django-baseviews 0.4

A small collection of Django view classes to build upon.

A small collection of base view classes to build upon. They are intended to handle a lot of the repetition in common view patterns and allow you to focus on what makes each view different.

This is just the beginning, and I plan on expanding these classes and adding more to cover other common view patterns. Feel free to fork and send pull requests - I’d be happy to review and integrate contributions.

Installation

Use pip to install the module:

$ pip install django-baseviews

Then simply import it for use in your views:

import baseviews

Writing Views

Basic Views

The simplest views can be handled by creating a subclass of BasicView, defining the template attribute, and implementing the get_context method.

from baseviews import BasicView
from lol.models import Cheezburger

class LolHome(BasicView):
    template = 'lol/home.html'

    def get_context(self):
        return {'burgers': Cheezburger.objects.i_can_has()}

Custom MIME type

As with Django itself, the MIME type defaults to the value of the DEFAULT_CONTENT_TYPE setting. This can be overriden by defining the content_type attribute.

from baseviews import BasicView
from lol.models import Cheezburger

class GoogleSiteMap(BasicView):
    template = 'sitemap.xml'
    content_type = 'application/xml'

Caching the Context

If you’d like to cache the context through the low-level cache API, add the cache_key and cache_time attributes and override the cached_context method instead of the get_context method. Additionally, you can override uncached_context to add context that shouldn’t be cached. If cache_time isn’t set, it defaults to the arbitrary length of 5 minutes.

class LolHome(BasicView):
    template = 'lol/home.html'
    cache_key = 'lol_home'
    cache_time = 60*20 # 20 minutes

    def cached_context(self):
        return {'burgers': Cheezburger.objects.i_can_has()}

The cache_key attribute can include string formatting, which you can populate by overriding the get_cache_key method:

class LolDetail(BasicView):
    template = 'lol/detail.html'
    cache_key = 'lol_detail:%s'
    cache_time = 60*20 # 20 minutes

    def __init__(self, request, lol_slug):
        self.lol = Lol.objects.get(slug=lol_slug)
        super(LolDetail, self).__init__(request)

    def get_cache_key(self):
        return self.cache_key % self.lol.slug

Ajax Views

The AjaxView class is a subclass of BasicView that takes the context and uses simplejson to dump it to a JSON object. If the view is not requested via Ajax, it raises an Http404 exception.

Decorators

Built-in decorators such as login_required don’t work by default with class-based views. This is because the first argument passed to the decorator is the class instance, not the request object.

To decorate a class-based view, simply use the helper django.utils.decorators.method_decorator on the __new__ method like this:

from django.utils.decorators import method_decorator
from django.contrib.auth.decorators import login_required
from baseviews import BasicView

class BucketFinder(BasicView):
    template = 'lol/wheres_mah_bucket.html'

    @method_decorator(login_required)
    def __new__(cls, *args, **kwargs):
        return super(BucketFinder, cls).__new__(cls, *args, **kwargs)

Form Views

Form processing can be simplified with a subclass of the FormView class. Define an extra attribute called form_class and set it to the form you’d like to use, and define an attribute called success_url with the name of the url to be redirected to after successful form processing. You can also override the get_success_url method to provide a dynamic success url.

The most basic processing can be handled without any further effort. FormView will get the form and add it to the context, and if the request method is POST it will attempt to validate and save it.

If you would like to do more, you can extend the get_form and process_form methods:

class KittehView(FormView):
    form_class = KittehForm

    def __init__(self, request, kitteh_slug):
        self.kitteh = get_object_or_404(Kitteh, slug=kitteh_slug)
        super(KittehView, self).__init__(request)

    def get_form(self):
        self.form_options = {'request': self.request, 'kitteh': self.kitteh}
        return super(KittehView, self).get_form()

    def process_form(self):
        if self.request.POST.get('edit', False):
            if self.form.is_valid():
                self.form.save()
                return redirect(self.get_success_url())
        elif self.request.POST.get('delete', False):
            self.kitteh.delete()
            return redirect('kitteh_deleted')

    def get_success_url(self):
        return reverse('kitteh_edited', args=[self.kitteh.slug])

Mapping the Views to URLs

In order to make the use of class attributes safe, baseviews overrides the __new__ method on the class. This means that you can simply map the url pattern directly to the class:

from lol import views

urlpatterns = patterns('',
    url(r'^$', views.LolHome, name='lol_home'),
)

Backwards-Incompatible Changes

Version 0.4

• ``view_factory`` removed - With the addition of the __new__ method override, the class can now used in the url mapping directly. This eliminates the need for a view factory.

• View args and kwargs handled in ``__init__`` - Previously, the view arguments such as request and args and kwargs from the url pattern were handled by the __call__ method. Now, they are (more appropriately) handled by the __init__ method and the __call__ method is called without any additional arguments. You’ll need to adjust your subclasses accordingly.

• ``decorate`` removed - Jannis Leidel pointed out that Django has an equivalent method decorator built in, at django.utils.decorators.method_decorator. This eliminates the need for a custom decorate decorator.