def __set__(self, instance, value):
"""
Set the related instance through the reverse relation.
With the example above, when setting ``place.restaurant = restaurant``:
- ``self`` is the descriptor managing the ``restaurant`` attribute
- ``instance`` is the ``place`` instance
- ``value`` is the ``restaurant`` instance on the right of the equal sign
Keep in mind that ``Restaurant`` holds the foreign key to ``Place``.
"""
# The similarity of the code below to the code in
# ForwardManyToOneDescriptor is annoying, but there's a bunch
# of small differences that would make a common base class convoluted.
if value is None:
# Update the cached related instance (if any) & clear the cache.
# Following the example above, this would be the cached
# ``restaurant`` instance (if any).
rel_obj = self.related.get_cached_value(instance, default=None)
if rel_obj is not None:
# Remove the ``restaurant`` instance from the ``place``
# instance cache.
self.related.delete_cached_value(instance)
# Set the ``place`` field on the ``restaurant``
# instance to None.
setattr(rel_obj, self.related.field.name, None)
elif not isinstance(value, self.related.related_model):
# An object must be an instance of the related class.
raise ValueError(
'Cannot assign "%r": "%s.%s" must be a "%s" instance.' % (
value,
instance._meta.object_name,
self.related.get_accessor_name(),
self.related.related_model._meta.object_name,
)
)
else:
if instance._state.db is None:
instance._state.db = router.db_for_write(instance.__class__, instance=value)
if value._state.db is None:
value._state.db = router.db_for_write(value.__class__, instance=instance)
if not router.allow_relation(value, instance):
raise ValueError('Cannot assign "%r": the current database router prevents this relation.' % value)
related_pk = tuple(getattr(instance, field.attname) for field in self.related.field.foreign_related_fields)
# Set the value of the related field to the value of the related object's related field
for index, field in enumerate(self.related.field.local_related_fields):
setattr(value, field.attname, related_pk[index])
# Set the related instance cache used by __get__ to avoid an SQL query
# when accessing the attribute we just set.
self.related.set_cached_value(instance, value)
# Set the forward accessor cache on the related object to the current
# instance to avoid an extra SQL query if it's accessed later on.
self.related.field.set_cached_value(value, instance)
def set(self, objs, *, clear=False):
if not rel.through._meta.auto_created:
opts = self.through._meta
raise AttributeError(
"Cannot set values on a ManyToManyField which specifies an "
"intermediary model. Use %s.%s's Manager instead." %
(opts.app_label, opts.object_name)
)
# Force evaluation of `objs` in case it's a queryset whose value
# could be affected by `manager.clear()`. Refs #19816.
objs = tuple(objs)
db = router.db_for_write(self.through, instance=self.instance)
with transaction.atomic(using=db, savepoint=False):
if clear:
self.clear()
self.add(*objs)
else:
old_ids = set(self.using(db).values_list(self.target_field.target_field.attname, flat=True))
new_objs = []
for obj in objs:
fk_val = (
self.target_field.get_foreign_related_value(obj)[0]
if isinstance(obj, self.model) else obj
)
if fk_val in old_ids:
old_ids.remove(fk_val)
else:
new_objs.append(obj)
self.remove(*old_ids)
self.add(*new_objs)
def add(self, *objs, bulk=True):
db = router.db_for_write(self.model, instance=self.instance)
def check_and_update_obj(obj):
if not isinstance(obj, self.model):
raise TypeError("'%s' instance expected, got %r" %
(self.model._meta.object_name, obj))
setattr(obj, self.content_type_field_name, self.content_type)
setattr(obj, self.object_id_field_name, self.pk_val)
if bulk:
pks = []
for obj in objs:
if obj._state.adding or obj._state.db != db:
raise ValueError(
"%r instance isn't saved. Use bulk=False or save "
"the object first." % obj)
check_and_update_obj(obj)
pks.append(obj.pk)
self.model._base_manager.using(db).filter(pk__in=pks).update(
**{
self.content_type_field_name: self.content_type,
self.object_id_field_name: self.pk_val,
})
else:
with transaction.atomic(using=db, savepoint=False):
for obj in objs:
check_and_update_obj(obj)
obj.save()
def update_or_create(self, **kwargs):
db = router.db_for_write(self.instance.__class__, instance=self.instance)
obj, created = super(ManyRelatedManager, self.db_manager(db)).update_or_create(**kwargs)
