I would like to make a queryset on a generic view in this way:
category_info = {
'queryset' : ModelObject.objects.filter(category=category_id)
}
where the category_id will be stated on the URL
(r'^category/(?P<category_id>\d+)$', 'object_list', category_info )
But I don't know how to take the data from the URL and pass it to the category info...
You'll have to define your own view and return the generic view from within:
urls.py:
(r'^category/(?P<category_id>\d+)$', 'myapp.views.category_list')
myapp/views.py
from django.views.generic.list_detail import object_list
def category_list(request, category_id):
queryset = ModelObject.objects.filter(category=category_id)
return object_list(request, queryset=queryset)
You can also customise the generic view further, using the parameters mentioned in the documentation. (You may like to also verify that the category exists, throwing a 404 when it doesn't)
Related
I've been learning Django and one source of confusion I have is with class based views and when to override the get method. I've looked through the documentation and it explains what get does but it doesn't explain when I should override get.
I originally created a view this way:
class ExampleView(generic.ListView):
template_name = 'ppm/ppm.html'
paginate_by = 5
def get(self, request):
profiles_set = EmployeeProfile.objects.all()
context = {
'profiles_set': profiles_set,
'title': 'Employee Profiles'
}
return render(request, self.template_name, context)
But I was recently told that my code was simple of enough for the default implementation, and that all I needed was this:
class ExampleView(generic.ListView):
model = EmployeeProfile
template_name = 'ppm/ppm.html'
So my Question is this: In what scenario/circumstance should I override the get method?
If you are using the builtin generic views, then you should rarely have to override get(). You'll end up either duplicating lots of functionality, or break features of the view.
For example, the paginate_by option will no longer work in your view, because you are not slicing the queryset in your get() method.
If you are using a generic class based view like ListView, you should try to override specific attributes or methods where possible, rather than overriding get().
The advantage of your view which overrides get() is that it's very clear what it does. You can see that the view fetches a queryset, includes it in a context, then renders the templates. You don't need to know about ListView to understand the view.
If you like the explicitness of overriding get() subclass View instead. You aren't using any of the features of ListView, so it doesn't make sense to subclass it.
from django.views.generic import View
class ExampleView(View):
template_name = 'ppm/ppm.html'
def get(self, request):
...
You should override the get method when you specifically want to do something other than the default view does. In this case, your code isn't doing anything other than rendering the template with the list of all EmployeeProfile objects, which is exactly what the generic ListView would do.
You might override it if you want to do something more complicated. For example, maybe you want to filter based on a URL parameter:
class ExampleView(generic.ListView):
template_name = 'ppm/ppm.html'
def get(self, request):
manager = request.GET.get('manager', None)
if manager:
profiles_set = EmployeeProfile.objects.filter(manager=manager)
else:
profiles_set = EmployeeProfile.objects.all()
context = {
'profiles_set': profiles_set,
'title': 'Employee Profiles'
}
return render(request, self.template_name, context)
In my url.py I have urls like:
url(r'^messstellen/monatlicher_verbrauch/(?P<pk>[0-9]+)/update/$',
generic.UpdateView.as_view(
model=MonatlicherVerbrauch,
form_class=MonatlicherVerbrauchForm,
success_url=reverse('messstellen:messstellen_index'),
template_name='messstellen/monatlich_form.html',
),
now I want to let the success_url be something like:
success_url = redirect('messstellen:messtelle_detail', pk=pk)
where the pk schould be the same like in the regex pattern (?P<pk>[0-9]+)
Is there a way to do it in the url.py view?
