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Add use_lists arg for cache.cache_model(), plus CacheKeyNotSupported

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Lance Edgar 2017-03-29 14:00:30 -05:00
parent 0b71aa8441
commit c27c3914ae
1 changed files with 26 additions and 9 deletions
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35
rattail/db/cache.py
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@ -1,8 +1,8 @@
# -*- coding: utf-8 -*- # -*- coding: utf-8; -*-
################################################################################ ################################################################################
# #
# Rattail -- Retail Software Framework # Rattail -- Retail Software Framework
# Copyright © 2010-2015 Lance Edgar # Copyright © 2010-2017 Lance Edgar
# #
# This file is part of Rattail. # This file is part of Rattail.
# #
@ -37,13 +37,22 @@ from rattail.db import model
log = logging.getLogger(__name__) log = logging.getLogger(__name__)
class CacheKeyNotSupported(Exception):
"""
Special error which a model cacher should raise when generating the cache
key for a given record/object, but when it is discovered the object does
not have sufficient data to generate the key.
"""
class ModelCacher(object): class ModelCacher(object):
""" """
Generic model data caching class. Generic model data caching class.
""" """
def __init__(self, session, model_class, key='uuid', omit_duplicates=False, def __init__(self, session, model_class, key='uuid', omit_duplicates=False,
query=None, order_by=None, query_options=None, normalizer=None): query=None, order_by=None, query_options=None, normalizer=None,
use_lists=False):
self.session = session self.session = session
self.model_class = model_class self.model_class = model_class
self.key = key self.key = key
@ -56,6 +65,7 @@ class ModelCacher(object):
self.normalize = lambda d: d self.normalize = lambda d: d
else: else:
self.normalize = normalizer self.normalize = normalizer
self.use_lists = use_lists
@property @property
def model_name(self): def model_name(self):
@ -107,14 +117,21 @@ class ModelCacher(object):
def cache_instance(self, instance): def cache_instance(self, instance):
normalized = self.normalize(instance) normalized = self.normalize(instance)
key = self.get_key(instance, normalized) try:
if key not in self.instances: key = self.get_key(instance, normalized)
self.instances[key] = normalized except CacheKeyNotSupported:
# this means the object doesn't belong in our cache
return
if self.use_lists:
self.instances.setdefault(key, []).append(normalized)
else: else:
self.duplicate_keys.add(key) if key not in self.instances:
if not self.omit_duplicates:
log.debug("cache already contained key, but overwriting: {}".format(repr(key)))
self.instances[key] = normalized self.instances[key] = normalized
else:
self.duplicate_keys.add(key)
if not self.omit_duplicates:
log.debug("cache already contained key, but overwriting: {}".format(repr(key)))
self.instances[key] = normalized
def cache_model(session, model_class, key='uuid', progress=None, **kwargs): def cache_model(session, model_class, key='uuid', progress=None, **kwargs):