689 lines
28 KiB
Python
689 lines
28 KiB
Python
"""
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Helper functions for creating Form classes from Django models
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and database field objects.
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"""
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from django.utils.encoding import smart_unicode
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from django.utils.datastructures import SortedDict
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from django.utils.text import get_text_list, capfirst
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from django.utils.translation import ugettext_lazy as _
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from util import ValidationError, ErrorList
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from forms import BaseForm, get_declared_fields
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from fields import Field, ChoiceField, IntegerField, EMPTY_VALUES
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from widgets import Select, SelectMultiple, HiddenInput, MultipleHiddenInput
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from widgets import media_property
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from formsets import BaseFormSet, formset_factory, DELETION_FIELD_NAME
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__all__ = (
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'ModelForm', 'BaseModelForm', 'model_to_dict', 'fields_for_model',
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'save_instance', 'form_for_fields', 'ModelChoiceField',
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'ModelMultipleChoiceField',
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)
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def save_instance(form, instance, fields=None, fail_message='saved',
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commit=True, exclude=None):
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"""
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Saves bound Form ``form``'s cleaned_data into model instance ``instance``.
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If commit=True, then the changes to ``instance`` will be saved to the
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database. Returns ``instance``.
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"""
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from django.db import models
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opts = instance._meta
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if form.errors:
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raise ValueError("The %s could not be %s because the data didn't"
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" validate." % (opts.object_name, fail_message))
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cleaned_data = form.cleaned_data
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for f in opts.fields:
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if not f.editable or isinstance(f, models.AutoField) \
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or not f.name in cleaned_data:
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continue
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if fields and f.name not in fields:
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continue
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if exclude and f.name in exclude:
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continue
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f.save_form_data(instance, cleaned_data[f.name])
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# Wrap up the saving of m2m data as a function.
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def save_m2m():
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opts = instance._meta
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cleaned_data = form.cleaned_data
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for f in opts.many_to_many:
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if fields and f.name not in fields:
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continue
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if f.name in cleaned_data:
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f.save_form_data(instance, cleaned_data[f.name])
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if commit:
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# If we are committing, save the instance and the m2m data immediately.
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instance.save()
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save_m2m()
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else:
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# We're not committing. Add a method to the form to allow deferred
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# saving of m2m data.
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form.save_m2m = save_m2m
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return instance
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def make_model_save(model, fields, fail_message):
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"""Returns the save() method for a Form."""
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def save(self, commit=True):
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return save_instance(self, model(), fields, fail_message, commit)
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return save
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def make_instance_save(instance, fields, fail_message):
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"""Returns the save() method for a Form."""
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def save(self, commit=True):
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return save_instance(self, instance, fields, fail_message, commit)
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return save
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def form_for_fields(field_list):
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"""
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Returns a Form class for the given list of Django database field instances.
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"""
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fields = SortedDict([(f.name, f.formfield())
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for f in field_list if f.editable])
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return type('FormForFields', (BaseForm,), {'base_fields': fields})
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# ModelForms #################################################################
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def model_to_dict(instance, fields=None, exclude=None):
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"""
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Returns a dict containing the data in ``instance`` suitable for passing as
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a Form's ``initial`` keyword argument.
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``fields`` is an optional list of field names. If provided, only the named
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fields will be included in the returned dict.
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``exclude`` is an optional list of field names. If provided, the named
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fields will be excluded from the returned dict, even if they are listed in
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the ``fields`` argument.
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"""
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# avoid a circular import
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from django.db.models.fields.related import ManyToManyField, OneToOneField
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opts = instance._meta
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data = {}
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for f in opts.fields + opts.many_to_many:
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if not f.editable:
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continue
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if fields and not f.name in fields:
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continue
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if exclude and f.name in exclude:
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continue
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if isinstance(f, ManyToManyField):
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# If the object doesn't have a primry key yet, just use an empty
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# list for its m2m fields. Calling f.value_from_object will raise
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# an exception.
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if instance.pk is None:
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data[f.name] = []
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else:
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# MultipleChoiceWidget needs a list of pks, not object instances.
