class Merb::Cache
cattr_accessor :cached_pages
self.cached_pages = {}
end
module Merb::Cache::ControllerClassMethods
# Mixed in Merb::Controller. Provides class methods related to page caching
# Page caching is mostly action caching with file backend using its own output directory of .html files
# Register the action for page caching
#
# ==== Parameters
# action<Symbol>:: The name of the action to register
# from_now<~minutes>::
# The number of minutes (from now) the cache should persist
#
# ==== Examples
# cache_page :mostly_static
# cache_page :barely_dynamic, 10
def cache_page(action, from_now = nil)
cache_pages([action, from_now])
end
# Register actions for page caching (before and after filters)
#
# ==== Parameter
# pages<Symbol,Array[Symbol,~minutes]>:: See #cache_page
#
# ==== Example
# cache_pages :mostly_static, [:barely_dynamic, 10]
def cache_pages(*pages)
if pages.any? && !Merb::Cache.cached_pages.key?(controller_name)
before(:cache_page_before)
after(:cache_page_after)
end
pages.each do |action, from_now|
_pages = Merb::Cache.cached_pages[controller_name] ||= {}
_pages[action] = [from_now, 0]
end
true
end
end
module Merb::Cache::ControllerInstanceMethods
# Mixed in Merb::Controller. Provides methods related to page caching
DEFAULT_PAGE_EXTENSION = 'html'
# Checks whether a cache entry exists
#
# ==== Parameter
# options<String,Hash>:: The options that will be passed to #key_for
#
# ==== Returns
# true if the cache entry exists, false otherwise
#
# ==== Example
# cached_page?(:action => 'show', :params => [params[:page]])
# cached_page?(:action => 'show', :extension => 'js')
def cached_page?(options)
key = Merb::Controller._cache.key_for(options, controller_name, true)
extension = options[:extension] || DEFAULT_PAGE_EXTENSION
File.file?(Merb::Controller._cache.config[:cache_html_directory] / "#{key}.#{extension}")
end
# Expires the page identified by the key computed after the parameters
#
# ==== Parameter
# options<String,Hash>:: The options that will be passed to #expire_key_for
#
# ==== Examples
# expire_page(:action => 'show', :controller => 'news')
# expire_page(:action => 'show', :match => true)
# expire_page(:action => 'show', :extension => 'js')
def expire_page(options)
config_dir = Merb::Controller._cache.config[:cache_html_directory]
Merb::Controller._cache.expire_key_for(options, controller_name, true) do |key, match|
if match
files = Dir.glob(config_dir / "#{key}*")
else
extension = options[:extension] || DEFAULT_PAGE_EXTENSION
files = config_dir / "#{key}.#{extension}"
end
FileUtils.rm_rf(files)
end
true
end
# Expires all the pages stored in config[:cache_html_directory]
def expire_all_pages
FileUtils.rm_rf(Dir.glob(Merb::Controller._cache.config[:cache_html_directory] / "*"))
end
# You can call this method if you need to prevent caching the page
# after it has been rendered.
def abort_cache_page
@capture_page = false
end
private
# Called by the before and after filters. Stores or recalls a cache entry.
# The name used for the cache file is based on request.path
# If the name ends with "/" then it is removed
# If the name is "/" then it will be replaced by "index"
#
# ==== Parameters
# data<String>:: the data to put in cache
#
# ==== Examples
# All the file are written to config[:cache_html_directory]
# If request.path is "/", the name will be "/index.html"
# If request.path is "/news/show/1", the name will be "/news/show/1.html"
# If request.path is "/news/show/", the name will be "/news/show.html"
# If request.path is "/news/styles.css", the name will be "/news/styles.css"
def _cache_page(data = nil)
return if Merb::Controller._cache.config[:disable_page_caching]
controller = controller_name
action = action_name.to_sym
pages = Merb::Controller._cache.cached_pages[controller]
return unless pages && pages.key?(action)
path = request.path.chomp("/")
path = "index" if path.empty?
no_format = params[:format].nil? || params[:format].empty?
ext = "." + (no_format ? DEFAULT_PAGE_EXTENSION : params[:format])
ext = nil if File.extname(path) == ext
cache_file = Merb::Controller._cache.config[:cache_html_directory] / "#{path}#{ext}"
if data
cache_directory = File.dirname(cache_file)
FileUtils.mkdir_p(cache_directory)
_expire_in = pages[action][0]
pages[action][1] = _expire_in.minutes.from_now unless _expire_in.nil?
cache_write_page(cache_file, data)
Merb.logger.info("cache: set (#{path})")
else
@capture_page = false
if File.file?(cache_file)
_data = cache_read_page(cache_file)
_expire_in, _expire_at = pages[action]
if _expire_in.nil? || Time.now < _expire_at
Merb.logger.info("cache: hit (#{path})")
throw(:halt, _data)
end
FileUtils.rm_f(cache_file)
end
@capture_page = true
end
true
end
# Read data from a file using exclusive lock
#
# ==== Parameters
# cache_file<String>:: the full path to the file
#
# ==== Returns
# data<String>:: the data that has been read from the file
def cache_read_page(cache_file)
_data = nil
File.open(cache_file, "r") do |cache_data|
cache_data.flock(File::LOCK_EX)
_data = cache_data.read
cache_data.flock(File::LOCK_UN)
end
_data
end
# Write data to a file using exclusive lock
#
# ==== Parameters
# cache_file<String>:: the full path to the file
# data<String>:: the data that will be written to the file
def cache_write_page(cache_file, data)
File.open(cache_file, "w+") do |cache_data|
cache_data.flock(File::LOCK_EX)
cache_data.write(data)
cache_data.flock(File::LOCK_UN)
end
true
end
# before filter
def cache_page_before
# recalls a cached entry or set @capture_page to true in order
# to grab the response in the after filter
_cache_page
end
# after filter
def cache_page_after
# takes the body of the response
# if the cache entry expired, if it doesn't exist or status is 200
_cache_page(body) if @capture_page && status == 200
end
end
