How do I validate XHTML, ATOM, and CSS in Ruby?

Question

I'd like to run validations on the static web content I'm creating. Are there any good validators for XHTML, ATOM, and CSS? (The first two would be covered by any general-purpose XML-DTD validator.)

Later

I failed to specify that I wanted local validation, not something that uses the W3C service.

Answer 1

Markup Validation Service, by w3c, can validate XHTML.

There are also a CSS Validation Service and a Feed Validation Service.

Is that what you were looking for?

If you want to validate from inside a ruby program, here is an article explaining how to do that using this services. I didn't try it, sorry.

Answer 2

Check W3C Validators Ruby Gem.

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

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

Otherwise, W3C's Validator has a SOAP API which you can use even from Ruby, or there is an article demonstrates how to validate HTML in Ruby with libxml.

Answer 3

Nokogiri ( http://github.com/tenderlove/nokogiri/tree/master ) is great tool for parsing XML/XHTML/HTML/etc and it looks like it can validate as well:

Nokogiri::XML.parse(string_or_io, nil, nil, Nokogiri::XML::PARSE_DTDVALID)

At the moment, I don't believe that you'll find a pure ruby project that will validate your CSS directives, but there are many that will let you use ruby code to generate valid CSS.

Answer 4

Just as an info: Nokogiri 1.3.0 was released today and now has validation classes for XML inside the official release. No need to get the trunk version.

http://nokogiri.rubyforge.org/nokogiri/

Answer 5

I use the following to validate the markup on all of our pages through our test suite: assert_valid_markup

It provides nice markup testing like:

class FooControllerTest < Test::Unit::TestCase
  def test_bar_markup
    get :bar
    assert_valid_markup
  end
end

or

class FooControllerTest < Test::Unit::TestCase
  def test_bar_markup
    assert_valid_markup "<div>Hello, world.</div>"
  end
end

# For the ultimate in convenience, use the class-level method to validate a slew of
# actions in one line. Par exemple:

class FooControllerTest < Test::Unit::TestCase
  assert_valid_markup :bar, :baz, :qux
end