def call(self,
callee,
callargs,
policy,
expiration=None,
ondefer=None):
"""
invokes the callee with callargs through the cache, with the
given cache policy. This is the main user-space method. It
returns a CacheEntry instance. The entry will only be
guaranteed to have storage if policy.store is true.
"""
# the canonical name and cache key are needed both for
# retrieve and store; just get them once
if expiration is not None:
expiration=time_convert(expiration)
args, kwargs=self._unpack_callargs(callargs)
if policy.defer and ondefer is None:
warnings.warn("cache policy DEFER in use without a deferral callback")
if policy.retrieve or policy.store:
cn=self.getCanonicalName(callee)
ck=self.getCacheKey((args, kwargs), False)
if policy.retrieve:
# has the callee changed since last checked?
self.validateCallable(callee, cn)
# get the cache entry if it exists
entry=self._retrieve(cn, ck)
if entry and policy.accept(entry):
entry.retrieved=time()
if policy.defer and ondefer:
return ondefer(entry, callee, callargs, expiration)
return entry
if policy.calculate or policy.defer:
# the callee can bypass the cache by raising a BypassCache
# exception with the return value
try:
val=callee(*args, **kwargs)
except BypassCache, b:
val=b.value
now=time()
return CacheEntry(val,
created=now,
retrieved=now,
expiration=now)
# the callee has a chance to determine the expiration by
# sending it out of band, through an "__expiration__"
# attribute on the return value or the callee. otherwise,
# value passed to this method will be used.
now=time()
expiration=getattr(val,
'__expiration__',
getattr(callee,
'__expiration__',
expiration)) or 0
if expiration:
expiration=time_convert(expiration)
entry=CacheEntry(val,
created=now,
retrieved=now,
expiration=expiration)
def expiration(self):
exp=self.namespace.get('__expiration',
Configuration.defaultCacheExpiration)
if not isinstance(exp, (int,float,long)):
exp=time_convert(exp)
return exp
def call(self,
callee,
callargs,
policy,
expiration=None,
ondefer=None):
"""
invokes the callee with callargs through the cache, with the
given cache policy. This is the main user-space method. It
returns a CacheEntry instance. The entry will only be
guaranteed to have storage if policy.store is true.
"""
# the canonical name and cache key are needed both for
# retrieve and store; just get them once
debug("policy is %r", policy)
if expiration is not None:
expiration=time_convert(expiration)
args, kwargs=self._unpack_callargs(callargs)
if policy.defer and ondefer is None:
warnings.warn("cache policy DEFER in use without a deferral callback")
if policy.retrieve or policy.store:
cn=self.getCanonicalName(callee)
ck=self.getCacheKey((args, kwargs), False)
if policy.retrieve:
# has the callee changed since last checked?
self.validateCallable(callee, cn)
# get the cache entry if it exists
entry=self._retrieve(cn, ck)
if entry and policy.accept(entry):
entry.retrieved=time()
if policy.defer and ondefer:
return ondefer(entry, callee, callargs, expiration)
return entry
if policy.calculate or policy.defer:
# the callee can bypass the cache by raising a BypassCache
# exception with the return value
try:
val=callee(*args, **kwargs)
except BypassCache, b:
val=b.value
now=time()
return CacheEntry(val,
created=now,
retrieved=now,
expiration=now)
# the callee has a chance to determine the expiration by
# sending it out of band, through an "__expiration__"
# attribute on the return value or the callee. otherwise,
# value passed to this method will be used.
now=time()
expiration=getattr(val,
'__expiration__',
getattr(callee,
'__expiration__',
expiration)) or 0
if expiration:
expiration=time_convert(expiration)
entry=CacheEntry(val,
created=now,
retrieved=now,
expiration=expiration)
