# Copyright (c) 2006 Richard Livsey, 2008 Steffen Rusitschka
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
module ActionController
module Caching
# Timed Fragment Caching
# Adds optional expiry to fragment caching which will cache that fragment for the alloted time
# Works by adding a 'meta' fragment for each timed fragment (inspired by metafragment code in typo
# http://www.typosphere.org/trac/browser/trunk/vendor/plugins/expiring_action_cache/lib/metafragment.rb)
#
# Works something like this:
#
# <% cache 'fragment_name', 10.minutes.from_now do %>
# the cached fragment which does something intensive
# <% end %>
#
# This will be cached for 10 minutes before it expires
#
# Also adds when_fragment_expired which you can use to only execute code if the fragment is not cached, or has
# expired:
#
# when_fragment_expired 'fragment_name', 10.minutes_from_now do
# # some intensive code
# end
#
# Note that if using the 'when_fragment_expired' in the controller, you don't need the expiry in the call to cache
# in the template, as 'when_fragment_expired' will expire the fragment for you.
module TimedFragment
def self.included(base) # :nodoc:
base.class_eval do
alias_method :write_fragment_without_expiry, :write_fragment
alias_method :write_fragment, :write_fragment_with_expiry
end
end
def write_fragment_with_expiry(name, content, options = nil, expiry = nil)
unless perform_caching then return content end
if expiry && fragment_expired?(name)
expire_and_write_meta(name, expiry)
end
write_fragment_without_expiry(name, content, options)
end
def expiry_time(name)
read_meta_fragment(name)
end
def fragment_expired?(name)
return true unless read_fragment(name)
expires = expiry_time(name)
expires.nil? || expires < Time.now
end
def read_meta_fragment(name)
YAML.load(read_fragment(meta_fragment_key(name))) rescue nil
end
def write_meta_fragment(name, meta)
write_fragment_without_expiry(meta_fragment_key(name), YAML.dump(meta))
end
def meta_fragment_key(name)
fragment_cache_key(name) + '_meta'
end
def when_fragment_expired(name, expiry=nil)
return unless fragment_expired?(name)
yield
expire_and_write_meta(name, expiry)
end
def expire_and_write_meta(name, expiry)
expire_fragment(name)
write_meta_fragment(name, expiry) if expiry
end
end
end
end
module ActionView
module Helpers
module TimedFragmentCacheHelper
def self.included(base) # :nodoc:
base.class_eval do
alias_method :cache_without_expiry, :cache
alias_method :cache, :cache_with_expiry
end
end
def cache_with_expiry(name = {}, expires = nil, &block)
if expires && @controller.fragment_expired?(name)
@controller.expire_and_write_meta(name, expires)
end
cache_without_expiry(name, &block)
end
end
end
end
ActionController::Base.send :include, ActionController::Caching::TimedFragment
ActionView::Base.send(:include, ActionView::Helpers::TimedFragmentCacheHelper)
