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Tag "metaclass"

Snippet List

Extended i18n base model

This snippet is an extension of [i18n base model for translatable content](http://djangosnippets.org/snippets/855/) so all the same usage applies. I have extended this module in several ways to make it more fully featured. * `I18NMixin` can be an additional (via multiple inheritance) or alternative superclass for your models juxtaposed with an `I18NModel`. * Adds a property `_` to access the appropriate I18NModel. `trans` aliases this (or rather vice versa) for template access. * In a call to `.filter` you can query on translated fields by wrapping those fields in a call to i18nQ. I like to import this as _ if I haven't already used that import. * A call to I18NFieldset will return an inline for use in the builtin admin app. I like to call this inline to the assignment to inlines. * If you need abstracted access to the I18N model from a model, I've added a property I18N referring to it. I've been using this with great convenience and stability.

  • models
  • i18n
  • metaclass
  • translated-content
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ModelMixin

Enables convenient adding of fields, methods and properties to Django models. Instead of: User.add_to_class('foo', models.CharField(...) User.add_to_class('bar', models.IntegerField(...) you can write: class UserMixin(ModelMixin): model = User foo = models.CharField(...) bar = models.IntegerField(...)

  • mixin
  • metaclass
  • util
  • metaprogramming
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i18n base model for translatable content

Together with my mentor, Dusty Phillips, I have developed a simple class that dynamically adds two fields to its subclasses. This is useful in cases when a single piece of content is divided into translatable and non-translatable fields, connected by a 1-to-many relationship. ## Update 2009/03/30 Since its inception, this snippet has grown into a significantly more powerful solution for translatable content (I use it myself with great joy :). The project is now hosted on github: [project page](http://github.com/foxbunny/django-i18n-model/tree/master) ## Update 2008/07/09 It is now possible to define `i18n_common_model` attribute in `class Meta` section. Here's an example: class Meta: i18n_common_model = "MyCommonModel" As you can see, it has to be a string, not the real class, and it is case-sensitive. ## Example class Article(models.Model): author = models.CharField(max_length = 40) class Admin: pass class ArticleI18N(I18NModel): title = models.CharField(max_length = 120) body = models.TextField() class Admin: pass # optionally, you can specify the base class # if it doesn't follow the naming convention: # # class Meta: # i18m_common_model = "Article" When the ArticleI18N class is created, it automatically gains two new fields. `lang` field is a CharField with choices limited to either `settings.LANGUAGES` or `django.conf.global_settings.LANGUAGES`. The other field is `i18n_common` field which is a ForeignKey to Article model. ## The conventions * call the translation model `SomeBaseModelI18N`, and the non-translation model SomeBaseModel (i.e., the translation model is called basename+"I18N") * the first convention can be overriden by specifying the base model name using the `i18n_common_model` attribute in `Meta` section of the `I18N` model * I18N model is a subclass of `I18NModel` class ## Original blog post [http://blog.papa-studio.com/2008/07/04/metaclasses-and-translations/](http://blog.papa-studio.com/2008/07/04/metaclasses-and-translations/)

  • models
  • i18n
  • metaclass
  • translated-content
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Multiple inheritance of newforms and modelforms

If you try to use multiple inheritance with a modelform (to mix in some fields from an already existing form class for example) you'll get the following rather terrifying error: > "Error when calling the metaclass bases metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases" The solution is to first create the ModelForm, then create a NEW class that inherits from both the ModelForm and the form you want to mixin, then finally apply the recipe from here: [http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/204197](http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/204197)

  • newforms
  • inheritance
  • modelforms
  • multipleinheritance
  • metaclasses
  • metaclass
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4 snippets posted so far.