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data[f.name] = [obj.pk for obj in f.value_from_object(instance)]
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else:
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data[f.name] = f.value_from_object(instance)
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return data
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def fields_for_model(model, fields=None, exclude=None, formfield_callback=lambda f: f.formfield()):
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"""
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Returns a ``SortedDict`` containing form fields for the given model.
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``fields`` is an optional list of field names. If provided, only the named
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fields will be included in the returned fields.
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``exclude`` is an optional list of field names. If provided, the named
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fields will be excluded from the returned fields, even if they are listed
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in the ``fields`` argument.
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"""
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# TODO: if fields is provided, it would be nice to return fields in that order
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field_list = []
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opts = model._meta
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for f in opts.fields + opts.many_to_many:
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if not f.editable:
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continue
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if fields and not f.name in fields:
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continue
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if exclude and f.name in exclude:
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continue
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formfield = formfield_callback(f)
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if formfield:
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field_list.append((f.name, formfield))
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return SortedDict(field_list)
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class ModelFormOptions(object):
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def __init__(self, options=None):
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self.model = getattr(options, 'model', None)
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self.fields = getattr(options, 'fields', None)
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self.exclude = getattr(options, 'exclude', None)
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class ModelFormMetaclass(type):
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def __new__(cls, name, bases, attrs):
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formfield_callback = attrs.pop('formfield_callback',
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lambda f: f.formfield())
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try:
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parents = [b for b in bases if issubclass(b, ModelForm)]
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except NameError:
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# We are defining ModelForm itself.
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parents = None
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declared_fields = get_declared_fields(bases, attrs, False)
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new_class = super(ModelFormMetaclass, cls).__new__(cls, name, bases,
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attrs)
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if not parents:
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return new_class
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if 'media' not in attrs:
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new_class.media = media_property(new_class)
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opts = new_class._meta = ModelFormOptions(getattr(new_class, 'Meta', None))
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if opts.model:
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# If a model is defined, extract form fields from it.
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fields = fields_for_model(opts.model, opts.fields,
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opts.exclude, formfield_callback)
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# Override default model fields with any custom declared ones
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# (plus, include all the other declared fields).
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fields.update(declared_fields)
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else:
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fields = declared_fields
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new_class.declared_fields = declared_fields
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new_class.base_fields = fields
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return new_class
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class BaseModelForm(BaseForm):
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def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None,
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initial=None, error_class=ErrorList, label_suffix=':',
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empty_permitted=False, instance=None):
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opts = self._meta
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if instance is None:
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# if we didn't get an instance, instantiate a new one
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self.instance = opts.model()
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object_data = {}
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else:
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self.instance = instance
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object_data = model_to_dict(instance, opts.fields, opts.exclude)
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# if initial was provided, it should override the values from instance
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if initial is not None:
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object_data.update(initial)
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super(BaseModelForm, self).__init__(data, files, auto_id, prefix, object_data,
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error_class, label_suffix, empty_permitted)
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def clean(self):
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self.validate_unique()
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return self.cleaned_data
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def validate_unique(self):
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from django.db.models.fields import FieldDoesNotExist
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# Gather a list of checks to perform. Since this is a ModelForm, some
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# fields may have been excluded; we can't perform a unique check on a
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# form that is missing fields involved in that check.
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unique_checks = []
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for check in self.instance._meta.unique_together[:]:
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fields_on_form = [field for field in check if field in self.fields]
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if len(fields_on_form) == len(check):
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unique_checks.append(check)
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form_errors = []
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# Gather a list of checks for fields declared as unique and add them to
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# the list of checks. Again, skip fields not on the form.
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for name, field in self.fields.items():
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try:
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f = self.instance._meta.get_field_by_name(name)[0]
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except FieldDoesNotExist:
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# This is an extra field that's not on the ModelForm, ignore it
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continue
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# MySQL can't handle ... WHERE pk IS NULL, so make sure we
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# don't generate queries of that form.
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is_null_pk = f.primary_key and self.cleaned_data[name] is None
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if name in self.cleaned_data and f.unique and not is_null_pk:
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unique_checks.append((name,))
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# Don't run unique checks on fields that already have an error.
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unique_checks = [check for check in unique_checks if not [x in self._errors for x in check if x in self._errors]]
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for unique_check in unique_checks:
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# Try to look up an existing object with the same values as this
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# object's values for all the unique field.
