Introduction

This library provides the same experience of builtin dict, plus automatical time-to-live (TTL) management.

How it Works

Different from some other libraries, this one does not require background thread and guarantees that the expired items do not affect results.

Note that technically our TTLDict class is a subclass of MutableMapping instead of dict.

Internally, it utilizes a dict to manage expiries. Because every item has the same TTL, the insert order of the dict matches the expiry order.

How to Install

Simply run pip install time-to-live-dict.

How to Use

It works just like builtin dict:

In [1]: from ttl_dict import TTLDict

In [2]: from datetime import timedelta

In [3]: from time import sleep

In [4]: ttl = timedelta(seconds=2)
   ...:
   ...: d = TTLDict(ttl, {"a": 1})
   ...: print(d)
   ...:
   ...: sleep(1)
   ...: print(d)
   ...:
   ...: sleep(1)
   ...: print(d)
{'a': 1}
{'a': 1}
{}

In [5]: ttl1 = timedelta(seconds=2)
   ...: ttl2 = timedelta(seconds=4)
   ...:
   ...: d1 = TTLDict(ttl1, {"a": 1})
   ...: d2 = TTLDict(ttl2, {"b": 2})
   ...:
   ...: d = d1 | d2
   ...: print(d)
   ...:
   ...: sleep(2)
   ...: print(d)
   ...:
   ...: sleep(2)
   ...: print(d)
{'a': 1, 'b': 2}
{'b': 2}
{}

In additional, it offers a few new methods:

• cleanup() cleans up all expired items. Note that this method is called automatically.
• cleanup_by_key(key) cleans up item with specified key if it is expired. Note that this method is called automatically.
• get_expiry(key) gets the expiry of specified key if it is not expired yet
• renew_expiry(key) renews the expiry of specified key (as if it was just inserted into)