Source code for cement.ext.ext_redis

"""
Cement redis extension module.
"""

import redis
from ..core import cache
from ..utils.misc import minimal_logger

LOG = minimal_logger(__name__)


[docs]class RedisCacheHandler(cache.CacheHandler): """ This class implements the :ref:`Cache <cement.core.cache>` Handler interface. It provides a caching interface using the `redis <http://github.com/andymccurdy/redis-py>`_ library. **Note** This extension has an external dependency on ``redis``. You must include ``redis`` in your applications dependencies as Cement explicitly does *not* include external dependencies for optional extensions. """
[docs] class Meta: """Handler meta-data.""" label = 'redis' config_defaults = dict( host='127.0.0.1', port=6379, db=0, expire_time=0, )
def __init__(self, *args, **kw): super(RedisCacheHandler, self).__init__(*args, **kw) self.mc = None
[docs] def _setup(self, *args, **kw): super(RedisCacheHandler, self)._setup(*args, **kw) self.r = redis.StrictRedis( host=self._config('host', default='127.0.0.1'), port=self._config('port', default=6379), db=self._config('db', default=0))
[docs] def _config(self, key, default=None): """ This is a simple wrapper, and is equivalent to: ``self.app.config.get('cache.redis', <key>)``. Args: key (str): The key to get a config value from the ``cache.redis`` config section. Returns: unknown: The value of the given key. """ return self.app.config.get(self._meta.config_section, key)
[docs] def get(self, key, fallback=None, **kw): """ Get a value from the cache. Additional keyword arguments are ignored. Args: key (str): The key of the item in the cache to get. Keyword Args: fallback: The value to return if the item is not found in the cache. Returns: unknown: The value of the item in the cache, or the ``fallback`` value. """ LOG.debug("getting cache value using key '%s'" % key) res = self.r.get(key) if res is None: return fallback else: return res.decode('utf-8')
[docs] def set(self, key, value, time=None, **kw): """ Set a value in the cache for the given ``key``. Additional keyword arguments are ignored. Args: key (str): The key of the item in the cache to set. value: The value of the item to set. time (int): The expiration time (in seconds) to keep the item cached. Defaults to ``expire_time`` as defined in the applications configuration. """ if time is None: time = int(self._config('expire_time')) if time == 0: self.r.set(key, value) else: self.r.setex(key, time, value)
[docs] def delete(self, key, **kw): """ Delete an item from the cache for the given ``key``. Additional keyword arguments are ignored. Args: key (str): The key to delete from the cache. """ self.r.delete(key)
[docs] def purge(self, **kw): """ Purge the entire cache, all keys and values will be lost. Any additional keyword arguments will be passed directly to the redis ``flush_all()`` function. """ keys = self.r.keys('*') if keys: self.r.delete(*keys)
def load(app): app.handler.register(RedisCacheHandler)