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lookup_kwargs = {}
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for field_name in unique_check:
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lookup_kwargs[field_name] = self.cleaned_data[field_name]
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qs = self.instance.__class__._default_manager.filter(**lookup_kwargs)
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# Exclude the current object from the query if we are editing an
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# instance (as opposed to creating a new one)
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if self.instance.pk is not None:
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qs = qs.exclude(pk=self.instance.pk)
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# This cute trick with extra/values is the most efficient way to
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# tell if a particular query returns any results.
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if qs.extra(select={'a': 1}).values('a').order_by():
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model_name = capfirst(self.instance._meta.verbose_name)
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# A unique field
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if len(unique_check) == 1:
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field_name = unique_check[0]
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field_label = self.fields[field_name].label
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# Insert the error into the error dict, very sneaky
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self._errors[field_name] = ErrorList([
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_(u"%(model_name)s with this %(field_label)s already exists.") % \
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{'model_name': unicode(model_name),
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'field_label': unicode(field_label)}
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])
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# unique_together
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else:
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field_labels = [self.fields[field_name].label for field_name in unique_check]
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field_labels = get_text_list(field_labels, _('and'))
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form_errors.append(
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_(u"%(model_name)s with this %(field_label)s already exists.") % \
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{'model_name': unicode(model_name),
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'field_label': unicode(field_labels)}
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)
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# Remove the data from the cleaned_data dict since it was invalid
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for field_name in unique_check:
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del self.cleaned_data[field_name]
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if form_errors:
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# Raise the unique together errors since they are considered form-wide.
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raise ValidationError(form_errors)
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def save(self, commit=True):
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"""
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Saves this ``form``'s cleaned_data into model instance
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``self.instance``.
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If commit=True, then the changes to ``instance`` will be saved to the
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database. Returns ``instance``.
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"""
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if self.instance.pk is None:
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fail_message = 'created'
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else:
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fail_message = 'changed'
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return save_instance(self, self.instance, self._meta.fields, fail_message, commit)
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class ModelForm(BaseModelForm):
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__metaclass__ = ModelFormMetaclass
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def modelform_factory(model, form=ModelForm, fields=None, exclude=None,
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formfield_callback=lambda f: f.formfield()):
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# HACK: we should be able to construct a ModelForm without creating
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# and passing in a temporary inner class
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class Meta:
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pass
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setattr(Meta, 'model', model)
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setattr(Meta, 'fields', fields)
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setattr(Meta, 'exclude', exclude)
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class_name = model.__name__ + 'Form'
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return ModelFormMetaclass(class_name, (form,), {'Meta': Meta,
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'formfield_callback': formfield_callback})
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# ModelFormSets ##############################################################
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class BaseModelFormSet(BaseFormSet):
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"""
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A ``FormSet`` for editing a queryset and/or adding new objects to it.
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"""
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model = None
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def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None,
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queryset=None, **kwargs):
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self.queryset = queryset
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defaults = {'data': data, 'files': files, 'auto_id': auto_id, 'prefix': prefix}
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defaults['initial'] = [model_to_dict(obj) for obj in self.get_queryset()]
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defaults.update(kwargs)
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super(BaseModelFormSet, self).__init__(**defaults)
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def _construct_form(self, i, **kwargs):
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if i < self._initial_form_count:
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kwargs['instance'] = self.get_queryset()[i]
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return super(BaseModelFormSet, self)._construct_form(i, **kwargs)
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def get_queryset(self):
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if not hasattr(self, '_queryset'):
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if self.queryset is not None:
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qs = self.queryset
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else:
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qs = self.model._default_manager.get_query_set()
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if self.max_num > 0:
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self._queryset = qs[:self.max_num]
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else:
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self._queryset = qs
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return self._queryset
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def save_new(self, form, commit=True):
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"""Saves and returns a new model instance for the given form."""
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return save_instance(form, self.model(), exclude=[self._pk_field.name], commit=commit)
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def save_existing(self, form, instance, commit=True):
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"""Saves and returns an existing model instance for the given form."""
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return save_instance(form, instance, exclude=[self._pk_field.name], commit=commit)
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def save(self, commit=True):
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"""Saves model instances for every form, adding and changing instances
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as necessary, and returns the list of instances.
