148 lines
5.5 KiB
Python
148 lines
5.5 KiB
Python
import inspect
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import os
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from django.conf import settings
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from django.core.exceptions import ImproperlyConfigured
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from django.utils.importlib import import_module
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DEFAULT_DB_ALIAS = 'default'
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def load_backend(backend_name):
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try:
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module = import_module('.base', 'django.db.backends.%s' % backend_name)
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import warnings
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warnings.warn(
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"Short names for DATABASE_ENGINE are deprecated; prepend with 'django.db.backends.'",
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PendingDeprecationWarning
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)
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return module
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except ImportError, e:
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# Look for a fully qualified database backend name
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try:
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return import_module('.base', backend_name)
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except ImportError, e_user:
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# The database backend wasn't found. Display a helpful error message
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# listing all possible (built-in) database backends.
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backend_dir = os.path.join(os.path.dirname(__file__), 'backends')
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try:
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available_backends = [f for f in os.listdir(backend_dir)
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if os.path.isdir(os.path.join(backend_dir, f))
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and not f.startswith('.')]
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except EnvironmentError:
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available_backends = []
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available_backends.sort()
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if backend_name not in available_backends:
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error_msg = ("%r isn't an available database backend. \n" +
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"Try using django.db.backends.XXX, where XXX is one of:\n %s\n" +
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"Error was: %s") % \
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(backend_name, ", ".join(map(repr, available_backends)), e_user)
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raise ImproperlyConfigured(error_msg)
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else:
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raise # If there's some other error, this must be an error in Django itself.
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class ConnectionDoesNotExist(Exception):
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pass
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class ConnectionHandler(object):
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def __init__(self, databases):
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self.databases = databases
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self._connections = {}
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def ensure_defaults(self, alias):
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"""
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Puts the defaults into the settings dictionary for a given connection
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where no settings is provided.
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"""
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try:
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conn = self.databases[alias]
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except KeyError:
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raise ConnectionDoesNotExist("The connection %s doesn't exist" % alias)
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conn.setdefault('ENGINE', 'django.db.backends.dummy')
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if conn['ENGINE'] == 'django.db.backends.' or not conn['ENGINE']:
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conn['ENGINE'] = 'django.db.backends.dummy'
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conn.setdefault('OPTIONS', {})
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conn.setdefault('TEST_CHARSET', None)
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conn.setdefault('TEST_COLLATION', None)
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conn.setdefault('TEST_NAME', None)
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conn.setdefault('TEST_MIRROR', None)
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conn.setdefault('TIME_ZONE', settings.TIME_ZONE)
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for setting in ('NAME', 'USER', 'PASSWORD', 'HOST', 'PORT'):
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conn.setdefault(setting, '')
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def __getitem__(self, alias):
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if alias in self._connections:
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return self._connections[alias]
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self.ensure_defaults(alias)
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db = self.databases[alias]
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backend = load_backend(db['ENGINE'])
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conn = backend.DatabaseWrapper(db, alias)
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self._connections[alias] = conn
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return conn
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def __iter__(self):
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return iter(self.databases)
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def all(self):
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return [self[alias] for alias in self]
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class ConnectionRouter(object):
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def __init__(self, routers):
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self.routers = []
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for r in routers:
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if isinstance(r, basestring):
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try:
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module_name, klass_name = r.rsplit('.', 1)
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module = import_module(module_name)
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router = getattr(module, klass_name)()
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except ImportError, e:
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raise ImproperlyConfigured('Error importing database router %s: "%s"' % (klass_name, e))
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except AttributeError:
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raise ImproperlyConfigured('Module "%s" does not define a "%s" database router' % (module, klass_name))
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else:
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router = r
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self.routers.append(router)
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def _router_func(action):
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def _route_db(self, model, **hints):
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chosen_db = None
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for router in self.routers:
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try:
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chosen_db = getattr(router, action)(model, **hints)
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if chosen_db:
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return chosen_db
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except AttributeError:
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# If the router doesn't have a method, skip to the next one.
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pass
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try:
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return hints['instance']._state.db or DEFAULT_DB_ALIAS
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except KeyError:
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return DEFAULT_DB_ALIAS
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return _route_db
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db_for_read = _router_func('db_for_read')
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db_for_write = _router_func('db_for_write')
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def allow_relation(self, obj1, obj2, **hints):
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for router in self.routers:
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try:
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allow = router.allow_relation(obj1, obj2, **hints)
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if allow is not None:
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return allow
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except AttributeError:
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# If the router doesn't have a method, skip to the next one.
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pass
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return obj1._state.db == obj2._state.db
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def allow_syncdb(self, db, model):
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for router in self.routers:
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try:
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allow = router.allow_syncdb(db, model)
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if allow is not None:
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return allow
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except AttributeError:
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# If the router doesn't have a method, skip to the next one.
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pass
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return True
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