Class based views
keeping your code classy
So, What is a view?
So, What is a view?
from django.http import HttpResponse
def current_datetime(request):
html = "<html><h1>Hello, Django Cali!!!!!.</h1></html>"
return HttpResponse(html)URLconf
Et voilà, a Web response magically appeared!
Class-Based Views
not a function, an object!
(and all that it implies)
Class-Based Views
code related to specific HTTP methods (GET, POST, etc.) addressed by separate methods instead of conditional branching.
Class-Based Views
code related to specific HTTP methods (GET, POST, etc.) addressed by separate methods instead of conditional branching.
def current_datetime(request):
if request.method == 'GET':
do_something()
elif request.method == 'POST':
do_something_else()from django.views.generic import View
class MyView(View):
def get(self, request, *args, **kwargs):
do_something()
def post(self, request, *args, **kwargs):
do_something_else()FROM
TO
Stay classy!
Class-Based Views
Object oriented techniques such as mixins (multiple inheritance) can be used to factor code into reusable components!!!!!!
Remember Django's philosophy,Don’t repeat yourself!
Class-Based Views
Object oriented techniques such as mixins (multiple inheritance) can be used to factor code into reusable components!!!!!!
from djangocali.models import Attendee
def DjangoCaliAttendeeDetail(request, *args, **kwargs):
if request.method == 'GET':
if not request.user.is_authenticated():
return HttpResponseForbidden()
ateendee_slug = kwargs['slug']
object = Attendee.objects.get(slug=ateendee_slug)
context = do_something(object)
return render(request, 'attendee_detail.html', context)Class-Based Views
Object oriented techniques such as mixins (multiple inheritance) can be used to factor code into reusable components!!!!!!
from django.views.generic import View
from django.views.generic.detail import SingleObjectMixin
from djangocali.models import Attendee
class DjangoCaliAttendeeDetail(SingleObjectMixin, View):
"""shows the information about the requested Attendee"""
model = Attendee
def get(self, request, *args, **kwargs):
if not request.user.is_authenticated():
return HttpResponseForbidden()
# Look up the Attendee that is related to the request.
self.object = self.get_object()
context = do_something(self.object)
return render(request, 'attendee_detail.html', context)Class-Based Views
Another object oriented technique: subclassing and overriding attributes and methods in the subclass
from django.http import HttpResponse
from django.views.generic import View
class GreetingView(View):
greeting = "Good Day"
def get(self, request):
return HttpResponse(self.greeting)
class MorningGreetingView(GreetingView):
greeting = "Morning to ya"
## another option
urlpatterns = [
url(r'^about/', GreetingView.as_view(greeting="G'day")),
]Class-Based Views
General usage
URL dispatcher
view
class-based
view
from django.conf.urls import url
from . import views
urlpatterns = [
url(r'^djangocali/attendee/$',
views.attendee_view),
url(r'^djangocali/history/$',
views.history_view),
url(r'^djangocali/someurl/$',
views.some_view),
]from django.conf.urls import url
from . import views
urlpatterns = [
url(r'^djangocali/attendee/$',
views.AttendeeView.as_view()),
url(r'^djangocali/history/$',
views.HistoryView.as_view()),
url(r'^djangocali/someurl/$',
views.SomeView.as_view()),
]Class-Based Views
General usage
URL dispatcher
class-based
view
from django.conf.urls import url
from . import views
urlpatterns = [
url(r'^djangocali/attendee/$',
views.AttendeeView.as_view()),
url(r'^djangocali/history/$',
views.HistoryView.as_view()),
url(r'^djangocali/someurl/$',
views.SomeView.as_view()),
].as_view creates an instance of your class and calls its dispatch() method.
dispatch looks at the request to determine whether it is a GET, POST, etc, and relays the request to a matching method if one is defined, or raises HttpResponseNotAllowed if not
Class-Based Views
General usage
Decorators
In the URLconf
In the definition
from django.utils.decorators import\
method_decorator
from django.views.generic import View
from django.views.decorators.cache import\
cache_page
class SomeView(View):
@method_decorator(cache_page(5))
def dispatch(self, *args, **kwargs):
return super(
SomeView, self).dispatch(*args,**kwargs)
// other option, decorate the class itself
// at name you can define the method to decorate
@method_decorator(cache_page(5),name='dispatch')
class SomeView(View):from django.conf.urls import url
from django.views.decorators.cache import\
cache_page
from . import views
urlpatterns = [
url(r'^djangocali/attendee/$',
views.AttendeeView.as_view()),
url(r'^djangocali/history/$',
views.HistoryView.as_view()),
url(r'^djangocali/someurl/$',
cache_page(5)(views.SomeView.as_view())),
]Some Class-Based Views
from django.http import HttpResponse
from django.views.generic import View, TemplateView
from djangocali.models import Attendee
class SomeView(View):
def get(self, request, *args, **kwargs):
html = "<html><h1>Hello, \
Django Cali!!!!!.</h1></html>"
return HttpResponse(html)
class AttendeeView(TemplateView):
template_name = "Attendee.html"
def get_context_data(self, **kwargs):
context = super(AttendeeViewView,
self).get_context_data(**kwargs)
context['attendees'] = Attendee.objects.all()
return contextfrom django.views.generic.edit import UpdateView,CreateView
from django.views.generic.edit import DeleteView
from django.core.urlresolvers import reverse_lazy
from djangocali.models import Attendee
class AttendeeCreateView(CreateView):
model = Attendee
fields = ['name','email']
class AttendeeUpdateView(UpdateView):
model = Attendee
fields = ['email']
template_name_suffix = '_update_form'
class AttendeeDeleteView(DeleteView):
model = Attendee
success_url = reverse_lazy('home')
def get_object(self, queryset=None):
obj =Attendee.objects.get(uuid=self.kwargs['uuid'])
return objSome Class-Based Views
from django.views.generic.edit import UpdateView,CreateView
from django.views.generic.edit import DeleteView
from django.core.urlresolvers import reverse_lazy
from djangocali.models import Attendee
class AttendeeCreateView(CreateView):
model = Attendee
fields = ['name','email']
class AttendeeUpdateView(UpdateView):
model = Attendee
fields = ['email']
template_name_suffix = '_update_form'
class AttendeeDeleteView(DeleteView):
model = Attendee
success_url = reverse_lazy('home')
def get_object(self, queryset=None):
obj =Attendee.objects.get(uuid=self.kwargs['uuid'])
return obj
<!--CreateView html example-->
<form action="" method="post">{% csrf_token %}
{{ form.as_p }}
<input type="submit" value="Create" />
</form>
<!--UpdateView html example-->
<form action="" method="post">{% csrf_token %}
{{ form.as_p }}
<input type="submit" value="Update" />
</form>
<!--Delete html example-->
<form action="" method="post">{% csrf_token %}
<p>Are you sure you want to delete "{{ object }}"?</p>
<input type="submit" value="Confirm" />
</form>And more Class-Based Views!!
https://ccbv.co.uk/
https://docs.djangoproject.com/en/1.8/ref/class-based-views/
Need more info?
Questions?
Class based views
keeping your code classy
classbasedviews
By Jose Ariza
classbasedviews
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