zulip/zephyr/lib/cache.py

88 lines
3.0 KiB
Python

from functools import wraps
import hashlib
from django.core.cache import cache as djcache
from django.core.cache import get_cache
def cache_with_key(keyfunc, cache_name=None, timeout=None):
"""Decorator which applies Django caching to a function.
Decorator argument is a function which computes a cache key
from the original function's arguments. You are responsible
for avoiding collisions with other uses of this decorator or
other uses of caching."""
def decorator(func):
@wraps(func)
def func_with_caching(*args, **kwargs):
if cache_name is None:
cache_backend = djcache
else:
cache_backend = get_cache(cache_name)
key = keyfunc(*args, **kwargs)
val = cache_backend.get(key)
# Values are singleton tuples so that we can distinguish
# a result of None from a missing key.
if val is not None:
return val[0]
val = func(*args, **kwargs)
cache_backend.set(key, (val,), timeout=timeout)
return val
return func_with_caching
return decorator
def cache(func):
"""Decorator which applies Django caching to a function.
Uses a key based on the function's name, filename, and
the repr() of its arguments."""
func_uniqifier = '%s-%s' % (func.func_code.co_filename, func.func_name)
@wraps(func)
def keyfunc(*args, **kwargs):
# Django complains about spaces because memcached rejects them
key = func_uniqifier + repr((args, kwargs))
return key.replace('-','--').replace(' ','-s')
return cache_with_key(keyfunc)(func)
def message_cache_key(message_id):
return "message:%d" % (message_id,)
def user_profile_by_email_cache_key(email):
return 'user_profile_by_email:%s' % (hashlib.sha1(email).hexdigest(),)
def user_profile_by_user_cache_key(user_id):
return 'user_profile_by_user_id:%d' % (user_id,)
def user_profile_by_id_cache_key(user_profile_id):
return "user_profile_by_id:%s" % (user_profile_id,)
def user_by_id_cache_key(user_id):
return 'user_by_id:%d' % (user_id,)
# Called by models.py to flush the user_profile cache whenever we save
# a user_profile object
def update_user_profile_cache(sender, **kwargs):
user_profile = kwargs['instance']
items_for_memcached = {}
items_for_memcached[user_profile_by_email_cache_key(user_profile.user.email)] = (user_profile,)
items_for_memcached[user_profile_by_user_cache_key(user_profile.user.id)] = (user_profile,)
items_for_memcached[user_profile_by_id_cache_key(user_profile.id)] = (user_profile,)
djcache.set_many(items_for_memcached)
# Called by models.py to flush the user_profile cache whenever we save
# a user_profile object
def update_user_cache(sender, **kwargs):
user = kwargs['instance']
items_for_memcached = {}
items_for_memcached[user_by_id_cache_key(user.id)] = (user,)
djcache.set_many(items_for_memcached)