If you don't define success_url, then Django will use your model's get_absolute_url method, which you could define as:
class MonatlicherVerbrauch(models.Model):
...
def get_absolute_url(self):
return reverse('messstellen:messtelle_detail', args=[self.pk])
If your get_absolute_url points to a different url, then I don't think it is possible to set the success_url dynamically in the urls. You will have to override the view, and define get_success_url.
class MonatlicherVerbrauchUpdateView(UpdateView):
def get_success_url(self):
return reverse('messstellen:messtelle_detail', args=[self.object.pk])
# define these attributes in the view as well, to keep urls simple
model=MonatlicherVerbrauch,
form_class=MonatlicherVerbrauchForm,
template_name='messstellen/monatlich_form.html',
Then use MonatlicherVerbrauchUpdateView in your urls instead of UpdateView.
url(r'^messstellen/monatlicher_verbrauch/(?P<pk>[0-9]+)/update/$',
MonatlicherVerbrauchUpdateView.as_view()),
The advantage of subclassing the generic view is that it separates the logic of your views from the urls.
I'd like to pass a success_url to the class-based ActivationView in Django Registration like this answer covers for function-based views and this answer covers for RegistrationView. What I have tried so far that has been unsuccessful:
url(r'^activate/(?P<activation_key>\w+)/$',
ActivationView.as_view({'success_url':'/activation_routing'}),
name='registration_activate',
),
returns "TypeError: as_view() takes exactly 1 argument (2 given)" I have also tried
and:
url(r'^activate/(?P<activation_key>\w+)/$',
ActivationView.as_view(success_url='/activation_routing'),
name='registration_activate',
),
returns "TypeError: ActivationView() received an invalid keyword 'success_url'. as_view only accepts arguments that are already attributes of the class."
I feel like I'm missing something with class-based views, or is subclassing ActivationView and putting in custom logic my best bet?
You can indeed only pass existing attributes to as_view(). As such, and looking at the source of django-registration, the view doesn't have a success_url attribute but it obtains its value by calling self.get_success_url(...).
By default this method is not implemented so you have little choice besides subclassing ActivationView and implementing get_success_url yourself.
I think you have to subclass the view and override the get_success_url method.
I opened pull request 57 to enable setting success_url as a class attribute, but it has not been merged yet.
As others confirmed, I was able to resolve this by subclassing ActivationView and overriding the get_success_url() and activate() methods:
"""
views.py
"""
from registration.views import ActivationView
class CustomActivation(ActivationView):
def activate(self, request, *args, **kwargs):
return True
def get_success_url(self, request, user):
success_url = # insert success URL here
return success_url
It's also important to set the correct URL in your urls.py file to override the default ActivationView that will be called by django-registration. One quirk to remember is that django-registration will set its URLs according to the filepath of auth.urls and not what you specify in your app's urls.py file:
"""
urls.py
"""
from yourapp.views import CustomActivation
urlpatterns += patterns('',
url(r'^user_settings/', include('auth.urls')),
url(r'^user_settings/activate/(?P<activation_key>\w+)/$',
CustomActivation.as_view(),
name='registration_activate',
),
# will still set registration URLs under user_settings!
url(r'^accounts/', include('registration.backends.default.urls')),
)
I'm migrating a project from Django 1.2 to Django 1.5. The project used function-based views such as this:
def notecard_product(request, stockcode):
if request.user.is_authenticated():
liked = Recommendation.objects.values_list('product_id',flat=True).filter(recommended=True, user=request.user)
unliked = Recommendation.objects.values_list('product_id',flat=True).filter(recommended=False, user=request.user)
extra_context = {"liked" : liked, "unliked":unliked}
else:
extra_context = {"liked" : [0], "unliked": [0]}
return object_detail(request, queryset=Product.objects.live(),
object_id=stockcode,
extra_context=extra_context,
template_name='products/notecard.html', template_object_name='notecard_product')`enter code here`
In this excerpt, stockcode is captured from the URL and used to determine object_id. So I'm wondering how I would do this in a class-based view. This is what I have so far:
class NotecardProductListView(ListView):
queryset=Product.objects.live()
pk=self.kwargs['stockcode']
template_name='products/notecard.html'
context_object_name='notecard_product'
def get_context_data(self, **kwargs):
context = super(BooksListView, self).get_context_data(**kwargs)
if self.request.user.is_authenticated():
liked = Recommendation.objects.values_list('product_id',flat=True).filter(recommended=True, user=self.request.user)
unliked = Recommendation.objects.values_list('product_id',flat=True).filter(recommended=False, user=self.request.user)
extra_context = {"liked" : liked, "unliked":unliked}
else:
extra_context = {"liked" : [0], "unliked": [0]}
context.update(extra_context)
return context
pk is the new name for the old object_id kwarg. Obviously, this code doesn't work, because I can't access self outside of a function. But I'm not really sure how to do this. I need to set pk to something in the keyword arguments, but can't find a way to do this, as pk needs to be set in the class body outside of any functions. I also don't really have a way to experiment and try things, because the entire project is broken right now due to deprecated function calls.
