ruby-on-rails – 在rake任务中包含Rails类？

我有一个名为PaymentGatewayCipher的类看起来像：

require 'openssl'

# Encapsulates payment gateway encryption / decryption utility functions
class PaymentGatewayCipher
  class << self
    def encrypt(file,options = {})
      cipher = create_cipher
      cipher.encrypt(cipher_key)
      data = cipher.update(File.read(file))
      data << cipher.final

      if to_file = options[:to]
        # Write it out to a different file
        File.open(to_file,'wb') do |f|
          f << data
        end
      end

      data
    end

    # Decrypts the given file
    def decrypt(file)
      cipher = create_cipher
      cipher.decrypt(cipher_key)
      encrypted_data = File.open(file,'rb') {|io| io.read}
      data = cipher.update(encrypted_data)
      data << cipher.final
    end

    # Generates the cipher to be used for encryption/decryption
    def create_cipher
      OpenSSL::Cipher::Cipher.new('aes-256-cbc')
    end

    # Loads the cipher key used for the symmetric algorithm
    def cipher_key
      File.open(File.join(Rails.root,'config/mystuff/live/cipher.key'),'rb') {|io| io.read}
    end
  end
end

我想写一个rake任务来运行它来解密文件.我试过把一个文件放在tasks / Rakefile中,看起来像：

directory "tasks"

task :decrypt_test do
  puts "Decypting"
  pay_pal_config = PaymentGatewayCipher.decrypt('hpa1')
end

然而,当我运行它时,它说无法找到Class :: Rails

救命？