Class: Moneta::Transformer

Inherits:

Proxy

• Object
• Proxy
• Moneta::Transformer

Defined in:

lib/moneta/transformer.rb,
lib/moneta/transformer/config.rb,
lib/moneta/transformer/helper.rb

Overview

Transforms keys and values (Marshal, YAML, JSON, Base64, MD5, …). You can bypass the transformer (e.g. serialization) by using the ‘:raw` option.

Examples:

Add ‘Moneta::Transformer` to proxy stack

Moneta.build do
  transformer :key => [:marshal, :escape], :value => [:marshal]
  adapter :File, :dir => 'data'
end

Bypass serialization

store.store('key', 'value', :raw => true)
store['key'] # raises an Exception
store.load('key', :raw => true) # returns 'value'

store['key'] = 'value'
store.load('key', :raw => true) # returns "\x04\bI\"\nvalue\x06:\x06ET"

Defined Under Namespace

Modules: Helper

Constant Summary

TRANSFORMER =

Available key/value transformers

{
  # Name    => [ Type,       Load,                           Dump,                             Library         ],
  :bencode  => [ :serialize, '::BEncode.load(%s)',           '::BEncode.dump(%s)',             'bencode'       ],
  :bert     => [ :serialize, '::BERT.decode(%s)',            '::BERT.encode(%s)',              'bert'          ],
  :bson     => [ :serialize, "::BSON.deserialize(%s)['v']",  "::BSON.serialize('v'=>%s).to_s", 'bson'          ],
  :json     => [ :serialize, '::MultiJson.load(%s).first',   '::MultiJson.dump([%s])',         'multi_json'    ],
  :marshal  => [ :serialize, '::Marshal.load(%s)',           '::Marshal.dump(%s)'                              ],
  :msgpack  => [ :serialize, '::MessagePack.unpack(%s)',     '::MessagePack.pack(%s)',         'msgpack'       ],
  :ox       => [ :serialize, '::Ox.parse_obj(%s)',           '::Ox.dump(%s)',                  'ox'            ],
  :tnet     => [ :serialize, '::TNetstring.parse(%s).first', '::TNetstring.dump(%s)',          'tnetstring'    ],
  :yaml     => [ :serialize, '::YAML.load(%s)',              '::YAML.dump(%s)',                'yaml'          ],
  :bzip2    => [ :compress,  '::Bzip2.uncompress(%s)',       '::Bzip2.compress(%s)',           'bzip2'         ],
  :lzma     => [ :compress,  '::LZMA.decompress(%s)',        '::LZMA.compress(%s)',            'lzma'          ],
  :lzo      => [ :compress,  '::LZO.decompress(%s)',         '::LZO.compress(%s)',             'lzoruby'       ],
  :snappy   => [ :compress,  '::Snappy.inflate(%s)',         '::Snappy.deflate(%s)',           'snappy'        ],
  :quicklz  => [ :compress,  '::QuickLZ.decompress(%s)',     '::QuickLZ.compress(%s)',         'qlzruby'       ],
  :zlib     => [ :compress,  '::Zlib::Inflate.inflate(%s)',  '::Zlib::Deflate.deflate(%s)',    'zlib'          ],
  :qp       => [ :encode,    "%s.unpack('M').first",         "[%s].pack('M').strip"                            ],
  :uuencode => [ :encode,    "%s.unpack('u').first",         "[%s].pack('u').strip"                            ],
  :base64   => RUBY_VERSION > '1.9' ?
               [ :encode,    "%s.unpack('m0').first",        "[%s].pack('m0')"                                 ] :
               [ :encode,    "%s.unpack('m').first",         "[%s].pack('m').gsub(\"\n\", '')"                 ],
  :escape   => [ :encode,    'Helper.unescape(%s)',          'Helper.escape(%s)'                               ],
  :hmac     => [ :hmac,      'Helper.hmacverify(%s, options[:secret] || @secret)',
                             'Helper.hmacsign(%s, options[:secret] || @secret)',               'openssl'       ],
  :truncate => [ :truncate,  nil,                            'Helper.truncate(%s, @maxlen)',   'digest/md5'    ],
  :md5      => [ :digest,    nil,                            '::Digest::MD5.hexdigest(%s)',    'digest/md5'    ],
  :rmd160   => [ :digest,    nil,                            '::Digest::RMD160.hexdigest(%s)', 'digest/rmd160' ],
  :sha1     => [ :digest,    nil,                            '::Digest::SHA1.hexdigest(%s)',   'digest/sha1'   ],
  :sha256   => [ :digest,    nil,                            '::Digest::SHA256.hexdigest(%s)', 'digest/sha2'   ],
  :sha384   => [ :digest,    nil,                            '::Digest::SHA384.hexdigest(%s)', 'digest/sha2'   ],
  :sha512   => [ :digest,    nil,                            '::Digest::SHA512.hexdigest(%s)', 'digest/sha2'   ],
  :prefix   => [ :prefix,    nil,                            '(options[:prefix] || @prefix)+%s'                ],
  :spread   => [ :spread,    nil,                            'Helper.spread(%s)'                               ],
  :to_s     => [ :string,    nil,                            '%s.to_s'                                         ],
  :inspect  => [ :string,    nil,                            '%s.inspect'                                      ],
}

VALUE_TRANSFORMER =

Allowed value transformers (Read it like a regular expression!)

'serialize? compress? hmac? encode?'

KEY_TRANSFORMER =

Allowed key transformers (Read it like a regular expression!)

'(serialize | string)? prefix? ((encode? truncate?) | (digest spread?))?'

Instance Attribute Summary

Attributes inherited from Proxy

#adapter

Class Method Summary

• .new(adapter, options = {}) ⇒ Transformer

  New Moneta transformer.

• .original_new ⇒ Object

Methods inherited from Proxy

#clear, #close, #create, #delete, #features, #increment, #initialize, #key?, #load, #store

Methods included from Defaults

#[], #[]=, #close, #create, #decrement, #features, #fetch, included, #increment, #key?, #supports?

Methods included from OptionSupport

#expires, #prefix, #raw, #with

Constructor Details

This class inherits a constructor from Moneta::Proxy

Class Method Details

.new(adapter, options = {}) ⇒ Transformer

Returns new Moneta transformer.

Parameters:

• adapter (Moneta store) —

  The underlying store

• options (Hash) (defaults to: {})

Options Hash (options):

• :key (Array) —

  List of key transformers in the order in which they should be applied

• :value (Array) —

  List of value transformers in the order in which they should be applied

• :prefix (String) —

  Prefix string for key namespacing (Used by the :prefix key transformer)

• :secret (String) —

  HMAC secret to verify values (Used by the :hmac value transformer)

• :maxlen (Integer) —

  Maximum key length (Used by the :truncate key transformer)

Returns:

• (Transformer) —

  new Moneta transformer

Raises:

• (ArgumentError)

# File 'lib/moneta/transformer.rb', line 32

def new(adapter, options = {})
  keys = [options[:key]].flatten.compact
  values = [options[:value]].flatten.compact
  raise ArgumentError, 'Option :key or :value is required' if keys.empty? && values.empty?
  options[:prefix] ||= '' if keys.include?(:prefix)
  name = class_name(keys, values)
  const_set(name, compile(keys, values)) unless const_defined?(name)
  const_get(name).original_new(adapter, options)
end

.original_new ⇒ Object

# File 'lib/moneta/transformer.rb', line 22

alias_method :original_new, :new