class ActionDispatch::Cookies::SignedCookieJar

def [](name)
  if signed_message = @parent_jar[name]
    @verifier.verify(signed_message)
  end
rescue ActiveSupport::MessageVerifier::InvalidSignature
  nil
end

def []=(key, options)
  if options.is_a?(Hash)
    options.symbolize_keys!
    options[:value] = @verifier.generate(options[:value])
  else
    options = { :value => @verifier.generate(options) }
  end
  raise CookieOverflow if options[:value].size > MAX_COOKIE_SIZE
  @parent_jar[key] = options
end

def ensure_secret_secure(secret)
  if secret.blank?
    raise ArgumentError, "A secret is required to generate an " +
      "integrity hash for cookie session data. Use " +
      "config.secret_token = \"some secret phrase of at " +
      "least #{SECRET_MIN_LENGTH} characters\"" +
      "in config/initializers/secret_token.rb"
  end
  if secret.length < SECRET_MIN_LENGTH
    raise ArgumentError, "Secret should be something secure, " +
      "like \"#{SecureRandom.hex(16)}\". The value you " +
      "provided, \"#{secret}\", is shorter than the minimum length " +
      "of #{SECRET_MIN_LENGTH} characters"
  end
end

def initialize(parent_jar, secret)
  ensure_secret_secure(secret)
  @parent_jar = parent_jar
  @verifier   = ActiveSupport::MessageVerifier.new(secret)
end

def method_missing(method, *arguments, &block)
  @parent_jar.send(method, *arguments, &block)
end