def __init__(self, expire_time=60 * 30, fields=[], dao=None):
"""
fields = (name, index, sql_type?)
"""
self.table_name = "cache_%s_temp" % self.__class__.__name__.lower()
self.cache_fields = dict(( (e[0], e) for e in fields ))
self.sql_parser = RawSQLResult()
self.dao = dao or QueryUtils(logging.getLogger("query.cache"))
self.ordered_fields = fields
self.expire_time = expire_time
if not self.exists_cache_table(): self.create_cache_table()
class BasicCache(object):
def __init__(self, expire_time=60 * 30, fields=[], dao=None):
"""
fields = (name, index, sql_type?)
"""
self.table_name = "cache_%s_temp" % self.__class__.__name__.lower()
self.cache_fields = dict(( (e[0], e) for e in fields ))
self.sql_parser = RawSQLResult()
self.dao = dao or QueryUtils(logging.getLogger("query.cache"))
self.ordered_fields = fields
self.expire_time = expire_time
if not self.exists_cache_table(): self.create_cache_table()
def update_query(self, query_or_sessionkey, sql=None, ignore_cache=False):
update_result = """insert into ${cache_table_name}(query_id, ${cache_fields})
select ${query_id}, ${cache_fields} from (${sql}) a
"""
created = query = None
if isinstance(query_or_sessionkey, basestring):
query, created = Query.objects.get_or_create(session_key=query_or_sessionkey)
elif isinstance(query_or_sessionkey, Query):
query = query_or_sessionkey
else:
raise RuntimeError, "need a 'Query' object or session key."
cached_time = datetime.now() - query.last_updated_time
cached_time = cached_time.seconds + cached_time.days * 60 * 60 * 24
if created or ignore_cache or query.cached_time > self.expire_time:
if created:
query.name = self.__class__.__name__
elif query.name and query.name != self.__class__.__name__:
raise RuntimeError, "cache name:%s!=%s, key=%s" % (query.name,
self.__class__.__name__,
query.session_key)
self.clean_cache(query)
sql_fields = self.sql_parser.parse_sql_fields(sql)
sql_fields = [ e for e in sql_fields if e in self.cache_fields ]
update_sql, vars = self.dao.replace_sql_parameter(update_result,
{"cache_table_name": self.table_name,
"query_id": query.id,
"cache_fields": ",".join(sql_fields),
"sql":sql
})
self.dao.execute_sql(update_sql, (), close_cursor=True)
query.sql = sql
query.last_updated_time = datetime.now()
query.last_access_time = datetime.now()
query.save()
return query
def clean_cache(self, query):
delete_sql = "delete from %s where query_id=%s" % (self.table_name,
query.id)
self.dao.execute_sql(delete_sql, (), close_cursor=True)
def get_cache_key(self, *query):
return hashlib.md5(";".join(query)).hexdigest()
def exists_cache_table(self, ):
try:
self.dao.execute_sql("select 1 from %s where 1=2" % self.table_name, ())
return True
except Exception, e:
if "doesn't exist" in str(e):
return False
else:
raise
