1295 lines
60 KiB
Python
1295 lines
60 KiB
Python
from operator import attrgetter
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from django.db import connection, router
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from django.db.backends import util
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from django.db.models import signals, get_model
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from django.db.models.fields import (AutoField, Field, IntegerField,
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PositiveIntegerField, PositiveSmallIntegerField, FieldDoesNotExist)
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from django.db.models.related import RelatedObject
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from django.db.models.query import QuerySet
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from django.db.models.query_utils import QueryWrapper
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from django.db.models.deletion import CASCADE
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from django.utils.encoding import smart_text
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from django.utils import six
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from django.utils.translation import ugettext_lazy as _, string_concat
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from django.utils.functional import curry, cached_property
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from django.core import exceptions
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from django import forms
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RECURSIVE_RELATIONSHIP_CONSTANT = 'self'
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pending_lookups = {}
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def add_lazy_relation(cls, field, relation, operation):
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"""
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Adds a lookup on ``cls`` when a related field is defined using a string,
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i.e.::
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class MyModel(Model):
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fk = ForeignKey("AnotherModel")
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This string can be:
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* RECURSIVE_RELATIONSHIP_CONSTANT (i.e. "self") to indicate a recursive
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relation.
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* The name of a model (i.e "AnotherModel") to indicate another model in
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the same app.
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* An app-label and model name (i.e. "someapp.AnotherModel") to indicate
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another model in a different app.
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If the other model hasn't yet been loaded -- almost a given if you're using
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lazy relationships -- then the relation won't be set up until the
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class_prepared signal fires at the end of model initialization.
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operation is the work that must be performed once the relation can be resolved.
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"""
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# Check for recursive relations
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if relation == RECURSIVE_RELATIONSHIP_CONSTANT:
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app_label = cls._meta.app_label
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model_name = cls.__name__
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else:
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# Look for an "app.Model" relation
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try:
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app_label, model_name = relation.split(".")
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except ValueError:
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# If we can't split, assume a model in current app
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app_label = cls._meta.app_label
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model_name = relation
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except AttributeError:
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# If it doesn't have a split it's actually a model class
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app_label = relation._meta.app_label
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model_name = relation._meta.object_name
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# Try to look up the related model, and if it's already loaded resolve the
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# string right away. If get_model returns None, it means that the related
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# model isn't loaded yet, so we need to pend the relation until the class
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# is prepared.
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model = get_model(app_label, model_name,
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seed_cache=False, only_installed=False)
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if model:
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operation(field, model, cls)
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else:
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key = (app_label, model_name)
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value = (cls, field, operation)
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pending_lookups.setdefault(key, []).append(value)
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def do_pending_lookups(sender, **kwargs):
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"""
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Handle any pending relations to the sending model. Sent from class_prepared.
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"""
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key = (sender._meta.app_label, sender.__name__)
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for cls, field, operation in pending_lookups.pop(key, []):
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operation(field, sender, cls)
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signals.class_prepared.connect(do_pending_lookups)
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#HACK
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class RelatedField(object):
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def contribute_to_class(self, cls, name):
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sup = super(RelatedField, self)
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# Store the opts for related_query_name()
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self.opts = cls._meta
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if hasattr(sup, 'contribute_to_class'):
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sup.contribute_to_class(cls, name)
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if not cls._meta.abstract and self.rel.related_name:
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self.rel.related_name = self.rel.related_name % {
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'class': cls.__name__.lower(),
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'app_label': cls._meta.app_label.lower(),
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}
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other = self.rel.to
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if isinstance(other, six.string_types) or other._meta.pk is None:
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def resolve_related_class(field, model, cls):
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field.rel.to = model
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field.do_related_class(model, cls)
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add_lazy_relation(cls, self, other, resolve_related_class)
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else:
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self.do_related_class(other, cls)
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def set_attributes_from_rel(self):
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self.name = self.name or (self.rel.to._meta.object_name.lower() + '_' + self.rel.to._meta.pk.name)
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if self.verbose_name is None:
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self.verbose_name = self.rel.to._meta.verbose_name
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self.rel.field_name = self.rel.field_name or self.rel.to._meta.pk.name
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def do_related_class(self, other, cls):
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self.set_attributes_from_rel()
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self.related = RelatedObject(other, cls, self)
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if not cls._meta.abstract:
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self.contribute_to_related_class(other, self.related)
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def get_prep_lookup(self, lookup_type, value):
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if hasattr(value, 'prepare'):
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return value.prepare()
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if hasattr(value, '_prepare'):
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return value._prepare()
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# FIXME: lt and gt are explicitly allowed to make
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# get_(next/prev)_by_date work; other lookups are not allowed since that
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# gets messy pretty quick. This is a good candidate for some refactoring
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# in the future.
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if lookup_type in ['exact', 'gt', 'lt', 'gte', 'lte']:
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return self._pk_trace(value, 'get_prep_lookup', lookup_type)
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if lookup_type in ('range', 'in'):
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return [self._pk_trace(v, 'get_prep_lookup', lookup_type) for v in value]
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elif lookup_type == 'isnull':
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return []
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raise TypeError("Related Field has invalid lookup: %s" % lookup_type)
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def get_db_prep_lookup(self, lookup_type, value, connection, prepared=False):
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if not prepared:
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value = self.get_prep_lookup(lookup_type, value)
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if hasattr(value, 'get_compiler'):
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value = value.get_compiler(connection=connection)
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if hasattr(value, 'as_sql') or hasattr(value, '_as_sql'):
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# If the value has a relabel_aliases method, it will need to
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# be invoked before the final SQL is evaluated
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if hasattr(value, 'relabel_aliases'):
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return value
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if hasattr(value, 'as_sql'):
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sql, params = value.as_sql()
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else:
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sql, params = value._as_sql(connection=connection)
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return QueryWrapper(('(%s)' % sql), params)
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# FIXME: lt and gt are explicitly allowed to make
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# get_(next/prev)_by_date work; other lookups are not allowed since that
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# gets messy pretty quick. This is a good candidate for some refactoring
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# in the future.
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if lookup_type in ['exact', 'gt', 'lt', 'gte', 'lte']:
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return [self._pk_trace(value, 'get_db_prep_lookup', lookup_type,
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connection=connection, prepared=prepared)]
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if lookup_type in ('range', 'in'):
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return [self._pk_trace(v, 'get_db_prep_lookup', lookup_type,
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connection=connection, prepared=prepared)
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for v in value]
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elif lookup_type == 'isnull':
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return []
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raise TypeError("Related Field has invalid lookup: %s" % lookup_type)
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def _pk_trace(self, value, prep_func, lookup_type, **kwargs):
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# Value may be a primary key, or an object held in a relation.
