Fixed a thinko-fix in toDict
The pick() view was broken because of this.
Patch by: Sverre Rabbelier
"""
Helper functions for creating Form classes from Django models
and database field objects.
"""
from django.utils.encoding import smart_unicode
from django.utils.datastructures import SortedDict
from django.utils.text import get_text_list, capfirst
from django.utils.translation import ugettext_lazy as _
from util import ValidationError, ErrorList
from forms import BaseForm, get_declared_fields
from fields import Field, ChoiceField, IntegerField, EMPTY_VALUES
from widgets import Select, SelectMultiple, HiddenInput, MultipleHiddenInput
from widgets import media_property
from formsets import BaseFormSet, formset_factory, DELETION_FIELD_NAME
try:
set
except NameError:
from sets import Set as set # Python 2.3 fallback
__all__ = (
'ModelForm', 'BaseModelForm', 'model_to_dict', 'fields_for_model',
'save_instance', 'form_for_fields', 'ModelChoiceField',
'ModelMultipleChoiceField',
)
def save_instance(form, instance, fields=None, fail_message='saved',
commit=True, exclude=None):
"""
Saves bound Form ``form``'s cleaned_data into model instance ``instance``.
If commit=True, then the changes to ``instance`` will be saved to the
database. Returns ``instance``.
"""
from django.db import models
opts = instance._meta
if form.errors:
raise ValueError("The %s could not be %s because the data didn't"
" validate." % (opts.object_name, fail_message))
cleaned_data = form.cleaned_data
for f in opts.fields:
if not f.editable or isinstance(f, models.AutoField) \
or not f.name in cleaned_data:
continue
if fields and f.name not in fields:
continue
if exclude and f.name in exclude:
continue
f.save_form_data(instance, cleaned_data[f.name])
# Wrap up the saving of m2m data as a function.
def save_m2m():
opts = instance._meta
cleaned_data = form.cleaned_data
for f in opts.many_to_many:
if fields and f.name not in fields:
continue
if f.name in cleaned_data:
f.save_form_data(instance, cleaned_data[f.name])
if commit:
# If we are committing, save the instance and the m2m data immediately.
instance.save()
save_m2m()
else:
# We're not committing. Add a method to the form to allow deferred
# saving of m2m data.
form.save_m2m = save_m2m
return instance
def make_model_save(model, fields, fail_message):
"""Returns the save() method for a Form."""
def save(self, commit=True):
return save_instance(self, model(), fields, fail_message, commit)
return save
def make_instance_save(instance, fields, fail_message):
"""Returns the save() method for a Form."""
def save(self, commit=True):
return save_instance(self, instance, fields, fail_message, commit)
return save
def form_for_fields(field_list):
"""
Returns a Form class for the given list of Django database field instances.
"""
fields = SortedDict([(f.name, f.formfield())
for f in field_list if f.editable])
return type('FormForFields', (BaseForm,), {'base_fields': fields})
# ModelForms #################################################################
def model_to_dict(instance, fields=None, exclude=None):
"""
Returns a dict containing the data in ``instance`` suitable for passing as
a Form's ``initial`` keyword argument.
``fields`` is an optional list of field names. If provided, only the named
fields will be included in the returned dict.
``exclude`` is an optional list of field names. If provided, the named
fields will be excluded from the returned dict, even if they are listed in
the ``fields`` argument.
"""
# avoid a circular import
from django.db.models.fields.related import ManyToManyField, OneToOneField
opts = instance._meta
data = {}
for f in opts.fields + opts.many_to_many:
if not f.editable:
continue
if fields and not f.name in fields:
continue
if exclude and f.name in exclude:
continue
if isinstance(f, ManyToManyField):
# If the object doesn't have a primry key yet, just use an empty
# list for its m2m fields. Calling f.value_from_object will raise
# an exception.
if instance.pk is None:
data[f.name] = []
else:
# MultipleChoiceWidget needs a list of pks, not object instances.
data[f.name] = [obj.pk for obj in f.value_from_object(instance)]
else:
data[f.name] = f.value_from_object(instance)
return data
def fields_for_model(model, fields=None, exclude=None, formfield_callback=lambda f: f.formfield()):
"""
Returns a ``SortedDict`` containing form fields for the given model.
``fields`` is an optional list of field names. If provided, only the named
fields will be included in the returned fields.
``exclude`` is an optional list of field names. If provided, the named
fields will be excluded from the returned fields, even if they are listed
in the ``fields`` argument.