# We only need to add() if created because if we got an object back
# from get() then the relationship already exists.
if created:
self.add(obj)
return obj, created
def handle(self, **options):
db = options['database']
interactive = options['interactive']
verbosity = options['verbosity']
for app_config in apps.get_app_configs():
content_types, app_models = get_contenttypes_and_models(
app_config, db, ContentType)
to_remove = [
ct for (model_name, ct) in content_types.items()
if model_name not in app_models
]
# Confirm that the content type is stale before deletion.
using = router.db_for_write(ContentType)
if to_remove:
if interactive:
ct_info = []
for ct in to_remove:
ct_info.append(' - Content type for %s.%s' %
(ct.app_label, ct.model))
collector = NoFastDeleteCollector(using=using)
collector.collect([ct])
for obj_type, objs in collector.data.items():
if objs != {ct}:
ct_info.append(' - %s %s object(s)' % (
len(objs),
obj_type._meta.label,
))
content_type_display = '\n'.join(ct_info)
self.stdout.write(
"""Some content types in your database are stale and can be deleted.
Any objects that depend on these content types will also be deleted.
The content types and dependent objects that would be deleted are:
%s
This list doesn't include any cascade deletions to data outside of Server's
models (uncommon).
Are you sure you want to delete these content types?
If you're unsure, answer 'no'.\n""" % content_type_display)
ok_to_delete = input(
"Type 'yes' to continue, or 'no' to cancel: ")
else:
ok_to_delete = False
if ok_to_delete == 'yes':
for ct in to_remove:
if verbosity >= 2:
self.stdout.write(
"Deleting stale content type '%s | %s'" %
(ct.app_label, ct.model))
ct.delete()
else:
if verbosity >= 2:
self.stdout.write("Stale content types remain.")
def get_deleted_objects(objs, request, admin_site):
"""
Find all objects related to ``objs`` that should also be deleted. ``objs``
must be a homogeneous iterable of objects (e.g. a QuerySet).
Return a nested list of strings suitable for display in the
template with the ``unordered_list`` filter.
"""
try:
obj = objs[0]
except IndexError:
return [], {}, set(), []
else:
using = router.db_for_write(obj._meta.model)
collector = NestedObjects(using=using)
collector.collect(objs)
perms_needed = set()
def format_callback(obj):
model = obj.__class__
has_admin = model in admin_site._registry
opts = obj._meta
no_edit_link = '%s: %s' % (capfirst(opts.verbose_name), obj)
if has_admin:
if not admin_site._registry[model].has_delete_permission(
request, obj):
perms_needed.add(opts.verbose_name)
try:
admin_url = reverse(
'%s:%s_%s_change' %
(admin_site.name, opts.app_label, opts.model_name), None,
(quote(obj.pk), ))
except NoReverseMatch:
# Change url doesn't exist -- don't display link to edit
return no_edit_link
# Display a link to the admin page.
return format_html('{}: <a href="{}">{}</a>',
capfirst(opts.verbose_name), admin_url, obj)
else:
# Don't display link to edit, because it either has no
# admin or is edited inline.
return no_edit_link
to_delete = collector.nested(format_callback)
protected = [format_callback(obj) for obj in collector.protected]
model_count = {
model._meta.verbose_name_plural: len(objs)
for model, objs in collector.model_objs.items()
}
return to_delete, model_count, perms_needed, protected
def delete(self, key, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s WHERE cache_key = %%s" % table,
[key])
def _clear(self, queryset, bulk):
db = router.db_for_write(self.model, instance=self.instance)
queryset = queryset.using(db)
if bulk:
# `QuerySet.delete()` creates its own atomic block which
# contains the `pre_delete` and `post_delete` signal handlers.
queryset.delete()
else:
with transaction.atomic(using=db, savepoint=False):
for obj in queryset:
obj.delete()
def _clear(self, queryset, bulk):
self._remove_prefetched_objects()
db = router.db_for_write(self.model, instance=self.instance)
queryset = queryset.using(db)
if bulk:
# `QuerySet.update()` is intrinsically atomic.
queryset.update(**{self.field.name: None})
else:
with transaction.atomic(using=db, savepoint=False):
for obj in queryset:
setattr(obj, self.field.name, None)
obj.save(update_fields=[self.field.name])
def create(self, **kwargs):
# This check needs to be done here, since we can't later remove this
# from the method lookup table, as we do with add and remove.
if not self.through._meta.auto_created:
opts = self.through._meta
raise AttributeError(
"Cannot use create() on a ManyToManyField which specifies "
"an intermediary model. Use %s.%s's Manager instead." %
(opts.app_label, opts.object_name)
)
db = router.db_for_write(self.instance.__class__, instance=self.instance)
new_obj = super(ManyRelatedManager, self.db_manager(db)).create(**kwargs)
self.add(new_obj)
return new_obj
def add(self, *objs):
if not rel.through._meta.auto_created:
opts = self.through._meta
raise AttributeError(
"Cannot use add() on a ManyToManyField which specifies an "
"intermediary model. Use %s.%s's Manager instead." %
(opts.app_label, opts.object_name)
)
self._remove_prefetched_objects()
db = router.db_for_write(self.through, instance=self.instance)
with transaction.atomic(using=db, savepoint=False):
self._add_items(self.source_field_name, self.target_field_name, *objs)
# If this is a symmetrical m2m relation to self, add the mirror entry in the m2m table
if self.symmetrical:
self._add_items(self.target_field_name, self.source_field_name, *objs)
def clear(self):
db = router.db_for_write(self.through, instance=self.instance)
with transaction.atomic(using=db, savepoint=False):
signals.m2m_changed.send(
sender=self.through, action="pre_clear",
instance=self.instance, reverse=self.reverse,
model=self.model, pk_set=None, using=db,
)
self._remove_prefetched_objects()
filters = self._build_remove_filters(super().get_queryset().using(db))
self.through._default_manager.using(db).filter(filters).delete()
signals.m2m_changed.send(
sender=self.through, action="post_clear",
instance=self.instance, reverse=self.reverse,
model=self.model, pk_set=None, using=db,
)
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
quote_name = connection.ops.quote_name
table = quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute(
'SELECT %s, %s, %s FROM %s WHERE %s = %%s' % (
quote_name('cache_key'),
quote_name('value'),
quote_name('expires'),
table,
quote_name('cache_key'),
), [key])
row = cursor.fetchone()
if row is None:
return default
expires = row[2]
expression = models.Expression(output_field=models.DateTimeField())
for converter in (connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
if func_supports_parameter(converter,
'context'): # RemovedInServer30Warning
expires = converter(expires, expression, connection, {})
else:
expires = converter(expires, expression, connection)
if expires < timezone.now():
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
with connection.cursor() as cursor:
cursor.execute(
'DELETE FROM %s WHERE %s = %%s' % (
table,
quote_name('cache_key'),
), [key])
return default
value = connection.ops.process_clob(row[1])
return pickle.loads(base64.b64decode(value.encode()))
def set(self, objs, *, bulk=True, clear=False):
