require 'active_support/core_ext/object/try' module ActionView module CollectionCaching # :nodoc: extend ActiveSupport::Concern included do # Fallback cache store if Action View is used without Rails. # Otherwise overridden in Railtie to use Rails.cache. mattr_accessor(:collection_cache) { ActiveSupport::Cache::MemoryStore.new } end private def cache_collection_render return yield unless cache_collection? keyed_collection = collection_by_cache_keys partial_cache = collection_cache.read_multi(*keyed_collection.keys) @collection = keyed_collection.reject { |key, _| partial_cache.key?(key) }.values rendered_partials = @collection.any? ? yield.dup : [] fetch_or_cache_partial(partial_cache, order_by: keyed_collection.each_key) do rendered_partials.shift end end def cache_collection? @options.fetch(:cache, automatic_cache_eligible?) end def automatic_cache_eligible? single_template_render? && !callable_cache_key? && @template.eligible_for_collection_caching?(as: @options[:as]) end def single_template_render? @template # Template is only set when a collection renders one template. end def callable_cache_key? @options[:cache].respond_to?(:call) end def collection_by_cache_keys seed = callable_cache_key? ? @options[:cache] : ->(i) { i } @collection.each_with_object({}) do |item, hash| hash[expanded_cache_key(seed.call(item))] = item end end def expanded_cache_key(key) key = @view.fragment_cache_key(@view.cache_fragment_name(key)) key.frozen? ? key.dup : key # #read_multi & #write may require mutability, Dalli 2.6.0. end def fetch_or_cache_partial(cached_partials, order_by:) cache_options = @options[:cache_options] || @locals[:cache_options] || {} order_by.map do |key| cached_partials.fetch(key) do yield.tap do |rendered_partial| collection_cache.write(key, rendered_partial, cache_options) end end end end end end