from django.db import connection, transaction from django.db.models import signals, get_model from django.db.models.fields import AutoField, Field, IntegerField, PositiveIntegerField, PositiveSmallIntegerField, FieldDoesNotExist from django.db.models.related import RelatedObject from django.db.models.query import QuerySet from django.db.models.query_utils import QueryWrapper from django.utils.text import capfirst from django.utils.translation import ugettext_lazy, string_concat, ungettext, ugettext as _ from django.utils.functional import curry from django.utils.encoding import smart_unicode from django.core import validators from django import oldforms from django import forms from django.dispatch import dispatcher try: set except NameError: from sets import Set as set # Python 2.3 fallback # Values for Relation.edit_inline. TABULAR, STACKED = 1, 2 RECURSIVE_RELATIONSHIP_CONSTANT = 'self' pending_lookups = {} def add_lazy_relation(cls, field, relation): """ Adds a lookup on ``cls`` when a related field is defined using a string, i.e.:: class MyModel(Model): fk = ForeignKey("AnotherModel") This string can be: * RECURSIVE_RELATIONSHIP_CONSTANT (i.e. "self") to indicate a recursive relation. * The name of a model (i.e "AnotherModel") to indicate another model in the same app. * An app-label and model name (i.e. "someapp.AnotherModel") to indicate another model in a different app. If the other model hasn't yet been loaded -- almost a given if you're using lazy relationships -- then the relation won't be set up until the class_prepared signal fires at the end of model initialization. """ # Check for recursive relations if relation == RECURSIVE_RELATIONSHIP_CONSTANT: app_label = cls._meta.app_label model_name = cls.__name__ else: # Look for an "app.Model" relation try: app_label, model_name = relation.split(".") except ValueError: # If we can't split, assume a model in current app app_label = cls._meta.app_label model_name = relation # Try to look up the related model, and if it's already loaded resolve the # string right away. If get_model returns None, it means that the related # model isn't loaded yet, so we need to pend the relation until the class # is prepared. model = get_model(app_label, model_name, False) if model: field.rel.to = model field.do_related_class(model, cls) else: key = (app_label, model_name) value = (cls, field) pending_lookups.setdefault(key, []).append(value) def do_pending_lookups(sender): """ Handle any pending relations to the sending model. Sent from class_prepared. """ key = (sender._meta.app_label, sender.__name__) for cls, field in pending_lookups.pop(key, []): field.rel.to = sender field.do_related_class(sender, cls) dispatcher.connect(do_pending_lookups, signal=signals.class_prepared) def manipulator_valid_rel_key(f, self, field_data, all_data): "Validates that the value is a valid foreign key" klass = f.rel.to try: klass._default_manager.get(**{f.rel.field_name: field_data}) except klass.DoesNotExist: raise validators.ValidationError, _("Please enter a valid %s.") % f.verbose_name #HACK class RelatedField(object): def contribute_to_class(self, cls, name): sup = super(RelatedField, self) # Add an accessor to allow easy determination of the related query path for this field self.related_query_name = curry(self._get_related_query_name, cls._meta) if hasattr(sup, 'contribute_to_class'): sup.contribute_to_class(cls, name) if not cls._meta.abstract and self.rel.related_name: self.rel.related_name = self.rel.related_name % {'class': cls.__name__.lower()} other = self.rel.to if isinstance(other, basestring): add_lazy_relation(cls, self, other) else: self.do_related_class(other, cls) def set_attributes_from_rel(self): self.name = self.name or (self.rel.to._meta.object_name.lower() + '_' + self.rel.to._meta.pk.name) self.verbose_name = self.verbose_name or self.rel.to._meta.verbose_name self.rel.field_name = self.rel.field_name or self.rel.to._meta.pk.name def do_related_class(self, other, cls): self.set_attributes_from_rel() related = RelatedObject(other, cls, self) if not cls._meta.abstract: self.contribute_to_related_class(other, related) def get_db_prep_lookup(self, lookup_type, value): # If we are doing a lookup on a Related Field, we must be # comparing object instances. The value should be the PK of value, # not value itself. def pk_trace(value): # Value may be a primary key, or an object held in a relation. # If it is an object, then we need to get the primary key value for # that object. In certain conditions (especially one-to-one relations), # the primary key may itself be an object - so we need to keep drilling # down until we hit a value that can be used for a comparison. v = value try: while True: v = getattr(v, v._meta.pk.name) except AttributeError: pass return v if hasattr(value, 'as_sql'): sql, params = value.as_sql() return QueryWrapper(('(%s)' % sql), params) if lookup_type == 'exact': return [pk_trace(value)] if