python-expirecache

A process-safe low-level python adapter to handle cache expiration.

Install

$ pip install expirecache

Usage

from expirecache import Cache

ec = Cache(cache,
  load = None,
  allow_stale = True)

ec.set('my-key', 'blah-blah', expire = 60 * 60)

Cache(cache, load = None, allow_stale = True)

• cache the cache instance to be wrapped. It should contain 3 methods:
  • set function(key, value)
  • get function(key)
  • remove function(key)
• load function(key) method to load the new value of the key. When ec.get(key) is called, if the key is expired, expirecache will try use this method to load the new value, set the key, and returns the new value. During the loading process, a lock key will set the prevent other processes to load the
• allow_stale bool=True by default, if a key has expired, we could still get the stale value of the key.

And then, one hour later:

ec.get('my-key'); // 'blah-blah', it is stale, but we could still get it.
ec.has('my-key'); // False. Always use `ec.has()` to check if a key has expired.

ec.has(key)

Checks if the key is in the cache. If the key has expired, it will return False.

ALWAYS use this method to detect if the key is available.

ec.get(key)

Gets the value. If allow_stale is True, and the key has expired, this method would still get the old(stale) value of the key.

ec.set(key, value, expire = None)

• expire int|None the unit of expire is 'second'

Sets a value by key.

ec.remove(key)

Removes a key.

License

MIT