W3C Validators Gem README

W3C Validators is a Ruby wrapper for the World Wide Web Consortium's online validation services.

It supports the nu validator, the feed validator and the CSS validator.

Installation

  gem install w3c_validators

Usage

There are three main validator classes available, the W3CValidators::NuValidator (used for HTML), the W3CValidators::FeedValidator and the W3CValidators::CSSValidator.

Warning: The W3CValidators::MarkupValidator also exist but is not anymore the preferred way to check HTML document. Indeed, it is working fine for non-HTML5 documents, but it is broken when you test an HTML5 document due to W3C redirection. W3CValidators::NuValidator should be used instead for standard cases.

Each validator has offers three different validation methods.

validate_text methods take a string
validate_file methods take a path to a file or an IO object
validate_uri methods take a published URL

In addition, the W3CValidators::MarkupValidator has a validate_uri_quickly method, which performs a HEAD request against the markup validation service. The Results of this call give an error count but no error details.

Using a local validator

Each of the three validators allows you to specify a custom path to the validator. You can set your own validator like this:

  validator = NuValidator.new(:validator_uri => 'http://localhost/check')

Using a proxy server

You can use a proxy server by passing in its information in the contructor.

  validator = NuValidator.new(:proxy_host => 'proxy.example.com',
                              :proxy_port => 80,
                              :proxy_user => 'optional',
                              :proxy_pass => 'optional')

Examples

Example #1: Nu validator, local file

  require 'w3c_validators'
  
  include W3CValidators

  @validator = NuValidator.new
  
  file = File.dirname(__FILE__) + '/fixtures/valid_html5.html'
  results = @validator.validate_file(file)

  if results.errors.length > 0
    results.errors.each do |err|
      puts err.to_s
    end
  else
    puts 'Valid!'
  end

Example #2: Feed validator, remote file

  require 'w3c_validators'
  
  include W3CValidators

  @validator = FeedValidator.new

  results = @validator.validate_uri('http://example.com/feed.xml')

  if results.errors.length > 0
    results.errors.each do |err|
      puts err.to_s
    end
  else
    puts 'Valid!'
  end

Example #3: CSS validator, text fragment

  require 'w3c_validators'
  
  include W3CValidators

  @validator = CSSValidator.new

  results = @validator.validate_text('body { margin: 0px; }')

  if results.errors.length > 0
    results.errors.each do |err|
      puts err.to_s
    end
  else
    puts 'Valid!'
  end

Example #4: Markup validator, local file

  require 'w3c_validators'
  
  include W3CValidators

  @validator = MarkupValidator.new
  
  # override the DOCTYPE
  @validator.set_doctype!(:html32)
  
  # turn on debugging messages
  @validator.set_debug!(true)

  file = File.dirname(__FILE__) + '/fixtures/markup.html'
  results = @validator.validate_file(fp)

  if results.errors.length > 0
    results.errors.each do |err|
      puts err.to_s
    end
  else
    puts 'Valid!'
  end
  
  puts 'Debugging messages'
  
  results.debug_messages.each do |key, value|
    puts "#{key}: #{value}"
  end

Examples with Ruby Frameworks

# you can easily incorporate this in your ruby based frameworks:

# Gemfile
group :test do
    gem 'w3c_validators'
end

# And in your relevant test file:

require 'w3c_validators'

class FoosControllerTest < ActionDispatch::IntegrationTest
  setup do  
    @validator = W3CValidators::NuValidator.new
  end
  
  test "index" do
    get foos_url
    assert_equal 0, @validator.validate_text(response.body).errors.length
  end
end

# granted it's not perfect, but hopefully that will at least get you going
# you might want to customise things so that it delivers a particular output in case an error shows up.