upload.py (customized for use with codereviews.googleopensourceprograms.com)
updated from latest Rietveld release.
Patch by: Todd Larsen
"Base Cache class."
from django.core.exceptions import ImproperlyConfigured
class InvalidCacheBackendError(ImproperlyConfigured):
pass
class BaseCache(object):
def __init__(self, params):
timeout = params.get('timeout', 300)
try:
timeout = int(timeout)
except (ValueError, TypeError):
timeout = 300
self.default_timeout = timeout
def add(self, key, value, timeout=None):
"""
Set a value in the cache if the key does not already exist. If
timeout is given, that timeout will be used for the key; otherwise
the default cache timeout will be used.
Returns True if the value was stored, False otherwise.
"""
raise NotImplementedError
def get(self, key, default=None):
"""
Fetch a given key from the cache. If the key does not exist, return
default, which itself defaults to None.
"""
raise NotImplementedError
def set(self, key, value, timeout=None):
"""
Set a value in the cache. If timeout is given, that timeout will be
used for the key; otherwise the default cache timeout will be used.
"""
raise NotImplementedError
def delete(self, key):
"""
Delete a key from the cache, failing silently.
"""
raise NotImplementedError
def get_many(self, keys):
"""
Fetch a bunch of keys from the cache. For certain backends (memcached,
pgsql) this can be *much* faster when fetching multiple values.
Returns a dict mapping each key in keys to its value. If the given
key is missing, it will be missing from the response dict.
"""
d = {}
for k in keys:
val = self.get(k)
if val is not None:
d[k] = val
return d
def has_key(self, key):
"""
Returns True if the key is in the cache and has not expired.
"""
return self.get(key) is not None
def __contains__(self, key):
"""
Returns True if the key is in the cache and has not expired.
"""
# This is a separate method, rather than just a copy of has_key(),
# so that it always has the same functionality as has_key(), even
# if a subclass overrides it.
return self.has_key(key)