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Add Redis cache.

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1 parent 4339f71 commit ff291299db4fa6e2890694c475ed9dad090e4942 rogelio committed with joshthecoder Oct 1, 2011
Showing with 80 additions and 1 deletion.
  1. +80 −1 tweepy/cache.py
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@@ -301,4 +301,83 @@ def cleanup(self):
def flush(self):
"""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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