cache.rb

Path: lib/i18n/backend/cache.rb
Last Update: Tue Apr 10 17:02:42 -0400 2012

This module allows you to easily cache all responses from the backend - thus speeding up the I18n aspects of your application quite a bit.

To enable caching you can simply include the Cache module to the Simple backend - or whatever other backend you are using:

  I18n::Backend::Simple.send(:include, I18n::Backend::Cache)

You will also need to set a cache store implementation that you want to use:

  I18n.cache_store = ActiveSupport::Cache.lookup_store(:memory_store)

You can use any cache implementation you want that provides the same API as ActiveSupport::Cache (only the methods fetch and write are being used).

The cache_key implementation assumes that you only pass values to I18n.translate that return a valid key from hash (see www.ruby-doc.org/core/classes/Object.html#M000337).

If you use a lambda as a default value in your translation like this:

  I18n.t(:"date.order", :default => lambda {[:month, :day, :year]})

Then you will always have a cache miss, because each time this method is called the lambda will have a different hash value. If you know the result of the lambda is a constant as in the example above, then to cache this you can make the lambda a constant, like this:

  DEFAULT_DATE_ORDER = lambda {[:month, :day, :year]}
  ...
  I18n.t(:"date.order", :default => DEFAULT_DATE_ORDER)

If the lambda may result in different values for each call then consider also using the Memoize backend.

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