"""
# TODO: if fields is provided, it would be nice to return fields in that order
field_list = []
opts = model._meta
for f in opts.fields + opts.many_to_many:
if not f.editable:
continue
if fields and not f.name in fields:
continue
if exclude and f.name in exclude:
continue
formfield = formfield_callback(f)
if formfield:
field_list.append((f.name, formfield))
return SortedDict(field_list)
class ModelFormOptions(object):
def __init__(self, options=None):
self.model = getattr(options, 'model', None)
self.fields = getattr(options, 'fields', None)
self.exclude = getattr(options, 'exclude', None)
class ModelFormMetaclass(type):
def __new__(cls, name, bases, attrs):
formfield_callback = attrs.pop('formfield_callback',
lambda f: f.formfield())
try:
parents = [b for b in bases if issubclass(b, ModelForm)]
except NameError:
# We are defining ModelForm itself.
parents = None
declared_fields = get_declared_fields(bases, attrs, False)
new_class = super(ModelFormMetaclass, cls).__new__(cls, name, bases,
attrs)
if not parents:
return new_class
if 'media' not in attrs:
new_class.media = media_property(new_class)
opts = new_class._meta = ModelFormOptions(getattr(new_class, 'Meta', None))
if opts.model:
# If a model is defined, extract form fields from it.
fields = fields_for_model(opts.model, opts.fields,
opts.exclude, formfield_callback)
# Override default model fields with any custom declared ones
# (plus, include all the other declared fields).
fields.update(declared_fields)
else:
fields = declared_fields
new_class.declared_fields = declared_fields
new_class.base_fields = fields
return new_class
class BaseModelForm(BaseForm):
def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None,
initial=None, error_class=ErrorList, label_suffix=':',
empty_permitted=False, instance=None):
opts = self._meta
if instance is None:
# if we didn't get an instance, instantiate a new one
self.instance = opts.model()
object_data = {}
else:
self.instance = instance
object_data = model_to_dict(instance, opts.fields, opts.exclude)
# if initial was provided, it should override the values from instance
if initial is not None:
object_data.update(initial)
super(BaseModelForm, self).__init__(data, files, auto_id, prefix, object_data,
error_class, label_suffix, empty_permitted)
def clean(self):
self.validate_unique()
return self.cleaned_data
def validate_unique(self):
from django.db.models.fields import FieldDoesNotExist
# Gather a list of checks to perform. Since this is a ModelForm, some
# fields may have been excluded; we can't perform a unique check on a
# form that is missing fields involved in that check.
unique_checks = []
for check in self.instance._meta.unique_together[:]:
fields_on_form = [field for field in check if field in self.fields]
if len(fields_on_form) == len(check):
unique_checks.append(check)
form_errors = []
# Gather a list of checks for fields declared as unique and add them to
# the list of checks. Again, skip fields not on the form.
for name, field in self.fields.items():
try:
f = self.instance._meta.get_field_by_name(name)[0]
except FieldDoesNotExist:
# This is an extra field that's not on the ModelForm, ignore it
continue
# MySQL can't handle ... WHERE pk IS NULL, so make sure we
# don't generate queries of that form.
is_null_pk = f.primary_key and self.cleaned_data[name] is None
if name in self.cleaned_data and f.unique and not is_null_pk:
unique_checks.append((name,))
# Don't run unique checks on fields that already have an error.
unique_checks = [check for check in unique_checks if not [x in self._errors for x in check if x in self._errors]]
bad_fields = set()
for unique_check in unique_checks:
# Try to look up an existing object with the same values as this
# object's values for all the unique field.
lookup_kwargs = {}
for field_name in unique_check:
lookup_kwargs[field_name] = self.cleaned_data[field_name]
qs = self.instance.__class__._default_manager.filter(**lookup_kwargs)
# Exclude the current object from the query if we are editing an
# instance (as opposed to creating a new one)
if self.instance.pk is not None:
qs = qs.exclude(pk=self.instance.pk)
# This cute trick with extra/values is the most efficient way to
# tell if a particular query returns any results.
if qs.extra(select={'a': 1}).values('a').order_by():
model_name = capfirst(self.instance._meta.verbose_name)
# A unique field
if len(unique_check) == 1:
field_name = unique_check[0]
field_label = self.fields[field_name].label
# Insert the error into the error dict, very sneaky
self._errors[field_name] = ErrorList([
_(u"%(model_name)s with this %(field_label)s already exists.") % \
{'model_name': unicode(model_name),
'field_label': unicode(field_label)}
])
# unique_together
else:
field_labels = [self.fields[field_name].label for field_name in unique_check]
field_labels = get_text_list(field_labels, _('and'))
form_errors.append(
_(u"%(model_name)s with this %(field_label)s already exists.") % \
{'model_name': unicode(model_name),
'field_label': unicode(field_labels)}
)
# Mark these fields as needing to be removed from cleaned data
# later.
for field_name in unique_check:
bad_fields.add(field_name)
for field_name in bad_fields:
del self.cleaned_data[field_name]
if form_errors:
# Raise the unique together errors since they are considered
# form-wide.
raise ValidationError(form_errors)
def save(self, commit=True):
"""
Saves this ``form``'s cleaned_data into model instance
``self.instance``.
