Mining eBay web services

Mining eBay Web Services:

Building Applications with the eBay API

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John Paul Mueller

Mining eBay Web Services:

Building Applications with the eBay API

San Francisco • London

Sybex

®

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Associate Publisher: Joel Fugazzotto

Acquisitions and Developmental Editor: Tom Cirtin

Production Editor: Leslie E.H. Light

Technical Editor: Russ Mullen

Copyeditor: Cheryl Hauser

Compositor: Happenstance Type-O-Rama

Graphic Illustrator: Happenstance Type-O-Rama

Proofreaders: Laurie O’Connell, Nancy Riddiough

Indexer: Lynnzee Elze

Cover Design and Illustration: Richard Miller, Calyx Design

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Library of Congress Card Number: 2004104104

ISBN: 0-7821-4339-3

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This book is dedicated to Matt Wagner—a source

of encouragement in troubled times and a voice of

reason when things go wrong, a friend in

weather foul and fair.

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Acknowledgments

T

hanks to my wife, Rebecca, for working with me to get this book completed. I really don’t

know what I would have done without her help in researching and compiling some of the

information that appears in this book. She also did a fine job of proofreading my rough draft

and page proofing the result.

Russ Mullen deserves thanks for his technical edit of this book. He greatly added to the

accuracy and depth of the material you see here. Russ is always providing me with great URLs

for new products and ideas. I also appreciated his hard work in testing endless versions of

applications and providing input in my ideas. This book is technically challenging in that it

relies on a number of programming languages, new and evolving technology, and several new

products. Russ met the challenge with an efficiency that few other people could match.

eBay was very helpful in putting this book together. I don’t know everyone from eBay who

worked on this book, but I can thank those that I do know by name. Gary Downing made

many introductions and acted as eBay’s ambassador for the book. Michael Knopp provided a

great many helpful comments and personal insights into eBay. I know that the book is much

better for all of the help I received from these and other individuals from eBay.

A number of people read all or part of this book to help me refine the approach and to test

the examples on a number of systems. These unpaid volunteers helped in ways too numerous

to mention here. I especially appreciate the efforts of Eva Beattie who read the entire book

and selflessly devoted herself to this project. Mike and Jody Cummings of The Treasure Mill

provided me with training on using eBay in a real world business environment, helped me

understand some of the nuances of the bidding process, and generally provided their expertise

on a decidedly complex environment. Alessandro Vernet provided a variety of helpful tips

and hints. Osvaldo Téllez Almirall provided extensive input on international issues, making

the book much better suited to international needs as a result. David Clark helped with

accessibility, user interface, and PHP development issues.

Matt Wagner, my agent, deserves credit for helping me get the contract in the first place

and taking care of all the details that most authors don’t really consider. I always appreciate

his help. It’s good to know that someone wants to help.

Finally, I would like to thank Tom Cirtin, Leslie Light, Cheryl Hauser, and the rest of the

editorial and production staff at Sybex for their assistance in bringing this book to print. It’s

always nice to work with such a great group of professionals and I very much appreciate the

friendship we have built over the last three books.