lookup_type == 'in': return [pk_trace(v) for v in value] elif lookup_type == 'isnull': return [] raise TypeError, "Related Field has invalid lookup: %s" % lookup_type def _get_related_query_name(self, opts): # This method defines the name that can be used to identify this # related object in a table-spanning query. It uses the lower-cased # object_name by default, but this can be overridden with the # "related_name" option. return self.rel.related_name or opts.object_name.lower() class SingleRelatedObjectDescriptor(object): # This class provides the functionality that makes the related-object # managers available as attributes on a model class, for fields that have # a single "remote" value, on the class pointed to by a related field. # In the example "place.restaurant", the restaurant attribute is a # SingleRelatedObjectDescriptor instance. def __init__(self, related): self.related = related self.cache_name = '_%s_cache' % related.get_accessor_name() def __get__(self, instance, instance_type=None): if instance is None: raise AttributeError, "%s must be accessed via instance" % self.related.opts.object_name try: return getattr(instance, self.cache_name) except AttributeError: params = {'%s__pk' % self.related.field.name: instance._get_pk_val()} rel_obj = self.related.model._default_manager.get(**params) setattr(instance, self.cache_name, rel_obj) return rel_obj def __set__(self, instance, value): if instance is None: raise AttributeError, "%s must be accessed via instance" % self.related.opts.object_name # The similarity of the code below to the code in # ReverseSingleRelatedObjectDescriptor is annoying, but there's a bunch # of small differences that would make a common base class convoluted. # If null=True, we can assign null here, but otherwise the value needs # to be an instance of the related class. if value is None and self.related.field.null == False: raise ValueError('Cannot assign None: "%s.%s" does not allow null values.' % (instance._meta.object_name, self.related.get_accessor_name())) elif value is not None and not isinstance(value, self.related.model): raise ValueError('Cannot assign "%r": "%s.%s" must be a "%s" instance.' % (value, instance._meta.object_name, self.related.get_accessor_name(), self.related.opts.object_name)) # Set the value of the related field setattr(value, self.related.field.rel.get_related_field().attname, instance) # 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. setattr(instance, self.cache_name, value) setattr(value, self.related.field.get_cache_name(), instance) class ReverseSingleRelatedObjectDescriptor(object): # This class provides the functionality that makes the related-object # managers available as attributes on a model class, for fields that have # a single "remote" value, on the class that defines the related field. # In the example "choice.poll", the poll attribute is a # ReverseSingleRelatedObjectDescriptor instance. def __init__(self, field_with_rel): self.field = field_with_rel def __get__(self, instance, instance_type=None): if instance is None: raise AttributeError, "%s must be accessed via instance" % self.field.name cache_name = self.field.get_cache_name() try: return getattr(instance, cache_name) except AttributeError: val = getattr(instance, self.field.attname) if val is None: # If NULL is an allowed value, return it. if self.field.null: return None raise self.field.rel.to.DoesNotExist other_field = self.field.rel.get_related_field() if other_field.rel: params = {'%s__pk' % self.field.rel.field_name: val} else: params = {'%s__exact' % self.field.rel.field_name: val} rel_obj = QuerySet(self.field.rel.to).get(**params) setattr(instance, cache_name, rel_obj) return rel_obj def __set__(self, instance, value): if instance is None: raise AttributeError, "%s must be accessed via instance" % self._field.name # If null=True, we can assign null here, but otherwise the value needs # to be an instance of the related class. if value is None and self.field.null == False: raise ValueError('Cannot assign None: "%s.%s" does not allow null values.' % (instance._meta.object_name, self.field.name)) elif value is not None and not isinstance(value, self.field.rel.to): raise ValueError('Cannot assign "%r": "%s.%s" must be a "%s" instance.' % (value, instance._meta.object_name, self.field.name, self.field.rel.to._meta.object_name)) # Set the value of the related field try: val = getattr(value, self.field.rel.get_related_field().attname) except AttributeError: val = None setattr(instance, self.field.attname, val) # Since we already know what the related object is, seed the related # object cache now, too. This avoids another db hit if you get the # object you just set. setattr(instance, self.field.get_cache_name(), value) 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: raise AttributeError, "Manager must be accessed via instance" rel_field = self.related.field rel_model = self.related.model # Dynamically create a class that subclasses the related # model's default manager. superclass = self.related.model._default_manager.