diff --git a/app/controllers/long_polling_controller.rb b/app/controllers/long_polling_controller.rb
index 5512175e8..fa5a99b6b 100644
--- a/app/controllers/long_polling_controller.rb
+++ b/app/controllers/long_polling_controller.rb
@@ -59,7 +59,7 @@ class LongPollingController < ApplicationController
       user_id = session[:user_id]
       user = {}
       if user_id
-        user = User.find( user_id )
+        user = User.find( user_id ).attributes
       end
       log 'notice', "send auth login (user_id #{user_id})", client_id
       Sessions.create( client_id, user, { :type => 'ajax' } )
diff --git a/lib/sessions.rb b/lib/sessions.rb
index 7d299ee7e..0962312d9 100644
--- a/lib/sessions.rb
+++ b/lib/sessions.rb
@@ -37,7 +37,7 @@ returns
         :user => session,
         :meta => meta,
       }
-      file.write Marshal.dump(data)
+      file.write data.to_json
     }
 
     # send update to browser
@@ -195,7 +195,7 @@ returns
     path = @path + '/' + client_id.to_s
     data[:meta][:last_ping] = Time.new.to_i.to_s
     File.open( path + '/session', 'wb' ) { |file|
-      file.write Marshal.dump(data)
+      file.write data.to_json
     }
     true
   end
@@ -234,7 +234,11 @@ returns
         file.flock( File::LOCK_EX )
         all = file.read
         file.flock( File::LOCK_UN )
-        data = Marshal.load( all )
+        dataJSON = JSON.parse( all )
+        if dataJSON
+          data = self.symbolize_keys(dataJSON)
+          data[:user] = dataJSON['user'] # for compat. reasons
+        end
       }
     rescue Exception => e
       puts e.inspect
@@ -567,4 +571,19 @@ returns
     puts "/LOOP #{client_id} - #{try_count}"
   end
 
-end
+  def self.symbolize_keys(hash)
+    hash.inject({}){|result, (key, value)|
+      new_key = case key
+                when String then key.to_sym
+                else key
+                end
+      new_value = case value
+                  when Hash then symbolize_keys(value)
+                  else value
+                  end
+      result[new_key] = new_value
+      result
+    }
+  end
+
+end
\ No newline at end of file