187 lines
7.9 KiB
Python
187 lines
7.9 KiB
Python
"""
|
|
Helper functions for creating Form classes from Django models
|
|
and database field objects.
|
|
"""
|
|
|
|
from django.utils.translation import gettext
|
|
from util import ValidationError
|
|
from forms import BaseForm, DeclarativeFieldsMetaclass, SortedDictFromList
|
|
from fields import Field, ChoiceField
|
|
from widgets import Select, SelectMultiple, MultipleHiddenInput
|
|
|
|
__all__ = ('save_instance', 'form_for_model', 'form_for_instance', 'form_for_fields',
|
|
'ModelChoiceField', 'ModelMultipleChoiceField')
|
|
|
|
def model_save(self, commit=True):
|
|
"""
|
|
Creates and returns model instance according to self.clean_data.
|
|
|
|
This method is created for any form_for_model Form.
|
|
"""
|
|
if self.errors:
|
|
raise ValueError("The %s could not be created because the data didn't validate." % self._model._meta.object_name)
|
|
return save_instance(self, self._model(), commit)
|
|
|
|
def save_instance(form, instance, commit=True):
|
|
"""
|
|
Saves bound Form ``form``'s clean_data into model instance ``instance``.
|
|
|
|
Assumes ``form`` has a field for every non-AutoField database field in
|
|
``instance``. If commit=True, then the changes to ``instance`` will be
|
|
saved to the database. Returns ``instance``.
|
|
"""
|
|
from django.db import models
|
|
opts = instance.__class__._meta
|
|
if form.errors:
|
|
raise ValueError("The %s could not be changed because the data didn't validate." % opts.object_name)
|
|
clean_data = form.clean_data
|
|
for f in opts.fields:
|
|
if not f.editable or isinstance(f, models.AutoField):
|
|
continue
|
|
setattr(instance, f.name, clean_data[f.name])
|
|
if commit:
|
|
instance.save()
|
|
for f in opts.many_to_many:
|
|
setattr(instance, f.attname, clean_data[f.name])
|
|
# GOTCHA: If many-to-many data is given and commit=False, the many-to-many
|
|
# data will be lost. This happens because a many-to-many options cannot be
|
|
# set on an object until after it's saved. Maybe we should raise an
|
|
# exception in that case.
|
|
return instance
|
|
|
|
def make_instance_save(instance):
|
|
"Returns the save() method for a form_for_instance Form."
|
|
def save(self, commit=True):
|
|
return save_instance(self, instance, commit)
|
|
return save
|
|
|
|
def form_for_model(model, form=BaseForm, formfield_callback=lambda f: f.formfield()):
|
|
"""
|
|
Returns a Form class for the given Django model class.
|
|
|
|
Provide ``form`` if you want to use a custom BaseForm subclass.
|
|
|
|
Provide ``formfield_callback`` if you want to define different logic for
|
|
determining the formfield for a given database field. It's a callable that
|
|
takes a database Field instance and returns a form Field instance.
|
|
"""
|
|
opts = model._meta
|
|
field_list = []
|
|
for f in opts.fields + opts.many_to_many:
|
|
if not f.editable:
|
|
continue
|
|
formfield = formfield_callback(f)
|
|
if formfield:
|
|
field_list.append((f.name, formfield))
|
|
fields = SortedDictFromList(field_list)
|
|
return type(opts.object_name + 'Form', (form,), {'base_fields': fields, '_model': model, 'save': model_save})
|
|
|
|
def form_for_instance(instance, form=BaseForm, formfield_callback=lambda f, **kwargs: f.formfield(**kwargs)):
|
|
"""
|
|
Returns a Form class for the given Django model instance.
|
|
|
|
Provide ``form`` if you want to use a custom BaseForm subclass.
|
|
|
|
Provide ``formfield_callback`` if you want to define different logic for
|
|
determining the formfield for a given database field. It's a callable that
|
|
takes a database Field instance, plus **kwargs, and returns a form Field
|
|
instance with the given kwargs (i.e. 'initial').
