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from __future__ import annotations
import sys
import warnings
from typing import Any
from django.conf import settings
from django.core.cache import BaseCache, caches
from django.db import models
from django_solo import settings as solo_settings
if sys.version_info >= (3, 11):
from typing import Self
else:
from typing_extensions import Self
DEFAULT_SINGLETON_INSTANCE_ID = 1
def get_cache(cache_name: str) -> BaseCache:
warnings.warn(
"'get_cache' is deprecated and will be removed in django-solo 2.4.0. "
"Instead, use 'caches' from 'django.core.cache'.",
DeprecationWarning,
stacklevel=2,
)
return caches[cache_name]
class SingletonModel(models.Model):
singleton_instance_id = DEFAULT_SINGLETON_INSTANCE_ID
class Meta:
abstract = True
def save(self, *args: Any, **kwargs: Any) -> None:
self.pk = self.singleton_instance_id
super().save(*args, **kwargs)
self.set_to_cache()
def delete(self, *args: Any, **kwargs: Any) -> tuple[int, dict[str, int]]:
self.clear_cache()
return super().delete(*args, **kwargs)
@classmethod
def clear_cache(cls) -> None:
cache_name = getattr(settings, "SOLO_CACHE", solo_settings.SOLO_CACHE)
if cache_name:
cache = caches[cache_name]
cache_key = cls.get_cache_key()
cache.delete(cache_key)
def set_to_cache(self) -> None:
cache_name = getattr(settings, "SOLO_CACHE", solo_settings.SOLO_CACHE)
if not cache_name:
return None
cache = caches[cache_name]
cache_key = self.get_cache_key()
timeout = getattr(settings, "SOLO_CACHE_TIMEOUT", solo_settings.SOLO_CACHE_TIMEOUT)
cache.set(cache_key, self, timeout)
@classmethod
def get_cache_key(cls) -> str:
prefix = getattr(settings, "SOLO_CACHE_PREFIX", solo_settings.SOLO_CACHE_PREFIX)
# Include the model's module in the cache key so similarly named models from different
# apps do not have the same cache key.
return f"{prefix}:{cls.__module__.lower()}:{cls.__name__.lower()}"
@classmethod
def get_solo(cls) -> Self:
cache_name = getattr(settings, "SOLO_CACHE", solo_settings.SOLO_CACHE)
if not cache_name:
obj, _ = cls.objects.get_or_create(pk=cls.singleton_instance_id)
return obj
cache = caches[cache_name]
cache_key = cls.get_cache_key()
obj = cache.get(cache_key)
if not obj:
obj, _ = cls.objects.get_or_create(pk=cls.singleton_instance_id)
obj.set_to_cache()
return obj
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