Thanks!
I'm not sure where you got the idea that pk is the new name for object_id, nor why you think that you need to set it to a value per request. The point of the class-level attributes in class-based views is that they are set per view class, not per instance: they refer to the place the view will go to look up the value, not the actual value itself.
Your first mistake is that the equivalent of the old object-detail view is, not surprisingly, DetailView, not ListView. As the documentation shows, ListView gets the ability to show an object detail via its inheritance from the SingleObjectMixin. That mixin expects a class-level attribute called pk_url_kwarg, which is the name of the argument captured from the URL which identifies the object's PK: in your case, this is the string 'stockcode'. The instance itself takes care of looking up that value in any particular request, you don't need to do it.
Django
Following the official documentation, I am creating a Django app (the same poll app as in the documentation page). While using the class-based view, I got a error. I did not understand much about class based view, for instance, may someone explain, what is the difference between a class based view from a normal view?
Here's my code:
class DetailView(generic.DetailView):
model = Poll
template_name = 'polls/details.html'
def get_queryset(self):
def detail(request, poll_id):
try:
poll = Poll.objects.get(pk=poll_id)
except Poll.DoesNotExist:
raise Http404
return render(request, 'polls/details.html', {'poll': poll})
*********************Error ********************
TypeError at /polls/2/results/
as_view() takes exactly 1 argument (3 given)
Request Method: GET
Request URL: <app-path>/polls/2/results/
Django Version: 1.5.1
Exception Type: TypeError
Exception Value:
as_view() takes exactly 1 argument (3 given)
*****the url***
url(r'^(?P<pk>\d+)/$', views.DetailView.as_view, name='detail')
as_view should be called, not referenced, according to the docs, your url should look like:
url(r'^(?P<pk>\d+)/$', views.DetailView.as_view(), name='detail')
Note the usage of parenthesis.
Also, you should rather call your class PollDetailView to avoid confusion for code readers.
Also, the detail() method you have defined will not be called at all. So you shouldn't define it at all. Also, leave the get_queryset() method alone for the moment, try to get the basic View to work first.
When you use url for the CBV ensure that you can not use the reference of the of the url filed, so first you need to add change the as_view to as_view().
And you can use DetailView like this.,
class PollDetail(DetailView):
model=Book
def get_context_data(self,*args,**kwargs):
context=super(PollDetail,self).get_context_data(*args,**kwargs)
print(context) #It will give you the data in your terminal
return context
And for accessing data you need to use {{object}},
and if you want to access other fields at that time use like this {{object.fieldname}}
In CBV the template name is automatically named as per class name so you don't need to give it.
Note:Don't give class name same as DetailView,In future you will confuse.
Since you are not modifying the view functionality, to use this generic view, you can simply do this:
in your urls.py (along with other stuff):
from django.views.generic.detail import DetailView
from poll.models import Poll
url(r'^(?P<pk>\d+)/$',
DetailView.as_view(model=Poll,
template_name='polls/details.html'), name='detail')
Then in poll/details.html, you just need:
{{ object }}