django1/django/db/__init__.py

81 lines
3.0 KiB
Python

import warnings
from django.conf import settings
from django.core import signals
from django.core.exceptions import ImproperlyConfigured
from django.db.utils import (DEFAULT_DB_ALIAS,
DataError, OperationalError, IntegrityError, InternalError,
ProgrammingError, NotSupportedError, DatabaseError,
InterfaceError, Error,
load_backend, ConnectionHandler, ConnectionRouter)
__all__ = ('backend', 'connection', 'connections', 'router', 'DatabaseError',
'IntegrityError', 'DEFAULT_DB_ALIAS')
if settings.DATABASES and DEFAULT_DB_ALIAS not in settings.DATABASES:
raise ImproperlyConfigured("You must define a '%s' database" % DEFAULT_DB_ALIAS)
connections = ConnectionHandler(settings.DATABASES)
router = ConnectionRouter(settings.DATABASE_ROUTERS)
# `connection`, `DatabaseError` and `IntegrityError` are convenient aliases
# for backend bits.
# DatabaseWrapper.__init__() takes a dictionary, not a settings module, so
# we manually create the dictionary from the settings, passing only the
# settings that the database backends care about. Note that TIME_ZONE is used
# by the PostgreSQL backends.
# We load all these up for backwards compatibility, you should use
# connections['default'] instead.
class DefaultConnectionProxy(object):
"""
Proxy for accessing the default DatabaseWrapper object's attributes. If you
need to access the DatabaseWrapper object itself, use
connections[DEFAULT_DB_ALIAS] instead.
"""
def __getattr__(self, item):
return getattr(connections[DEFAULT_DB_ALIAS], item)
def __setattr__(self, name, value):
return setattr(connections[DEFAULT_DB_ALIAS], name, value)
def __delattr__(self, name):
return delattr(connections[DEFAULT_DB_ALIAS], name)
connection = DefaultConnectionProxy()
backend = load_backend(connection.settings_dict['ENGINE'])
def close_connection(**kwargs):
warnings.warn(
"close_connection is superseded by close_old_connections.",
PendingDeprecationWarning, stacklevel=2)
# Avoid circular imports
from django.db import transaction
for conn in connections:
# If an error happens here the connection will be left in broken
# state. Once a good db connection is again available, the
# connection state will be cleaned up.
transaction.abort(conn)
connections[conn].close()
# Register an event to reset saved queries when a Django request is started.
def reset_queries(**kwargs):
for conn in connections.all():
conn.queries = []
signals.request_started.connect(reset_queries)
# Register an event to reset transaction state and close connections past
# their lifetime. NB: abort() doesn't do anything outside of a transaction.
def close_old_connections(**kwargs):
for conn in connections.all():
# Remove this when the legacy transaction management goes away.
try:
conn.abort()
except DatabaseError:
pass
conn.close_if_unusable_or_obsolete()
signals.request_started.connect(close_old_connections)
signals.request_finished.connect(close_old_connections)