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#searchto determine if a query string isCSSorXPath
Private Instance Methods
# File lib/nokogiri/xml/searchable.rb, line 210 def css_internal(node, rules, handler, ns) xpath_internal(node, css_rules_to_xpath(rules, ns), handler, ns, nil) end
# File lib/nokogiri/xml/searchable.rb, line 241 def css_rules_to_xpath(rules, ns) rules.map { |rule| xpath_query_from_css_rule(rule, ns) } end
# File lib/nokogiri/xml/searchable.rb, line 229 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 ctx.evaluate(path, handler) end
# File lib/nokogiri/xml/searchable.rb, line 214 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
# File lib/nokogiri/xml/searchable.rb, line 245 def xpath_query_from_css_rule(rule, ns) visitor = Nokogiri::CSS::XPathVisitor.new( builtins: Nokogiri::CSS::XPathVisitor::BuiltinsConfig::OPTIMAL, doctype: document.xpath_doctype, ) 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
Searching via XPath or CSS Queries
↑ topPublic Instance Methods
Search this node’s immediate children using CSS selector selector
# File lib/nokogiri/xml/searchable.rb, line 201 def >(selector) # rubocop:disable Naming/BinaryOperatorParameterName ns = (document.root&.namespaces || {}) xpath(CSS.xpath_for(selector, prefix: "./", ns: ns).first) end
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 74 def at(*args) search(*args).first end
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 143 def at_css(*args) css(*args).first end
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 193 def at_xpath(*args) xpath(*args).first end
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 which are mapped to a custom XPath function. 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 matching context NodeSet. Any other arguments are ones that you pass in. For example:
handler = Class.new { def regex(node_set, regex) node_set.find_all { |node| node['some_attribute'] =~ /#{regex}/ } end }.new node.css('title:regex("\w+")', handler)
💡 Some XPath syntax is supported in CSS queries. For example, to query for an attribute:
node.css('img > @href') # returns all +href+ attributes on an +img+ element node.css('img / @href') # same # ⚠ this returns +class+ attributes from all +div+ elements AND THEIR CHILDREN! node.css('div @class') node.css
💡 Array-like syntax is supported in CSS queries as an alternative to using +:nth-child()+.
⚠ NOTE that indices are 1-based like :nth-child and not 0-based like Ruby Arrays. For example:
# equivalent to 'li:nth-child(2)' node.css('li[2]') # retrieve the second li element in a list
⚠ NOTE that the CSS query string is case-sensitive with regards to your document type. HTML tags will match only lowercase CSS queries, so if you search for “H1” in an HTML document, you’ll never find anything. 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 129 def css(*args) rules, handler, ns, _ = extract_params(args) css_internal(self, rules, handler, ns) end
Search this object for paths. paths must be one or more XPath or CSS queries:
node.search("div.employee", ".//title")
A hash of namespace bindings may be appended:
node.search('.//bike:tire', {'bike' => 'http://schwinn.com/'}) node.search('bike|tire', {'bike' => 'http://schwinn.com/'})
For XPath queries, a hash of variable bindings may also be appended to the namespace bindings. For example:
node.search('.//address[@domestic=$value]', nil, {:value => 'Yes'})
💡 Custom XPath functions and CSS pseudo-selectors may also be defined. To define custom functions create a class and implement the function you want to define, which will be in the ‘nokogiri` namespace in XPath queries.
The first argument to the method will be the current matching NodeSet. Any other arguments are ones that you pass in. Note that this class may appear anywhere in the argument list. For example:
handler = Class.new { def regex node_set, regex node_set.find_all { |node| node['some_attribute'] =~ /#{regex}/ } end }.new node.search('.//title[nokogiri:regex(., "\w+")]', 'div.employee:regex("[0-9]+")', handler)
See Searchable#xpath and Searchable#css for further usage help.
# File lib/nokogiri/xml/searchable.rb, line 54 def search(*args) paths, handler, ns, binds = extract_params(args) xpaths = paths.map(&:to_s).map do |path| LOOKS_LIKE_XPATH.match?(path) ? path : xpath_query_from_css_rule(path, ns) end.flatten.uniq xpath(*(xpaths + [ns, handler, binds].compact)) end
Search this node for XPath paths. paths must be one or more XPath queries.
node.xpath('.//title')
A hash of namespace bindings may be appended. For example:
node.xpath('.//foo:name', {'foo' => 'http://example.org/'}) node.xpath('.//xmlns:name', node.root.namespaces)
A hash of variable bindings may also be appended to the namespace bindings. For example:
node.xpath('.//address[@domestic=$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, which will be in the ‘nokogiri` namespace.
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:
handler = Class.new { def regex(node_set, regex) node_set.find_all { |node| node['some_attribute'] =~ /#{regex}/ } end }.new node.xpath('.//title[nokogiri:regex(., "\w+")]', handler)
# File lib/nokogiri/xml/searchable.rb, line 179 def xpath(*args) paths, handler, ns, binds = extract_params(args) xpath_internal(self, paths, handler, ns, binds) end