timecache 0.0.3

Time Cache

timecache is a timeout-based cache implementation for Python 3.x without any external dependencies. Depending on the selected backend, the cache can be made persistent to survive a fresh start of a script (currently, json and pickle files are supported as backend).

Warning: this is an early alpha version so the interface may change in future versions.

Setup

Install timecache using pip:

pip install -U timecache

Example

A cache with a memory backend can be created as follows:

import time
from timecache import Cache, FIVE_SECONDS

# create cache with memory backend
cache = Cache()

# add a value to the cache with a default duration of 1 minute
cache["one"] = 1

# add a value to the cache with a duration of 5 seconds
cache.set("two", 2, FIVE_SECONDS)

print("two in cache: {}".format("two" in cache))

# show cache entry
print(cache)

# wait for 6 s
time.sleep(6)

# show cache entry
print(cache)

print("two in cache: {}".format("two" in cache))

A cache with a json file backend can be created as follows:

import time
from timecache import Cache, JsonBackend, FIVE_SECONDS

# create cache with json backend
cache = Cache(backend=JsonBackend())

if not cache.is_existing:
    # add a value to the cache with a default duration of 1 minute
    print("adding new value to the cache...")
    cache["one"] = 1
    print("savíng cache to file '{}'".format(cache.filename))
    cache.save()

# show cache entry
print(cache)

When calling the script again the cached value will be loaded from the json file.

Testing

For testing additionally install nose and then run the tests:

pip install nose
nosetests

Hint

If you do not need a time-based cache, consider the lru_cache function of Python’s functools module (https://docs.python.org/3/library/functools.html).