django-baseclasses is a small set of helpers and abstract base model classes for django.

Installation

python ./setup.py install

Or with pip:

pip install django-baseclasses

Abstract classes provided in baseclasses.models

DateAuditModel

Stores a record of when the model was created and last changed, in the creation_date and last_updated fields, orders on creation_date, and provides get_next and get_prev methods respecting the ordering.

BaseContentModel

Extends DateAuditModel, adding is_live and pub_date fields, and provides a live method on the default manager which returns only objects with is_live set and a non-future pub_date. Also orders by pub_date, and provides next_live and prev_live methods which only cycle through "live" objects.

BaseImageModel

Provides caption, image and sort_order fields. Orders on sort_order.

BaseModelWithImages

Parent model for use with a BaseImageModel with a ForeignKey to this model. Provides primary_image property which returns the first related image object, or None. The ForeignKey's related_name must be "image_set"

BaseHierarchyModel

Provides parent field to create a simple hierarchy system, i.e. categories and subcategories. Provides get_hierarchy method, which returns a list of objects in the tree, from the top level to the current.

Model fields

baseclasses.fields.ConstrainedImageField

Resizes the image on upload and overwrites the original. Use max_dimensions argument to determine the resize behaviour.

Helpers

baseclasses.util.next_or_prev_in_order

Arguments: (instance, prev=False, qs=None, loop=False)

Get the next (or previous with prev=True) item for an instance, from the given queryset (which is assumed to contain instance), respecting queryset ordering. If loop is True, return the first/last item when the end/start is reached.

baseclasses.admin.ContentModelAdminMixin

Enables (cache-safe) admin preview of non-live objects. Example

@admin.register(MyModel)
class MyModelAdmin(ContentModelAdminMixin, admin.ModelAdmin):
    ...

Pass the request to the model's live manager method to enable preview:

def my_model_view(request, slug)
    instance = get_object_or_404(MyModel.objects.live(request), slug=slug)
    ...

Example:

# models.py

from django.db import models
from baseclasses.models import BaseContentModel, BaseModelWithImages, \
                               BaseImageModel


class Article(BaseContentModel, BaseModelWithImages):
    title = models.CharField(max_length=190) 
    text = models.TextField()
    
 
class ArticleImage(BaseImageModel):
    article = models.ForeignKey(Article, related_name='image_set')

With the above model definition, you can do the following:

articles = Article.objects.live() # get queryset of all live articles
article = articles[0]
article.primary_image # get primary image (model instance) for the article
article.next_live # get next live article