fn:base-uri

base-uri() ➔ xs:anyURI?

Returns the base URI of the context node.

There are no arguments
Result		xs:anyURI?

base-uri($arg as node()?) ➔ xs:anyURI?

Returns the base URI of a specified node.

Arguments
	$arg	node()?	The node whose base URI is required
Result		xs:anyURI?

Namespace

http://www.w3.org/2005/xpath-functions

Links to W3C specifications

XPath 3.1 Functions and Operators

Saxon availability

Available in XPath 2.0, XSLT 2.0, XQuery 1.0, and later versions. Available in all Saxon editions. Available for all platforms.

Details

If a node is supplied to Saxon as a JAXP Source object, then the base URI of the document node will be the value returned by the method Source.getSystemId(). The base URI of other nodes within the document may differ from this for either of two reasons:

An xml:base attribute may be present on an element to identify the base URI for that element and its contained subtree.
In the case of documents delivered by a SAX parser, the base URI of nodes constructed from the content of an external entity will reflect the location of that entity.

It is possible for the base URI of a document to be absent (unknown). This happens when the document is supplied to Saxon with no location information: for example when the node is represented using a tree model such as DOM that has no base URI information; or when a Source is supplied for which getSystemId() returns null. The most common example of this is a Source created using new StreamSource(new FileInputStream("input.xml")). The problem can be fixed by using the second argument of the StreamSource constructor, or by using the constructor that expects a File rather than an InputStream.

If the base URI is absent, the base-uri() function returns an empty sequence. No error occurs unless an operation is needed that requires a base URI, for example using the base URI as an argument of resolve-uri().