Ruby/Rails Whitespace Stripper

ws_strip.rb

#!/usr/bin/env ruby

# Original Author, Dan Kubb (https://github.com/dkubb)
# Modified by Kevin English (https://github.com/monkseal)
# encoding: utf-8

require 'pathname'

# files and extensions to process
FILES      = %w[ capfile Capfile Gemfile Gemfile.lock Guardfile CHANGELOG LICENSE Manifest README README.rdoc README_FOR_APP RUBY-STYLE RUNNING_UNIT_TESTS Rakefile RUBY-STYLE SPECS TODO USAGE .autotest .gitignore .htaccess .rspec .rcov .rvmrc Vagrantfile .yardopts ].freeze
EXTENSIONS = %w[ builder cgi coffee conf css deploy erb example fcgi feature gemspec haml hs htc htm html js json key liquid markdown md opts php rake ratom rb rcsv rdf rdoc reek rhtml rip rjs rpdf ru rxml sake sass scss sh slim smil sql thor txt vcf xml yml java rabl jade ].freeze

paths = ARGV.map { |arg| Pathname.glob(arg) }.flatten

paths.each do |path_in|
  start_path = path_in.directory? ? path_in + '**/*' : path_in

  Pathname.glob((start_path).to_s).each do |path|
    unless path.file? && path.size? && path.readable? && path.writable? && (FILES.include?(path.basename.to_s) || EXTENSIONS.include?(path.extname[1..-1]))
      next
    end

    # replace leading whitespace (including tabs) with spaces
    # replace trailing whitespace with a newline
    document = path.open('r') do |fh|
      fh.collect { |line| line.gsub(/\G\s/, ' ').rstrip << "\n" }.join.rstrip.gsub(/\n{2,8}/, "\n\n")
    end << "\n"

    # truncate the file if it is empty
    document = '' if document.strip.empty?

    # skip it if the file was not modified
    next if document == path.read

    puts "Modifying #{path}"
    path.open('w') { |fh| fh.write document }
  end
end

I usually place this in /usr/local/bin/ws_strip.rb.

To run on a branch:

git diff master --name-only | xargs ws_strip.rb

To run on staged filed:

git diff --cached --name-only | xargs ws_strip.rb

pre-commit:

#!/bin/sh

echo "Running pre-commit hook, to run with out do 'git commit -n'"
echo "Running ws_strip...."
output=`git diff --cached --name-only | xargs /Users/kenglish/bin/ws_strip.rb `
if [[ $output == *Modifying* ]]
then
  echo "Extra whitespace, failing commit";
  exit 1
fi