__class__ class RelatedManager(superclass): def get_query_set(self): return superclass.get_query_set(self).filter(**(self.core_filters)) def add(self, *objs): for obj in objs: setattr(obj, rel_field.name, instance) obj.save() add.alters_data = True def create(self, **kwargs): new_obj = self.model(**kwargs) self.add(new_obj) return new_obj 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(instance, rel_field.rel.get_related_field().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, instance) remove.alters_data = True def clear(self): for obj in self.all(): setattr(obj, rel_field.name, None) obj.save() clear.alters_data = True manager = RelatedManager() attname = rel_field.rel.get_related_field().name manager.core_filters = {'%s__%s' % (rel_field.name, attname): getattr(instance, attname)} manager.model = self.related.model return manager 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) def create_many_related_manager(superclass): """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, core_filters=None, instance=None, symmetrical=None, join_table=None, source_col_name=None, target_col_name=None): super(ManyRelatedManager, self).__init__() self.core_filters = core_filters self.model = model self.symmetrical = symmetrical self.instance = instance self.join_table = join_table self.source_col_name = source_col_name self.target_col_name = target_col_name self._pk_val = self.instance._get_pk_val() 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): return superclass.get_query_set(self).filter(**(self.core_filters)) def add(self, *objs): self._add_items(self.source_col_name, self.target_col_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_col_name, self.source_col_name, *objs) add.alters_data = True def remove(self, *objs): self._remove_items(self.source_col_name, self.target_col_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_col_name, self.source_col_name, *objs) remove.alters_data = True def clear(self): self._clear_items(self.source_col_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_col_name) clear.alters_data = True def create(self, **kwargs): new_obj = self.model(**kwargs) new_obj.save() self.add(new_obj) return new_obj create.alters_data = True def _add_items(self, source_col_name, target_col_name, *objs): # join_table: name of the m2m link table # source_col_name: the PK colname in join_table for the source object # target_col_name: the PK colname 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. if objs: # Check that all the objects are of the right type new_ids = set() for obj in objs: if isinstance(obj, self.model): new_ids.add(obj._get_pk_val()) else: new_ids.add(obj) # Add the newly created or already existing objects to the join table. # First find out which items are already added, to avoid adding them twice cursor = connection.cursor() cursor.execute("SELECT %s FROM %s WHERE %s = %%s AND %s IN (%s)" % \ (target_col_name, self.join_table, source_col_name, target_col_name, ",".join(['%s'] * len(new_ids))), [self._pk_val] + list(new_ids)) existing_ids = set([row[0] for row in cursor.fetchall()]) # Add the ones that aren't there already for obj_id in (new_ids - existing_ids): cursor.execute("INSERT INTO %s (%s, %s) VALUES (%%s, %%s)" % \ (self.join_table, source_col_name, target_col_name), [self._pk_val, obj_id]) transaction.commit_unless_managed() def _remove_items(self, source_col_name, target_col_name, *objs): # source_col_name: the PK colname in join_table for the source object # target_col_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._get_pk_val()) else: old_ids.add(obj) # Remove the specified objects from the join table cursor = connection.cursor() cursor.execute("DELETE FROM %s WHERE %s = %%s AND %s IN (%s)" % \ (self.join_table, source_col_name, target_col_name, ",".join(['%s'] * len(old_ids))), [self._pk_val] + list(old_ids)) transaction.commit_unless_managed() def _clear_items(self, source_col_name): # source_col_name: the PK colname in join_table for the source object cursor = connection.cursor() cursor.execute("DELETE FROM %s WHERE %s = %%s" % \ (self.join_table, source_col_name), [self._pk_val]) transaction.commit_unless_managed() 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 def __get__(self, instance, instance_type=None): if instance is None: raise AttributeError, "Manager must be accessed via instance" # Dynamically create a class that subclasses the related # model's default manager. rel_model = self.related.model superclass = rel_model._default_manager.