Cache for Django model properties.

decorators.py

from __future__ import unicode_literals
import functools

from django.core.cache import cache


class cached(object):
    """Save the return of the function on the cache.
    """

    def __init__(self, timeout=None, model=None):
        self.timeout = timeout
        self.model = model

    def __call__(self, func):
        @functools.wraps(func)
        def decorated(instance, *args, **kwargs):
            if self.model is None:
                self.model = instance._meta.model_name

            # Set the cache name
            self.cache_name = '{}_{}'.format(self.model, func.__name__)

            # Check if the cache exists
            if cache.get(self.cache_name) is None:
                cache_dict = {}
            else:
                cache_dict = cache.get(self.cache_name)

            # Check if the result for the current is cached
            if instance.pk in cache_dict:
                # Return the cached result
                return cache_dict[instance.pk]

            # Calculate the value of the current method
            val = func(instance, *args, **kwargs)

            # Update the cache dictionary of values with the new value
            cache_dict[instance.pk] = val

            # Save the cache
            cache.set(self.cache_name, cache_dict, self.timeout)

            # Return the calculated value
            return val

        # Execute the callback
        return decorated