1  # encoding: utf-8
   2 
   3  require 'i18n/backend/base'
   4  require 'active_support/json'
   5 
   6  module I18n
   7    module Backend
   8      # This is a basic backend for key value stores. It receives on
   9      # initialization the store, which should respond to three methods:
  10      #
  11      # * store#[](key)         - Used to get a value
  12      # * store#[]=(key, value) - Used to set a value
  13      # * store#keys            - Used to get all keys
  14      #
  15      # Since these stores only supports string, all values are converted
  16      # to JSON before being stored, allowing it to also store booleans,
  17      # hashes and arrays. However, this store does not support Procs.
  18      #
  19      # As the ActiveRecord backend, Symbols are just supported when loading
  20      # translations from the filesystem or through explicit store translations.
  21      #
  22      # Also, avoid calling I18n.available_locales since it's a somehow
  23      # expensive operation in most stores.
  24      #
  25      # == Example
  26      #
  27      # To setup I18n to use TokyoCabinet in memory is quite straightforward:
  28      #
  29      #   require 'rufus/tokyo/cabinet' # gem install rufus-tokyo
  30      #   I18n.backend = I18n::Backend::KeyValue.new(Rufus::Tokyo::Cabinet.new('*'))
  31      #
  32      # == Performance
  33      #
  34      # You may make this backend even faster by including the Memoize module.
  35      # However, notice that you should properly clear the cache if you change
  36      # values directly in the key-store.
  37      #
  38      # == Subtrees
  39      #
  40      # In most backends, you are allowed to retrieve part of a translation tree:
  41      #
  42      #   I18n.backend.store_translations :en, :foo => { :bar => :baz }
  43      #   I18n.t "foo" #=> { :bar => :baz }
  44      #
  45      # This backend supports this feature by default, but it slows down the storage
  46      # of new data considerably and makes hard to delete entries. That said, you are
  47      # allowed to disable the storage of subtrees on initialization:
  48      #
  49      #   I18n::Backend::KeyValue.new(@store, false)
  50      #
  51      # This is useful if you are using a KeyValue backend chained to a Simple backend.
  52      class KeyValue
  53        module Implementation
  54          attr_accessor :store
  55 
  56          include Base, Flatten
  57 
  58          def initialize(store, subtrees=true)
  59            @store, @subtrees = store, subtrees
  60          end
  61 
  62          def store_translations(locale, data, options = {})
  63            escape = options.fetch(:escape, true)
  64            flatten_translations(locale, data, escape, @subtrees).each do |key, value|
  65              key = "#{locale}.#{key}"
  66 
  67              case value
  68              when Hash
  69                if @subtrees && (old_value = @store[key])
  70                  old_value = ActiveSupport::JSON.decode(old_value)
  71                  value = old_value.deep_symbolize_keys.deep_merge!(value) if old_value.is_a?(Hash)
  72                end
  73              when Proc
  74                raise "Key-value stores cannot handle procs"
  75              end
  76 
  77              @store[key] = ActiveSupport::JSON.encode(value) unless value.is_a?(Symbol)
  78            end
  79          end
  80 
  81          def available_locales
  82            locales = @store.keys.map { |k| k =~ /\./; $` }
  83            locales.uniq!
  84            locales.compact!
  85            locales.map! { |k| k.to_sym }
  86            locales
  87          end
  88 
  89        protected
  90 
  91          def lookup(locale, key, scope = [], options = {})
  92            key   = normalize_flat_keys(locale, key, scope, options[:separator])
  93            value = @store["#{locale}.#{key}"]
  94            value = ActiveSupport::JSON.decode(value) if value
  95            value.is_a?(Hash) ? value.deep_symbolize_keys : value
  96          end
  97        end
  98 
  99        include Implementation
 100      end
 101    end
 102  en