|
|
"""
|
|
model = instance.__class__
|
|
opts = model._meta
|
|
field_list = []
|
|
for f in opts.fields + opts.many_to_many:
|
|
if not f.editable:
|
|
continue
|
|
current_value = f.value_from_object(instance)
|
|
formfield = formfield_callback(f, initial=current_value)
|
|
if formfield:
|
|
field_list.append((f.name, formfield))
|
|
fields = SortedDictFromList(field_list)
|
|
return type(opts.object_name + 'InstanceForm', (form,),
|
|
{'base_fields': fields, '_model': model, 'save': make_instance_save(instance)})
|
|
|
|
def form_for_fields(field_list):
|
|
"Returns a Form class for the given list of Django database field instances."
|
|
fields = SortedDictFromList([(f.name, f.formfield()) for f in field_list if f.editable])
|
|
return type('FormForFields', (BaseForm,), {'base_fields': fields})
|
|
|
|
class QuerySetIterator(object):
|
|
def __init__(self, queryset, empty_label, cache_choices):
|
|
self.queryset, self.empty_label, self.cache_choices = queryset, empty_label, cache_choices
|
|
|
|
def __iter__(self):
|
|
if self.empty_label is not None:
|
|
yield (u"", self.empty_label)
|
|
for obj in self.queryset:
|
|
yield (obj._get_pk_val(), str(obj))
|
|
# Clear the QuerySet cache if required.
|
|
if not self.cache_choices:
|
|
self.queryset._result_cache = None
|
|
|
|
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.
|
|
def __init__(self, queryset, empty_label=u"---------", cache_choices=False,
|
|
required=True, widget=Select, label=None, initial=None, help_text=None):
|
|
self.queryset = queryset
|
|
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)
|
|
self.widget.choices = self.choices
|
|
|
|
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 QuerySetIterator(self.queryset, self.empty_label, self.cache_choices)
|
|
|
|
def _set_choices(self, value):
|
|
# This method is copied from ChoiceField._set_choices(). It's necessary
|
|
# because property() doesn't allow a subclass to overwrite only
|
|
# _get_choices without implementing _set_choices.
|
|
self._choices = self.widget.choices = list(value)
|
|
|
|
choices = property(_get_choices, _set_choices)
|
|
|
|
def clean(self, value):
|
|
Field.clean(self, value)
|
|
if value in ('', None):
|
|
return None
|
|
try:
|
|
value = self.queryset.model._default_manager.get(pk=value)
|
|
except self.queryset.model.DoesNotExist:
|
|
raise ValidationError(gettext(u'Select a valid choice. That choice is not one of the available choices.'))
|
|
return value
|
|
|
|
class ModelMultipleChoiceField(ModelChoiceField):
|
|
"A MultipleChoiceField whose choices are a model QuerySet."
|
|
hidden_widget = MultipleHiddenInput
|
|
def __init__(self, queryset, cache_choices=False, required=True,
|
|
widget=SelectMultiple, label=None, initial=None, help_text=None):
|
|
super(ModelMultipleChoiceField, self).__init__(queryset, None, cache_choices,
|
|
required, widget, label, initial, help_text)
|
|
|
|
def clean(self, value):
|
|
if self.required and not value:
|
|
raise ValidationError(gettext(u'This field is required.'))
|
|
elif not self.required and not value:
|
|
return []
|
|
if not isinstance(value, (list, tuple)):
|
|
raise ValidationError(gettext(u'Enter a list of values.'))
|
|
final_values = []
|
|
for val in value:
|
|
try:
|
|
obj = self.queryset.model._default_manager.get(pk=val)
|
|
except self.queryset.model.DoesNotExist:
|
|
raise ValidationError(gettext(u'Select a valid choice. %s is not one of the available choices.') % val)
|
|
else:
|
|
final_values.append(obj)
|
|
return final_values
|