# Force evaluation of `objs` in case it's a queryset whose value
# could be affected by `manager.clear()`. Refs #19816.
objs = tuple(objs)
db = router.db_for_write(self.model, instance=self.instance)
with transaction.atomic(using=db, savepoint=False):
if clear:
self.clear()
self.add(*objs, bulk=bulk)
else:
old_objs = set(self.using(db).all())
new_objs = []
for obj in objs:
if obj in old_objs:
old_objs.remove(obj)
else:
new_objs.append(obj)
self.remove(*old_objs)
self.add(*new_objs, bulk=bulk)
def _remove_items(self, source_field_name, target_field_name, *objs):
# source_field_name: the PK colname in join table for the source object
# target_field_name: the PK colname in join table for the target object
# *objs - objects to remove
if not objs:
return
# Check that all the objects are of the right type
old_ids = set()
for obj in objs:
if isinstance(obj, self.model):
fk_val = self.target_field.get_foreign_related_value(obj)[0]
old_ids.add(fk_val)
else:
old_ids.add(obj)
db = router.db_for_write(self.through, instance=self.instance)
with transaction.atomic(using=db, savepoint=False):
# Send a signal to the other end if need be.
signals.m2m_changed.send(
sender=self.through, action="pre_remove",
instance=self.instance, reverse=self.reverse,
model=self.model, pk_set=old_ids, using=db,
)
target_model_qs = super().get_queryset()
if target_model_qs._has_filters():
old_vals = target_model_qs.using(db).filter(**{
'%s__in' % self.target_field.target_field.attname: old_ids})
else:
old_vals = old_ids
filters = self._build_remove_filters(old_vals)
self.through._default_manager.using(db).filter(filters).delete()
signals.m2m_changed.send(
sender=self.through, action="post_remove",
instance=self.instance, reverse=self.reverse,
model=self.model, pk_set=old_ids, using=db,
)
def save(self, must_create=False):
"""
Save the current session data to the database. If 'must_create' is
True, raise a database error if the saving operation doesn't create a
new entry (as opposed to possibly updating an existing entry).
"""
if self.session_key is None:
return self.create()
data = self._get_session(no_load=must_create)
obj = self.create_model_instance(data)
using = router.db_for_write(self.model, instance=obj)
try:
with transaction.atomic(using=using):
obj.save(force_insert=must_create,
force_update=not must_create,
using=using)
except IntegrityError:
if must_create:
raise CreateError
raise
except DatabaseError:
if not must_create:
raise UpdateError
raise
def __set__(self, instance, value):
"""
Set the related instance through the forward relation.
With the example above, when setting ``child.parent = parent``:
- ``self`` is the descriptor managing the ``parent`` attribute
- ``instance`` is the ``child`` instance
- ``value`` is the ``parent`` instance on the right of the equal sign
"""
# An object must be an instance of the related class.
if value is not None and not isinstance(value, self.field.remote_field.model._meta.concrete_model):
raise ValueError(
'Cannot assign "%r": "%s.%s" must be a "%s" instance.' % (
value,
instance._meta.object_name,
self.field.name,
self.field.remote_field.model._meta.object_name,
)
)
elif value is not None:
if instance._state.db is None:
instance._state.db = router.db_for_write(instance.__class__, instance=value)
if value._state.db is None:
value._state.db = router.db_for_write(value.__class__, instance=instance)
if not router.allow_relation(value, instance):
raise ValueError('Cannot assign "%r": the current database router prevents this relation.' % value)
remote_field = self.field.remote_field
# If we're setting the value of a OneToOneField to None, we need to clear
# out the cache on any old related object. Otherwise, deleting the
# previously-related object will also cause this object to be deleted,
# which is wrong.
if value is None:
# Look up the previously-related object, which may still be available
# since we've not yet cleared out the related field.
# Use the cache directly, instead of the accessor; if we haven't
# populated the cache, then we don't care - we're only accessing
# the object to invalidate the accessor cache, so there's no
# need to populate the cache just to expire it again.
related = self.field.get_cached_value(instance, default=None)
# If we've got an old related object, we need to clear out its
# cache. This cache also might not exist if the related object
# hasn't been accessed yet.
if related is not None:
remote_field.set_cached_value(related, None)
for lh_field, rh_field in self.field.related_fields:
setattr(instance, lh_field.attname, None)
# Set the values of the related field.
else:
for lh_field, rh_field in self.field.related_fields:
setattr(instance, lh_field.attname, getattr(value, rh_field.attname))