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# If it is an object, then we need to get the primary key value for
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# that object. In certain conditions (especially one-to-one relations),
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# the primary key may itself be an object - so we need to keep drilling
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# down until we hit a value that can be used for a comparison.
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v = value
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# In the case of an FK to 'self', this check allows to_field to be used
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# for both forwards and reverse lookups across the FK. (For normal FKs,
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# it's only relevant for forward lookups).
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if isinstance(v, self.rel.to):
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field_name = getattr(self.rel, "field_name", None)
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else:
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field_name = None
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try:
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while True:
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if field_name is None:
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field_name = v._meta.pk.name
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v = getattr(v, field_name)
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field_name = None
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except AttributeError:
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pass
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except exceptions.ObjectDoesNotExist:
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v = None
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field = self
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while field.rel:
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if hasattr(field.rel, 'field_name'):
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field = field.rel.to._meta.get_field(field.rel.field_name)
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else:
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field = field.rel.to._meta.pk
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if lookup_type in ('range', 'in'):
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v = [v]
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v = getattr(field, prep_func)(lookup_type, v, **kwargs)
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if isinstance(v, list):
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v = v[0]
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return v
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def related_query_name(self):
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# This method defines the name that can be used to identify this
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# related object in a table-spanning query. It uses the lower-cased
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# object_name by default, but this can be overridden with the
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# "related_name" option.
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return self.rel.related_name or self.opts.object_name.lower()
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class SingleRelatedObjectDescriptor(object):
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# This class provides the functionality that makes the related-object
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# managers available as attributes on a model class, for fields that have
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# a single "remote" value, on the class pointed to by a related field.
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# In the example "place.restaurant", the restaurant attribute is a
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# SingleRelatedObjectDescriptor instance.
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def __init__(self, related):
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self.related = related
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self.cache_name = related.get_cache_name()
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def is_cached(self, instance):
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return hasattr(instance, self.cache_name)
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def get_query_set(self, **db_hints):
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db = router.db_for_read(self.related.model, **db_hints)
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return self.related.model._base_manager.using(db)
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def get_prefetch_query_set(self, instances):
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rel_obj_attr = attrgetter(self.related.field.attname)
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instance_attr = lambda obj: obj._get_pk_val()
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instances_dict = dict((instance_attr(inst), inst) for inst in instances)
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params = {'%s__pk__in' % self.related.field.name: list(instances_dict)}
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qs = self.get_query_set(instance=instances[0]).filter(**params)
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# Since we're going to assign directly in the cache,
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# we must manage the reverse relation cache manually.
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rel_obj_cache_name = self.related.field.get_cache_name()
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for rel_obj in qs:
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instance = instances_dict[rel_obj_attr(rel_obj)]
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setattr(rel_obj, rel_obj_cache_name, instance)
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return qs, rel_obj_attr, instance_attr, True, self.cache_name
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def __get__(self, instance, instance_type=None):
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if instance is None:
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return self
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try:
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rel_obj = getattr(instance, self.cache_name)
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except AttributeError:
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params = {'%s__pk' % self.related.field.name: instance._get_pk_val()}
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try:
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rel_obj = self.get_query_set(instance=instance).get(**params)
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except self.related.model.DoesNotExist:
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rel_obj = None
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else:
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setattr(rel_obj, self.related.field.get_cache_name(), instance)
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setattr(instance, self.cache_name, rel_obj)
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if rel_obj is None:
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raise self.related.model.DoesNotExist
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else:
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return rel_obj
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def __set__(self, instance, value):
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if instance is None:
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raise AttributeError("%s must be accessed via instance" % self.related.opts.object_name)
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# The similarity of the code below to the code in
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# ReverseSingleRelatedObjectDescriptor is annoying, but there's a bunch
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# of small differences that would make a common base class convoluted.
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# If null=True, we can assign null here, but otherwise the value needs
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# to be an instance of the related class.
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if value is None and self.related.field.null == False:
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raise ValueError('Cannot assign None: "%s.%s" does not allow null values.' %
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(instance._meta.object_name, self.related.get_accessor_name()))
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elif value is not None and not isinstance(value, self.related.model):
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raise ValueError('Cannot assign "%r": "%s.%s" must be a "%s" instance.' %
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(value, instance._meta.object_name,
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self.related.get_accessor_name(), self.related.opts.object_name))
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elif value is not None:
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if instance._state.db is None:
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instance._state.db = router.db_for_write(instance.__class__, instance=value)
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elif value._state.db is None:
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value._state.db = router.db_for_write(value.__class__, instance=instance)
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elif value._state.db is not None and instance._state.db is not None:
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if not router.allow_relation(value, instance):
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raise ValueError('Cannot assign "%r": instance is on database "%s", value is on database "%s"' %
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(value, instance._state.db, value._state.db))
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# Set the value of the related field to the value of the related object's related field
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setattr(value, self.related.field.attname, getattr(instance, self.related.field.rel.get_related_field().attname))
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# Since we already know what the related object is, seed the related
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# object caches now, too. This avoids another db hit if you get the
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# object you just set.
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setattr(instance, self.cache_name, value)
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setattr(value, self.related.field.get_cache_name(), instance)
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class ReverseSingleRelatedObjectDescriptor(object):
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# This class provides the functionality that makes the related-object
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# managers available as attributes on a model class, for fields that have
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# a single "remote" value, on the class that defines the related field.
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# In the example "choice.poll", the poll attribute is a
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# ReverseSingleRelatedObjectDescriptor instance.
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def __init__(self, field_with_rel):
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self.field = field_with_rel
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self.cache_name = self.field.get_cache_name()
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def is_cached(self, instance):
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return hasattr(instance, self.cache_name)
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def get_query_set(self, **db_hints):
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db = router.db_for_read(self.field.rel.to, **db_hints)
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rel_mgr = self.field.rel.to._default_manager
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# If the related manager indicates that it should be used for
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# related fields, respect that.
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if getattr(rel_mgr, 'use_for_related_fields', False):
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return rel_mgr.using(db)
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else:
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return QuerySet(self.field.rel.to).using(db)
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def get_prefetch_query_set(self, instances):
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other_field = self.field.rel.get_related_field()
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rel_obj_attr = attrgetter(other_field.attname)
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instance_attr = attrgetter(self.field.attname)
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instances_dict = dict((instance_attr(inst), inst) for inst in instances)
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if other_field.rel:
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params = {'%s__pk__in' % self.field.rel.field_name: list(instances_dict)}
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else:
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params = {'%s__in' % self.field.rel.field_name: list(instances_dict)}
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qs = self.get_query_set(instance=instances[0]).filter(**params)
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# Since we're going to assign directly in the cache,
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# we must manage the reverse relation cache manually.
