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 Searchable#search to determine if a query string is CSS or XPath

Public Instance Methods

search *paths, [namespace-bindings, xpath-variable-bindings, custom-handler-class]
Alias for: at
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 Searchable#search for more information.

# File lib/nokogiri/xml/searchable.rb, line 70
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 Searchable#css for more information.

# File lib/nokogiri/xml/searchable.rb, line 122
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 Searchable#xpath for more information.

# File lib/nokogiri/xml/searchable.rb, line 169
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 109
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 156
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

@!endgroup

# File lib/nokogiri/xml/searchable.rb, line 177
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 208
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 196
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 181
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 212
def xpath_query_from_css_rule(rule, ns)
  visitor = Nokogiri::CSS::XPathVisitorOptimallyUseBuiltins.new
  self.class::IMPLIED_XPATH_CONTEXTS.map do |implied_xpath_context|
    CSS.xpath_for(rule.to_s, {:prefix => implied_xpath_context, :ns => ns,
                              :visitor => visitor})
  end.join(" | ")
end