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"""
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if not commit:
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self.saved_forms = []
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def save_m2m():
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for form in self.saved_forms:
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form.save_m2m()
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self.save_m2m = save_m2m
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return self.save_existing_objects(commit) + self.save_new_objects(commit)
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def save_existing_objects(self, commit=True):
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self.changed_objects = []
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self.deleted_objects = []
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if not self.get_queryset():
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return []
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# Put the objects from self.get_queryset into a dict so they are easy to lookup by pk
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existing_objects = {}
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for obj in self.get_queryset():
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existing_objects[obj.pk] = obj
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saved_instances = []
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for form in self.initial_forms:
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obj = existing_objects[form.cleaned_data[self._pk_field.name]]
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if self.can_delete and form.cleaned_data[DELETION_FIELD_NAME]:
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self.deleted_objects.append(obj)
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obj.delete()
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else:
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if form.changed_data:
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self.changed_objects.append((obj, form.changed_data))
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saved_instances.append(self.save_existing(form, obj, commit=commit))
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if not commit:
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self.saved_forms.append(form)
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return saved_instances
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def save_new_objects(self, commit=True):
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self.new_objects = []
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for form in self.extra_forms:
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if not form.has_changed():
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continue
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# If someone has marked an add form for deletion, don't save the
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# object.
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if self.can_delete and form.cleaned_data[DELETION_FIELD_NAME]:
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continue
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self.new_objects.append(self.save_new(form, commit=commit))
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if not commit:
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self.saved_forms.append(form)
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return self.new_objects
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def add_fields(self, form, index):
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"""Add a hidden field for the object's primary key."""
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from django.db.models import AutoField
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self._pk_field = pk = self.model._meta.pk
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if pk.auto_created or isinstance(pk, AutoField):
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form.fields[self._pk_field.name] = IntegerField(required=False, widget=HiddenInput)
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super(BaseModelFormSet, self).add_fields(form, index)
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def modelformset_factory(model, form=ModelForm, formfield_callback=lambda f: f.formfield(),
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formset=BaseModelFormSet,
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extra=1, can_delete=False, can_order=False,
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max_num=0, fields=None, exclude=None):
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"""
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Returns a FormSet class for the given Django model class.
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"""
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form = modelform_factory(model, form=form, fields=fields, exclude=exclude,
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formfield_callback=formfield_callback)
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FormSet = formset_factory(form, formset, extra=extra, max_num=max_num,
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can_order=can_order, can_delete=can_delete)
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FormSet.model = model
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return FormSet
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# InlineFormSets #############################################################
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class BaseInlineFormSet(BaseModelFormSet):
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"""A formset for child objects related to a parent."""
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def __init__(self, data=None, files=None, instance=None,
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save_as_new=False, prefix=None):
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from django.db.models.fields.related import RelatedObject
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self.instance = instance
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self.save_as_new = save_as_new
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# is there a better way to get the object descriptor?
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self.rel_name = RelatedObject(self.fk.rel.to, self.model, self.fk).get_accessor_name()
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super(BaseInlineFormSet, self).__init__(data, files, prefix=prefix or self.rel_name)
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def _construct_forms(self):
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if self.save_as_new:
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self._total_form_count = self._initial_form_count
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self._initial_form_count = 0
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super(BaseInlineFormSet, self)._construct_forms()
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def _construct_form(self, i, **kwargs):
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form = super(BaseInlineFormSet, self)._construct_form(i, **kwargs)
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if self.save_as_new:
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# Remove the primary key from the form's data, we are only
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# creating new instances
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form.data[form.add_prefix(self._pk_field.name)] = None
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return form
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def get_queryset(self):
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"""
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Returns this FormSet's queryset, but restricted to children of
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self.instance
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"""
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kwargs = {self.fk.name: self.instance}
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return self.model._default_manager.filter(**kwargs)
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def save_new(self, form, commit=True):
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kwargs = {self.fk.get_attname(): self.instance.pk}
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new_obj = self.model(**kwargs)
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return save_instance(form, new_obj, exclude=[self._pk_field.name], commit=commit)
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def add_fields(self, form, index):
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super(BaseInlineFormSet, self).add_fields(form, index)
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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
|