CSS Server-side Constants for Ruby/Rails

RCSS implements CSS-SSC in Ruby.

Main features:

* Create rich CSS files using: o ERB templates o Server-side constants o Server-side classes (preliminary) * Simply add RCSS files to any Rails application * Process RCSS files off-line using command line executable

แนะนำ

ช่วยในการสร้าง Dynamic CSS stylesheets in Rails

RCSS addresses issue of CSS maintainability. Even a minor change in complex stylesheet usually requires using search-and-replace. A simple way to fix this flaw is to allow some kind of constant/variable substitution inside CSS. Using RCSS you can achieve that in three ways: ERB templates

ERB templating is the most flexible solution. It uses standard ERB syntax (the same you can find in rhtml files). ERB allows you to inlude in the CSS values defined in controller. This gives access to database through ActiveRecord^? and allows database-driven CSS themes.

Strengths

* Access to application data (through ActiveRecord^?) * Flexible Ruby syntax (allowing programmatic CSS)

Weaknesses

* Syntax unfamiliar to CSS designers * A bit ugly and sometimes error-prone embedding * Not portable

Example

<% template_color = "#000" template_background = "#fff" template_highlight = "#fa3" %> body { color: <%= template_color %>; background-color: <%= template_background %>; }

h1 { color: <%= template_background %>; background-color: <%= template_highlight %>; }

Server-side Constants

Server-side Constants were originaly developed by Shaun Inman in PHP. SSC extends CSS syntax in a simple way. SCC is cross-platform and easy to use.

RCSS differs from original implementation in two ways :

* Constants may have complex values (including spaces and commas) * Includes are not implemented

Strengths

* Simple syntax * SSC-CSS files can be used in both Rails and PHP applications

Weaknesses

* Only simple constant substitution

ตัวอย่างการเขียน code

Controller

class StylesheetsController < ApplicationController
  layout  nil
  session :off
  def rcss
    if rcss = params[:rcss]
      file_base = rcss.gsub(/\.css$/i, '')
      file_path = "#{RAILS_ROOT}/app/views/stylesheets/#{file_base}.rcss"
      @color = '#f77' # example setting
      render(:file => file_path, :content_type => "text/css")
    else
      render(:nothing => true, :status => 404)
    end
  end
end