I have recently started using Django frameworks class-based views.
Assume I have a model Book. Is it possible using class-based views, to besides sending one object of type Book, send a boolean value, which I could set in the view?
For example, I would like the view to send the dictionary context = {object: Book, green: True} to a template.
Yes, of course it's possible.
You can override get_context_data and add anything you like.
Edit
get_object gets the specific database object that the view is displaying/editing. In the default implementation, get_context_data returns a dictionary consisting of the value returned by get_object. You can call the superclass method then add your own values to the result.
Related
Each of this is for displaying a single template as we want,then what is actually it's difference which make it differ? And which is better for using and Why?
TemplateView: Just a simple view to render an HTML template with provided context data.
DetailView: Generic view that works on a model object, expect a lookup kwarg in URL or get_object() can be overridden to return a single model object. and then pass that object in context data to be used in the template.
Big picture: I'd like my reverse method in get_absolute_url (see below) to return a url with a query parameter appended to it at the end, e.g. <url>?foo=bar. Further, I'd like bar to be specified by the POST request that triggered the call to get_absolute_url, either as an input to the form (but not a field represented by the model, something temporary) or as a url query parameter. I am easily able to access bar in my view using either method, but I can't seem to figure out how to access it in my model.
The motivation here is that my detail page splits up the fields from my model into different tabs using javascript (think https://www.w3schools.com/howto/howto_js_tabs.asp). When the user is updating the model, they choose which tab they want to update, and then the update template only renders the fields from the model which are related to that tab. More importantly, after the user submits the update, I want the detail page to know to open the specific tab that the user just edited.
(I understand how this works if the field is a part of the model; in get_absolute_url with parameters, the solution is pretty straightforward and involves using self.id. In my case though, bar is not a part of the model and I can't figure out how else to access it)
Some specifics: I have a model in my project called Context. I have implemented a generic DetailView and an update page for the model using a modelform called ContextForm and a generic UpdateView called ContextUpdate. Once the form is submitted, I redirect to the detail page using get_absolute_url in models.py:
def get_absolute_url(self):
return reverse("context:review",kwargs={"slug": self.slug})
My urlpatterns in urls.py looks something like:
urlpatterns = [
url(r'^(?P<slug>[-\w]+)$',views.ContextDetail.as_view(),name="review"),
url(r'^(?P<slug>[\w]+)/edit$',views.ContextUpdate.as_view(),name="edit"),
]
I am able to access this parameter in my UpdateView quite easily:
def post(self,request,**kwargs):
print (request.POST.get("bar")) #accessing input to form
print (request.GET.get("bar")) #accesssing url parameter
return super().post(request,**kwargs)
But when get_absolute_url is called inside the model, it seems I no longer have access to it.
Any suggestions for how to accomplish this? I want to use get_absolute_url (along with modelforms, generic views, etc.) so that I can follow Django conventions, but it seems like using get_absolute_url is making the functionality that I want difficult to accomplish. If the redirect to the detail view following the POST request were to happen inside my view, then I would know how to solve this (I think). Any thoughts or ideas would be greatly appreciated!
As you say, you can't access the request inside your get_absolute_url method. Therefore you should override get_success_url, from which you can access it.
def get_success_url(self):
return reverse(reverse("context:review", kwargs={"slug": self.object.slug}) + '?bar=%s' % self.request.GET.get('bar')
Or if you want to re-use get_absolute_url:
def get_success_url(self):
return self.object.get_absolute_url + '?bar=%s' % self.request.GET.get('bar')
The second option is DRYer but would break if get_absolute_url was changed to include a querystring like ?foo=foo.
I've tried to create a simple ModelForm, and I notice that even if I pass an instance for update like that
mymodel = MyModel.objects.get(pk=1)
MyModelForm(instance=mymodel)
django does not create an hidden field or include in some way the pk of the object in the template. So I need to pass this by myself?
I prefer not passing the my id's like 1,2,3.. to the templates, so I would prefer passing something like uuid, or using signing.dumps(object_id), and then signing.loads(object_id), from django signing library.
So if I want to include this id in my template with the form POST data,
I didn't understand who is exactly responsible for the retrieve of that id - Is that the view or the form itself?
