DLC's tornado.web.RequestHandler add on's

basehandler.py

class BaseHandler(tornado.web.RequestHandler):
  #lazy initializer of Connection reference
  @property
  def db(self):
    if not hasattr(self, '_db'):
      self._db = Connection(options.db_master, options.db_port)[options.db_name]
    return self._db

  #overriding the default get_current_user to use an encrypted, pickled python object
  def get_current_user(self):
    cookie_string = self.get_secure_cookie(options.cookie_user)
    try:
      return pickle.loads(cookie_string)
    except:
      return None
  
  #this allows you to access alerts in a unified manner
  #without relying on server side sessions	
  def get_flash_alerts(self):
    alerts = self.get_secure_cookie(options.cookie_alerts)
    try:
      alerts = pickle.loads(alerts)
      self.clear_cookie(options.cookie_alerts)
      return alerts
    except:
      return None
  
  #override the default render method to inject in the flash alerts,
  #or other properties	
  def render(self, *args, **kwargs):
    flash_alerts = self.get_flash_alerts()
    if 'alerts' not in kwargs:
      kwargs['alerts'] = flash_alerts
    elif flash_alerts is not None:
      kwargs['alerts'].extend(flash_alerts)
    tornado.web.RequestHandler.render(self, *args, **kwargs)
  
  #override the default error pages with your own html
  def write_error(self, status_code, **kwargs):
    error_trace = None
    if self.settings.get("debug") and "exc_info" in kwargs:
      import traceback
      error_trace= ""
      for line in traceback.format_exception(*kwargs["exc_info"]):
        error_trace += line 
    self.render("base_error.html", status_code=status_code, error_trace=error_trace)