This is a pre-production deployment of Warehouse. Changes made here affect the production instance of PyPI (pypi.python.org).
Help us improve Python packaging - Donate today!

Caching results of functions in Python

Project Description

Caching results of functions in Python.

Features

  • Storing cached data either on disk or in memory
  • Setting up time-to-live and the number of function calls for your cache
  • Encryption of cached data (symmetric encryption (RSA) algorithm is used)

Note

  • Encryption functionality requires pycrypto package to be installed
  • When using cache-to-file functionality you have to to clean up (if needed) created file(s) manually

Examples

from cachepy import *

mycache = Cache() # cache to memory without encryption

@mycache
def my_heavy_function(x):
    """Performs heavy computations"""
    print('Hi, I am called...')
    return x**2

my_heavy_function(2)
# "Hi, I am called..." will be printed to stdout only once
my_heavy_function(2)

To store data to file, you need to create decorator as follows:

# create cache-to-file decorator
filecache = Cache('mycache.dat')

Its behaviour is the same as a memory-based one.

One can set up time-to-live and/or maximum number of retrievals for cached data when a decorator is created:

import time
from cachepy import *
# or from cachepy import Cache

cache_with_ttl = Cache(ttl=2) # ttl given in seconds

@cache_with_ttl
def my_heavy_function(x):
    """Performs heavy computations"""
    print('Hi, I am called...')
    return x**2

my_heavy_function(3)
my_heavy_function(3) # This will not print 'Hi, I am called ...'
time.sleep(2)
my_heavy_function(3) # 'Hi, I am called ...' will be printed again

cache_with_noc = Cache(noc=2) # Number-of-calls = 2

@cache_with_noc
def my_heavy_function(x):
    """Performs heavy computations"""
    print('Hi, I am called...')
    return x**2

my_heavy_function(3)
my_heavy_function(3) # This will not print 'Hi, I am called ...'
my_heavy_function(3) # 'Hi, I am called ...' will be printed again

It is easy to use both noc and ttl arguments on a cache decorator:

cache_with_noc_ttl = Cache(noc=2, ttl=1)

@cache_with_noc_ttl
def my_heavy_function(x):
    """Performs heavy computations"""
    print('Hi, I am called...')
    return x**2

my_heavy_function(3)
my_heavy_function(3) # This will not print 'Hi, I am called ...'
my_heavy_function(3) # This will print 'Hi, I am called ...'
time.sleep(2) # get ttl to be expired
my_heavy_function(3) # This will print 'Hi, I am called ...'

One can encrypt cached data by providing non-empty key argument as a password (RSA algo is used):

cache_to_file_ttl_noc = Cache('mycache.dat',
                               noc=2, ttl = 2, key='mypassword')

@cache_to_file_ttl_noc
def my_heavy_function(x):
    """Performs heavy computations"""
    print('Hi, I am called...')
    return x**2

my_heavy_function(2) # Will print 'Hi, I am called...'
my_heavy_function(2) # Will not print 'Hi, I am called...'

Calling the my_heavy_function function being decorated by cache_to_file_ttl_noc will store 4 (result of computations) in the file mycache.dat; along with the result of computations, additional info will be stored (these all will be encrypted by the RSA algo with the password mypassword): result expiration time (computed from ttl), noc and the number of performed calls of the decorated function (my_heavy_function). Data will not be encrypted, if pycrypto package isn’t installed. If you pass non- empty key parameter to the Cache constructor, the warning will occurred (“Pycrypto not installed. Data isn’t encrypted”); In this case, the cache will work without encryption functionality.

Testing

The code tested (and works as expected) in Python > 2.7.x and Python > 3.4.x.

python -m cachepy.tests

TODO

  • Writing backend for redis server
  • Testing in Python 3.x causes Error 11?!

Log list

  • Version 0.1

    • initial release

Code author: Dmitry Kislov <kislov@easydan.com>

Release History

Release History

This version
History Node

0.1

Download Files

Download Files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

File Name & Checksum SHA256 Checksum Help Version File Type Upload Date
cachepy-0.1.tar.gz (8.3 kB) Copy SHA256 Checksum SHA256 Source Mar 31, 2016

Supported By

WebFaction WebFaction Technical Writing Elastic Elastic Search Pingdom Pingdom Monitoring Dyn Dyn DNS Sentry Sentry Error Logging CloudAMQP CloudAMQP RabbitMQ Heroku Heroku PaaS Kabu Creative Kabu Creative UX & Design Fastly Fastly CDN DigiCert DigiCert EV Certificate Rackspace Rackspace Cloud Servers DreamHost DreamHost Log Hosting