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if not self.field.rel.multiple:
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rel_obj_cache_name = self.field.related.get_cache_name()
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for rel_obj in qs:
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instance = instances_dict[rel_obj_attr(rel_obj)]
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setattr(rel_obj, rel_obj_cache_name, instance)
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return qs, rel_obj_attr, instance_attr, True, self.cache_name
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def __get__(self, instance, instance_type=None):
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if instance is None:
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return self
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try:
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rel_obj = getattr(instance, self.cache_name)
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except AttributeError:
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val = getattr(instance, self.field.attname)
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if val is None:
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rel_obj = None
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else:
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other_field = self.field.rel.get_related_field()
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if other_field.rel:
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params = {'%s__%s' % (self.field.rel.field_name, other_field.rel.field_name): val}
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else:
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params = {'%s__exact' % self.field.rel.field_name: val}
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qs = self.get_query_set(instance=instance)
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# Assuming the database enforces foreign keys, this won't fail.
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rel_obj = qs.get(**params)
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if not self.field.rel.multiple:
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setattr(rel_obj, self.field.related.get_cache_name(), instance)
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setattr(instance, self.cache_name, rel_obj)
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if rel_obj is None and not self.field.null:
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raise self.field.rel.to.DoesNotExist
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else:
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return rel_obj
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def __set__(self, instance, value):
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if instance is None:
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raise AttributeError("%s must be accessed via instance" % self.field.name)
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# If null=True, we can assign null here, but otherwise the value needs
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# to be an instance of the related class.
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if value is None and self.field.null == False:
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raise ValueError('Cannot assign None: "%s.%s" does not allow null values.' %
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(instance._meta.object_name, self.field.name))
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elif value is not None and not isinstance(value, self.field.rel.to):
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raise ValueError('Cannot assign "%r": "%s.%s" must be a "%s" instance.' %
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(value, instance._meta.object_name,
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self.field.name, self.field.rel.to._meta.object_name))
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elif value is not None:
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if instance._state.db is None:
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instance._state.db = router.db_for_write(instance.__class__, instance=value)
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elif value._state.db is None:
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value._state.db = router.db_for_write(value.__class__, instance=instance)
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elif value._state.db is not None and instance._state.db is not None:
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if not router.allow_relation(value, instance):
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raise ValueError('Cannot assign "%r": instance is on database "%s", value is on database "%s"' %
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(value, instance._state.db, value._state.db))
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|
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# If we're setting the value of a OneToOneField to None, we need to clear
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# out the cache on any old related object. Otherwise, deleting the
|
|
# previously-related object will also cause this object to be deleted,
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# which is wrong.
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if value is None:
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# Look up the previously-related object, which may still be available
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# since we've not yet cleared out the related field.
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# Use the cache directly, instead of the accessor; if we haven't
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# populated the cache, then we don't care - we're only accessing
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# the object to invalidate the accessor cache, so there's no
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# need to populate the cache just to expire it again.
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related = getattr(instance, self.cache_name, None)
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# If we've got an old related object, we need to clear out its
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# cache. This cache also might not exist if the related object
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# hasn't been accessed yet.
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if related is not None:
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setattr(related, self.field.related.get_cache_name(), None)
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|
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# Set the value of the related field
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try:
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val = getattr(value, self.field.rel.get_related_field().attname)
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except AttributeError:
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val = None
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setattr(instance, self.field.attname, val)
|
|
|
|
# Since we already know what the related object is, seed the related
|
|
# object caches now, too. This avoids another db hit if you get the
|
|
# object you just set.
|
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setattr(instance, self.cache_name, value)
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if value is not None and not self.field.rel.multiple:
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setattr(value, self.field.related.get_cache_name(), instance)
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|
|
class ForeignRelatedObjectsDescriptor(object):
|
|
# This class provides the functionality that makes the related-object
|
|
# managers available as attributes on a model class, for fields that have
|
|
# multiple "remote" values and have a ForeignKey pointed at them by
|
|
# some other model. In the example "poll.choice_set", the choice_set
|
|
# attribute is a ForeignRelatedObjectsDescriptor instance.
|
|
def __init__(self, related):
|
|
self.related = related # RelatedObject instance
|
|
|
|
def __get__(self, instance, instance_type=None):
|
|
if instance is None:
|
|
return self
|
|
|
|
return self.related_manager_cls(instance)
|
|
|
|
def __set__(self, instance, value):
|
|
if instance is None:
|
|
raise AttributeError("Manager must be accessed via instance")
|
|
|
|
manager = self.__get__(instance)
|
|
# If the foreign key can support nulls, then completely clear the related set.
|
|
# Otherwise, just move the named objects into the set.
|
|
if self.related.field.null:
|
|
manager.clear()
|
|
manager.add(*value)
|
|
|
|
@cached_property
|
|
def related_manager_cls(self):
|
|
# Dynamically create a class that subclasses the related model's default
|
|
# manager.
|
|
superclass = self.related.model._default_manager.__class__
|
|
rel_field = self.related.field
|
|
rel_model = self.related.model
|
|
attname = rel_field.rel.get_related_field().attname
|
|
|
|
class RelatedManager(superclass):
|
|
def __init__(self, instance):
|
|
super(RelatedManager, self).__init__()
|
|
self.instance = instance
|
|
self.core_filters = {
|
|
'%s__%s' % (rel_field.name, attname): getattr(instance, attname)
|
|
}
|
|
self.model = rel_model
|
|
|
|
def get_query_set(self):
|
|
try:
|
|
return self.instance._prefetched_objects_cache[rel_field.related_query_name()]
|
|
except (AttributeError, KeyError):
|
|
db = self._db or router.db_for_read(self.model, instance=self.instance)
|
|
qs = super(RelatedManager, self).get_query_set().using(db).filter(**self.core_filters)
|
|
qs._known_related_object = (rel_field.name, self.instance)
|
|
return qs
|
|
|
|
def get_prefetch_query_set(self, instances):
|
|
rel_obj_attr = attrgetter(rel_field.attname)
|
|
instance_attr = attrgetter(attname)
|
|
instances_dict = dict((instance_attr(inst), inst) for inst in instances)
|
|
db = self._db or router.db_for_read(self.model, instance=instances[0])
|
|
query = {'%s__%s__in' % (rel_field.name, attname): list(instances_dict)}
|
|
qs = super(RelatedManager, self).get_query_set().using(db).filter(**query)
