActiveX, JScript, Microsoft, MSDN, Visual Basic, Visual C++, Win32, Windows, and Windows NT are registered trademarks and Active Directory is a trademark of Microsoft Corporation Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks Where those designations appear in this book, and O’Reilly & Associates, Inc was aware of a trademark claim, the designations have been printed in caps or initial caps The association between the image of an asp and developing ASP components is a trademark of O’Reilly & Associates, Inc.

While every precaution has been taken in the preparation of this book, the publisher assumes

no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein.

ISBN: 1-56592-750-8

[M]

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About the Author

Shelley Powersis a consultant/author with her own company, Burning Bird prises In the last several years, she has worked with a variety of distributed,Internet, and Web development applications, for different platforms and using avariety of tools Shelley has authored or coauthored books on Dynamic HTML,JavaScript, Java, CGI, Perl, P2P, general Web technologies, and more Shelley can

Enter-be reached at shelleyp@yasd.com, and her book support site can Enter-be found at

http://www.burningbirdenterprises.com.

Colophon

Our look is the result of reader comments, our own experimentation, and back from distribution channels Distinctive covers complement our distinctiveapproach to technical topics, breathing personality and life into potentially drysubjects

feed-The animal on the cover of Developing ASP Components, Second Edition, is an asp,

which is a term applied to various venomous snakes, including the depicted asp

viper (Vipera aspis) of Europe as well as the Egyptian cobra (Naja haje), thought

to have been the means of Cleopatra’s suicide

Needing to eat at least 50-60% of their body weight in food per week, Europeanasp vipers hunt by lying in wait for approaching prey After grabbing and biting asmall rodent or other prey, they release it and wait several minutes for it to stopmoving; the generally sluggish viper rarely chases prey Vipers know their hometerritory very well, which allows quick escape from their asp-kicking naturalenemies, serpent eagles, and hedgehogs This trick hasn’t helped them escapefrom their greatest threat, the expansion of human civilization, which frequentlywipes out large sections of their territory

The chemical composition of asp viper venom can vary from one population tothe next, hampering initial antivenin development until 1896, but few viper bitefatalities occur in Europe today

Leanne Soylemez was the production editor and proofreader for Developing ASP

Components, Second Edition Norma Emory was the copyeditor, Mary Anne Weeks

Mayo and Colleen Gorman provided quality control, and John Bickelhaupt wrotethe index

Hanna Dyer designed the cover of this book, based on a series design by EdieFreedman The cover image is a 19th-century engraving from the Dover Pictorial

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Archive Emma Colby produced the cover layout with QuarkXPress 4.1 usingAdobe’s ITC Garamond font.

David Futato designed the interior layout based on a series design by Nancy Priest.Judy Hoer converted the files from MSWord to FrameMaker 5.5 using tools created

by Mike Sierra The text and heading fonts are ITC Garamond Light and mond Book; the code font is Constant Willison The illustrations that appear in thebook were produced by Robert Romano using Macromedia FreeHand 8 andAdobe Photoshop 5 This colophon was written by Nancy Wolfe Kotary

Gara-Whenever possible, our books use a durable and flexible lay-flat binding If thepage count exceeds this binding’s limit, perfect binding is used

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Oracle 8i Internal Services for Waits, Latches, Locks, and Memory, eMatter Edition

