lib/rabl/cache_engine.rb
# Defines the default cache engine for RABL when caching is invoked for a template.
# You can define your own caching engines by creating an object that responds to fetch and
# setting the configuration option:
#
# config.cache_engine = AdvancedCacheEngine.new
#
class LRU < Hash
attr_accessor :max_size
def initialize
super
self.max_size = 100_000
end
def []= k,v
r = super
limit_size
r
end
def limit_size
if size > max_size then
delete keys.shift while size > max_size
end
end
end
module Rabl
class CacheEngine
def initialize
unless defined?(Rails)
@cache = LRU.new
end
end
# Fetch given a key and options and a fallback block attempts to find the key in the cache
# and stores the block result in there if no key is found.
#
# cache = Rabl::CacheEngine.new; cache.fetch("some_key") { "fallback data" }
#
def fetch(key, cache_options, &block)
if defined?(Rails)
Rails.cache.fetch(key, cache_options, &block)
else
@cache[key] ||= yield
end
end
def write(key, value, options = {})
if defined?(Rails)
Rails.cache.write(key, value, options)
else
@cache[key] = yield
end
end
def read_multi(*keys)
options = keys.extract_options!
if defined?(Rails)
Rails.cache.read_multi(*keys, options)
else
keys.inject({}) { |hash, key| hash[key] = nil; hash }
end
end
end
end