|
|
# Since we just bypassed this class' get_query_set(), we must manage
|
|
# the reverse relation manually.
|
|
for rel_obj in qs:
|
|
instance = instances_dict[rel_obj_attr(rel_obj)]
|
|
setattr(rel_obj, rel_field.name, instance)
|
|
cache_name = rel_field.related_query_name()
|
|
return qs, rel_obj_attr, instance_attr, False, cache_name
|
|
|
|
def add(self, *objs):
|
|
for obj in objs:
|
|
if not isinstance(obj, self.model):
|
|
raise TypeError("'%s' instance expected, got %r" % (self.model._meta.object_name, obj))
|
|
setattr(obj, rel_field.name, self.instance)
|
|
obj.save()
|
|
add.alters_data = True
|
|
|
|
def create(self, **kwargs):
|
|
kwargs[rel_field.name] = self.instance
|
|
db = router.db_for_write(self.model, instance=self.instance)
|
|
return super(RelatedManager, self.db_manager(db)).create(**kwargs)
|
|
create.alters_data = True
|
|
|
|
def get_or_create(self, **kwargs):
|
|
# Update kwargs with the related object that this
|
|
# ForeignRelatedObjectsDescriptor knows about.
|
|
kwargs[rel_field.name] = self.instance
|
|
db = router.db_for_write(self.model, instance=self.instance)
|
|
return super(RelatedManager, self.db_manager(db)).get_or_create(**kwargs)
|
|
get_or_create.alters_data = True
|
|
|
|
# remove() and clear() are only provided if the ForeignKey can have a value of null.
|
|
if rel_field.null:
|
|
def remove(self, *objs):
|
|
val = getattr(self.instance, attname)
|
|
for obj in objs:
|
|
# Is obj actually part of this descriptor set?
|
|
if getattr(obj, rel_field.attname) == val:
|
|
setattr(obj, rel_field.name, None)
|
|
obj.save()
|
|
else:
|
|
raise rel_field.rel.to.DoesNotExist("%r is not related to %r." % (obj, self.instance))
|
|
remove.alters_data = True
|
|
|
|
def clear(self):
|
|
self.update(**{rel_field.name: None})
|
|
clear.alters_data = True
|
|
|
|
return RelatedManager
|
|
|
|
|
|
def create_many_related_manager(superclass, rel):
|
|
"""Creates a manager that subclasses 'superclass' (which is a Manager)
|
|
and adds behavior for many-to-many related objects."""
|
|
class ManyRelatedManager(superclass):
|
|
def __init__(self, model=None, query_field_name=None, instance=None, symmetrical=None,
|
|
source_field_name=None, target_field_name=None, reverse=False,
|
|
through=None, prefetch_cache_name=None):
|
|
super(ManyRelatedManager, self).__init__()
|
|
self.model = model
|
|
self.query_field_name = query_field_name
|
|
self.core_filters = {'%s__pk' % query_field_name: instance._get_pk_val()}
|
|
self.instance = instance
|
|
self.symmetrical = symmetrical
|
|
self.source_field_name = source_field_name
|
|
self.target_field_name = target_field_name
|
|
self.reverse = reverse
|
|
self.through = through
|
|
self.prefetch_cache_name = prefetch_cache_name
|
|
self._pk_val = self.instance.pk
|
|
if self._pk_val is None:
|
|
raise ValueError("%r instance needs to have a primary key value before a many-to-many relationship can be used." % instance.__class__.__name__)
|
|
|
|
def get_query_set(self):
|
|
try:
|
|
return self.instance._prefetched_objects_cache[self.prefetch_cache_name]
|
|
except (AttributeError, KeyError):
|
|
db = self._db or router.db_for_read(self.instance.__class__, instance=self.instance)
|
|
return super(ManyRelatedManager, self).get_query_set().using(db)._next_is_sticky().filter(**self.core_filters)
|
|
|
|
def get_prefetch_query_set(self, instances):
|
|
instance = instances[0]
|
|
from django.db import connections
|
|
db = self._db or router.db_for_read(instance.__class__, instance=instance)
|
|
query = {'%s__pk__in' % self.query_field_name:
|
|
set(obj._get_pk_val() for obj in instances)}
|
|
qs = super(ManyRelatedManager, self).get_query_set().using(db)._next_is_sticky().filter(**query)
|
|
|
|
# M2M: need to annotate the query in order to get the primary model
|
|
# that the secondary model was actually related to. We know that
|
|
# there will already be a join on the join table, so we can just add
|
|
# the select.
|
|
|
|
# For non-autocreated 'through' models, can't assume we are
|
|
# dealing with PK values.
|
|
fk = self.through._meta.get_field(self.source_field_name)
|
|
source_col = fk.column
|
|
join_table = self.through._meta.db_table
|
|
connection = connections[db]
|
|
qn = connection.ops.quote_name
|
|
qs = qs.extra(select={'_prefetch_related_val':
|
|
'%s.%s' % (qn(join_table), qn(source_col))})
|
|
select_attname = fk.rel.get_related_field().get_attname()
|
|
return (qs,
|
|
attrgetter('_prefetch_related_val'),
|
|
attrgetter(select_attname),
|
|
False,
|
|
self.prefetch_cache_name)
|
|
|
|
# If the ManyToMany relation has an intermediary model,
|
|
# the add and remove methods do not exist.
|
|
if rel.through._meta.auto_created:
|
|
def add(self, *objs):
|
|
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)
|
|
add.alters_data = True
|
|
|
|
def remove(self, *objs):
|
|
self._remove_items(self.source_field_name, self.target_field_name, *objs)
|
|
|
|
# If this is a symmetrical m2m relation to self, remove the mirror entry in the m2m table
|
|
if self.symmetrical:
|
|
self._remove_items(self.target_field_name, self.source_field_name, *objs)
|
|
remove.alters_data = True
|
|
|
|
def clear(self):
|
|
self._clear_items(self.source_field_name)
|
|
|
|
# If this is a symmetrical m2m relation to self, clear the mirror entry in the m2m table
|
|
if self.symmetrical:
|
|
self._clear_items(self.target_field_name)
|
|
clear.alters_data = True
|
|
|
|
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
|
|
create.alters_data = True
|
|
|
|
def get_or_create(self, **kwargs):
|
|
db = router.db_for_write(self.instance.__class__, instance=self.instance)
|
|
obj, created = \
|
|
super(ManyRelatedManager, self.db_manager(db)).get_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
|
|
get_or_create.alters_data = True
|
|
|
|
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 django.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))
|
|
new_ids.add(obj.pk)
|
|
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)
|
|
vals = vals.filter(**{
|
|
source_field_name: self._pk_val,
|
|
'%s__in' % target_field_name: new_ids,
|
|
})
|
|
new_ids = new_ids - set(vals)
|
|
|
|
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._pk_val,
|
|
'%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 _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 there aren't any objects, there is nothing to do.
