StyleInliner 
Inline CSS style rules into style attributes of each HTML element.
Installation
Add this line to your application's Gemfile:
gem "style_inliner"And then execute:
bundleOr install it yourself as:
gem install style_inlinerUsage
html = <<-EOS
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<style>
body {
background-color: red;
}
td {
background-color: blue
}
</style>
</head>
<body>
<table>
<tr>
<td>example</td>
</tr>
</table>
</body>
</html>
EOS
puts StyleInliner::Document.new(html, replace_properties_to_attributes: true).inline<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body style="background-color: red">
<table>
<tr>
<td bgcolor="blue">example</td>
</tr>
</table>
</body>
</html>Ruby version compatibility
StyleInliner is tested on Ruby 2.2.0.
Development
After checking out the repo, run bin/setup to install dependencies. You can also run bin/console for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.
Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/r7kamura/style_inliner.
License
The gem is available as open source under the terms of the MIT License.