Class: Moneta::Transformer

Inherits:
Proxy
  • Object
show all
Defined in:
lib/moneta/transformer.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
  use :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"

Instance Attribute Summary

Attributes inherited from Proxy

#adapter

Instance Method Summary collapse

Methods inherited from Proxy

#clear, #close, #config, features_mask, not_supports

Methods included from Config

#config, included

Methods included from Defaults

#[], #[]=, #close, #decrement, #fetch, included, #update

Methods included from OptionSupport

#expires, #prefix, #raw, #with

Constructor Details

#initialize(adapter, options = {}) ⇒ Transformer

Returns a new instance of Transformer.



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# File 'lib/moneta/transformer.rb', line 31

def initialize(adapter, options = {})
  super

  if config.key.empty?
    @key_decodable = true
  else
    @key_transforms = load_transforms(
      config.key,
      options.merge(serialize_unless_string: config.serialize_keys_unless_string)
    )
    @key_decodable = @key_transforms.all?(&:decodable?)
    @key_encoder = make_encoder(@key_transforms)
    if @key_decodable
      @key_decoder = make_decoder(@key_transforms)
    end
  end

  unless config.value.empty?
    @value_transforms = load_transforms(config.value, options)
    raise "Not all value transforms are decodable (#{@value_transforms.reject(&:decodable?)})" \
      unless @value_transforms.all?(&:decodable?)
    @value_encoder = make_encoder(@value_transforms)
    @value_decoder = make_decoder(@value_transforms)
  end
end

Instance Method Details

#create(key, value, options = {}) ⇒ Object 



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# File 'lib/moneta/transformer.rb', line 102

def create(key, value, options = {})
  super(encode_key(key), encode_value(value, options[:raw]), options)
end

#delete(key, options = {}) ⇒ Object 



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# File 'lib/moneta/transformer.rb', line 115

def delete(key, options = {})
  decode_value(super(encode_key(key), options), options[:raw])
end

#each_key ⇒ Object

Yields keys from the underlying store that it is possible to decode. The method tries to avoid decoding any keys that are definitely invalid by checking the decodable? method, but also ignores any keys that throw errors while decoding.

Raises:

  • (NotImplementedError) 


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# File 'lib/moneta/transformer.rb', line 83

def each_key
  raise NotImplementedError, "each_key is not supported on this transformer" \
    unless supports? :each_key

  return super unless block_given?

  super do |key|
    next unless encoded_key?(key)
    yield decode_key(key)
  rescue
    # Silently ignore any error raised trying to decode the key.
    next
  end
end

#features ⇒ Object 



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# File 'lib/moneta/transformer.rb', line 66

def features
  @features ||=
    begin
      features = super
      features -= [:each_key] unless supports?(:each_key)
      features.freeze
    end
end

#fetch_values(*keys, raw: false, **options) ⇒ Object 



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# File 'lib/moneta/transformer.rb', line 123

def fetch_values(*keys, raw: false, **options)
  if block_given?
    encoded_keys = keys.map { |key| encode_key(key) }
    dictionary = encoded_keys.zip(keys).to_h

    encoded_values =
      super(*encoded_keys, **options) do |encoded_key|
        decoded_value = yield dictionary[encoded_key]
        encode_value(decoded_value, raw) if decoded_value != nil
      end

    encoded_values.map { |value| decode_value(value, raw) }
  else
    values_at(*keys, **options)
  end
end

#increment(key, amount = 1, options = {}) ⇒ Object 



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# File 'lib/moneta/transformer.rb', line 98

def increment(key, amount = 1, options = {})
  super(encode_key(key), amount, options)
end

#key?(key, options = {}) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/moneta/transformer.rb', line 75

def key?(key, options = {})
  super(encode_key(key), options)
end

#load(key, options = {}) ⇒ Object 



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# File 'lib/moneta/transformer.rb', line 106

def load(key, options = {})
  decode_value(super(encode_key(key), options), options[:raw])
end

#merge!(pairs, options = {}) ⇒ Object 



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# File 'lib/moneta/transformer.rb', line 150

def merge!(pairs, options = {})
  encoded_pairs = pairs.map { |key, value| [encode_key(key), encode_value(value, options[:raw])] }
  if block_given?
    key_dictionary = encoded_pairs.map(&:first).zip(pairs.map(&:first)).to_h
    value_dictionary = encoded_pairs.map(&:last).zip(pairs.map(&:last)).to_h

    super(encoded_pairs, options) do |encoded_key, existing_encoded_value, new_encoded_value|
      key = key_dictionary[encoded_key]
      existing_value = decode_value(existing_encoded_value, options[:raw])
      new_value = value_dictionary[new_encoded_value]
      value = yield(key, existing_value, new_value)
      encode_value(value, options[:raw])
    end
  else
    super(encoded_pairs, options)
  end
end

#slice(*keys, raw: false, **options) ⇒ Object 



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# File 'lib/moneta/transformer.rb', line 140

def slice(*keys, raw: false, **options)
  encoded_keys = keys.map { |key| encode_key(key) }
  dictionary = encoded_keys.zip(keys).to_h

  encoded_pairs = super(*encoded_keys, **options)
  encoded_pairs.map do |encoded_key, encoded_value|
    [dictionary[encoded_key], decode_value(encoded_value, raw)]
  end
end

#store(key, value, options = {}) ⇒ Object 



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# File 'lib/moneta/transformer.rb', line 110

def store(key, value, options = {})
  super(encode_key(key), encode_value(value, options[:raw]), options)
  value
end

#supports?(feature) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/moneta/transformer.rb', line 57

def supports?(feature)
  supported = super
  if supported && feature == :each_key && !@key_decodable
    false
  else
    supported
  end
end

#values_at(*keys, raw: false, **options) ⇒ Object 



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# File 'lib/moneta/transformer.rb', line 119

def values_at(*keys, raw: false, **options)
  super(*keys.map { |key| encode_key(key) }, **options).map { |value| decode_value(value, raw) }
end