convert_string_encoding.rb

# Encodes a string from encoding "from" to encoding "to" in
# a way that works for both ruby 1.8 and 1.9
def convert_string_encoding(to, from, str)
  if "1.9".respond_to?(:force_encoding)
    str = str.dup if str.frozen?
    str.encode(to, from, :undef => :replace)
  else
    require 'iconv'
    Iconv.conv(to, from, str)
  end
end

csv_bridge.rb

require 'csv'
require 'fastercsv'

if CSV.const_defined?(:Reader)
  class CSVBridge < FasterCSV
  end
else
  class CSVBridge < CSV
  end
end

force_utf8_params.rb

# See http://stackoverflow.com/questions/8268778/rails-2-3-9-encoding-of-query-parameters
# See https://rails.lighthouseapp.com/projects/8994/tickets/4807
# See http://jasoncodes.com/posts/ruby19-rails2-encodings (thanks for the following code, Jason!)
def force_utf8_params
  traverse = lambda do |object, block|
    if object.kind_of?(Hash)
      object.each_value { |o| traverse.call(o, block) }
    elsif object.kind_of?(Array)
      object.each { |o| traverse.call(o, block) }
    else
      block.call(object)
    end
    object
  end
  force_encoding = lambda do |o|
    RubyBridge.force_utf8_encoding(o)
  end
  traverse.call(params, force_encoding)
end

gemfile.rb

group :development do
  gem 'ruby-debug', :platforms => :ruby_18
  gem 'debugger', :platforms => :ruby_19
end