Add ActionDispatch::Session::CacheStore as a generic way of storing sessions in a cache.

2 files changed, 51 insertions, 0 deletions

diff --git a/actionpack/lib/action_dispatch.rb b/actionpack/lib/action_dispatch.rb
index c13850f378..1e92d14542 100644
--- a/actionpack/lib/action_dispatch.rb
+++ b/actionpack/lib/action_dispatch.rb
@@ -83,6 +83,7 @@ module ActionDispatch
     autoload :AbstractStore, 'action_dispatch/middleware/session/abstract_store'
     autoload :CookieStore,   'action_dispatch/middleware/session/cookie_store'
     autoload :MemCacheStore, 'action_dispatch/middleware/session/mem_cache_store'
+    autoload :CacheStore,    'action_dispatch/middleware/session/cache_store'
   end
 
   autoload_under 'testing' do
diff --git a/actionpack/lib/action_dispatch/middleware/session/cache_store.rb b/actionpack/lib/action_dispatch/middleware/session/cache_store.rb
new file mode 100644
index 0000000000..d3b6fd12fa
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/session/cache_store.rb
@@ -0,0 +1,50 @@
+require 'action_dispatch/middleware/session/abstract_store'
+require 'rack/session/memcache'
+
+module ActionDispatch
+  module Session
+    # Session store that uses an ActiveSupport::Cache::Store to store the sessions. This store is most useful
+    # if you don't store critical data in your sessions and you don't need them to live for extended periods
+    # of time.
+    class CacheStore < AbstractStore
+      # Create a new store. The cache to use can be passed in the <tt>:cache</tt> option. If it is
+      # not specified, <tt>Rails.cache</tt> will be used.
+      def initialize(app, options = {})
+        @cache = options[:cache] || Rails.cache
+        options[:expire_after] ||= @cache.options[:expires_in]
+        super
+      end
+
+      # Get a session from the cache.
+      def get_session(env, sid)
+        sid ||= generate_sid
+        session = @cache.read(cache_key(sid))
+        session ||= {}
+        [sid, session]
+      end
+
+      # Set a session in the cache.
+      def set_session(env, sid, session, options)
+        key = cache_key(sid)
+        if session
+          @cache.write(key, session, :expires_in => options[:expire_after])
+        else
+          @cache.delete(key)
+        end
+        sid
+      end
+
+      # Remove a session from the cache.
+      def destroy_session(env, sid, options)
+        @cache.delete(cache_key(sid))
+        generate_sid
+      end
+
+      private
+        # Turn the session id into a cache key.
+        def cache_key(sid)
+          "_session_id:#{sid}"
+        end
+    end
+  end
+end