Table of Contents

Preface xi

1 Writing ASP Components 1

The Role ASP Components Play 2

Why Use ASP Components? 3

COM+ Services and ASP Components 5

Accessing Data with ASP Components 8

Windows 2000 Technologies Accessible from ASP Components 10

A Rose by Any Other Name: Programming Language Choice 11

What About ASP.NET? 13

2 Setting Up the ASP Development Environment 14

Configuring the IIS Environment 15

Remote Administration of IIS 27

Using ADSI to Administer IIS Programmatically 29

IIS Admin Object Overview 46

The IIS Base Admin Objects 59

3 ASP Components and COM 69

Overview of COM for ASP Component Developers 70

How COM Is Implemented 76

Notable COM Interfaces 80

COM Datatypes 87

4 ASP Components, Threads, and Contexts 91

What Are Threads? 92

Threads and Apartments 95

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vi Table of Contents

The Threading Models 96

What Are COM+ Contexts? 110

5 COM+ Services and ASP Components and Applications 114

Developing Component-Based Systems 114

The COM+ Interfaces 116

Porting MTS Packages to COM+ Applications 124

Activating COM+ Applications 125

COM+ Services 127

6 ASP Interaction: Scripting and ASP Components 136

Scripting Language Support Within ASP 136

Instantiating Components 139

COM+ Datatypes and Script/Component Interaction 145

Passing Arrays as Parameters 159

Error Handling Between Component and Script 174

7 Creating a Simple Visual Basic ASP Component 180

Creating an In-Process or Out-Of-Process Component 181

Component Instancing 182

Component Execution and Threads 184

Creating an ASP Project 187

Creating Component Methods 188

Generating, Registering, Installing, and Testing the Component 190

Adding Support for COM+ Services 191

Converting MTS Components for Use with COM+ 201

Accessing the ASP Built-in Objects 202

Error Handling 220

Debugging 222

Performance Issues 222

8 Creating ASP/ADO Components 225

Accessing ADO from a VB Component 226

Creating a Simple ADO Component 227

The ADO Model 233

File and Directory Access with ADO Streams and the Record Object 256

Persisting Data 262

9 Creating an ASP Middle Tier with ADO 266

How Separate Should the Layers Be? 267

Creating ADO Data Wrappers 268

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Table of Contents vii

Defining Business Objects 281

Other Data Integrity Issues 295

10 Server-Side XML Through VB ASP Components 298

XML Basics 298

Formatting XML 302

Working with XML in ASP Applications 307

XML and ADO: Saving Recordsets as XML 315

11 Take a Message: Accessing CDO from ASP Components 321

A Brief Overview of CDO 322

The CDO Object Model 322

Send This URL to a Friend 324

Working with the Message Body 328

Retrieving and Reading Messages 338

12 Working with Active Directory from ASP Applications 344

A Brief Overview of Active Directory in Windows 2000 345

Setting Up an Isolated Active Directory Environment 345

A Refresher on ADSI 347

Binding to Active Directory Objects 349

Using the Active Directory Services Viewer 355

Manipulating Containers 357

Searching Active Directory with ADO 362

ASP Example: Add and Manage Users Through the Web 366

13 Working with MSMQ Components 380

MSMQ/ASP Basics 380

Working with Queues 382

Working with MSMQ Messages 389

Using Transactions 394

Journaling 407

A Brief Word on Message Security 412

14 Creating C++ ASP Components 414

ATL or MFC 415

Using ATL AppWizard to Generate the Basic ASP Component Project 416

Adding an ATL Object 421

Code Changes Based on Adding a New Object 426

Adding Methods to the Interface 427

Adding Support for COM+ Services 432

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viii Table of Contents

Converting MTS Components for Use with COM+ 440

Error Handling 463

15 Adding Data Access to C++ Components with ADO 468

ADO Access in Visual C++ 468

The ADO Object Model 469

The Connection Object 470

The Recordset Object 479

The IADORecordBinding Interface 486

The Command Object 490

Stream and Record Objects 497

16 The CDO Interfaces from C++ Components 506

Accessing CDO Interfaces in C++ 506

Creating and Sending a Message 509

Retrieving and Reading Messages 521

17 Accessing Active Directory from C++ Components 528

Binding to Active Directory Objects 529

ADSI Helper Functions 536

Filtering Collections 538

Creating and Removing Active Directory Objects Using ADSI 540

Searching Active Directory with IDirectorySearch 544

18 Accessing MSMQ from C++ ASP Components 550

Adding Support for MSMQ to the C++ Project 550

Working with Queues 553

Searching for a Specific Queue 560

Working with MSMQ Messages 568

Using Transactions 574

19 Persistence with ASP Components Using ATL and MFC 581

Combining MFC and ATL 581

File Access from ASP Components 584

Creating a Serializable Class 588

Persistence Through Object Serialization 591

20 ASP Components Created with Java 596

Creating Java Components 597

Invoking a COM Object in a Java Component 606

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Table of Contents ix

Working with COM+ Services 611

The ASP Built-in Object and Helper Interfaces 619

Accessing ADO from Java Components 633

