If you inherit from ValidatedModel instead of from models.Model, then full_clean() will be called before save(). So, add validators to your field definitions, and all your fields will be validated before they go to the database. The same thing can be accomplished with a pre_save signal, but the code is quite a bit messier than the simple inheritance above.
A project I'm working on requires multiple different classes of users, all with different fields/attributes. Having a single UserProfile class with a generic relation was a complete pain in practice. So, I changed my classes to all subclass User directly and then used django-model-utils to create a custom ModelBackend that returns the appropriate class when accessing request.user. The InheritanceQuerySet manager provided by django-model-utils makes it all possible and with only a single database query. No need to add anything directly to the User class, by the way. Just subclass it directly with each of your custom classes: class CustomUser1(User): field1 = models.CharField(...) class CustomUser2(User): field2 = models.CharField(...)
HTML allows an option in a <select> to be disabled. In other words it will appear in the list of choices but won't be selectable. This is done by adding a 'disabled' attribute to the <option> tag, for example: `<option value="" disabled="disabled">Disabled option</option>` This code subclasses the regular Django Select widget, overriding the render_option method to allow disabling options. Example of usage: class FruitForm(forms.Form): choices = (('apples', 'Apples'), ('oranges', 'Oranges'), ('bananas', {'label': 'Bananas', 'disabled': True}), # Yes, we have no bananas ('grobblefruit', 'Grobblefruit')) fruit = forms.ChoiceField(choices=choices, widget=SelectWithDisabled())
When you're using Django model inheritance, sometimes you want to be able to get objects of the base class that aren't instances of any of the subclasses. You might expect the obvious way of doing this, `SuperModel.objects.filter(submodel__isnull=True)`, to work, but unfortunately it doesn't. (Neither does `SuperModel.objects.filter(submodel__supermodel_ptr=None)`, or any other convoluted way I could think of doing it.) Here's a nicer approach for doing this. [The blog entry is here.](http://sciyoshi.com/blog/2008/aug/07/custom-django-manager-excludes-subclasses/)
Nutshell: Subclass this form with the required fields defined to automatically generate a form based on a model in a similar fashion to how form_for_model works, but in a way that tries to be a little easier if you want to customize the form. It handles updates and creations automatically as long as any database field requirements are met. This is something I made while trying to understand newforms, and is my own attempt at something between the simplicity of a stock form_for_model form, and a full blown custom form. The proper way is to use a callback function to customize form_for_model, but that felt cumbersome so I did it my way :) It works for me, but I'm relatively new to both python and Django so please test yourself before trusting.
5 snippets posted so far.