class REXML::XPath

Wrapper class. Use this class to access the XPath functions.

Constants

EMPTY_HASH: A base Hash object, supposing to be used when initializing a default empty namespaces set, but is currently unused. TODO: either set the namespaces=EMPTY_HASH, or deprecate this.

Public Class Methods

each(element, path=nil, namespaces=nil, variables={}) click to toggle source

Iterates over nodes that match the given path, calling the supplied block with the match.

element: The context element
path: The xpath to search for. If not supplied or nil, defaults to '*'
namespaces: If supplied, a Hash which defines a namespace mapping
variables: If supplied, a Hash which maps $variables in the query to values. This can be used to avoid XPath injection attacks or to automatically handle escaping string values.

XPath.each( node ) { |el| ... }
XPath.each( node, '/*[@attr='v']' ) { |el| ... }
XPath.each( node, 'ancestor::x' ) { |el| ... }
XPath.each( node, '/book/publisher/text()=$publisher', {}, {"publisher"=>"O'Reilly"}) \
  {|el| ... }

# File lib/rexml/xpath.rb, line 59
def XPath::each element, path=nil, namespaces=nil, variables={}, &block
  raise "The namespaces argument, if supplied, must be a hash object." unless namespaces.nil? or namespaces.kind_of?(Hash)
  raise "The variables argument, if supplied, must be a hash object." unless variables.kind_of?(Hash)
  parser = XPathParser.new
  parser.namespaces = namespaces
  parser.variables = variables
  path = "*" unless path
  element = [element] unless element.kind_of? Array
  parser.parse(path, element).each( &block )
end

first(element, path=nil, namespaces=nil, variables={}) click to toggle source

Finds and returns the first node that matches the supplied xpath.

element: The context element
path: The xpath to search for. If not supplied or nil, returns the first node matching '*'.
namespaces: If supplied, a Hash which defines a namespace mapping.
variables: If supplied, a Hash which maps $variables in the query to values. This can be used to avoid XPath injection attacks or to automatically handle escaping string values.

XPath.first( node )
XPath.first( doc, "//b"} )
XPath.first( node, "a/x:b", { "x"=>"http://doofus" } )
XPath.first( node, '/book/publisher/text()=$publisher', {}, {"publisher"=>"O'Reilly"})

# File lib/rexml/xpath.rb, line 30
def XPath::first element, path=nil, namespaces=nil, variables={}
  raise "The namespaces argument, if supplied, must be a hash object." unless namespaces.nil? or namespaces.kind_of?(Hash)
  raise "The variables argument, if supplied, must be a hash object." unless variables.kind_of?(Hash)
  parser = XPathParser.new
  parser.namespaces = namespaces
  parser.variables = variables
  path = "*" unless path
  element = [element] unless element.kind_of? Array
  parser.parse(path, element).flatten[0]
end

match(element, path=nil, namespaces=nil, variables={}) click to toggle source

Returns an array of nodes matching a given XPath.

# File lib/rexml/xpath.rb, line 71
def XPath::match element, path=nil, namespaces=nil, variables={}
  parser = XPathParser.new
  parser.namespaces = namespaces
  parser.variables = variables
  path = "*" unless path
  element = [element] unless element.kind_of? Array
  parser.parse(path,element)
end