PhpSessionStore middleware to allow sharing session with legacy PHP app

php_session_store.rb

# Overrides functionality in Rack::Session::Memcache from Rack 1.4.1 to support sharing PHP sessions
# - PHP side is 5.3.6 configured with session.save_handler = memcache
# - Requires php-serialize gem for serialization: https://github.com/jqr/php-serialize

module ActionDispatch
  module Session
    class PhpSessionStore < ActionDispatch::Session::MemCacheStore
      require 'php_serialize'
      
      def initialize(app, options = {})
        require 'memcache'
        options[:expire_after] ||= options[:expires]
        
        # Default to no namespace and cookie name matching PHP settings
        super(app, options.merge(:namespace => nil, :key => 'PHPSESSID'))
      end
      
      def get_session(env, sid)
        with_lock(env, [nil, {}]) do
          unless session = deserialize_session(sid)
            sid, session = generate_sid, {}
            
            unless /^STORED/ =~ @pool.add(sid, PHP.serialize_session(session), 0, true)
              raise "Session collision on '#{sid.inspect}'"
            end
          end
          [sid, session]
        end
      end
      
      def set_session(env, session_id, new_session, options)
        expiry = options[:expire_after]
        expiry = expiry.nil? ? 0 : expiry + 1

        with_lock(env, false) do
          @pool.set session_id, PHP.serialize_session(new_session), expiry, true
          session_id
        end
      end

      protected

      def deserialize_session(session_id)
        if session_id
          raw_session = @pool.get(session_id, true)

          if raw_session && raw_session != ''
            PHP.unserialize(raw_session)
          end
        end
      end
    end
  end
end