How do I call Nodejs in Windows environment from a Rake task to compile some LESS files?

Question

What it is the correct way to call nodejs from a Rake task? I want to compile some LESS files into CSS. I have the cssless compiler installed globally.

Answer 1

The command line Less compiler invoked with the lessc command should work.

You can start with installing the Ruby version of Less, which make the Less compiler available for Ruby: sudo gem install less

Notice that you also will have to install therubyracer ( sudo gem install therubyracer ) if you will get this compiler working (not required when you replace the compiler with the node version).

Now you should be able to run the following command: lessc -v . This should output something like that lessc 1.7.0 (LESS Compiler) [Ruby] 2.6.0 to the console.

After these steps you can run npm install -g less which will install the Node Less compiler (and replace the Ruby compiler, both command install the executable on the same location). Now the lessc -v command should output the following to the console lessc 1.7.5 (Less Compiler) [JavaScript]

Finally you can create a Rake task to compile Less. An example of such as task can be found at: https://gist.github.com/pfig/1969062 and will look like that shown below:

require 'rubygems'
require 'less'
require 'rake'

SOURCE = "."
LESS = File.join( SOURCE, "path", "to", "less", "files" )
CONFIG = {
  'less'   => File.join( LESS, "less" ),
  'css'    => File.join( LESS, "css" ),
  'input'  => "style.less",
  'output' => "style.css"
}

desc "Compile Less"
task :lessc do
  less   = CONFIG['less']

  input  = File.join( less, CONFIG['input'] )
  output = File.join( CONFIG['css'], CONFIG['output'] )

  source = File.open( input, "r" ).read

  parser = Less::Parser.new( :paths => [less] )
  tree = parser.parse( source )

  File.open( output, "w+" ) do |f|
    f.puts tree.to_css( :compress => true )
  end
end # task :lessc