Class: REXML::XPath

Inherits:
Object show all
Includes:
Functions
Defined in:
lib/rexml/xpath.rb

Overview

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

Constant Summary collapse

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.

{}

Class Method Summary collapse

Methods included from Functions

boolean, ceiling, compare_language, concat, contains, context=, count, false, floor, get_namespace, id, lang, last, local_name, method_missing, name, namespace_context, namespace_context=, namespace_uri, normalize_space, not, number, position, processing_instruction, round, starts_with, string, string_length, string_value, substring, substring_after, substring_before, sum, text, translate, true, variables, variables=

Class Method Details

.each(element, path = nil, namespaces = nil, variables = {}, &block) ⇒ Object

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| ... }

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# File 'lib/rexml/xpath.rb', line 60

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 = {}) ⇒ Object

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"})

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# File 'lib/rexml/xpath.rb', line 31

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 = {}) ⇒ Object

Returns an array of nodes matching a given XPath.


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# File 'lib/rexml/xpath.rb', line 72

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