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Contents at a Glance

Introduction xx

Part I Discovering eBay Web Services 1

Chapter 1: Learning about eBay Web Services 3

Chapter 2: Using eBay Web Services to Your Advantage 25

Chapter 3: Defining a Search 47

Chapter 4: Working with Web Service Data 63

Part II Writing eBay Web Services Programs 95

Chapter 5: Starting the Development Process 97

Chapter 6: Writing Browser-Based Applications 121

Chapter 7: Writing Applications Using VBA 143

Chapter 8: Writing Applications Using Visual Studio 171

Chapter 9: Writing Applications Using PHP 215

Chapter 10: Writing Applications Using Java 239

Chapter 11: Writing Applications for Mobile Devices 261

Part III Refining Your eBay Web Services Program 281

Chapter 12: Crafting Your Application 283

Chapter 13: Considering User Needs 297

Chapter 14: Other Refinements You Should Consider 313

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Appendices

Appendix A: Helpful Third Party Resource Sites 331

Appendix B: eBay License Checklist 337

Appendix C: Late Breaking eBay Web Services News 345

Glossary 359

Index 381

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Contents

Introduction xx

Part I Discovering eBay Web Services 1

Chapter 1 Learning about eBay Web Services 3

Understanding the eBay Web Services 4

What Is a Web Service? 4

How Do Web Services Work? 6

Considering the Usage Requirements 7

What Is Sandbox Mode? 9

Discovering Uses for the eBay Web Services 9

Buying Products 10

Selling and Relisting Products 10

Determining Product Facts 11

Discovering Product Payment and Shipping Methods 12

Giving and Receiving Feedback 12

Learning about a Store 13

Working with User Information 13

Performing Research 13

Creating an Offline Archive 14

Downloading and Installing the Kit 15

Determining Which Licensing Level Is Best 15

Becoming an eBay Developer Program Member 17

Obtaining Your License 18

Performing the Download 18

Installing the Kit 18

System Setup Considerations 20

Understanding Connectivity Requirements 20

Programming Setups for the Non-Developer 21

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Contents ❘ xiii

Considering the User 22

Using Multiple Test Devices 23

Emulating the Real World 24

Your Call to Action 24

Chapter 2 Using eBay Web Services to Your Advantage 25

Knowing What to Expect As Output 26

Limitations of eBay Web Services Output 26

Making Sensible Queries 29

Defining Static and Dynamic Data 30

Understanding the Certification Requirements 31

Creating a Test User 32

Working in Sandbox Mode 34

Getting Your Application Certified 35

Working with Some Simple Examples 37

Understanding the Example Types 37

Using a Browser Example 38

Viewing the XSLT Example 39

Viewing the Desktop Example 40

Viewing the Pocket PC Example 41

Manipulating Data to Meet Specific Needs 42

Understanding Data Transformation Requirements 43

Viewing the eBay Examples 44

Using the PERL Example 44

Your Call to Action 46

Chapter 3 Defining a Search 47

Performing a Typical Search 48

Adding Search Conditions 50

Using an Advanced Search 50

Using Other Special Search Techniques 52

Considering the URL Search Form 55

Understanding the Developer Search Options 58

Changing the Presentation 59

Localizing the Information 60

Your Call to Action 60

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xiv ❘ Contents

Chapter 4 Working with Web Service Data 63

Understanding XML Basics 64

Defining the Parts of an XML Message 65

Viewing XML Data in Your Browser 66

Getting XML Data Tools 68

Sending Special Characters Using URL Encoding 72

Learning More about XML 75

Using XSLT for Presentation 76

Using a Script to Call an XSLT Page 76

Understanding How XSLT Works 78

Writing a Simple XSLT Page 80

Learning More about XSLT 81

Using the eBay API Test Tool 82

Creating Messages for eBay Using XML 86

Determining Where XML Fits into eBay Web Services 87

Understanding Privacy Issues 88

Privacy Required by the eBay License 89

General User Privacy 90

Understanding Security Issues 90

General Security Issues 90

Using SSL to Contact eBay 91

Security Required by the eBay License 91

Your Call to Action 92

Part II Writing eBay Web Services Programs 95

Chapter 5 Starting the Development Process 97

Choosing a Communication Method 99

Choosing between the API and SDK 99

Using XML over HTTPS 100

Using XSLT 101

Defining the Common Communication Elements 102

Getting a User Token 103

Selecting a Platform 109

Writing Desktop Applications 109

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Contents ❘ xv

Writing Small Form Factor Applications 112

Writing Mixed Environment Applications 114

Selecting a Development Language 115

Choosing a Language that Meets Specific Needs 115

Considering Your Skills and Abilities 116

Defining Language Limitations 116

Understanding Internationalization Issues 117

Learning the Limits of Translation 117

Considering the User’s Location 119

Using the SiteId to Your Advantage 119

Your Call to Action 119

Chapter 6 Writing Browser-Based Applications 121

Using JavaScript to Access eBay Web Services 122

Understanding the Basic Access Technique 123

Modifying the Basic Technique to Use XSLT 127

Modifying the Basic Technique to Perform Authentication 129

Performing a Category Search 136

Developing the Basic Category Search 136

Augmenting the Category Search with XSLT 139

Your Call to Action 140

Chapter 7 Writing Applications Using VBA 143

Understanding the Benefits of Using VBA 143

Resources for Learning VBA 144

Understanding Scripting of Web Services 145

An Alternative to VBA 145

Using the eBay API Test Tool to Authenticate a User 147

Using the Microsoft and eBay Examples 148

Developing with Microsoft Excel 154

Developing an Application with the SDK 155

Developing an Application with the API 160

Using Microsoft Access as a Database 164

Caching as a Practical Performance Enhancing Technique 165

Creating a Cached Application 166

Your Call to Action 169

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