django-viewsets

Contents

• Problematic
• Solution
• Installation
• Usage
  • ModelViewSet
    • Provided views and urls
    • Basic use
    • Advanced use
    • Basic Attributes
    • Advanced attributes

Problematic

When having a look at Ruby on Rails, I discovered a nice feature that was missing in Django: controllers. Contrary to what I often read, views in Django are not really equivalent to controllers in Rails. A Rails controller basically is a set of Django views and Django URL patterns. Apart from driving off boring URL work, this is a clean way to group views that belongs to the same model.

Any good djangonaut would make the connection with generic views − especially class-based. This is the easiest solution to avoid repeating the same code with a few changes. But this is not simplifying URL patterns and we often have to define such files:

# views.py
from django.views.generic import ListView, DetailView  # and so on…
from .models import Example


class ExampleListView(ListView):
    model = Example


class ExampleDetailView(DetailView):
    model = Example

# and so on…

# urls.py
from django.conf.urls import patterns, url
from .views import *


urlpatterns = patterns('',
    url('^examples/$', ExampleListView.as_view(), name='example_index'),
    url('^examples/(?P<pk>\d+)$', ExampleDetailView.as_view(),
        name='example_detail'),
    # and so on…
)

With a single model, this looks easy. With complex applications containing dozens of models, this looks painful − and definitely not DRY [1].

Solution

django-viewsets proposes a solution inspired of Rails controllers. ViewSet is a class that builds a set of URL patterns from a set of class-based generic views. It is designed to be overridable, so that it fits standard as well as advanced use.

Installation

[sudo] pip install django-viewsets

You don't have to change your project settings.py.

Usage

ModelViewSet

Provided views and urls

Generic view	URL	URL name
ListView	your-models/	your-model_index
DetailView	your-models/[pk]	your-model_detail
CreateView	your-models/create/	your-model_create
UpdateView	your-models/[pk]/update	your-model_update
DeleteView	your-models/[pk]/delete	your-model_delete

Basic use

In your application (or project) urls.py:

from django.conf.urls import patterns, url, include
from viewsets import ModelViewSet
from .models import YourModel

urlpatterns = patterns('',
    url('', include(ModelViewSet(YourModel).urls)),
)

You can also provide other basic attributes as keyword arguments. For example, if you want to use slugs instead of primary keys in URL patterns, lines 2 and 6 become:

from viewsets import ModelViewSet, SLUG  # line 2
url('', include(ModelViewSet(YourModel, id_pattern=SLUG).urls)),  # line 6

Advanced use

This allow more customization.

In your application views.py:

from viewsets import ModelViewSet
from .models import YourModel

class YourModelViewSet(ModelViewSet):
    model = YourModel

In your application (or project) urls.py:

from django.conf.urls import patterns, url, include
from .views import YourModelViewSet

urlpatterns = patterns('',
    url('', include(YourModelViewSet().urls)),
)

What is interesting in this use is that you can easily customize views and urls. Let's say you want to use primary keys in update and delete url patterns, but you want to use slugs in detail view. The fastest way to do it is:

from viewsets import ModelViewSet, SLUG

class CustomModelViewSet(ModelViewSet):
    def __init__(self, *args, **kwargs):
        self.views['detail_view']['pattern'] = SLUG
        super(CustomModelViewSet, self).__init__(*args, **kwargs)

Here we don't set the model attribute, so that CustomModelViewSet can be used for any of your models. Of course, you can now use CustomModelViewSet with basic use as well as Advanced use. And we could have set model, if this viewset was meant to be used only with a specific model.

Basic Attributes

model

The model class from which ModelViewSet will create views and urls. This is the only mandatory attribute.

base_url_pattern

Overrides your-models in all URL patterns. Calculated from model._meta.verbose_name_plural if unset.

base_url_name

Overrides your-model in all URL names. Calculated from model._meta.verbose_name if unset.

id_pattern

Overrides [pk] in all URL patterns. You can either use viewsets.PK or viewsets.SLUG.

excluded_views

A sequence of keys from the views. Unset by default. Example: ('create_view', 'delete_view',).

namespace

Set this if your application has a URL namespace. It is used to redirect to main_view in delete_view. You can also set main_url.

main_view

Used to calculate main_url. 'list_view' by default.

main_url

The main url where delete_view redirects. If set, main_view is ignored.

Advanced attributes

views

Dictionary defining views and URLs. CRUD [2] by default.

[1]	Don't Repeat Yourself

[2]	Create Read Update Delete