Commit ff291299 authored by rogelio's avatar rogelio Committed by Joshua Roesslein
Browse files

Add Redis cache.

parent 4339f719
...@@ -301,4 +301,83 @@ class MemCacheCache(Cache): ...@@ -301,4 +301,83 @@ class MemCacheCache(Cache):
def flush(self): def flush(self):
"""Delete all cached entries. NO-OP""" """Delete all cached entries. NO-OP"""
pass raise NotImplementedError
class RedisCache(Cache):
'''Cache running in a redis server'''
def __init__(self, client, timeout=60, keys_container = 'tweepy:keys', pre_identifier = 'tweepy:'):
Cache.__init__(self, timeout)
self.client = client
self.keys_container = keys_container
self.pre_identifier = pre_identifier
def _is_expired(self, entry, timeout):
# Returns true if the entry has expired
return timeout > 0 and (time.time() - entry[0]) >= timeout
def store(self, key, value):
'''Store the key, value pair in our redis server'''
# Prepend tweepy to our key, this makes it easier to identify tweepy keys in our redis server
key = self.pre_identifier + key
# Get a pipe (to execute several redis commands in one step)
pipe = self.client.pipeline()
# Set our values in a redis hash (similar to python dict)
pipe.set(key, pickle.dumps((time.time(), value)))
# Set the expiration
pipe.expire(key, self.timeout)
# Add the key to a set containing all the keys
pipe.sadd(self.keys_container, key)
# Execute the instructions in the redis server
pipe.execute()
def get(self, key, timeout=None):
'''Given a key, returns an element from the redis table'''
key = self.pre_identifier + key
# Check to see if we have this key
unpickled_entry = self.client.get(key)
if not unpickled_entry:
# No hit, return nothing
return None
entry = pickle.loads(unpickled_entry)
# Use provided timeout in arguments if provided
# otherwise use the one provided during init.
if timeout is None:
timeout = self.timeout
# Make sure entry is not expired
if self._is_expired(entry, timeout):
# entry expired, delete and return nothing
self.delete_entry(key)
return None
# entry found and not expired, return it
return entry[1]
def count(self):
'''Note: This is not very efficient, since it retreives all the keys from the redis
server to know how many keys we have'''
return len(self.client.smembers(self.keys_container))
def delete_entry(self, key):
'''Delete an object from the redis table'''
pipe = self.client.pipeline()
pipe.srem(self.keys_container, key)
pipe.delete(key)
pipe.execute()
def cleanup(self):
'''Cleanup all the expired keys'''
keys = self.client.smembers(self.keys_container)
for key in keys:
entry = self.client.get(key)
if entry:
entry = pickle.loads(entry)
if self._is_expired(entry, self.timeout):
self.delete_entry(key)
def flush(self):
'''Delete all entries from the cache'''
keys = self.client.smembers(self.keys_container)
for key in keys:
self.delete_entry(key)
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