By view I mean to the built-ins FormView, or UpdateView, how these views find the object id? Assume to store the output of signing.dumps(object_id) in a hidden field
By the time you are in the template the form construction has completed. You can try accessing form.instance.id if its modelForm.
However, most likely you do not need the pk in the template, do you ? You can also inject a hidden form field with the instance pk value if you like. Why do you need the pk in the template ?
If you want to redirect to another page from the POST data you will have access to the object pk in the view itself.
According to official documentation the Built-in Views inherit from django.views.generic.detail.SingleObjectTemplateResponseMixin class which requires the views it is mixed with to provide a self.object attribute.
I'm trying to manage my REST API like that :
http://xxx/users/userid[0-9]+/projects/projectid[0-9]+/tasks/taskid[0-9]+/
So I can access the JSON easily in my website. But, the thing is, I defined my view classes using the REST framework generic views. For example, here is my UserDetail view :
class UserDetail(generics.RetrieveUpdateDestroyAPIView):
queryset = User.objects.all()
serializer_class = UserSerializer
But of course I don't want all my users to be displayed, I just want my user with the ID userid to be displayed. I don't really know how to do it, I tried
queryset = User.objects.filter(id=userid)
but of course userid is not defined... Any help please ?
Edit : just to clarify, here is the url that leads to this view :
url(r'^users/(?P<pku>[0-9]+)/$', views.UserDetail.as_view(
), name='user-detail'),
First of all, If you want to use class based views, you should read some more about them. They are thoroughly explained on Django's docs and you can read about the specific generics of the framework you're using on the REST framework docs too. I'm not saying that you haven't read those, just that you seem to be missing some basic concepts that are explained there.
Now, to the problem at hand, if you look at the doc's of the generic view you're extending, you can see that it represents the endpoints for a single instance, meaning that it won't act on all your model's instances (as you seem to assume).
Also, you can see that this view is built on top of a series of other classes, the more critical one being GenericAPIView. On there you can see two things:
The queryset class field in this context is meant for filtering the posible instances you can manipulate, not obtaining the specific instance described on your url.
The lookup_field is the field that defines which attribute from your model will be used for getting the actual instance. You should define this field to whatever field you're going to use on your url to identify your object (generally it's pk). It's also important to note that the url should include a keyword argument corresponding to this value.
Internally, the view will take care of calling the get_object method, which usese the lookup_field value to find the specific model, and then feed that object to the serializer and return the result back to the client.
DISCLAIMER: I've never used Django REST framework, I put this answer togheter by reading the relevants docs and based on my experience.
I guess you need this:
Resolve function (django 1.4)
Then in your view class method you can do:
temp1, args, kwargs = resolve(self.request.path)
Like much documentation on generic views in Django, I can't find docs that explicitly describe how to use the new Class-Based Generic Views with Django Forms.
How is it done?
What have you tried so far? The class based views are pretty new, and the docs don't have a lot of examples, so I think you're going to need to get your hands dirty and experiment!
If you want to update an existing object, then try using UpdateView. Look at the mixins it uses (e.g ModelFormMixin, SingleObjectMixin, FormMixin) to see which methods you can/have to override.
Good luck!
The easiest way to use model forms with class based views is to pass in the model and keep a slug / pk captured in url, in which case you will not need to write any view code.
url(r'^myurl/$', CreateView.as_view(model=mymodel))
#Creates a model form for model mymodel
url(r'^myurl/(?<pk>\w+)/$', UpdateView.as_view(model=mymodel))
#Creates a model form for model mymodel and updates the object having pk as specified in url
url(r'^myurl/(?<slug>\w+)/$', DeleteView.as_view(model=mymodel, slug_field="myfield"))
#Creates a model form for model mymodel and deletes the object denoted by mymodel.objects.get(my_field=slug)
You can also override methods to obtain more complex logic. You can also pass a queryset instead of a model object.
Another way is to create a modelform in forms.py and then pass form_class to the url as
url(r'^myurl/$', CreateView.as_view(form_class=myform))
This method allows you to define form functions as well as Meta attributes for the form.