21 Creating ASP Components with Delphi 642

Using the COM Wizards to Create ASP Components 642

Manually Adding Support for COM+/ASP 653

Working with the ASP Objects 660

Working with ADO 668

Working with Windows 2000 Functionality: CDO 672

22 Perl-Based Components Using ActiveState’s PDK 677

Setting Up PDK 678

Building a Basic Perl Component 679

Working with Data 709

Working with the Win2K Environment 716

23 Creating Scripting Language Components 719

The Windows Script Components Architecture 719

Elements of a WSC File 722

Script Components and ADO 733

The WSC Wizard 736

Creating Script Components with JScript 741

Accessing Windows 2000 Functionality 744

A ASP Built-in Object Quick Reference 751

B The Weaver Database 776

Index 791

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ASP components are nothing more than specific types of COM-based nents; that is, they’re COM components designed to interface with Active ServerPages and, most commonly, with Microsoft’s Internet Information Server (IIS).Consequently, you need to develop a certain level of familiarity with COM, theComponent Object Model that underlies much of Microsoft’s technology Becom-ing familiar with COM development in turn requires that you become familiar withthreads, so that you can understand how a COM component interacts with a cli-ent as well as the performance issues involved with clients and components thatare based on different threading models.

Once you’ve become familiar with working with a tool that supports COM nent development and you’re aware of some of the issues involved with COMdevelopment, you still have other new technologies to learn As you develop ASPcomponents, you need to become familiar with web-based development in gen-eral and with the ASP environment in particular The way in which your compo-nents interact with the “world” they find themselves in—with the web server, thebrowser, or the web page reader—occurs through built-in objects that Microsofthas provided for ASP development

compo-Originally, the built-in objects could only be instantiated based on specific eventhandlers In IIS 4.0, however, the built-in objects could be accessed from MicrosoftTransaction Server (MTS) objects And now, in IIS 5.0, the ASP built-in objects can

be accessed from COM+ objects In addition, COM+ Services provides a number of

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pool-to need pool-to become familiar with COM+ as well.

This seems like a very formidable list of tools and technologies, and it is Butwe’re not finished yet Most applications—including more and more ASP applica-tions—require some form of data access If you need to provide support for dataaccess, then you need to become familiar with ActiveX Data Objects (ADO), thedata access technology from Microsoft that’s built on top of OLE DB Frequently,the content of an ASP page is assembled from data found in a message store, orconversely the data gathered from the user’s interaction with an ASP page is sent

in an email or placed in a message store For applications such as these, you need

to become familiar with Collaborative Data Objects for Windows 2000 (CDO).Under Windows 2000 and IIS, a good deal of system information is stored inActive Directory; to retrieve information from and write information to ActiveDirectory, you should know the Active Directory Service Interface (ADSI) Finally,ASP applications, and particularly ASP e-commerce applications, often requirecommunication across systems and involve events that can occur at different times(as, for example, when a user orders products online and a pick list is needed by

a system in the warehouse for printing) To take advantage of such loosely pled events, you should be familiar with Microsoft Message Queue (MSMQ).Finally, once you know the programming language used for the component, thetool used to build the component, the implications of developing a COM-basedcomponent, the functionality available through built-in and COM+–suppliedobjects, and how you can access data and the other services needed by yourapplication, then and only then you can take on the functionality that your com-ponent needs to provide Then, you add additional functionality such as file inputand output, object serialization, access to other Windows functionality, and so on

cou-So, do you feel tired before you even start? Well, I want to tell you that ing ASP components really isn’t all that bad, and in fact, you are about to start hav-ing some fun Not only that, you are also going to learn to work with technologythat faces directly on that road racing to the future: the road to distributed andcomponent-based development

develop-This book introduces you to working with COM development as well as workingwith threads and those pesky little “not threads, not processes”—apartments Italso provides an overview of the ASP operating environment as well as somethings you need to know about COM+ and how to work with it Finally, to com-plete this environment overview, the book explores the interaction between thecomponent and the script used to instantiate and invoke the methods of that com-ponent