# Set the related instance cache used by __get__ to avoid an SQL query
# when accessing the attribute we just set.
self.field.set_cached_value(instance, value)
# If this is a one-to-one relation, set the reverse accessor cache on
# the related object to the current instance to avoid an extra SQL
# query if it's accessed later on.
if value is not None and not remote_field.multiple:
remote_field.set_cached_value(value, instance)
def __init__(self, model, data, mapping, layer=0,
source_srs=None, encoding='utf-8',
transaction_mode='commit_on_success',
transform=True, unique=None, using=None):
"""
A LayerMapping object is initialized using the given Model (not an instance),
a DataSource (or string path to an OGR-supported data file), and a mapping
dictionary. See the module level docstring for more details and keyword
argument usage.
"""
# Getting the DataSource and the associated Layer.
if isinstance(data, str):
self.ds = DataSource(data, encoding=encoding)
else:
self.ds = data
self.layer = self.ds[layer]
self.using = using if using is not None else router.db_for_write(model)
self.spatial_backend = connections[self.using].ops
# Setting the mapping & model attributes.
self.mapping = mapping
self.model = model
# Checking the layer -- initialization of the object will fail if
# things don't check out before hand.
self.check_layer()
# Getting the geometry column associated with the model (an
# exception will be raised if there is no geometry column).
if connections[self.using].features.supports_transform:
self.geo_field = self.geometry_field()
else:
transform = False
# Checking the source spatial reference system, and getting
# the coordinate transformation object (unless the `transform`
# keyword is set to False)
if transform:
self.source_srs = self.check_srs(source_srs)
self.transform = self.coord_transform()
else:
self.transform = transform
# Setting the encoding for OFTString fields, if specified.
if encoding:
# Making sure the encoding exists, if not a LookupError
# exception will be thrown.
from codecs import lookup
lookup(encoding)
self.encoding = encoding
else:
self.encoding = None
if unique:
self.check_unique(unique)
transaction_mode = 'autocommit' # Has to be set to autocommit.
self.unique = unique
else:
self.unique = None
# Setting the transaction decorator with the function in the
# transaction modes dictionary.
self.transaction_mode = transaction_mode
if transaction_mode == 'autocommit':
self.transaction_decorator = None
elif transaction_mode == 'commit_on_success':
self.transaction_decorator = transaction.atomic
else:
raise LayerMapError('Unrecognized transaction mode: %s' % transaction_mode)
def clear(self):
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute('DELETE FROM %s' % table)
def _add_items(self, source_field_name, target_field_name, *objs):
# source_field_name: the PK fieldname in join table for the source object
# target_field_name: the PK fieldname in join table for the target object
# *objs - objects to add. Either object instances, or primary keys of object instances.
# If there aren't any objects, there is nothing to do.
from server.db.models import Model
if objs:
new_ids = set()
for obj in objs:
if isinstance(obj, self.model):
if not router.allow_relation(obj, self.instance):
raise ValueError(
'Cannot add "%r": instance is on database "%s", value is on database "%s"' %
(obj, self.instance._state.db, obj._state.db)
)
fk_val = self.through._meta.get_field(
target_field_name).get_foreign_related_value(obj)[0]
if fk_val is None:
raise ValueError(
'Cannot add "%r": the value for field "%s" is None' %
(obj, target_field_name)
)
new_ids.add(fk_val)
elif isinstance(obj, Model):
raise TypeError(
"'%s' instance expected, got %r" %
(self.model._meta.object_name, obj)
)
else:
new_ids.add(obj)
db = router.db_for_write(self.through, instance=self.instance)
vals = (self.through._default_manager.using(db)
.values_list(target_field_name, flat=True)
.filter(**{
source_field_name: self.related_val[0],
'%s__in' % target_field_name: new_ids,
}))
new_ids.difference_update(vals)
with transaction.atomic(using=db, savepoint=False):
if self.reverse or source_field_name == self.source_field_name:
