Cache
A simple cache using the database.
The Plain Cache stores JSON-serializable values in a CachedItem model.
Cached data can be set to expire after a certain amount of time.
Access to the cache is provided through the Cached class.
from plain.cache import Cached
cached = Cached("my-cache-key")
if cached.exists():
print("Cache hit and not expired!")
print(cached.value)
else:
print("Cache miss!")
cached.set("a JSON-serializable value", expiration=60)
# Delete the item if you need to
cached.delete()
Expired cache items can be cleared with plain cache clear-expired.
You can run this on a schedule through various cron-like tools or plain-worker.
Installation
Add plain.cache to your INSTALLED_PACKAGES:
# app/settings.py
INSTALLED_PACKAGES = [
# ...
"plain.cache",
]
CLI
plain cache clear-expired- Clear all expired cache itemsplain cache clear-all- Clear all cache itemsplain cache stats- Show cache statistics
1import click
2
3from .models import CachedItem
4
5
6@click.group()
7def cli():
8 pass
9
10
11@cli.command()
12def clear_expired():
13 click.echo("Clearing expired cache items...")
14 result = CachedItem.objects.expired().delete()
15 click.echo(f"Deleted {result[0]} expired cache items.")
16
17
18@cli.command()
19@click.option("--force", is_flag=True)
20def clear_all(force):
21 if not force and not click.confirm(
22 "Are you sure you want to delete all cache items?"
23 ):
24 return
25 click.echo("Clearing all cache items...")
26 result = CachedItem.objects.all().delete()
27 click.echo(f"Deleted {result[0]} cache items.")
28
29
30@cli.command()
31def stats():
32 total = CachedItem.objects.count()
33 expired = CachedItem.objects.expired().count()
34 unexpired = CachedItem.objects.unexpired().count()
35 forever = CachedItem.objects.forever().count()
36
37 click.echo(f"Total: {click.style(total, bold=True)}")
38 click.echo(f"Expired: {click.style(expired, bold=True)}")
39 click.echo(f"Unexpired: {click.style(unexpired, bold=True)}")
40 click.echo(f"Forever: {click.style(forever, bold=True)}")