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import warnings
from django.core import signals
from django.db.utils import (DEFAULT_DB_ALIAS, DataError, OperationalError,
IntegrityError, InternalError, ProgrammingError, NotSupportedError,
DatabaseError, InterfaceError, Error, load_backend,
ConnectionHandler, ConnectionRouter)
from django.utils.deprecation import RemovedInDjango18Warning
from django.utils.functional import cached_property
__all__ = [
'backend', 'connection', 'connections', 'router', 'DatabaseError',
'IntegrityError', 'InternalError', 'ProgrammingError', 'DataError',
'NotSupportedError', 'Error', 'InterfaceError', 'OperationalError',
'DEFAULT_DB_ALIAS'
]
connections = ConnectionHandler()
router = ConnectionRouter()
# `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)
def __eq__(self, other):
return connections[DEFAULT_DB_ALIAS] == other
def __ne__(self, other):
return connections[DEFAULT_DB_ALIAS] != other
connection = DefaultConnectionProxy()
class DefaultBackendProxy(object):
"""
Temporary proxy class used during deprecation period of the `backend` module
variable.
"""
@cached_property
def _backend(self):
warnings.warn("Accessing django.db.backend is deprecated.",
RemovedInDjango18Warning, stacklevel=2)
return load_backend(connections[DEFAULT_DB_ALIAS].settings_dict['ENGINE'])
def __getattr__(self, item):
return getattr(self._backend, item)
def __setattr__(self, name, value):
return setattr(self._backend, name, value)
def __delattr__(self, name):
return delattr(self._backend, name)
backend = DefaultBackendProxy()
def close_connection(**kwargs):
warnings.warn(
"close_connection is superseded by close_old_connections.",
RemovedInDjango18Warning, 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)
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