vendor/rails/actionpack/lib/action_controller/session/mem_cache_store.rb

   1 # cgi/session/memcached.rb - persistent storage of marshalled session data
   2 #
   3 # == Overview
   4 #
   5 # This file provides the CGI::Session::MemCache class, which builds
   6 # persistence of storage data on top of the MemCache library.  See
   7 # cgi/session.rb for more details on session storage managers.
   8 #
   9
  10 begin
  11   require 'cgi/session'
  12   require_library_or_gem 'memcache'
  13
  14   class CGI
  15     class Session
  16       # MemCache-based session storage class.
  17       #
  18       # This builds upon the top-level MemCache class provided by the
  19       # library file memcache.rb.  Session data is marshalled and stored
  20       # in a memcached cache.
  21       class MemCacheStore
  22         def check_id(id) #:nodoc:#
  23           /[^0-9a-zA-Z]+/ =~ id.to_s ? false : true
  24         end
  25
  26         # Create a new CGI::Session::MemCache instance
  27         #
  28         # This constructor is used internally by CGI::Session. The
  29         # user does not generally need to call it directly.
  30         #
  31         # +session+ is the session for which this instance is being
  32         # created. The session id must only contain alphanumeric
  33         # characters; automatically generated session ids observe
  34         # this requirement.
  35         #
  36         # +options+ is a hash of options for the initializer. The
  37         # following options are recognized:
  38         #
  39         # cache::  an instance of a MemCache client to use as the
  40         #      session cache.
  41         #
  42         # expires:: an expiry time value to use for session entries in
  43         #     the session cache. +expires+ is interpreted in seconds
  44         #     relative to the current time if it\92s less than 60*60*24*30
  45         #     (30 days), or as an absolute Unix time (e.g., Time#to_i) if
  46         #     greater. If +expires+ is +0+, or not passed on +options+,
  47         #     the entry will never expire.
  48         #
  49         # This session's memcache entry will be created if it does
  50         # not exist, or retrieved if it does.
  51         def initialize(session, options = {})
  52           id = session.session_id
  53           unless check_id(id)
  54             raise ArgumentError, "session_id '%s' is invalid" % id
  55           end
  56           @cache = options['cache'] || MemCache.new('localhost')
  57           @expires = options['expires'] || 0
  58           @session_key = "session:#{id}"
  59           @session_data = {}
  60           # Add this key to the store if haven't done so yet
  61           unless @cache.get(@session_key)
  62             @cache.add(@session_key, @session_data, @expires)
  63           end
  64         end
  65
  66         # Restore session state from the session's memcache entry.
  67         #
  68         # Returns the session state as a hash.
  69         def restore
  70           @session_data = @cache[@session_key] || {}
  71         end
  72
  73         # Save session state to the session's memcache entry.
  74         def update
  75           @cache.set(@session_key, @session_data, @expires)
  76         end
  77
  78         # Update and close the session's memcache entry.
  79         def close
  80           update
  81         end
  82
  83         # Delete the session's memcache entry.
  84         def delete
  85           @cache.delete(@session_key)
  86           @session_data = {}
  87         end
  88
  89         def data
  90           @session_data
  91         end
  92
  93       end
  94     end
  95   end
  96 rescue LoadError
  97   # MemCache wasn't available so neither can the store be
  98 end