If commit=True, then the changes to ``instance`` will be saved to the
database. Returns ``instance``.
"""
if self.instance.pk is None:
fail_message = 'created'
else:
fail_message = 'changed'
return save_instance(self, self.instance, self._meta.fields, fail_message, commit)
class ModelForm(BaseModelForm):
__metaclass__ = ModelFormMetaclass
def modelform_factory(model, form=ModelForm, fields=None, exclude=None,
formfield_callback=lambda f: f.formfield()):
# HACK: we should be able to construct a ModelForm without creating
# and passing in a temporary inner class
class Meta:
pass
setattr(Meta, 'model', model)
setattr(Meta, 'fields', fields)
setattr(Meta, 'exclude', exclude)
class_name = model.__name__ + 'Form'
return ModelFormMetaclass(class_name, (form,), {'Meta': Meta,
'formfield_callback': formfield_callback})
# ModelFormSets ##############################################################
class BaseModelFormSet(BaseFormSet):
"""
A ``FormSet`` for editing a queryset and/or adding new objects to it.
"""
model = None
def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None,
queryset=None, **kwargs):
self.queryset = queryset
defaults = {'data': data, 'files': files, 'auto_id': auto_id, 'prefix': prefix}
defaults['initial'] = [model_to_dict(obj) for obj in self.get_queryset()]
defaults.update(kwargs)
super(BaseModelFormSet, self).__init__(**defaults)
def _construct_form(self, i, **kwargs):
if i < self._initial_form_count:
kwargs['instance'] = self.get_queryset()[i]
return super(BaseModelFormSet, self)._construct_form(i, **kwargs)
def get_queryset(self):
if not hasattr(self, '_queryset'):
if self.queryset is not None:
qs = self.queryset
else:
qs = self.model._default_manager.get_query_set()
if self.max_num > 0:
self._queryset = qs[:self.max_num]
else:
self._queryset = qs
return self._queryset
def save_new(self, form, commit=True):
"""Saves and returns a new model instance for the given form."""
return save_instance(form, self.model(), exclude=[self._pk_field.name], commit=commit)
def save_existing(self, form, instance, commit=True):
"""Saves and returns an existing model instance for the given form."""
return save_instance(form, instance, exclude=[self._pk_field.name], commit=commit)
def save(self, commit=True):
"""Saves model instances for every form, adding and changing instances
as necessary, and returns the list of instances.
"""
if not commit:
self.saved_forms = []
def save_m2m():
for form in self.saved_forms:
form.save_m2m()
self.save_m2m = save_m2m
return self.save_existing_objects(commit) + self.save_new_objects(commit)
def save_existing_objects(self, commit=True):
self.changed_objects = []
self.deleted_objects = []
if not self.get_queryset():
return []
# Put the objects from self.get_queryset into a dict so they are easy to lookup by pk
existing_objects = {}
for obj in self.get_queryset():
existing_objects[obj.pk] = obj
saved_instances = []
for form in self.initial_forms:
obj = existing_objects[form.cleaned_data[self._pk_field.name]]
if self.can_delete and form.cleaned_data[DELETION_FIELD_NAME]:
self.deleted_objects.append(obj)
obj.delete()
else:
if form.changed_data:
self.changed_objects.append((obj, form.changed_data))
saved_instances.append(self.save_existing(form, obj, commit=commit))
if not commit:
self.saved_forms.append(form)
return saved_instances
def save_new_objects(self, commit=True):
self.new_objects = []
for form in self.extra_forms:
if not form.has_changed():
continue
# If someone has marked an add form for deletion, don't save the
# object.
if self.can_delete and form.cleaned_data[DELETION_FIELD_NAME]:
continue
self.new_objects.append(self.save_new(form, commit=commit))
if not commit:
self.saved_forms.append(form)
return self.new_objects
def add_fields(self, form, index):
"""Add a hidden field for the object's primary key."""
from django.db.models import AutoField
self._pk_field = pk = self.model._meta.pk
if pk.auto_created or isinstance(pk, AutoField):
form.fields[self._pk_field.name] = IntegerField(required=False, widget=HiddenInput)
super(BaseModelFormSet, self).add_fields(form, index)
def modelformset_factory(model, form=ModelForm, formfield_callback=lambda f: f.formfield(),
formset=BaseModelFormSet,
extra=1, can_delete=False, can_order=False,
max_num=0, fields=None, exclude=None):
"""
Returns a FormSet class for the given Django model class.