|
|
if objs:
|
|
# Check that all the objects are of the right type
|
|
old_ids = set()
|
|
for obj in objs:
|
|
if isinstance(obj, self.model):
|
|
old_ids.add(obj.pk)
|
|
else:
|
|
old_ids.add(obj)
|
|
# Work out what DB we're operating on
|
|
db = router.db_for_write(self.through, instance=self.instance)
|
|
# Send a signal to the other end if need be.
|
|
if self.reverse or source_field_name == self.source_field_name:
|
|
# Don't send the signal when we are deleting the
|
|
# duplicate data row for symmetrical reverse entries.
|
|
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)
|
|
# Remove the specified objects from the join table
|
|
self.through._default_manager.using(db).filter(**{
|
|
source_field_name: self._pk_val,
|
|
'%s__in' % target_field_name: old_ids
|
|
}).delete()
|
|
if self.reverse or source_field_name == self.source_field_name:
|
|
# Don't send the signal when we are deleting the
|
|
# duplicate data row for symmetrical reverse entries.
|
|
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 _clear_items(self, source_field_name):
|
|
db = router.db_for_write(self.through, instance=self.instance)
|
|
# source_field_name: the PK colname in join table for the source object
|
|
if self.reverse or source_field_name == self.source_field_name:
|
|
# Don't send the signal when we are clearing the
|
|
# duplicate data rows for symmetrical reverse entries.
|
|
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.through._default_manager.using(db).filter(**{
|
|
source_field_name: self._pk_val
|
|
}).delete()
|
|
if self.reverse or source_field_name == self.source_field_name:
|
|
# Don't send the signal when we are clearing the
|
|
# duplicate data rows for symmetrical reverse entries.
|
|
signals.m2m_changed.send(sender=self.through, action="post_clear",
|
|
instance=self.instance, reverse=self.reverse,
|
|
model=self.model, pk_set=None, using=db)
|
|
|
|
return ManyRelatedManager
|
|
|
|
class ManyRelatedObjectsDescriptor(object):
|
|
# This class provides the functionality that makes the related-object
|
|
# managers available as attributes on a model class, for fields that have
|
|
# multiple "remote" values and have a ManyToManyField pointed at them by
|
|
# some other model (rather than having a ManyToManyField themselves).
|
|
# In the example "publication.article_set", the article_set attribute is a
|
|
# ManyRelatedObjectsDescriptor instance.
|
|
def __init__(self, related):
|
|
self.related = related # RelatedObject instance
|
|
|
|
@cached_property
|
|
def related_manager_cls(self):
|
|
# Dynamically create a class that subclasses the related
|
|
# model's default manager.
|
|
return create_many_related_manager(
|
|
self.related.model._default_manager.__class__,
|
|
self.related.field.rel
|
|
)
|
|
|
|
def __get__(self, instance, instance_type=None):
|
|
if instance is None:
|
|
return self
|
|
|
|
rel_model = self.related.model
|
|
|
|
manager = self.related_manager_cls(
|
|
model=rel_model,
|
|
query_field_name=self.related.field.name,
|
|
prefetch_cache_name=self.related.field.related_query_name(),
|
|
instance=instance,
|
|
symmetrical=False,
|
|
source_field_name=self.related.field.m2m_reverse_field_name(),
|
|
target_field_name=self.related.field.m2m_field_name(),
|
|
reverse=True,
|
|
through=self.related.field.rel.through,
|
|
)
|
|
|
|
return manager
|
|
|
|
def __set__(self, instance, value):
|
|
if instance is None:
|
|
raise AttributeError("Manager must be accessed via instance")
|
|
|
|
if not self.related.field.rel.through._meta.auto_created:
|
|
opts = self.related.field.rel.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))
|
|
|
|
manager = self.__get__(instance)
|
|
manager.clear()
|
|
manager.add(*value)
|
|
|
|
|
|
class ReverseManyRelatedObjectsDescriptor(object):
|
|
# This class provides the functionality that makes the related-object
|
|
# managers available as attributes on a model class, for fields that have
|
|
# multiple "remote" values and have a ManyToManyField defined in their
|
|
# model (rather than having another model pointed *at* them).
|
|
# In the example "article.publications", the publications attribute is a
|
|
# ReverseManyRelatedObjectsDescriptor instance.
|
|
def __init__(self, m2m_field):
|
|
self.field = m2m_field
|
|
|
|
@property
|
|
def through(self):
|
|
# through is provided so that you have easy access to the through
|
|
# model (Book.authors.through) for inlines, etc. This is done as
|
|
# a property to ensure that the fully resolved value is returned.
|
|
return self.field.rel.through
|
|
|
|
@cached_property
|
|
def related_manager_cls(self):
|
|
# Dynamically create a class that subclasses the related model's
|
|
# default manager.
|
|
return create_many_related_manager(
|
|
self.field.rel.to._default_manager.__class__,
|
|
self.field.rel
|
|
)
|
|
|
|
def __get__(self, instance, instance_type=None):
|
|
if instance is None:
|
|
return self
|
|
|
|
manager = self.related_manager_cls(
|
|
model=self.field.rel.to,
|
|
query_field_name=self.field.related_query_name(),
|
|
prefetch_cache_name=self.field.name,
|
|
instance=instance,
|
|
symmetrical=self.field.rel.symmetrical,
|
|
source_field_name=self.field.m2m_field_name(),
|
|
target_field_name=self.field.m2m_reverse_field_name(),
|
|
reverse=False,
|
|
through=self.field.rel.through,
|
|
)
|
|
|
|
return manager
|
|
|
|
def __set__(self, instance, value):
|
|
if instance is None:
|
|
raise AttributeError("Manager must be accessed via instance")
|
|
|
|
if not self.field.rel.through._meta.auto_created:
|
|
opts = self.field.rel.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))
|
|
|
|
manager = self.__get__(instance)
|
|
manager.clear()
|
|
manager.add(*value)
|
|
|
|
class ManyToOneRel(object):
|
|
def __init__(self, to, field_name, related_name=None, limit_choices_to=None,
|
|
parent_link=False, on_delete=None):
|
|
try:
|
|
to._meta
|
|
except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
|
|
assert isinstance(to, six.string_types), "'to' must be either a model, a model name or the string %r" % RECURSIVE_RELATIONSHIP_CONSTANT
|
|
self.to, self.field_name = to, field_name
|
|
self.related_name = related_name
|
|
if limit_choices_to is None:
|
|
limit_choices_to = {}
|
|
self.limit_choices_to = limit_choices_to
|
|
self.multiple = True
|
|
self.parent_link = parent_link
|
|
self.on_delete = on_delete
|
|
|
|
def is_hidden(self):
|
|
"Should the related object be hidden?"
