Ruby parsing HTML for CSS files

Question

I am working with some HTML for my site, basically moving my site from PHP to Rails.

I have thousands of pages and some parts of the site have different CSS files from others.

I can grab the <link> tags fine but I added some conditions for different stylesheets to be loaded if it's IE6/IE7/IE8 etc.

I am trying to figure out how to parse this:

<!--[if lt IE 7]>
<link type="text/css" rel="stylesheet" media="all" href="/templates/default/css/ie6.css" />
<![endif]-->
<!--[if IE 7]>
<link type="text/css" rel="stylesheet" media="all" href="/templates/default/css/ie7.css" />
<![endif]-->      
<!--[if IE 8]>
<link type="text/css" rel="stylesheet" media="all" href="/templates/default/css/ie8.css" />
<![endif]-->

And end up with:

/templates/default/css/ie6.css<br />
/templates/default/css/ie7.css<br />
/templates/default/css/ie8.css<br />

I am using Nokogiri to pull any other information I need, but can not get these URLs due to them being wrapped in comments.

Mike Tunnicliffe · Accepted Answer · 2010-07-12 10:30:52Z

2

The Nokogiri documentation implies that it creates nodes in the document to represent comments (http://nokogiri.org/Nokogiri/XML/Comment.html), if you can get the content of these nodes then you can use a simple RegExp to extract the URL.

Something like:

/<link[^>]*?href="([^"]+)"/

answered Jul 12, 2010 at 10:30

Mike Tunnicliffe

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2 Comments

the Tin Man Over a year ago

It isn't necessary to use regex. Nokogiri can provide a clean, regex-free solution, allowing you to get at arbitrarily deeply nested tags. Regex in this solution is subject to the same weaknesses always exhibited by regex when parsing HTML or XML. It isn't the right tool for the job, causing the pattern to mushroom if your HTML is anything more than trivial. See my answer to see how.

Mike Tunnicliffe Over a year ago

@the Tin Man: Cool. Much better solution.

the Tin Man · Accepted Answer · 2012-02-07 20:39:32Z

Nokogiri can get you where you want. The problem is that the content of a comment node is text, so you have to reparse that text to continue using Nokogiri's juju.

require 'nokogiri'

doc = Nokogiri::HTML(<<EOT)
<!--[if lt IE 7]>
<link type="text/css" rel="stylesheet" media="all" href="/templates/default/css/ie6.css" />
<![endif]-->
<!--[if IE 7]>
<link type="text/css" rel="stylesheet" media="all" href="/templates/default/css/ie7.css" />
<![endif]-->      
<!--[if IE 8]>
<link type="text/css" rel="stylesheet" media="all" href="/templates/default/css/ie8.css" />
<![endif]-->
EOT

puts doc.search('//comment()').map{ |c|
  Nokogiri::HTML::DocumentFragment.parse( c.content ).at('link')['href']
}

Which outputs:

/templates/default/css/ie6.css
/templates/default/css/ie7.css
/templates/default/css/ie8.css

Kieran Allen · Accepted Answer · 2010-07-12 12:47:35Z

0

Pretty sure

/href="(.+).css"/i

would work fine

answered Jul 12, 2010 at 12:47

Kieran Allen

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1 Comment

RailsSon Over a year ago

This does work find, but I was wanting to grab the CSS files from in between the comments and only those ones.

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