"""
form = modelform_factory(model, form=form, fields=fields, exclude=exclude,
formfield_callback=formfield_callback)
FormSet = formset_factory(form, formset, extra=extra, max_num=max_num,
can_order=can_order, can_delete=can_delete)
FormSet.model = model
return FormSet
# InlineFormSets #############################################################
class BaseInlineFormSet(BaseModelFormSet):
"""A formset for child objects related to a parent."""
def __init__(self, data=None, files=None, instance=None,
save_as_new=False, prefix=None):
from django.db.models.fields.related import RelatedObject
self.instance = instance
self.save_as_new = save_as_new
# is there a better way to get the object descriptor?
self.rel_name = RelatedObject(self.fk.rel.to, self.model, self.fk).get_accessor_name()
super(BaseInlineFormSet, self).__init__(data, files, prefix=prefix or self.rel_name)
def _construct_forms(self):
if self.save_as_new:
self._total_form_count = self._initial_form_count
self._initial_form_count = 0
super(BaseInlineFormSet, self)._construct_forms()
def _construct_form(self, i, **kwargs):
form = super(BaseInlineFormSet, self)._construct_form(i, **kwargs)
if self.save_as_new:
# Remove the primary key from the form's data, we are only
# creating new instances
form.data[form.add_prefix(self._pk_field.name)] = None
return form
def get_queryset(self):
"""
Returns this FormSet's queryset, but restricted to children of
self.instance
"""
kwargs = {self.fk.name: self.instance}
return self.model._default_manager.filter(**kwargs)
def save_new(self, form, commit=True):
kwargs = {self.fk.get_attname(): self.instance.pk}
new_obj = self.model(**kwargs)
return save_instance(form, new_obj, exclude=[self._pk_field.name], commit=commit)
def add_fields(self, form, index):
super(BaseInlineFormSet, self).add_fields(form, index)
if self._pk_field == self.fk:
form.fields[self._pk_field.name] = IntegerField(required=False, widget=HiddenInput)
def _get_foreign_key(parent_model, model, fk_name=None):
"""
Finds and returns the ForeignKey from model to parent if there is one.
If fk_name is provided, assume it is the name of the ForeignKey field.
"""
# avoid circular import
from django.db.models import ForeignKey
opts = model._meta
if fk_name:
fks_to_parent = [f for f in opts.fields if f.name == fk_name]
if len(fks_to_parent) == 1:
fk = fks_to_parent[0]
if not isinstance(fk, ForeignKey) or \
(fk.rel.to != parent_model and
fk.rel.to not in parent_model._meta.get_parent_list()):
raise Exception("fk_name '%s' is not a ForeignKey to %s" % (fk_name, parent_model))
elif len(fks_to_parent) == 0:
raise Exception("%s has no field named '%s'" % (model, fk_name))
else:
# Try to discover what the ForeignKey from model to parent_model is
fks_to_parent = [
f for f in opts.fields
if isinstance(f, ForeignKey)
and (f.rel.to == parent_model
or f.rel.to in parent_model._meta.get_parent_list())
]
if len(fks_to_parent) == 1:
fk = fks_to_parent[0]
elif len(fks_to_parent) == 0:
raise Exception("%s has no ForeignKey to %s" % (model, parent_model))
else:
raise Exception("%s has more than 1 ForeignKey to %s" % (model, parent_model))
return fk
def inlineformset_factory(parent_model, model, form=ModelForm,
formset=BaseInlineFormSet, fk_name=None,
fields=None, exclude=None,
extra=3, can_order=False, can_delete=True, max_num=0,
formfield_callback=lambda f: f.formfield()):
"""
Returns an ``InlineFormSet`` for the given kwargs.
You must provide ``fk_name`` if ``model`` has more than one ``ForeignKey``
to ``parent_model``.
