î Þ^Q\Õã@sCdZddlmZddlmZGdd„dejƒZdS)aö tl;dr: See FutureModelForm's docstring. Many apps provide new related managers to extend your django models with. For example, django-tagulous provides a TagField which abstracts an M2M relation with the Tag model, django-gm2m provides a GM2MField which abstracts an relation, django-taggit provides a TaggableManager which abstracts a relation too, django-generic-m2m provides RelatedObjectsDescriptor which abstracts a relation again. While that works pretty well, it gets a bit complicated when it comes to encapsulating the business logic for saving such data in a form object. This is three-part problem: - getting initial data, - saving instance attributes, - saving relations like reverse relations or many to many. Django's ModelForm calls the form field's ``value_from_object()`` method to get the initial data. ``FutureModelForm`` tries the ``value_from_object()`` method from the form field instead, if defined. Unlike the model field, the form field doesn't know its name, so ``FutureModelForm`` passes it when calling the form field's ``value_from_object()`` method. Django's ModelForm calls the form field's ``save_form_data()`` in two occasions: - in ``_post_clean()`` for model fields in ``Meta.fields``, - in ``_save_m2m()`` for model fields in ``Meta.virtual_fields`` and ``Meta.many_to_many``, which then operate on an instance which as a PK. If we just added ``save_form_data()`` to form fields like for ``value_from_object()`` then it would be called twice, once in ``_post_clean()`` and once in ``_save_m2m()``. Instead, ``FutureModelForm`` would call the following methods from the form field, if defined: - ``save_object_data()`` in ``_post_clean()``, to set object attributes for a given value, - ``save_relation_data()`` in ``_save_m2m()``, to save relations for a given value. For example: - a generic foreign key only sets instance attributes, its form field would do that in ``save_object_data()``, - a tag field saves relations, its form field would do that in ``save_relation_data()``. é)Úchain)ÚformscsUeZdZdZ‡fdd†Z‡fdd†Zdd„Zdd d „Z‡S) ÚFutureModelForma1 ModelForm which adds extra API to form fields. Form fields may define new methods for FutureModelForm: - ``FormField.value_from_object(instance, name)`` should return the initial value to use in the form, overrides ``ModelField.value_from_object()`` which is what ModelForm uses by default, - ``FormField.save_object_data(instance, name, value)`` should set instance attributes. Called by ``save()`` **before** writting the database, when ``instance.pk`` may not be set, it overrides ``ModelField.save_form_data()`` which is normally used in this occasion for non-m2m and non-virtual model fields. - ``FormField.save_relation_data(instance, name, value)`` should save relations required for value on the instance. Called by ``save()`` **after** writting the database, when ``instance.pk`` is necessarely set, it overrides ``ModelField.save_form_data()`` which is normally used in this occasion for m2m and virtual model fields. For complete rationale, see this module's docstring. csntt|ƒj||ŽxN|jjƒD]=\}}t|dƒsJq)n|j|j|ƒ|j|/var/www/dbchiro/venv/lib/python3.4/site-packages/dal/forms.pyrNs zFutureModelForm.__init__csqtt|ƒjƒxW|jjƒD]F\}}t|dƒsDq#n|j|j||jj |dƒƒq#WdS)z;Override that uses the form field's ``save_object_data()``.Úsave_object_dataN) rrÚ _post_cleanrr r rr Ú cleaned_dataÚget)r rr)rrrrXszFutureModelForm._post_cleanc Cs?|j}|jj}|jj}|jj}g}xY|jjƒD]H\}}t|dƒsdqCn|j|j|||ƒ|j|ƒqCWx©t |j |j ƒD]’}|j |krÀq¥nt|dƒsÕq¥n|rð|j |krðq¥n|r |j |kr q¥n|j |kr¥|j |j||j ƒq¥q¥WdS)z;Override that uses the form field's ``save_object_data()``.Úsave_relation_dataÚsave_form_dataN)rÚ_metaÚexcluderr r r rÚappendrZ many_to_manyZvirtual_fieldsrr) r rrrÚoptsZhandledrrÚfrrrÚ _save_m2mfs0     zFutureModelForm._save_m2mTcCss|jr@td|jjj|jjjr0dndfƒ‚n|r`|jjƒ|jƒn |j|_ |jS)z"Backport from Django 1.9+ for 1.8.z8The %s could not be %s because the data didn't validate.ÚcreatedÚchanged) ÚerrorsÚ ValueErrorr rZ object_nameÚ_stateZaddingÚsaver Zsave_m2m)r Zcommitrrrr&Œs  %   zFutureModelForm.save)Ú__name__Ú __module__Ú __qualname__Ú__doc__rrr r&rr)rrr7s   &rN)r*Ú itertoolsrZdjangorZ ModelFormrrrrrÚ0s