cache.py

# Standard library imports
from datetime import datetime
from pathlib import Path
from pickle import dumps, loads


class CachedObject:
	def __init__(self, value):
		self.value = value
		self.cached_at = datetime.now()


class Cache:
	def __init__(self, cache={}):
		self.cache = cache

	def get(self, table, key, expires_after=None):
		if not self.cache.get(table):
			self.cache[table] = {}

		item = self.cache[table].get(key)

		if item and not (expires_after and item.cached_at + expires_after <= datetime.now()):
			return item.value

	def put(self, table, key, value):
		if not self.cache.get(table):
			self.cache[table] = {}

		self.cache[table][key] = CachedObject(value)
		return value

	def save(self, file_name='cache.pkl'):
		with open(file_name, 'wb') as file:
			file.write(dumps(self.cache))

	@classmethod
	def load(this, file_name='cache.pkl'):
		if Path(file_name).is_file():
			with open(file_name, 'rb') as file:
				return this(loads(file.read()))
		else:
			return this()