# Don't send the signal when we are inserting the
# duplicate data row for symmetrical reverse entries.
signals.m2m_changed.send(
sender=self.through, action='pre_add',
instance=self.instance, reverse=self.reverse,
model=self.model, pk_set=new_ids, using=db,
)
# Add the ones that aren't there already
self.through._default_manager.using(db).bulk_create([
self.through(**{
'%s_id' % source_field_name: self.related_val[0],
'%s_id' % target_field_name: obj_id,
})
for obj_id in new_ids
])
if self.reverse or source_field_name == self.source_field_name:
# Don't send the signal when we are inserting the
# duplicate data row for symmetrical reverse entries.
signals.m2m_changed.send(
sender=self.through, action='post_add',
instance=self.instance, reverse=self.reverse,
model=self.model, pk_set=new_ids, using=db,
)
def _base_set(self, mode, key, value, timeout=DEFAULT_TIMEOUT):
timeout = self.get_backend_timeout(timeout)
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
quote_name = connection.ops.quote_name
table = quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("SELECT COUNT(*) FROM %s" % table)
num = cursor.fetchone()[0]
now = timezone.now()
now = now.replace(microsecond=0)
if timeout is None:
exp = datetime.max
elif settings.USE_TZ:
exp = datetime.utcfromtimestamp(timeout)
else:
exp = datetime.fromtimestamp(timeout)
exp = exp.replace(microsecond=0)
if num > self._max_entries:
self._cull(db, cursor, now)
pickled = pickle.dumps(value, pickle.HIGHEST_PROTOCOL)
# The DB column is expecting a string, so make sure the value is a
# string, not bytes. Refs #19274.
b64encoded = base64.b64encode(pickled).decode('latin1')
try:
# Note: typecasting for datetimes is needed by some 3rd party
# database backends. All core backends work without typecasting,
# so be careful about changes here - test suite will NOT pick
# regressions.
with transaction.atomic(using=db):
cursor.execute(
'SELECT %s, %s FROM %s WHERE %s = %%s' % (
quote_name('cache_key'),
quote_name('expires'),
table,
quote_name('cache_key'),
), [key])
result = cursor.fetchone()
if result:
current_expires = result[1]
expression = models.Expression(
output_field=models.DateTimeField())
for converter in (
connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
if func_supports_parameter(
converter,
'context'): # RemovedInServer30Warning
current_expires = converter(
current_expires, expression, connection,
{})
else:
current_expires = converter(
current_expires, expression, connection)
exp = connection.ops.adapt_datetimefield_value(exp)
if result and mode == 'touch':
cursor.execute(
'UPDATE %s SET %s = %%s WHERE %s = %%s' %
(table, quote_name('expires'),
quote_name('cache_key')), [exp, key])
elif result and (mode == 'set' or
(mode == 'add'
and current_expires < now)):
cursor.execute(
'UPDATE %s SET %s = %%s, %s = %%s WHERE %s = %%s' %
(
table,
quote_name('value'),
quote_name('expires'),
quote_name('cache_key'),
), [b64encoded, exp, key])
elif mode != 'touch':
cursor.execute(
'INSERT INTO %s (%s, %s, %s) VALUES (%%s, %%s, %%s)'
% (
table,
quote_name('cache_key'),
quote_name('value'),
quote_name('expires'),
), [key, b64encoded, exp])
else:
return False # touch failed.
except DatabaseError:
# To be threadsafe, updates/inserts are allowed to fail silently
return False
else:
return True
def add_view(self, request, form_url='', extra_context=None):
with transaction.atomic(using=router.db_for_write(self.model)):
return self._add_view(request, form_url, extra_context)
def update_or_create(self, **kwargs):
kwargs[self.content_type_field_name] = self.content_type
kwargs[self.object_id_field_name] = self.pk_val
db = router.db_for_write(self.model, instance=self.instance)
return super().using(db).update_or_create(**kwargs)
def update_or_create(self, **kwargs):
kwargs[self.field.name] = self.instance
db = router.db_for_write(self.model, instance=self.instance)
return super(RelatedManager, self.db_manager(db)).update_or_create(**kwargs)
