Rack::Censor.rb

module Rack
  class Censor
    
    WORDS = [ 'shit', 'fuck', 'cock', 'cunt', 'cameltoe', 'mooseknuckle' ].map { |w| Regexp.new(w, Regexp::IGNORECASE) }.freeze

    attr_reader :options, :request
    
    def initialize(app, options={})
      @app, @options = app, {
        :replacement => '*****'
      }.merge(options)
    end
    
    def call(env)
      @request = Rack::Request.new(env)
      censor_input
      @app.call(env)
    end
    
    
    private
    
    def censor_input
      form_input = request.env['rack.request.form_hash']
      
      form_input.each do |name,value|
        WORDS.each do |word|
          request.env['rack.request.form_hash'][name].gsub!(word, options[:replacement]) if value =~ word
        end
      end if form_input
    end
 
  end
end