|
|
return self.related_name and self.related_name[-1] == '+'
|
|
|
|
def get_related_field(self):
|
|
"""
|
|
Returns the Field in the 'to' object to which this relationship is
|
|
tied.
|
|
"""
|
|
data = self.to._meta.get_field_by_name(self.field_name)
|
|
if not data[2]:
|
|
raise FieldDoesNotExist("No related field named '%s'" %
|
|
self.field_name)
|
|
return data[0]
|
|
|
|
class OneToOneRel(ManyToOneRel):
|
|
def __init__(self, to, field_name, related_name=None, limit_choices_to=None,
|
|
parent_link=False, on_delete=None):
|
|
super(OneToOneRel, self).__init__(to, field_name,
|
|
related_name=related_name, limit_choices_to=limit_choices_to,
|
|
parent_link=parent_link, on_delete=on_delete
|
|
)
|
|
self.multiple = False
|
|
|
|
class ManyToManyRel(object):
|
|
def __init__(self, to, related_name=None, limit_choices_to=None,
|
|
symmetrical=True, through=None):
|
|
self.to = to
|
|
self.related_name = related_name
|
|
if limit_choices_to is None:
|
|
limit_choices_to = {}
|
|
self.limit_choices_to = limit_choices_to
|
|
self.symmetrical = symmetrical
|
|
self.multiple = True
|
|
self.through = through
|
|
|
|
def is_hidden(self):
|
|
"Should the related object be hidden?"
|
|
return self.related_name and self.related_name[-1] == '+'
|
|
|
|
def get_related_field(self):
|
|
"""
|
|
Returns the field in the to' object to which this relationship is tied
|
|
(this is always the primary key on the target model). Provided for
|
|
symmetry with ManyToOneRel.
|
|
"""
|
|
return self.to._meta.pk
|
|
|
|
class ForeignKey(RelatedField, Field):
|
|
empty_strings_allowed = False
|
|
default_error_messages = {
|
|
'invalid': _('Model %(model)s with pk %(pk)r does not exist.')
|
|
}
|
|
description = _("Foreign Key (type determined by related field)")
|
|
def __init__(self, to, to_field=None, rel_class=ManyToOneRel, **kwargs):
|
|
try:
|
|
to_name = to._meta.object_name.lower()
|
|
except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
|
|
assert isinstance(to, six.string_types), "%s(%r) is invalid. First parameter to ForeignKey must be either a model, a model name, or the string %r" % (self.__class__.__name__, to, RECURSIVE_RELATIONSHIP_CONSTANT)
|
|
else:
|
|
assert not to._meta.abstract, "%s cannot define a relation with abstract class %s" % (self.__class__.__name__, to._meta.object_name)
|
|
# For backwards compatibility purposes, we need to *try* and set
|
|
# the to_field during FK construction. It won't be guaranteed to
|
|
# be correct until contribute_to_class is called. Refs #12190.
|
|
to_field = to_field or (to._meta.pk and to._meta.pk.name)
|
|
kwargs['verbose_name'] = kwargs.get('verbose_name', None)
|
|
|
|
if 'db_index' not in kwargs:
|
|
kwargs['db_index'] = True
|
|
|
|
kwargs['rel'] = rel_class(to, to_field,
|
|
related_name=kwargs.pop('related_name', None),
|
|
limit_choices_to=kwargs.pop('limit_choices_to', None),
|
|
parent_link=kwargs.pop('parent_link', False),
|
|
on_delete=kwargs.pop('on_delete', CASCADE),
|
|
)
|
|
Field.__init__(self, **kwargs)
|
|
|
|
def validate(self, value, model_instance):
|
|
if self.rel.parent_link:
|
|
return
|
|
super(ForeignKey, self).validate(value, model_instance)
|
|
if value is None:
|
|
return
|
|
|
|
using = router.db_for_read(model_instance.__class__, instance=model_instance)
|
|
qs = self.rel.to._default_manager.using(using).filter(
|
|
**{self.rel.field_name: value}
|
|
)
|
|
qs = qs.complex_filter(self.rel.limit_choices_to)
|
|
if not qs.exists():
|
|
raise exceptions.ValidationError(self.error_messages['invalid'] % {
|
|
'model': self.rel.to._meta.verbose_name, 'pk': value})
|
|
|
|
def get_attname(self):
|
|
return '%s_id' % self.name
|
|
|
|
def get_validator_unique_lookup_type(self):
|
|
return '%s__%s__exact' % (self.name, self.rel.get_related_field().name)
|
|
|
|
def get_default(self):
|
|
"Here we check if the default value is an object and return the to_field if so."
|
|
field_default = super(ForeignKey, self).get_default()
|
|
if isinstance(field_default, self.rel.to):
|
|
return getattr(field_default, self.rel.get_related_field().attname)
|
|
return field_default
|
|
|
|
def get_db_prep_save(self, value, connection):
|
|
if value == '' or value == None:
|
|
return None
|
|
else:
|
|
return self.rel.get_related_field().get_db_prep_save(value,
|
|
connection=connection)
|
|
|
|
def value_to_string(self, obj):
|
|
if not obj:
|
|
# In required many-to-one fields with only one available choice,
|
|
# select that one available choice. Note: For SelectFields
|
|
# we have to check that the length of choices is *2*, not 1,
|
|
# because SelectFields always have an initial "blank" value.
|
|
if not self.blank and self.choices:
|
|
choice_list = self.get_choices_default()
|
|
if len(choice_list) == 2:
|
|
return smart_text(choice_list[1][0])
|
|
return Field.value_to_string(self, obj)
|
|
|
|
def contribute_to_class(self, cls, name):
|
|
super(ForeignKey, self).contribute_to_class(cls, name)
|
|
setattr(cls, self.name, ReverseSingleRelatedObjectDescriptor(self))
|
|
if isinstance(self.rel.to, six.string_types):
|
|
target = self.rel.to
|
|
else:
|
|
target = self.rel.to._meta.db_table
|
|
cls._meta.duplicate_targets[self.column] = (target, "o2m")
|
|
|
|
def contribute_to_related_class(self, cls, related):