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Who This Book Is For

This book is geared to the developer who has worked with one of the target guages/tools but either has not created COM objects before or has not workedwith developing ASP components or ASP applications I hope that the book pro-vides enough of an introduction to COM and threads to make you feel more com-fortable with these topics if you haven’t worked with them before and to provide agood review if you have The book does not provide an exhaustive overview ofCOM+ and developing COM+ components but does provide, again, enough of anoverview so you feel comfortable working as a developer in a COM+ environ-ment

lan-The book also provides a comprehensive overview of the ASP component ronment, including using tools and wizards in each language/tool to assist in creat-ing the components, and covering every aspect of accessing the built-in ASPcomponents essential for your development effort In addition, the book also pro-vides good coverage of data access using ADO, messaging using CDO for Win-dows 2000, and message queuing using MSMQ

envi-How This Book Is Structured

Informally, this book is divided into four parts The first part introduces ASP ponent development and covers topics that are of concern to all component devel-opers, regardless of the language they use This part consists of six chapters

com-Chapter 1, Writing ASP Components, examines some of the reasons that you'd

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components Chapter 2, Setting Up the ASP Development Environment, examines

how to set up your development environment to insure that you can develop withmaximum productivity and that your testing doesn't impact on a production sys-tem In addition, the chapter covers programmatic administration of IIS using

Active Directory and the IIS Admin Objects Chapter 3, ASP Components and COM,

examines Microsoft's Component Object Model (COM), which provides the basis

for developing all types of components Chapter 4, ASP Components, Threads, and

Contexts, provides developers with the information that they need to know about

threading models when developing ASP components, and particularly whenaccessing global data from the ASP Application object It also examines the notion

of context (a grouping of objects that share the same requirements), an standing of which is essential to working successfully with COM+ Chapter 5,

under-COM+ Services and ASP Components and Applications, examines the new

inter-faces supported by COM+, shows how components written to take advantage ofCOM+'s predecessor, Microsoft Transaction Server (MTS), can be ported to COM+,

and examines range of services provided by COM+ Chapter 6, ASP Interaction:

Scripting and ASP Components, covers an often-neglected component ment topic: your component may be accessed by any of a number of scripting lan-guages—VBScript, JScript, PerlScript, Python, Rexx, etc.—and communicationbetween script and component is often not as seamless as you'd like The chapterlooks at what you can do when developing your ASP component to insure that itcan work with as many scripting languages as possible

develop-The second portion of the book, which consists of seven chapters, focuses oncomponent development using Visual Basic In addition, its chapters serve as akind of model for how to develop ASP components if you're using a high-levellanguage like Visual Basic that masks much of the complexity of COM and COM+

Chapter 7, Creating a Simple Visual Basic ASP Component, introduces Visual Basic

as a tool for ASP component development and examines how to access the ASP

object model from Visual Basic Chapter 8, Creating ASP/ADO Components, looks

at accessing data in heterogeneous sources using ActiveX Data Objects (ADO)

Chapter 9, Creating an ASP Middle Tier with ADO, discusses component design for

multi-tier applications, focusing particularly on the degree of separation betweenthe middle tier and the client tier The remaining chapters focus on individualtechnologies that developers frequently use when creating ASP Components.These include the following:

• XML is discussed in Chapter 10, Server-Side XML Through VB ASP Components.

• Collaborative Data Objects (CDO) for Windows 2000 is covered in Chapter 11,

Take a Message: Accessing CDO from ASP Components.

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Preface xv

• Active Directory is discussed in Chapter 12, Working with Active Directory

from ASP Applications.

• Microsoft Message Queue (MSMQ) is examined in Chapter 13, Working with

MSMQ Components.

