Ruby: how to add “# encoding: UTF-8” automatically?

Question

Is there any gem which adds # encoding: UTF-8 to each Ruby file automatically?

Or is there any other way to prevent from the invalid multibyte cha

Answer 1

How about just running a script?

#!/usr/bin/env ruby1.9.1
require 'find'

fixfile = []

Find.find('.') do |path|
  next unless /\.rb$/.match(path);
  File.open(path) do |file|
    count = 0;
    type = :lib
    file.each do |line|
      if count == 0 and /#!/.match(line)
        type = :script
      end
      if  /utf/.match(line)
        break
      end
      if (count += 1) > 10 then
        fixfile.push path:path, type:type
        break
      end
    end
    if file.eof?
        fixfile.push path:path, type:type
    end
  end
end

fixfile.each do |info|
  path = info[:path]
  backuppath = path + '~'
  type = info[:type]
  begin
     File.delete(backuppath) if File.exist?(backuppath)
     File.link(path, backuppath)
  rescue Errno::ENOENT => x
     puts "could not make backup file '#{backuppath}' for '#{ path }': #{$!}"
     raise
  end
  begin
    inputfile = File.open(backuppath, 'r')
    File.unlink(path)
    File.open(path, 'w') do |outputfile|
      if type == :script
        line = inputfile.readline
        outputfile.write line
      end
      outputfile.write "# encoding: utf-8\n"
      inputfile.each do |line|
        outputfile.write line
      end
      inputfile.close
      outputfile.close
    end
  rescue => x
    puts "error: #{x} #{$!}"
    exit
  end

To make it automatic add this to your Rakefile.

You could run file -bi #{path} and look for charset=utf-8 if you only want to update files that have utf-8 chars.