View layer

Introduction

If you are using django in a fullstack way, meaning with django views and templates, you surely want to use this extra requirement.

Just install the package like this:

pip install ai-django-core[view-layer]

If you are using pipenv, you can add the following line to your Pipfile:

ai-django-core = {extras = ["view-layer"],version = "*"}

Forms

Mixins

// todo tbr

Formsets

CountChildrenFormsetMixin

This mixin provides a method which returns the current number of children of this formset. It automatically takes care of deleted or to-be-deleted children. Have a look at the example use-case below:

class DataFieldFormset(CountChildrenFormsetMixin, BaseInlineFormSet):

    def clean(self):
        cleaned_data = super().clean()

        # Count children
        number_of_children = self.get_number_of_children()

        # do some magic

        return cleaned_data

Note that the form needs to be validated before you can use this method.

Formset Views

This package provides two mixins supporting class-based views combined with formsets. The FormsetCreateViewMixin is to be used with a generic.CreateView, the FormsetUpdateViewMixin together with generic.UpdateView.

The idea behind these mixins to make handling formset less pain and provide the comfy feeling you are used from regular forms.

Here is an example for a create view:

class MyModelCreateView(FormsetCreateViewMixin, generic.CreateView):
    model = MyModel
    template_name = 'my_app/my_model_edit.html'
    form_class = MyModelEditForm
    formset_class = inlineformset_factory(MyModel, MyModelChild,
                                          form=MyModelChildForm,
                                          formset=MyModelChildFormset)

    def get_formset_kwargs(self):
        # this is optional!
        kwargs = super().get_formset_kwargs()
        kwargs['request'] = self.request
        return kwargs

You just define - similar to the regular form - a formset_class as a class attribute. All the required handling like validation will happen magically. If you need to pass additional values to your formset, just extend the method get_formset_kwargs() as you would for djangos get_form_kwargs().

If you want to update a model and its children, here is an example for the edit-case:

class MyModelEditView(FormsetUpdateViewMixin, generic.UpdateView):
    model = MyModel
    template_name = 'my_app/my_model_edit.html'
    form_class = MyModelEditForm
    formset_class = inlineformset_factory(MyModel, MyModelChild,
                                          form=MyModelChildForm,
                                          formset=MyModelChildFormset)

    def get_formset_kwargs(self):
        # this is optional!
        kwargs = super().get_formset_kwargs()
        kwargs['request'] = self.request
        return kwargs

View mixins

CustomPermissionMixin

If you want to handle some custom permission check for which you cannot use the regular django permissions, just derive your class-based view from CustomPermissionMixin and add the method validate_permissions() with your custom logic. Notice that it has to return a boolean value.

For example, you want to allow only the “owner” of an object to view its detail page:

from django.views import generic

class MyModelDetailView(CustomPermissionMixin, generics.DetailView):
    ...

        def validate_permissions(self):
            object = super().get_object()
            if self.request.user.employee:
                return False
            return True

If the method returns False, the regular dispatch will just simply render your 403 page and skip all the other things within the view.

RequestInFormKwargsMixin

The RequestInFormKwargsMixin is a handy helper for passing the request automated form the view to the form. If you need for example the current request user within the form, you need to have the current request available.

Just add the mixin to the parents of your class-based view class:

from django.views import generic

class MyModelEditView(RequestInFormKwargsMixin, generic.CreateView):
    model = MyModel
    template_name = 'myapp/mymodel_edit.html'
    form_class = MyModelForm
    ...

class MyModelEditView(RequestInFormKwargsMixin, generic.UpdateView):
    model = MyModel
    template_name = 'myapp/mymodel_edit.html'
    form_class = MyModelForm
    ...

Make sure that you overwrite the __init__\ ``method of your form and move the `request` to the class. Otherwise thesuper()`` will detect an unrecognised parameter within the kwargs and raise an error:

from django.forms.models import ModelForm

class MyModelForm(ModelForm):

    def __init__(self, *args, **kwargs):

        # Get request from kwargs
        self.request = kwargs.pop('request', None)

        # Call the parent method
        super().__init__(*args, **kwargs)

That’s it.