lib/session_off.rb
def session(*args)
      options = args.extract_options!

      options[:disabled] = false if args.delete(:on)
      options[:disabled] = true unless args.empty?
      options[:only] = [*options[:only]].map { |o| o.to_s } if options[:only]
      options[:except] = [*options[:except]].map { |o| o.to_s } if options[:except]
      if options[:only] && options[:except]
        raise ArgumentError, "only one of either :only or :except are allowed"
      end

      if session_options_array
        self.session_options_array += [ options ]
      else
        self.session_options_array  = [ options ]
      end
    end
def session(*args)
      options = args.extract_options!

      options[:disabled] = false if args.delete(:on)
      options[:disabled] = true unless args.empty?
      options[:only] = [*options[:only]].map { |o| o.to_s } if options[:only]
      options[:except] = [*options[:except]].map { |o| o.to_s } if options[:except]
      if options[:only] && options[:except]
        raise ArgumentError, "only one of either :only or :except are allowed"
      end

      if session_options_array
        self.session_options_array += [ options ]
      else
        self.session_options_array  = [ options ]
      end
    end
Specify how sessions ought to be managed for a subset of the actions on
 the controller. Like filters, you can specify <tt>:only</tt> and
 <tt>:except</tt> clauses to restrict the subset, otherwise options
 apply to all actions on this controller.

 The session options are inheritable, as well, so if you specify them in
 a parent controller, they apply to controllers that extend the parent.

 Usage:

   # turn off session management for all actions.
   session :off

   # turn off session management for all actions _except_ foo and bar.
   session :off, :except => %w(foo bar)

   # turn off session management for only the foo and bar actions.
   session :off, :only => %w(foo bar)

   # the session will only work over HTTPS, but only for the foo action
   session :only => :foo, :session_secure => true

   # the session by default uses HttpOnly sessions for security reasons.
   # this can be switched off.
   session :only => :foo, :session_http_only => false

   # the session will only be disabled for 'foo', and only if it is
   # requested as a web service
   session :off, :only => :foo,
           :if => Proc.new { |req| req.parameters[:ws] }

   # the session will be disabled for non html/ajax requests
   session :off,
     :if => Proc.new { |req| !(req.format.html? || req.format.js?) }

   # turn the session back on, useful when it was turned off in the
   # application controller, and you need it on in another controller
   session :on

 All session options described for ActionController::Base.process_cgi
 are valid arguments.