__class__ RelatedManager = create_many_related_manager(superclass) qn = connection.ops.quote_name manager = RelatedManager( model=rel_model, core_filters={'%s__pk' % self.related.field.name: instance._get_pk_val()}, instance=instance, symmetrical=False, join_table=qn(self.related.field.m2m_db_table()), source_col_name=qn(self.related.field.m2m_reverse_name()), target_col_name=qn(self.related.field.m2m_column_name()) ) return manager def __set__(self, instance, value): if instance is None: raise AttributeError, "Manager must be accessed via instance" 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 def __get__(self, instance, instance_type=None): if instance is None: raise AttributeError, "Manager must be accessed via instance" # Dynamically create a class that subclasses the related # model's default manager. rel_model=self.field.rel.to superclass = rel_model._default_manager.__class__ RelatedManager = create_many_related_manager(superclass) qn = connection.ops.quote_name manager = RelatedManager( model=rel_model, core_filters={'%s__pk' % self.field.related_query_name(): instance._get_pk_val()}, instance=instance, symmetrical=(self.field.rel.symmetrical and instance.__class__ == rel_model), join_table=qn(self.field.m2m_db_table()), source_col_name=qn(self.field.m2m_column_name()), target_col_name=qn(self.field.m2m_reverse_name()) ) return manager def __set__(self, instance, value): if instance is None: raise AttributeError, "Manager must be accessed via instance" manager = self.__get__(instance) manager.clear() manager.add(*value) class ManyToOneRel(object): def __init__(self, to, field_name, num_in_admin=3, min_num_in_admin=None, max_num_in_admin=None, num_extra_on_change=1, edit_inline=False, related_name=None, limit_choices_to=None, lookup_overrides=None, parent_link=False): try: to._meta except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT assert isinstance(to, basestring), "'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.num_in_admin, self.edit_inline = num_in_admin, edit_inline self.min_num_in_admin, self.max_num_in_admin = min_num_in_admin, max_num_in_admin self.num_extra_on_change, self.related_name = num_extra_on_change, related_name if limit_choices_to is None: limit_choices_to = {} self.limit_choices_to = limit_choices_to self.lookup_overrides = lookup_overrides or {} self.multiple = True self.parent_link = parent_link 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, num_in_admin=0, min_num_in_admin=None, max_num_in_admin=None, num_extra_on_change=None, edit_inline=False, related_name=None, limit_choices_to=None, lookup_overrides=None, parent_link=False): # NOTE: *_num_in_admin and num_extra_on_change are intentionally # ignored here. We accept them as parameters only to match the calling # signature of ManyToOneRel.__init__(). super(OneToOneRel, self).__init__(to, field_name, num_in_admin, edit_inline=edit_inline, related_name=related_name, limit_choices_to=limit_choices_to, lookup_overrides=lookup_overrides, parent_link=parent_link) self.multiple = False class ManyToManyRel(object): def __init__(self, to, num_in_admin=0, related_name=None, limit_choices_to=None, symmetrical=True): self.to = to self.num_in_admin = num_in_admin self.related_name = related_name if limit_choices_to is None: limit_choices_to = {} self.limit_choices_to = limit_choices_to self.edit_inline = False self.symmetrical = symmetrical self.multiple = True class ForeignKey(RelatedField, Field): empty_strings_allowed = False 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, basestring), "%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: to_field = to_field or to._meta.pk.name kwargs['verbose_name'] = kwargs.get('verbose_name', '') if 'edit_inline_type' in kwargs: import warnings warnings.warn("edit_inline_type is deprecated. Use edit_inline instead.", DeprecationWarning) kwargs['edit_inline'] = kwargs.pop('edit_inline_type') kwargs['rel'] = rel_class(to, to_field, num_in_admin=kwargs.pop('num_in_admin', 3), min_num_in_admin=kwargs.pop('min_num_in_admin', None), max_num_in_admin=kwargs.pop('max_num_in_admin', None), num_extra_on_change=kwargs.pop('num_extra_on_change', 1), edit_inline=kwargs.pop('edit_inline', False), related_name=kwargs.pop('related_name', None), limit_choices_to=kwargs.pop('limit_choices_to', None), lookup_overrides=kwargs.pop('lookup_overrides', None), parent_link=kwargs.pop('parent_link', False)) Field.__init__(self, **kwargs) self.db_index = True 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 prepare_field_objs_and_params(self, manipulator, name_prefix): params = {'validator_list': self.validator_list[:], 'member_name': name_prefix + self.attname} if self.null: field_objs = [oldforms.NullSelectField] else: field_objs = [oldforms.SelectField] params['choices'] = self.get_choices_default() return field_objs, params 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_manipulator_field_objs(self): rel_field = self.rel.get_related_field() return [oldforms.IntegerField] def get_db_prep_save(self, value): if value == '' or value == None: return None else: return self.rel.get_related_field().get_db_prep_save(value) def flatten_data(self, follow, obj=None): 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 {self.attname: