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Subjects

JAVASCRIPTHTMLCSSPYTHONSQLJAVACPPCSHARPPHPTYPESCRIPTCRUBYGOSWIFTKOTLINRUSTRBASHSCALAOBJECTIVE-CDARTPERLLUAMATLABXMLJSONMARKDOWNASSEMBLYLATEXYAMLSOLIDITYBLOCKCHAIN

Topics

XML Basics

Introduction to XMLXML SyntaxXML ElementsXML AttributesXML NamespacesXML CommentsXML CDATA SectionsXML White Space HandlingXML Encoding

XML Document Structure

XML PrologXML Root ElementXML Child ElementsXML Sibling ElementsXML Document TreeXML Well-formednessXML Validity

XML DTD

XML DTD IntroductionXML DTD InternalXML DTD ExternalXML DTD ElementsXML DTD AttributesXML DTD EntitiesXML DTD Notations

XML Schema

XML Schema IntroductionXML Schema Simple TypesXML Schema Complex TypesXML Schema ElementsXML Schema AttributesXML Schema RestrictionsXML Schema FacetsXML Schema Indicators

XML Parsing

XML DOM ParsingXML SAX ParsingXML StAX ParsingXML Pull ParsingXML Parser Validation

XML Transformation

XSLT IntroductionXSLT StylesheetsXSLT TemplatesXSLT ElementsXSLT FunctionsXSLT Sorting and GroupingXPath Expressions in XSLT

XML APIs and Libraries

XML DOM APIXML SAX APIXML JAXPXML JAXBXML XQuery

XML Security

XML EncryptionXML Digital SignaturesXML Security Best Practices

XML in Web Development

XML and AJAXXML and REST APIsXML and SOAP Web ServicesXML RSS FeedsXML Sitemaps

XML Best Practices

XML Naming ConventionsXML Performance OptimizationXML VersioningXML DocumentationXML Error Handling

Advanced XML Concepts

XML Namespaces AdvancedXML XIncludeXML XLinkXML XPointerXML Catalogs

XML White Space Handling

White space handling is a crucial aspect of XML processing. It determines how parsers and applications interpret spaces, tabs, and line breaks within XML documents. Understanding white space handling is essential for maintaining the integrity and readability of your XML data.

What is XML White Space?

In XML, white space refers to any combination of space characters, tab characters, carriage returns, and line feeds. These characters are often used for formatting and improving readability in XML documents. However, their treatment can vary depending on the context and parsing rules.

White Space Preservation vs. Normalization

XML processors handle white space in two primary ways:

  1. White Space Preservation: All white space characters are retained exactly as they appear in the document.
  2. White Space Normalization: Consecutive white space characters are collapsed into a single space, and leading/trailing white space is removed.

Controlling White Space Handling

XML provides mechanisms to control how white space is handled:

1. xml:space Attribute

The xml:space attribute can be used to specify white space handling for specific elements:

<element xml:space="preserve">
    This text   will   retain   all   spaces.
</element>

<element xml:space="default">
    This text will have normalized spaces.
</element>

2. DTD and XML Schema

When using DTDs or XML Schemas, you can define white space handling rules for specific elements:

<!-- In DTD -->
<!ELEMENT pre (#PCDATA)>
<!ATTLIST pre xml:space (preserve) #FIXED "preserve">

<!-- In XML Schema -->
<xs:element name="pre">
  <xs:complexType>
    <xs:simpleContent>
      <xs:extension base="xs:string">
        <xs:attribute ref="xml:space" fixed="preserve"/>
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>
</xs:element>

Best Practices for XML White Space Handling

  • Use xml:space="preserve" for elements where exact white space is significant, such as pre-formatted text or code snippets.
  • Allow default white space normalization for most elements to improve readability and reduce file size.
  • Be consistent with indentation and formatting in your XML documents to enhance human readability.
  • When parsing XML, be aware of how your chosen parser handles white space by default.
  • Document your white space handling expectations, especially for elements where it's critical.

White Space in Different XML Contexts

White space handling can vary depending on the XML context:

Context White Space Handling
Element Content Typically normalized unless specified otherwise
Attribute Values Always normalized
CDATA Sections Preserved
Processing Instructions Preserved
Comments Preserved

Conclusion

Proper white space handling is crucial for maintaining the integrity and intended structure of XML documents. By understanding and effectively using white space preservation and normalization techniques, you can ensure that your XML data is processed correctly and remains human-readable. Remember to consider white space handling when designing your XML schemas and processing workflows.