XML - XML Base

What XML Base Is

  • XML Base is a W3C specification that allows you to define a base URI for relative links inside an XML document.

  • It uses the attribute xml:base.

  • Any relative URI in the document will be resolved using this base.

Why It’s Useful

  • Makes it easier to manage links in XML documents.

  • Instead of writing full absolute URLs everywhere, you set a base once and then use shorter relative paths.

  • If the base changes, you only update it in one place.

Example

<books xml:base="http://example.com/library/">
  <book href="book1.xml">XML Guide</book>
  <book href="book2.xml">Advanced XML</book>
</books>

How links resolve:

  • book1.xml → http://example.com/library/book1.xml

  • book2.xml → http://example.com/library/book2.xml

Key Points

  • Attribute: xml:base="URI"

  • It can be applied at any element, and child elements will inherit it (unless overridden).

  • Useful in XML vocabularies like XLink, RDF, and SVG, where links often appear.

In Short

XML Base = a way to define a base URI inside an XML document so that relative links can be resolved consistently.