choice_list[1][0]} return Field.flatten_data(self, follow, 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, basestring): 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): setattr(cls, related.get_accessor_name(), ForeignRelatedObjectsDescriptor(related)) def formfield(self, **kwargs): defaults = {'form_class': forms.ModelChoiceField, 'queryset': self.rel.to._default_manager.complex_filter(self.rel.limit_choices_to)} defaults.update(kwargs) return super(ForeignKey, self).formfield(**defaults) def db_type(self): # 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. rel_field = self.rel.get_related_field() if isinstance(rel_field, (AutoField, PositiveIntegerField, PositiveSmallIntegerField)): return IntegerField().db_type() return rel_field.db_type() 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. """ def __init__(self, to, to_field=None, **kwargs): kwargs['unique'] = True if 'num_in_admin' not in kwargs: kwargs['num_in_admin'] = 0 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)) if not cls._meta.one_to_one_field: cls._meta.one_to_one_field = self class ManyToManyField(RelatedField, Field): def __init__(self, to, **kwargs): kwargs['verbose_name'] = kwargs.get('verbose_name', None) kwargs['rel'] = ManyToManyRel(to, num_in_admin=kwargs.pop('num_in_admin', 0), related_name=kwargs.pop('related_name', None), limit_choices_to=kwargs.pop('limit_choices_to', None), symmetrical=kwargs.pop('symmetrical', True)) self.db_table = kwargs.pop('db_table', None) Field.__init__(self, **kwargs) msg = ugettext_lazy('Hold down "Control", or "Command" on a Mac, to select more than one.') self.help_text = string_concat(self.help_text, ' ', msg) def get_manipulator_field_objs(self): choices = self.get_choices_default() return [curry(oldforms.SelectMultipleField, size=min(max(len(choices), 5), 15), choices=choices)] 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.db_table: return self.db_table else: return '%s_%s' % (opts.db_table, self.name) def _get_m2m_column_name(self, related): "Function that can be curried to provide the source column name for the m2m table" # If this is an m2m relation to self, avoid the inevitable name clash if related.model == related.parent_model: return 'from_' + related.model._meta.object_name.lower() + '_id' else: return related.model._meta.object_name.lower() + '_id' def _get_m2m_reverse_name(self, related): "Function that can be curried to provide the related column name for the m2m table" # If this is an m2m relation to self, avoid the inevitable name clash if related.model == related.parent_model: return 'to_' + related.parent_model._meta.object_name.lower() + '_id' else: return related.parent_model._meta.object_name.lower() + '_id' def isValidIDList(self, field_data, all_data): "Validates that the value is a valid list of foreign keys" mod = self.rel.to try: pks = map(int, field_data.split(',')) except ValueError: # the CommaSeparatedIntegerField validator will catch this error return objects = mod._default_manager.in_bulk(pks) if len(objects) != len(pks): badkeys = [k for k in pks if k not in objects] raise validators.ValidationError, ungettext("Please enter valid %(self)s IDs. The value %(value)r is invalid.", "Please enter valid %(self)s IDs. The values %(value)r are invalid.", len(badkeys)) % { 'self': self.verbose_name, 'value': len(badkeys) == 1 and badkeys[0] or tuple(badkeys), } def flatten_data(self, follow, obj = None): new_data = {} if obj: instance_ids = [instance._get_pk_val() for instance in getattr(obj, self.name).all()] new_data[self.name] = instance_ids else: # In required many-to-many fields with only one available choice, # select that one available choice. if not self.blank and not self.rel.edit_inline: choices_list = self.get_choices_default() if len(choices_list) == 1: new_data[self.name] = [choices_list[0][0]] return new_data def contribute_to_class(self, cls, name): super(ManyToManyField, self).contribute_to_class(cls, name) # 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) if isinstance(self.rel.to, basestring): 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): # m2m relations to self do not have a ManyRelatedObjectsDescriptor, # as it would be redundant - unless the field is non-symmetrical. if related.model != related.parent_model or not self.rel.symmetrical: # Add the descriptor for the m2m relation 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_column_name, related) self.m2m_reverse_name = curry(self._get_m2m_reverse_name, related) 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): defaults = {'form_class': forms.ModelMultipleChoiceField, 'queryset': self.rel.to._default_manager.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: defaults['initial'] = [i._get_pk_val() for i in defaults['initial']] return super(ManyToManyField, self).formfield(**defaults) def db_type(self): # A ManyToManyField is not represented by a single column, # so return None. return None