Nokogiri Rails 3

Nokogiri is a simple HTML / XML parser with much of its interface borrowed from Hpricot. It uses libxml2 to parse and search, so it is very fast.


Installation is very easy. Just use the following command and add to your Gemfile

gem "nokogiri"

Quick start to parsing HTML

Parsing HTML is easy, and you can take advantage of CSS selectors or XPath queries to find things in your document:

require 'open-uri'
require 'nokogiri'

# Perform a google search
doc = Nokogiri::HTML(open(''))

# Print out each link using a CSS selector
doc.css('h3.r > a.l').each do |link|
  puts link.content

Here is an example parsing some HTML and searching it using a combination of CSS selectors and XPath selectors:

require 'nokogiri'

doc = Nokogiri::HTML.parse(<<-eohtml)
    <title>Hello World</title>
    <h1>This is an awesome document</h1>
      I am a paragraph
        <a href="">I am a link</a>

# Search for nodes by css
doc.css('p > a').each do |a_tag|
  puts a_tag.content

# Search for nodes by xpath
doc.xpath('//p/a').each do |a_tag|
  puts a_tag.content

# Or mix and match.'//p/a', 'p > a').each do |a_tag|
  puts a_tag.content

# Find attributes and their values'a').first['href']


require 'rubygems'
require 'nokogiri'

@builder = do |doc|
  doc.html {
    doc.head {
      doc.script {
        doc.text "alert('hello world');"
      } {
        doc.text "div#thing { background: red; }"
      doc.title "Awesome Page" 
    doc.body {
      doc.div.rad.thing! {
        doc.h1 "This is an h1"
        doc.text "This is a div with class 'rad' and id 'thing'"

        doc.div( :some_attribute => 'foo' ) {
          doc.p "This is an awesome paragraph!"

puts @builder.to_html

Is there an easy way to create html partials e.g. menu instead of a full HTML document?
The only workaround I’ve found is to use inner_html:

require 'rubygems'
require 'nokogiri'

@builder = do |doc|
  doc.ul { 'hello'

puts @builder.doc.inner_html 
# <ul><li>hello</li></ul>

About me
Interested about Ruby on Rails

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