create_file.rb

require 'thor/actions/empty_directory'

class Thor
  module Actions
    # Create a new file relative to the destination root with the given data,
    # which is the return value of a block or a data string.
    #
    # ==== Parameters
    # destination<String>:: the relative path to the destination root.
    # data<String|NilClass>:: the data to append to the file.
    # config<Hash>:: give :verbose => false to not log the status.
    #
    # ==== Examples
    #
    #   create_file "lib/fun_party.rb" do
    #     hostname = ask("What is the virtual hostname I should use?")
    #     "vhost.name = #{hostname}"
    #   end
    #
    #   create_file "config/apache.conf", "your apache config"
    #
    def create_file(destination, *args, &block)
      config = args.last.is_a?(Hash) ? args.pop : {}
      data = args.first
      action CreateFile.new(self, destination, block || data.to_s, config)
    end
    alias_method :add_file, :create_file

    # CreateFile is a subset of Template, which instead of rendering a file with
    # ERB, it gets the content from the user.
    #
    class CreateFile < EmptyDirectory #:nodoc:
      attr_reader :data

      def initialize(base, destination, data, config = {})
        @data = data
        super(base, destination, config)
      end

      # Checks if the content of the file at the destination is identical to the rendered result.
      #
      # ==== Returns
      # Boolean:: true if it is identical, false otherwise.
      #
      def identical?
        exists? && File.binread(destination) == render
      end

      # Holds the content to be added to the file.
      #
      def render
        @render ||= if data.is_a?(Proc)
                      data.call
                    else
                      data
                    end
      end

      def invoke!
        invoke_with_conflict_check do
          FileUtils.mkdir_p(File.dirname(destination))
          File.open(destination, 'wb') { |f| f.write render }
        end
        given_destination
      end

    protected

      # Now on conflict we check if the file is identical or not.
      #
      def on_conflict_behavior(&block)
        if identical?
          say_status :identical, :blue
        else
          options = base.options.merge(config)
          force_or_skip_or_conflict(options[:force], options[:skip], &block)
        end
      end

      # If force is true, run the action, otherwise check if it's not being
      # skipped. If both are false, show the file_collision menu, if the menu
      # returns true, force it, otherwise skip.
      #
      def force_or_skip_or_conflict(force, skip, &block)
        if force
          say_status :force, :yellow
          block.call unless pretend?
        elsif skip
          say_status :skip, :yellow
        else
          say_status :conflict, :red
          force_or_skip_or_conflict(force_on_collision?, true, &block)
        end
      end

      # Shows the file collision menu to the user and gets the result.
      #
      def force_on_collision?
        base.shell.file_collision(destination) { render }
      end
    end
  end
end