Premailer - prep your HTML email by inlining CSS

At what must be the nexus of the open source universe, we’re posting a cool project from Alex Dunae aka theCHANGELOG. Premailer is a Ruby library to help you prep your HTML email templates for better viewing in most web clients by:

making all your CSS inline
changing relative links to absolute links
moving any CSS pseudo-classes (like :hover) to the <head>
checking your HTML and CSS for compatibiliy with e-mail programs
creating a plain-text version of your message

To use:

sudo gem install premailer

and then

premailer = Premailer.new('http://example.com/myfile.html', :warn_level => Premailer::Warnings::SAFE)

# Write the HTML output
fout = File.open("output.html", "w")
fout.puts premailer.to_inline_css
fout.close

# Write the plain-text output
fout = File.open("ouput.txt", "w")
fout.puts premailer.to_plain_text
fout.close

# Output any CSS warnings
premailer.warnings.each do |w|
  puts "#{w[:message]} (#{w[:level]}) may not render properly in #{w[:clients]}"
end

For the terminally challenged there’s also a nifty web interface

[Source on GitHub] [Home page]