api.py

import recurly as recurly_api
from django.core.cache import cache
from django.conf import settings
from hashlib import sha512

def string_to_key(string):
    return sha512(string).hexdigest()[:250]  # max size of caching keys in memcached


def function_cache(timeout=300, override_key=None):
    def decorator(func):
        def wrapper(*args, **kwargs):
            if not timeout:
                return func(*args, **kwargs)
            if override_key:
                cache_key = string_to_key(override_key)
            else:
                caching_keys = [func.__name__]
                if args is not None:
                    caching_keys.extend(args)
                if kwargs is not None:
                    caching_keys.extend(sorted(kwargs.iteritems()))
                caching_keys = map(str, caching_keys)
                cache_key = '_'.join(caching_keys)
                cache_key = string_to_key(cache_key)
            output = cache.get(cache_key)
            if output is None:
                output = func(*args, **kwargs)
                cache.set(cache_key, output, timeout)
            return output
        return wrapper
    return decorator


class CachedObject(object):

    CACHE_TIME = 60*60*24
    CACHED_ATRIBUTES = ()

    def __getattr__(self, name, skip_cache=False):
        if not skip_cache and name in self.CACHED_ATRIBUTES:
            @function_cache(self.CACHE_TIME, "%s%s" % (self.__class__, name))
            def cache_getattr(obj, name):
                return obj.__getattr__(name, True)
            return cache_getattr(self, name)
        else:
            return super(CachedObject, self).__getattr__(name)


    def __setattr__(self, name, value):
        if name in self.CACHED_ATRIBUTES:
            cache.set(string_to_key("%s%s" % (self.__class__, name)), value, self.CACHE_TIME)
        return super(CachedObject, self).__setattr__(name, value)


class CachedAccount(CachedObject, recurly_api.Account):

    CACHE_TIME = 60*60*24
    CACHED_ATRIBUTES = ('billing_info',)

    def __init__(self, *args, **kwargs):
        super(CachedAccount, self).__init__(*args, **kwargs)


    @classmethod
    @function_cache(CACHE_TIME)
    def get(cls, uuid):
        return super(CachedAccount, cls).get(uuid)


    def update_billing_info(self, billing_info):
        self.billing_info = billing_info
        super(CachedAccount, self).update_billing_info(billing_info)