module Nokogiri::XML::Searchable

The Searchable module declares the interface used for searching your DOM.

It implements the public methods `search`, `css`, and `xpath`, as well as allowing specific implementations to specialize some of the important behaviors.

Constants

LOOKS_LIKE_XPATH

Regular expression used by #search to determine if a query string is CSS or XPath

Public Instance Methods

%(*args)
Alias for: at
/(*args)
Alias for: search
search *paths, [namespace-bindings, xpath-variable-bindings, custom-handler-class] click to toggle source

Search this object for paths, and return only the first result. paths must be one or more XPath or CSS queries.

See #search for more information.

# File lib/nokogiri/xml/searchable.rb, line 66
def at *args
  search(*args).first
end
Also aliased as: %
css *rules, [namespace-bindings, custom-pseudo-class] click to toggle source

Search this object for CSS rules, and return only the first match. rules must be one or more CSS selectors.

See #css for more information.

# File lib/nokogiri/xml/searchable.rb, line 117
def at_css *args
  css(*args).first
end
xpath *paths, [namespace-bindings, variable-bindings, custom-handler-class] click to toggle source

Search this node for XPath paths, and return only the first match. paths must be one or more XPath queries.

See #xpath for more information.

# File lib/nokogiri/xml/searchable.rb, line 164
def at_xpath *args
  xpath(*args).first
end
css *rules, [namespace-bindings, custom-pseudo-class] click to toggle source

Search this object for CSS rules. rules must be one or more CSS selectors. For example:

node.css('title')
node.css('body h1.bold')
node.css('div + p.green', 'div#one')

A hash of namespace bindings may be appended. For example:

node.css('bike|tire', {'bike' => 'http://schwinn.com/'})

Custom CSS pseudo classes may also be defined. To define custom pseudo classes, create a class and implement the custom pseudo class you want defined. The first argument to the method will be the current matching NodeSet. Any other arguments are ones that you pass in. For example:

node.css('title:regex("\w+")', Class.new {
  def regex node_set, regex
    node_set.find_all { |node| node['some_attribute'] =~ /#{regex}/ }
  end
}.new)

Note that the CSS query string is case-sensitive with regards to your document type. That is, if you're looking for “H1” in an HTML document, you'll never find anything, since HTML tags will match only lowercase CSS queries. However, “H1” might be found in an XML document, where tags names are case-sensitive (e.g., “H1” is distinct from “h1”).

# File lib/nokogiri/xml/searchable.rb, line 104
def css *args
  rules, handler, ns, _ = extract_params(args)

  css_internal self, rules, handler, ns
end
xpath *paths, [namespace-bindings, variable-bindings, custom-handler-class] click to toggle source

Search this node for XPath paths. paths must be one or more XPath queries.

node.xpath('.//title')

A hash of namespace bindings may be appended. For example:

node.xpath('.//foo:name', {'foo' => 'http://example.org/'})
node.xpath('.//xmlns:name', node.root.namespaces)

A hash of variable bindings may also be appended to the namespace bindings. For example:

node.xpath('.//address[@domestic=$value]', nil, {:value => 'Yes'})

Custom XPath functions may also be defined. To define custom functions create a class and implement the function you want to define. The first argument to the method will be the current matching NodeSet. Any other arguments are ones that you pass in. Note that this class may appear anywhere in the argument list. For example:

node.xpath('.//title[regex(., "\w+")]', Class.new {
  def regex node_set, regex
    node_set.find_all { |node| node['some_attribute'] =~ /#{regex}/ }
  end
}.new)
# File lib/nokogiri/xml/searchable.rb, line 151
def xpath *args
  paths, handler, ns, binds = extract_params(args)

  xpath_internal self, paths, handler, ns, binds
end

Private Instance Methods

css_internal(node, rules, handler, ns) click to toggle source
# File lib/nokogiri/xml/searchable.rb, line 170
def css_internal node, rules, handler, ns
  xpath_internal node, css_rules_to_xpath(rules, ns), handler, ns, nil
end
css_rules_to_xpath(rules, ns) click to toggle source
# File lib/nokogiri/xml/searchable.rb, line 201
def css_rules_to_xpath(rules, ns)
  rules.map { |rule| xpath_query_from_css_rule(rule, ns) }
end
xpath_impl(node, path, handler, ns, binds) click to toggle source
# File lib/nokogiri/xml/searchable.rb, line 189
def xpath_impl node, path, handler, ns, binds
  ctx = XPathContext.new(node)
  ctx.register_namespaces(ns)
  path = path.gsub(/xmlns:/, ' :') unless Nokogiri.uses_libxml?

  binds.each do |key,value|
    ctx.register_variable key.to_s, value
  end if binds

  ctx.evaluate(path, handler)
end
xpath_internal(node, paths, handler, ns, binds) click to toggle source
# File lib/nokogiri/xml/searchable.rb, line 174
def xpath_internal node, paths, handler, ns, binds
  document = node.document
  return NodeSet.new(document) unless document

  if paths.length == 1
    return xpath_impl(node, paths.first, handler, ns, binds)
  end

  NodeSet.new(document) do |combined|
    paths.each do |path|
      xpath_impl(node, path, handler, ns, binds).each { |set| combined << set }
    end
  end
end
xpath_query_from_css_rule(rule, ns) click to toggle source
# File lib/nokogiri/xml/searchable.rb, line 205
def xpath_query_from_css_rule rule, ns
  self.class::IMPLIED_XPATH_CONTEXTS.map do |implied_xpath_context|
    CSS.xpath_for(rule.to_s, :prefix => implied_xpath_context, :ns => ns)
  end.join(' | ')
end