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687 lines
28 KiB
687 lines
28 KiB
""" |
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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|
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# ModelForms ################################################################# |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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def validate_unique(self): |
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from django.db.models.fields import FieldDoesNotExist |
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|
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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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|
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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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|
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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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|
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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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|
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qs = self.instance.__class__._default_manager.filter(**lookup_kwargs) |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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class ModelForm(BaseModelForm): |
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__metaclass__ = ModelFormMetaclass |
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|
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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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|
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|
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# ModelFormSets ############################################################## |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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|
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# InlineFormSets ############################################################# |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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: |
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form.fields[self._pk_field.name] = IntegerField(required=False, widget=HiddenInput) |
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|
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def _get_foreign_key(parent_model, model, fk_name=None): |
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""" |
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Finds and returns the ForeignKey from model to parent if there is one. |
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If fk_name is provided, assume it is the name of the ForeignKey field. |
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""" |
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# avoid circular import |
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from django.db.models import ForeignKey |
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opts = model._meta |
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if fk_name: |
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fks_to_parent = [f for f in opts.fields if f.name == fk_name] |
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if len(fks_to_parent) == 1: |
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fk = fks_to_parent[0] |
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if not isinstance(fk, ForeignKey) or \ |
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(fk.rel.to != parent_model and |
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fk.rel.to not in parent_model._meta.get_parent_list()): |
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raise Exception("fk_name '%s' is not a ForeignKey to %s" % (fk_name, parent_model)) |
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elif len(fks_to_parent) == 0: |
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raise Exception("%s has no field named '%s'" % (model, fk_name)) |
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else: |
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# Try to discover what the ForeignKey from model to parent_model is |
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fks_to_parent = [ |
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f for f in opts.fields |
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if isinstance(f, ForeignKey) |
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and (f.rel.to == parent_model |
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or f.rel.to in parent_model._meta.get_parent_list()) |
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] |
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if len(fks_to_parent) == 1: |
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fk = fks_to_parent[0] |
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elif len(fks_to_parent) == 0: |
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raise Exception("%s has no ForeignKey to %s" % (model, parent_model)) |
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else: |
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raise Exception("%s has more than 1 ForeignKey to %s" % (model, parent_model)) |
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return fk |
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|
|
|
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def inlineformset_factory(parent_model, model, form=ModelForm, |
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formset=BaseInlineFormSet, fk_name=None, |
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fields=None, exclude=None, |
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extra=3, can_order=False, can_delete=True, max_num=0, |
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formfield_callback=lambda f: f.formfield()): |
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""" |
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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.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
|
|
|