"""
fk = _get_foreign_key(parent_model, model, fk_name=fk_name)
# enforce a max_num=1 when the foreign key to the parent model is unique.
if fk.unique:
max_num = 1
if exclude is not None:
exclude = list(exclude)
exclude.append(fk.name)
else:
exclude = [fk.name]
kwargs = {
'form': form,
'formfield_callback': formfield_callback,
'formset': formset,
'extra': extra,
'can_delete': can_delete,
'can_order': can_order,
'fields': fields,
'exclude': exclude,
'max_num': max_num,
}
FormSet = modelformset_factory(model, **kwargs)
FormSet.fk = fk
return FormSet
# Fields #####################################################################
class ModelChoiceIterator(object):
def __init__(self, field):
self.field = field
self.queryset = field.queryset
def __iter__(self):
if self.field.empty_label is not None:
yield (u"", self.field.empty_label)
if self.field.cache_choices:
if self.field.choice_cache is None:
self.field.choice_cache = [
self.choice(obj) for obj in self.queryset.all()
]
for choice in self.field.choice_cache:
yield choice
else:
for obj in self.queryset.all():
yield self.choice(obj)
def choice(self, obj):
if self.field.to_field_name:
# FIXME: The try..except shouldn't be necessary here. But this is
# going in just before 1.0, so I want to be careful. Will check it
# out later.
try:
key = getattr(obj, self.field.to_field_name).pk
except AttributeError:
key = getattr(obj, self.field.to_field_name)
else:
key = obj.pk
return (key, self.field.label_from_instance(obj))
class ModelChoiceField(ChoiceField):
"""A ChoiceField whose choices are a model QuerySet."""
# This class is a subclass of ChoiceField for purity, but it doesn't
# actually use any of ChoiceField's implementation.
default_error_messages = {
'invalid_choice': _(u'Select a valid choice. That choice is not one of'
u' the available choices.'),
}
def __init__(self, queryset, empty_label=u"---------", cache_choices=False,
required=True, widget=None, label=None, initial=None,
help_text=None, to_field_name=None, *args, **kwargs):
self.empty_label = empty_label
self.cache_choices = cache_choices
# Call Field instead of ChoiceField __init__() because we don't need
# ChoiceField.__init__().
Field.__init__(self, required, widget, label, initial, help_text,
*args, **kwargs)
self.queryset = queryset
self.choice_cache = None
self.to_field_name = to_field_name
def _get_queryset(self):
return self._queryset
def _set_queryset(self, queryset):
self._queryset = queryset
self.widget.choices = self.choices
queryset = property(_get_queryset, _set_queryset)
# this method will be used to create object labels by the QuerySetIterator.
# Override it to customize the label.
def label_from_instance(self, obj):
"""
This method is used to convert objects into strings; it's used to
generate the labels for the choices presented by this object. Subclasses
can override this method to customize the display of the choices.
"""
return smart_unicode(obj)
def _get_choices(self):
# If self._choices is set, then somebody must have manually set
# the property self.choices. In this case, just return self._choices.
if hasattr(self, '_choices'):
return self._choices
# Otherwise, execute the QuerySet in self.queryset to determine the
# choices dynamically. Return a fresh QuerySetIterator that has not been
# consumed. Note that we're instantiating a new QuerySetIterator *each*
# time _get_choices() is called (and, thus, each time self.choices is
# accessed) so that we can ensure the QuerySet has not been consumed. This
# construct might look complicated but it allows for lazy evaluation of
# the queryset.
return ModelChoiceIterator(self)
choices = property(_get_choices, ChoiceField._set_choices)
def clean(self, value):
Field.clean(self, value)
if value in EMPTY_VALUES:
return None
try:
key = self.to_field_name or 'pk'
value = self.queryset.get(**{key: value})
except self.queryset.model.DoesNotExist:
raise ValidationError(self.error_messages['invalid_choice'])
return value
class ModelMultipleChoiceField(ModelChoiceField):
"""A MultipleChoiceField whose choices are a model QuerySet."""
widget = SelectMultiple
hidden_widget = MultipleHiddenInput
default_error_messages = {
'list': _(u'Enter a list of values.'),
'invalid_choice': _(u'Select a valid choice. %s is not one of the'
u' available choices.'),
}
def __init__(self, queryset, cache_choices=False, required=True,
widget=None, label=None, initial=None,
help_text=None, *args, **kwargs):
super(ModelMultipleChoiceField, self).__init__(queryset, None,
cache_choices, required, widget, label, initial, help_text,
*args, **kwargs)
def clean(self, value):
if self.required and not value:
raise ValidationError(self.error_messages['required'])
elif not self.required and not value:
return []
if not isinstance(value, (list, tuple)):
raise ValidationError(self.error_messages['list'])
final_values = []
for val in value:
try:
obj = self.queryset.get(pk=val)
except self.queryset.model.DoesNotExist:
raise ValidationError(self.error_messages['invalid_choice'] % val)
else:
final_values.append(obj)
return final_values