XInclude

XML Inclusion

Splice a parsed XML document into another with parse="xml"

#XML Inclusion

parse="xml" is the default xi:include mode. The processor fetches the resource named by href, parses it as XML, and splices its document element in place of the xi:include:

xml 
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude"
            href="shared-section.xml"/>

Only the target's document element is spliced in. A comment or a processing instruction that sits outside the target's root element is not included.

#Resolving href

href resolves against the in-scope base URI. That base is the including document's base URI, adjusted by an xml:base attribute on any ancestor element, and by an xml:base attribute on the xi:include element itself.

A fragment identifier in href (a # character) is a fatal error. XInclude 1.0 §4.2 reserves fragments for selecting into the parsed result, not the resource itself. Use the xpointer or fragid attribute instead — see XPointer.

#Cyclic and over-deep inclusion

A resource that includes itself, directly or through a chain of other includes, is a fatal error. The processor tracks every target currently being expanded and rejects a repeat.

Nesting deeper than MaxIncludeDepth is also a fatal error. See Security and Limits for the default and how to change it.

# xml:base and xml:lang fixup (§4.5)

The processor splices a top-level included element into the host document. It then stamps two attributes on that element, unless the element already carries its own:

  • xml:base, set to the resolved target URI. A descendant element that moves with the include still resolves its own relative URIs correctly, because it inherits this stamped xml:base.

  • xml:lang, set to the in-scope xml:lang from the xi:include's ancestor chain, if any is in scope.

Only the top-level included element receives this fixup. A descendant element resolves its base and language through the stamped attribute plus its own existing xml:base/xml:lang chain. This is the normal resolution rule for any XML document.

#Sub-resource selection

An xi:include with an xpointer or fragid attribute selects a subset of the target instead of its whole document element. The same attribute with no href selects from the including document itself. See XPointer for the pointer syntax and evaluation rules.