require 'rexml/functions'
require 'rexml/xpath_parser'
module REXML
# Wrapper class. Use this class to access the XPath functions.
class XPath
include Functions
# 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.
EMPTY_HASH = {}
# 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"})
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
# 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| ... }
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
# Returns an array of nodes matching a given XPath.
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
end
end
