Perl and XML: XML Processing with Perl

XML is a text-based markup language that has taken the programming world by storm. More powerful than HTML yet less demanding than SGML, XML has proven itself to be flexible and resilient. XML is the perfect tool for formatting documents with even the smallest bit of complexity, from Web pages to legal contracts to books. However, XML has also proven itself to be indispensable for organizing and conveying other sorts of data as well, thus its central role in web services like SOAP and XML-RPC. As the Perl programming language was tailor-made for manipulating text, few people have disputed the fact that Perl and XML are perfectly suited for one another. The only question has been what's the best way to do it. That's where this book comes in. Perl & XML is aimed at Perl programmers who need to work with XML documents and data. The book covers all the major modules for XML processing in Perl, including XML::Simple, XML::Parser, XML::LibXML, XML::XPath, XML::Writer, XML::Pyx, XML::Parser::PerlSAX, XML::SAX, XML::SimpleObject, XML::TreeBuilder, XML::Grove, XML::DOM, XML::RSS, XML::Generator::DBI, and SOAP::Lite. But this book is more than just a listing of modules; it gives a complete, comprehensive tour of the landscape of Perl and XML, making sense of the myriad of modules, terminology, and techniques. This book covers: * parsing XML documents and writing them out again * working with event streams and SAX * tree processing and the Document Object Model * advanced tree processing with XPath and XSLT Most valuably, the last two chapters of Perl & XML give complete examples of XML applications, pulling together all the tools at your disposal. All together, Perl & XML is the single book that gives you a solid grounding in XML processing with Perl. Table of Contents 3 Preface 5 Assumptions 5 How This Book Is Organized 5 Resources 6 Font Conventions 6 How to Contact Us 6 Acknowledgments 7 1. Perl and XML 8 1.1 Why Use Perl with XML? 8 1.2 XML Is Simple with XML::Simple 8 1.3 XML Processors 11 1.4 A Myriad of Modules 12 1.5 Keep in Mind... 12 1.6 XML Gotchas 13 2. An XML Recap 15 2.1 A Brief History of XML 15 2.2 Markup, Elements, and Structure 17 2.3 Namespaces 19 2.4 Spacing 20 2.5 Entities 21 2.6 Unicode, Character Sets, and Encodings 23 2.7 The XML Declaration 23 2.8 Processing Instructions and Other Markup 23 2.9 Free-Form XML and Well-Formed Documents 25 2.10 Declaring Elements and Attributes 26 2.11 Schemas 26 2.12 Transformations 28 3. XML Basics: Reading and Writing 32 3.1 XML Parsers 32 3.2 XML::Parser 38 3.3 Stream-Based Versus Tree-Based Processing 42 3.4 Putting Parsers to Work 43 3.5 XML::LibXML 45 3.6 XML::XPath 47 3.7 Document Validation 48 3.8 XML::Writer 50 3.9 Character Sets and Encodings 54 4. Event Streams 59 4.1 Working with Streams 59 4.2 Events and Handlers 59 4.3 The Parser as Commodity 61 4.4 Stream Applications 61 4.5 XML::PYX 62 4.6 XML::Parser 64 5. SAX 68 5.1 SAX Event Handlers 68 5.2 DTD Handlers 74 5.3 External Entity Resolution 77 5.4 Drivers for Non-XML Sources 78 5.5 A Handler Base Class 80 5.6 XML::Handler::YAWriter as a Base Handler Class 81 5.7 XML::SAX: The Second Generation 82 6. Tree Processing 94 6.1 XML Trees 94 6.2 XML::Simple 95 6.3 XML::Parser's Tree Mode 97 6.4 XML::SimpleObject 98 6.5 XML::TreeBuilder 100 6.6 XML::Grove 102 7. DOM 104 7.1 DOM and Perl 104 7.2 DOM Class Interface Reference 104 7.3 XML::DOM 111 7.4 XML::LibXML 113 8. Beyond Trees: XPath, XSLT, and More 116 8.1 Tree Climbers 116 8.2 XPath 118 8.3 XSLT 125 8.4 Optimized Tree Processing 127 9. RSS, SOAP, and Other XML Applications 129 9.1 XML Modules 129 9.2 XML::RSS 130 9.3 XML Programming Tools 136 9.4 SOAP::Lite 138 10. Coding Strategies 141 10.1 Perl and XML Namespaces 141 10.2 Subclassing 143 10.3 Converting XML to HTML with XSLT 148 10.4 A Comics Index 155 Colophon 158 XML processing with Perl XML is a text-based markup language that has taken the programming world by storm. More powerful than HTML yet less demanding than SGML, XML has proven itself to be flexible and resilient. XML is the perfect tool for formatting documents with even the smallest bit of complexity, from Web pages to legal contracts to books. However, XML has also proven itself to be indispensable for organizing and conveying other sorts of data as well, thus its central role in web services like SOAP and XML-RPC.As the Perl programming language was tailor-made for manipulating text, few people have disputed the fact that Perl and XML are perfectly suited for one another. The only question has been what's the best way to do it. That's where this book comes in.Perl & XML is aimed at Perl programmers who need to work with XML documents and data. The book covers all the major modules for XML processing in Perl, including XML::Simple, XML::Parser, XML::LibXML, XML::XPath, XML::Writer, XML::Pyx, XML::Parser::PerlSAX, XML::SAX, XML::SimpleObject, XML::TreeBuilder, XML::Grove, XML::DOM, XML::RSS, XML::Generator::DBI, and SOAP::Lite. But this book is more than just a listing of modules; it gives a complete, comprehensive tour of the landscape of Perl and XML, making sense of the myriad of modules, terminology, and techniques.This book covers:parsing XML documents and writing them out againworking with event streams and SAXtree processing and the Document Object Modeladvanced tree processing with XPath and XSLTMost valuably, the last two chapters of Perl & XML give complete examples of XML applications, pulling together all the tools at your disposal. All together, Perl & XML is the single book that gives you a solid grounding in XML processing with Perl. Written for Perl programmers who need to work with XML documents and data, this handbook offers a comprehensive tour of the landscape of Perl and XML, and its myriad modules, terminology, and techniques Discusses topics including parsing and validating XML documents in Perl, working with event streams, XML document trees, the Document Object Model, and turning arbitrary data sources into XML.