Nullcreations.net | Ramblings & Photography of Jerrett Taylor

CodeRay helper for Rails

May 10th, 2007 | 5 comments

While I'm using Markdown for formatting blog entries, I wanted to have some decent syntax highlighting support as well. After looking around I decided to use CodeRay. It's fast, customizable, has nice output, and is easy to extend.

All I had to do to make it work with Rails was to create a helper. I wanted to have a simple syntax so I could do stuff like:

<code:ruby> ... code here ... </code>

The helper isn't very complicated:

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def parse_coderay(text)
  text.scan(/(<code\:([a-z].+?)>(.+?)<\/code>)/m).each do |match|
  text.gsub!(match[0],CodeRay.scan(match[2], match[1].to_sym).div( :line_numbers => :table,:css => :class))
  end
  return text
end

Then to add the CSS, I added this to my main layout:

style { CodeRay::Encoders[:html]::CSS.new(:jerrett).stylesheet }

or for non-markaby users...

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<style>
<%= CodeRay::Encoders[:html]::CSS.new(:jerrett).stylesheet %>
</style>

If you call CSS.new without an argument it will use the default style, which is almost identical to the one I'm using here. I just changed a few colors to make it fit the site better. In the coderay/styles/ directory are two ruby files, cycnus.rb and murphy.rb - these define the CSS styles. By default it will use cycnus, and murphy is a black-based theme. Easiest way to make a new theme is just copy one of the existing to a new .rb file, and tweak.

The only thing missing was JavaScript syntax highlighting support, by I found a pastie by Josh Goebel of a JavaScript CodeRay Scanner

All you need to do is add that to a javascript.rb file in the coderay/scanners folder, and viola, JavaScript support!