The third portion of the book, consisting of six chapters, treats component opment using Visual C++ In addition, its chapters serve as a kind of model forASP component development using a high-level language like Visual C++ that

devel-exposes much of the complexity of COM and COM+ Chapter 14, Creating C++

ASP Components, introduces Visual C++ as a tool for ASP component

develop-ment and examines how to access the ASP intrinsic objects from a Visual C++

component Chapter 15, Adding Data Access to C++ Components with ADO,

exam-ines accessing data in heterogeneous sources using ADO The next three chapterscover the following individual technologies that are often used in developing com-ponents for IIS 5.0:

• Collaborative Data Objects (CDO) for Windows 2000 is covered in Chapter 16,

The CDO Interfaces from C++ Components.

• Active Directory is discussed in Chapter 17, Accessing Active Directory from

C++ Components.

• Microsoft Message Queue (MSMQ) is examined in Chapter 18, Accessing

MSMQ from C++ ASP Components.

Finally, coverage of Visual C++ and ASP component development ends with

Chapter 19, Persistence with ASP Components Using ATL and MFC, which

dis-cusses ways in which your component can save its data to the filesystem

The final portion of this book features individual chapters on component ment using the following programming languages and environments:

develop-• Java is covered in Chapter 20, ASP Components Created with Java.

• Delphi is discussed in Chapter 21, Creating ASP Components with Delphi.

• Perl is covered in Chapter 22, Perl-Based Components Using ActiveState’s PDK.

• Windows Script Components (WSC), a scriptable yet powerful development

environment for creating ASP components, is discussed in Chapter 23,

Creat-ing ScriptCreat-ing Language Components.

Finally, the book includes two appendixes Appendix A, ASP Built-in Object Quick

Reference, provides a handy guide to the objects, properties, methods, and events

of the ASP object model Appendix B, The Weaver Database, examines the tables

contained in the sample Weaver database, which is used in the book's examples

It can be downloaded from http://vb.oreilly.com.

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xvi Preface

Obtaining the Sample Code

All of the example source code from Developing ASP Components, Second Edition,

along with the sample Weaver database discussed in Appendix A, is freely

down-loadable from the O’Reilly & Associates web site at http://vb.oreilly.com Just low the link to the book’s title page, then click on the Examples link.

fol-Conventions Used in This Book

Throughout this book, we have used the following typographic conventions:

Italic

Represents intrinsic and application-defined functions, the names of systemelements such as directories and files, and Internet resources such as web doc-uments New terms are also italicized when they are first introduced

Constant width

Indicates a language construct such as a language statement, a constant, or anexpression Interface names appear in constant width Lines of code alsoappear in constant width, as do function and method prototypes

Constant width italic

Indicates replaceable parameter names in prototypes or command syntax andindicates variable and parameter names in body text

Indicates a note or tip.

Indicates a warning.

Comments and Questions

Please address comments and questions concerning this book to the publisher:O’Reilly & Associates, Inc

101 Morris Street

Sebastopol, CA 95472

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Acknowledgments

I want to thank the book’s tech reviewers, Daniel Creeron and Matt Childs, fortheir thorough reviews and helpful comments I also want to thank Bob Herbst-man and Tatiana Diaz, members of the O’Reilly editorial staff, for their hard workand dedication to this project

I also want to thank my long-suffering editor, Ron Petrusha This is the second tion of this particular book, and he’s done a terrific job of editing both of them Ialso want to thank my coworkers at Skyfish.com for being a terrific group of peo-ple Specifically, I want to thank a certain group of Australians in the company—guys, the best to you all, and may your dreams find you

edi-Finally, thanks to my readers—I’m here because you’re here

Tiêu đề	Developing asp components
Tác giả	Shelley Powers
Người hướng dẫn	Ron Petrusha
Trường học	O'Reilly & Associates, Inc.
Thể loại	sách
Năm xuất bản	2001
Thành phố	Sebastopol

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Số trang	40
Dung lượng	888,13 KB