core.ratelimit
==============

.. py:module:: core.ratelimit


Classes
-------

.. autoapisummary::

   core.ratelimit.RateLimit


Functions
---------

.. autoapisummary::

   core.ratelimit.cleanOldRateLocks


Module Contents
---------------

.. py:class:: RateLimit(resource, maxRate, minutes, method)

   Bases: :py:obj:`object`


   This class is used to restrict access to certain functions to *maxRate* calls per minute.

   Usage: Create an instance of this object in you modules __init__ function. then call
   isQuotaAvailable before executing the action to check if there is quota available and
   after executing the action decrementQuota.


   Initializes a new RateLimit gate.

   :param resource: Name of the resource to protect
   :param maxRate: Amount of tries allowed in the give time-span
   :param minutes: Length of the time-span in minutes
   :param method: Lock by IP or by the current user


   .. py:attribute:: rateLimitKind
      :value: 'viur-ratelimit'



   .. py:attribute:: resource


   .. py:attribute:: maxRate


   .. py:attribute:: minutes


   .. py:attribute:: steps


   .. py:attribute:: secondsPerStep


   .. py:attribute:: useUser


   .. py:method:: _getEndpointKey()

      :warning:
          It's invalid to call _getEndpointKey if method is set to user and there's no user logged in!

      :return: the key associated with the current endpoint (it's IP or the key of the current user)



   .. py:method:: _getCurrentTimeKey()

      :return: the current lockperiod used in second position of the memcache key



   .. py:method:: decrementQuota()

      Removes one attempt from the pool of available Quota for that user/ip



   .. py:method:: isQuotaAvailable()

      Checks if there's currently quota available for the current user/ip
      :return: True if there's quota available, False otherwise



   .. py:method:: assertQuotaIsAvailable(setRetryAfterHeader = True)

      Assert quota is available.

      If not quota is available a :class:`viur.core.errors.TooManyRequests`
      exception will be raised.

      :param setRetryAfterHeader: Set the Retry-After header on the
          current request response, if the quota is exceeded.
      :return: True if quota is available.
      :raises: :exc:`viur.core.errors.TooManyRequests`, if no quote is available.



.. py:function:: cleanOldRateLocks(*args, **kwargs)