114 lines
3.4 KiB
Ruby
114 lines
3.4 KiB
Ruby
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# frozen_string_literal: true
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# This module allows you to easily cache all responses from the backend - thus
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# speeding up the I18n aspects of your application quite a bit.
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#
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# To enable caching you can simply include the Cache module to the Simple
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# backend - or whatever other backend you are using:
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#
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# I18n::Backend::Simple.send(:include, I18n::Backend::Cache)
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#
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# You will also need to set a cache store implementation that you want to use:
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#
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# I18n.cache_store = ActiveSupport::Cache.lookup_store(:memory_store)
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#
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# You can use any cache implementation you want that provides the same API as
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# ActiveSupport::Cache (only the methods #fetch and #write are being used).
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#
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# The cache_key implementation by default assumes you pass values that return
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# a valid key from #hash (see
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# http://www.ruby-doc.org/core/classes/Object.html#M000337). However, you can
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# configure your own digest method via which responds to #hexdigest (see
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# http://ruby-doc.org/stdlib/libdoc/digest/rdoc/index.html):
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#
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# I18n.cache_key_digest = Digest::MD5.new
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#
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# If you use a lambda as a default value in your translation like this:
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#
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# I18n.t(:"date.order", :default => lambda {[:month, :day, :year]})
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#
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# Then you will always have a cache miss, because each time this method
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# is called the lambda will have a different hash value. If you know
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# the result of the lambda is a constant as in the example above, then
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# to cache this you can make the lambda a constant, like this:
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#
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# DEFAULT_DATE_ORDER = lambda {[:month, :day, :year]}
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# ...
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# I18n.t(:"date.order", :default => DEFAULT_DATE_ORDER)
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#
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# If the lambda may result in different values for each call then consider
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# also using the Memoize backend.
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#
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module I18n
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class << self
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@@cache_store = nil
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@@cache_namespace = nil
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@@cache_key_digest = nil
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def cache_store
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@@cache_store
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end
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def cache_store=(store)
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@@cache_store = store
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end
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def cache_namespace
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@@cache_namespace
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end
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def cache_namespace=(namespace)
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@@cache_namespace = namespace
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end
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def cache_key_digest
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@@cache_key_digest
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end
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def cache_key_digest=(key_digest)
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@@cache_key_digest = key_digest
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end
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def perform_caching?
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!cache_store.nil?
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end
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end
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module Backend
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# TODO Should the cache be cleared if new translations are stored?
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module Cache
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def translate(locale, key, options = EMPTY_HASH)
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I18n.perform_caching? ? fetch(cache_key(locale, key, options)) { super } : super
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end
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protected
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def fetch(cache_key, &block)
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result = _fetch(cache_key, &block)
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throw(:exception, result) if result.is_a?(MissingTranslation)
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result = result.dup if result.frozen? rescue result
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result
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end
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def _fetch(cache_key, &block)
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result = I18n.cache_store.read(cache_key)
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return result unless result.nil?
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result = catch(:exception, &block)
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I18n.cache_store.write(cache_key, result) unless result.is_a?(Proc)
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result
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end
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def cache_key(locale, key, options)
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# This assumes that only simple, native Ruby values are passed to I18n.translate.
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"i18n/#{I18n.cache_namespace}/#{locale}/#{digest_item(key)}/#{digest_item(options)}"
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end
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private
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def digest_item(key)
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I18n.cache_key_digest ? I18n.cache_key_digest.hexdigest(key.to_s) : key.to_s.hash
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end
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end
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end
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end
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