|
|
# Internal FK's - i.e., those with a related name ending with '+' -
|
|
# don't get a related descriptor.
|
|
if not self.rel.is_hidden():
|
|
setattr(cls, related.get_accessor_name(), ForeignRelatedObjectsDescriptor(related))
|
|
if self.rel.limit_choices_to:
|
|
cls._meta.related_fkey_lookups.append(self.rel.limit_choices_to)
|
|
if self.rel.field_name is None:
|
|
self.rel.field_name = cls._meta.pk.name
|
|
|
|
def formfield(self, **kwargs):
|
|
db = kwargs.pop('using', None)
|
|
if isinstance(self.rel.to, six.string_types):
|
|
raise ValueError("Cannot create form field for %r yet, because "
|
|
"its related model %r has not been loaded yet" %
|
|
(self.name, self.rel.to))
|
|
defaults = {
|
|
'form_class': forms.ModelChoiceField,
|
|
'queryset': self.rel.to._default_manager.using(db).complex_filter(self.rel.limit_choices_to),
|
|
'to_field_name': self.rel.field_name,
|
|
}
|
|
defaults.update(kwargs)
|
|
return super(ForeignKey, self).formfield(**defaults)
|
|
|
|
def db_type(self, connection):
|
|
# The database column type of a ForeignKey is the column type
|
|
# of the field to which it points. An exception is if the ForeignKey
|
|
# points to an AutoField/PositiveIntegerField/PositiveSmallIntegerField,
|
|
# in which case the column type is simply that of an IntegerField.
|
|
# If the database needs similar types for key fields however, the only
|
|
# thing we can do is making AutoField an IntegerField.
|
|
rel_field = self.rel.get_related_field()
|
|
if (isinstance(rel_field, AutoField) or
|
|
(not connection.features.related_fields_match_type and
|
|
isinstance(rel_field, (PositiveIntegerField,
|
|
PositiveSmallIntegerField)))):
|
|
return IntegerField().db_type(connection=connection)
|
|
return rel_field.db_type(connection=connection)
|
|
|
|
class OneToOneField(ForeignKey):
|
|
"""
|
|
A OneToOneField is essentially the same as a ForeignKey, with the exception
|
|
that always carries a "unique" constraint with it and the reverse relation
|
|
always returns the object pointed to (since there will only ever be one),
|
|
rather than returning a list.
|
|
"""
|
|
description = _("One-to-one relationship")
|
|
def __init__(self, to, to_field=None, **kwargs):
|
|
kwargs['unique'] = True
|
|
super(OneToOneField, self).__init__(to, to_field, OneToOneRel, **kwargs)
|
|
|
|
def contribute_to_related_class(self, cls, related):
|
|
setattr(cls, related.get_accessor_name(),
|
|
SingleRelatedObjectDescriptor(related))
|
|
|
|
def formfield(self, **kwargs):
|
|
if self.rel.parent_link:
|
|
return None
|
|
return super(OneToOneField, self).formfield(**kwargs)
|
|
|
|
def save_form_data(self, instance, data):
|
|
if isinstance(data, self.rel.to):
|
|
setattr(instance, self.name, data)
|
|
else:
|
|
setattr(instance, self.attname, data)
|
|
|
|
def create_many_to_many_intermediary_model(field, klass):
|
|
from django.db import models
|
|
managed = True
|
|
if isinstance(field.rel.to, six.string_types) and field.rel.to != RECURSIVE_RELATIONSHIP_CONSTANT:
|
|
to_model = field.rel.to
|
|
to = to_model.split('.')[-1]
|
|
def set_managed(field, model, cls):
|
|
field.rel.through._meta.managed = model._meta.managed or cls._meta.managed
|
|
add_lazy_relation(klass, field, to_model, set_managed)
|
|
elif isinstance(field.rel.to, six.string_types):
|
|
to = klass._meta.object_name
|
|
to_model = klass
|
|
managed = klass._meta.managed
|
|
else:
|
|
to = field.rel.to._meta.object_name
|
|
to_model = field.rel.to
|
|
managed = klass._meta.managed or to_model._meta.managed
|
|
name = '%s_%s' % (klass._meta.object_name, field.name)
|
|
if field.rel.to == RECURSIVE_RELATIONSHIP_CONSTANT or to == klass._meta.object_name:
|
|
from_ = 'from_%s' % to.lower()
|
|
to = 'to_%s' % to.lower()
|
|
else:
|
|
from_ = klass._meta.object_name.lower()
|
|
to = to.lower()
|
|
meta = type('Meta', (object,), {
|
|
'db_table': field._get_m2m_db_table(klass._meta),
|
|
'managed': managed,
|
|
'auto_created': klass,
|
|
'app_label': klass._meta.app_label,
|
|
'db_tablespace': klass._meta.db_tablespace,
|
|
'unique_together': (from_, to),
|
|
'verbose_name': '%(from)s-%(to)s relationship' % {'from': from_, 'to': to},
|
|
'verbose_name_plural': '%(from)s-%(to)s relationships' % {'from': from_, 'to': to},
|
|
})
|
|
# Construct and return the new class.
|
|
return type(name, (models.Model,), {
|
|
'Meta': meta,
|
|
'__module__': klass.__module__,
|
|
from_: models.ForeignKey(klass, related_name='%s+' % name, db_tablespace=field.db_tablespace),
|
|
to: models.ForeignKey(to_model, related_name='%s+' % name, db_tablespace=field.db_tablespace)
|
|
})
|
|
|
|
class ManyToManyField(RelatedField, Field):
|
|
description = _("Many-to-many relationship")
|
|
def __init__(self, to, **kwargs):
|
|
try:
|
|
assert not to._meta.abstract, "%s cannot define a relation with abstract class %s" % (self.__class__.__name__, to._meta.object_name)
|
|
except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
|
|
assert isinstance(to, six.string_types), "%s(%r) is invalid. First parameter to ManyToManyField must be either a model, a model name, or the string %r" % (self.__class__.__name__, to, RECURSIVE_RELATIONSHIP_CONSTANT)
|
|
# Python 2.6 and earlier require dictionary keys to be of str type,
|
|
# not unicode and class names must be ASCII (in Python 2.x), so we
|
|
# forcibly coerce it here (breaks early if there's a problem).
|
|
to = str(to)
|
|
|
|
kwargs['verbose_name'] = kwargs.get('verbose_name', None)
|
|
kwargs['rel'] = ManyToManyRel(to,
|
|
related_name=kwargs.pop('related_name', None),
|
|
limit_choices_to=kwargs.pop('limit_choices_to', None),
|
|
symmetrical=kwargs.pop('symmetrical', to==RECURSIVE_RELATIONSHIP_CONSTANT),
|
|
through=kwargs.pop('through', None))
|
|
|
|
self.db_table = kwargs.pop('db_table', None)
|
|
if kwargs['rel'].through is not None:
|
|
assert self.db_table is None, "Cannot specify a db_table if an intermediary model is used."
|
|
|
|
Field.__init__(self, **kwargs)
|
|
|
|
msg = _('Hold down "Control", or "Command" on a Mac, to select more than one.')
