Namespaces¶

XML namespaces prevent naming conflicts by qualifying element and attribute names with a URI.

Reading Namespaces¶

doc = XML::Parser.string('<root xmlns:dc="http://purl.org/dc/elements/1.1/"/>').parse
node = doc.root

node.namespaces.each do |ns|
  puts "#{ns.prefix}: #{ns.href}"
end

Namespace Properties¶

ns = node.namespaces.first
ns.prefix     # => "dc" (nil for default namespace)
ns.href       # => "http://purl.org/dc/elements/1.1/"

Default Namespace¶

doc = XML::Parser.string('<root xmlns="http://example.com"/>').parse
ns = doc.root.namespaces.default
ns.href       # => "http://example.com"

XPath with Namespaces¶

Default namespaces require a prefix when using XPath. See XPath for details.

doc.find('//ns:element', 'ns:http://example.com')

Setting a Default Prefix¶

To simplify XPath queries on documents with a default namespace:

doc.root.namespaces.default_prefix = 'ns'
doc.find('//ns:element')