xml.DomDocument.selectByXPath

Returns a DomNodeList object containing all DomNode objects matching a XPath 1.0 expression.

Syntax

selectByXPath(
   expr STRING
   [, args ] )
  RETURNS xml.DomNodeList

expr defines the XPath 1.0 expression.
args is a variable list of parameters that define a list of prefixes bound to namespaces to resolve qualified names in the XPath expression.

Usage

This method returns a DomNodeList object containing all DomNode objects matching an XPath 1.0 expression.

Important:

This method is not part of W3C standard API.

args is a variable list of parameters that define a list of prefix/namespace pairs used to resolve qualified names in the XPath expression. You must provide an even number of parameters, where each set of two parameters represent a prefix (alias) and its corresponding namespace:

selectByXPath( expr,
  "prefix-1", "namespace-1",
  "prefix-2", "namespace-2",
  "prefix-3", "namespace-3",
  ... )

A namespace must be an absolute URI; for example, 'http://' or 'file://'.

If args is NULL, the prefixes and namespaces defined in the document itself are used when available:

selectByXPath( expr, NULL )

If the XML document uses a default namespace without a prefix, you must provide a prefix in the selectByXPath() expression. In this example, the xmlns attribute in the XML document HTML tag does not have a prefix.

<html lang="en" xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">

In this case, the search for the tag name FORM with the attribute NAME equal to "login" with args NULL in the example will not be found because the namespace does not have a prefix.

selectByXPath('//FORM[@NAME="login"]',NULL)

Instead you must provide a prefix for the namespace; it can be any name, it does not have to be "alias" as in the example. You specify the prefix and namespace in the args parameter of the selectByXPath() similar to this:

selectByXPath('//alias:FORM[@NAME="login"]',"alias","http://www.w3.org/1999/xhtml")

In case of error, the method throws an exception and sets the status variable. Depending on the error, a human-readable description of the problem is available in the sqlca.sqlerrm register. See Error handling in GWS calls (status).

Example

selectByXPath( "../../d:Record/*[last()]", 
  "d", "http://defaultnamespace" )

selectByXPath( "ns:Record", NULL )

selectByXPath( "ns1:Records/ns2:Record", 
  "ns1", "http://namespace1",
  "ns2", "http://namespace2" )

Invalid example:

selectByXPath( "ns1:Record", "ns1" )