|
|
self.help_text = string_concat(self.help_text, ' ', msg)
|
|
|
|
def get_choices_default(self):
|
|
return Field.get_choices(self, include_blank=False)
|
|
|
|
def _get_m2m_db_table(self, opts):
|
|
"Function that can be curried to provide the m2m table name for this relation"
|
|
if self.rel.through is not None:
|
|
return self.rel.through._meta.db_table
|
|
elif self.db_table:
|
|
return self.db_table
|
|
else:
|
|
return util.truncate_name('%s_%s' % (opts.db_table, self.name),
|
|
connection.ops.max_name_length())
|
|
|
|
def _get_m2m_attr(self, related, attr):
|
|
"Function that can be curried to provide the source accessor or DB column name for the m2m table"
|
|
cache_attr = '_m2m_%s_cache' % attr
|
|
if hasattr(self, cache_attr):
|
|
return getattr(self, cache_attr)
|
|
for f in self.rel.through._meta.fields:
|
|
if hasattr(f,'rel') and f.rel and f.rel.to == related.model:
|
|
setattr(self, cache_attr, getattr(f, attr))
|
|
return getattr(self, cache_attr)
|
|
|
|
def _get_m2m_reverse_attr(self, related, attr):
|
|
"Function that can be curried to provide the related accessor or DB column name for the m2m table"
|
|
cache_attr = '_m2m_reverse_%s_cache' % attr
|
|
if hasattr(self, cache_attr):
|
|
return getattr(self, cache_attr)
|
|
found = False
|
|
for f in self.rel.through._meta.fields:
|
|
if hasattr(f,'rel') and f.rel and f.rel.to == related.parent_model:
|
|
if related.model == related.parent_model:
|
|
# If this is an m2m-intermediate to self,
|
|
# the first foreign key you find will be
|
|
# the source column. Keep searching for
|
|
# the second foreign key.
|
|
if found:
|
|
setattr(self, cache_attr, getattr(f, attr))
|
|
break
|
|
else:
|
|
found = True
|
|
else:
|
|
setattr(self, cache_attr, getattr(f, attr))
|
|
break
|
|
return getattr(self, cache_attr)
|
|
|
|
def value_to_string(self, obj):
|
|
data = ''
|
|
if obj:
|
|
qs = getattr(obj, self.name).all()
|
|
data = [instance._get_pk_val() for instance in qs]
|
|
else:
|
|
# In required many-to-many fields with only one available choice,
|
|
# select that one available choice.
|
|
if not self.blank:
|
|
choices_list = self.get_choices_default()
|
|
if len(choices_list) == 1:
|
|
data = [choices_list[0][0]]
|
|
return smart_text(data)
|
|
|
|
def contribute_to_class(self, cls, name):
|
|
# To support multiple relations to self, it's useful to have a non-None
|
|
# related name on symmetrical relations for internal reasons. The
|
|
# concept doesn't make a lot of sense externally ("you want me to
|
|
# specify *what* on my non-reversible relation?!"), so we set it up
|
|
# automatically. The funky name reduces the chance of an accidental
|
|
# clash.
|
|
if self.rel.symmetrical and (self.rel.to == "self" or self.rel.to == cls._meta.object_name):
|
|
self.rel.related_name = "%s_rel_+" % name
|
|
|
|
super(ManyToManyField, self).contribute_to_class(cls, name)
|
|
|
|
# The intermediate m2m model is not auto created if:
|
|
# 1) There is a manually specified intermediate, or
|
|
# 2) The class owning the m2m field is abstract.
|
|
if not self.rel.through and not cls._meta.abstract:
|
|
self.rel.through = create_many_to_many_intermediary_model(self, cls)
|
|
|
|
# Add the descriptor for the m2m relation
|
|
setattr(cls, self.name, ReverseManyRelatedObjectsDescriptor(self))
|
|
|
|
# Set up the accessor for the m2m table name for the relation
|
|
self.m2m_db_table = curry(self._get_m2m_db_table, cls._meta)
|
|
|
|
# Populate some necessary rel arguments so that cross-app relations
|
|
# work correctly.
|
|
if isinstance(self.rel.through, six.string_types):
|
|
def resolve_through_model(field, model, cls):
|
|
field.rel.through = model
|
|
add_lazy_relation(cls, self, self.rel.through, resolve_through_model)
|
|
|
|
if isinstance(self.rel.to, six.string_types):
|
|
target = self.rel.to
|
|
else:
|
|
target = self.rel.to._meta.db_table
|
|
cls._meta.duplicate_targets[self.column] = (target, "m2m")
|
|
|
|
def contribute_to_related_class(self, cls, related):
|
|
# Internal M2Ms (i.e., those with a related name ending with '+')
|
|
# don't get a related descriptor.
|
|
if not self.rel.is_hidden():
|
|
setattr(cls, related.get_accessor_name(), ManyRelatedObjectsDescriptor(related))
|
|
|
|
# Set up the accessors for the column names on the m2m table
|
|
self.m2m_column_name = curry(self._get_m2m_attr, related, 'column')
|
|
self.m2m_reverse_name = curry(self._get_m2m_reverse_attr, related, 'column')
|
|
|
|
self.m2m_field_name = curry(self._get_m2m_attr, related, 'name')
|
|
self.m2m_reverse_field_name = curry(self._get_m2m_reverse_attr, related, 'name')
|
|
|
|
get_m2m_rel = curry(self._get_m2m_attr, related, 'rel')
|
|
self.m2m_target_field_name = lambda: get_m2m_rel().field_name
|
|
get_m2m_reverse_rel = curry(self._get_m2m_reverse_attr, related, 'rel')
|
|
self.m2m_reverse_target_field_name = lambda: get_m2m_reverse_rel().field_name
|
|
|
|
def set_attributes_from_rel(self):
|
|
pass
|
|
|
|
def value_from_object(self, obj):
|
|
"Returns the value of this field in the given model instance."
|
|
return getattr(obj, self.attname).all()
|
|
|
|
def save_form_data(self, instance, data):
|
|
setattr(instance, self.attname, data)
|
|
|
|
def formfield(self, **kwargs):
|
|
db = kwargs.pop('using', None)
|
|
defaults = {
|
|
'form_class': forms.ModelMultipleChoiceField,
|
|
'queryset': self.rel.to._default_manager.using(db).complex_filter(self.rel.limit_choices_to)
|
|
}
|
|
defaults.update(kwargs)
|
|
# If initial is passed in, it's a list of related objects, but the
|
|
# MultipleChoiceField takes a list of IDs.
|
|
if defaults.get('initial') is not None:
|
|
initial = defaults['initial']
|
|
if callable(initial):
|
|
initial = initial()
|
|
defaults['initial'] = [i._get_pk_val() for i in initial]
|
|
return super(ManyToManyField, self).formfield(**defaults)
|
|
|
|
def db_type(self, connection):
|
|
# A ManyToManyField is not represented by a single column,
|
|
# so return None.
|
|
return None
|