code: function get_username(req,next){
      if(req.session !== undefined && req.session.name !== undefined){
          return next(null,{'user_name':req.session.name})
      }else{
          return next(null,{})
      }
  }
docs: get_username
  
  get the user name provided by the CAS server, stored in the current session
  
  You can also directly access them at req.session.name, but
  just in case that changes you can always rely on this to do the
  right thing
  
  will invoke the callback with (error,{'username':username})
  
  If there is no username (perhaps you do not have a CAS session),
  then it will invoke callback with (error,{}) (an empty object)
  
  @param {Object} req the http.IncomingMessage (from express or connect)
  @param {Function} next the callback to invoke with the username object
  @return {Object} returns whatever next invocation returns
  @api public