Which method should be overridden to add additional checks and redirect accordingly?
i.e. I've a DetailView for my product page, and if this product is not published (and brand has more products) I want to redirect to the brand page.
I added this check to get method and I'm calling get_object() manually and then doing my checks, but in the end I'm also calling the super().get() which calls get_object() as well, this makes the SQL run twice.
The solution I've found is overriding the get_object() method as following..
def get_object(self, queryset=None):
if not hasattr(self, 'object') or not self.object:
self.object = super().get_object(queryset=queryset)
return self.object
This doesn't feel right though, what is the best way to do checks without triggering get_object twice?
My code that calls get_object twice looks like this: without the hack above.
def get(self, request, *args, **kwargs):
product = self.get_object()
if not product.published:
if product.brand and #more products from brand exists#
return redirect(reverse('brand',
args=(product.brand.slug,)))
else:
return redirect(reverse('pages:home'))
return super().get(request, *args, **kwargs)
just for reference super().get looks like this, and I don't want to rewrite these lines.
https://ccbv.co.uk/projects/Django/1.10/django.views.generic.detail/DetailView/#get
def get(self, request, *args, **kwargs):
self.object = self.get_object()
context = self.get_context_data(object=self.object)
return self.render_to_response(context)
I think this is cleaner - store the response of the super().get(...) call, which will also populate self.object, then redirect if necessary, or return the response stored from the super().get(...) call:
def get(self, request, *args, **kwargs):
super_response = super().get(request, *args, **kwargs)
if not self.object.published:
if self.object.brand and #more products from brand exists#
return redirect(reverse('brand',
args=(self.object.brand.slug,)))
else:
return redirect(reverse('pages:home'))
return super_response
Note that this does have the overhead of creating a valid response for an unpublished object. To avoid that, simply avoid the super call - yes, this means duplicating two lines of code from the superclass' method:
def get(self, request, *args, **kwargs):
self.object = self.get_object()
if not self.object.published:
if self.object.brand and #more products from brand exists#
return redirect(reverse('brand',
args=(self.object.brand.slug,)))
else:
return redirect(reverse('pages:home'))
context = self.get_context_data(object=self.object)
return self.render_to_response(context)
Related
I am trying to build CBV with class View parent. This view takes slug of object and find that object between two django models. The functions from services.py was doing a lot of DB queries, so, I tried to reduce them by giving to FeedbackSection necessary attributes(slug, model_instance and context) and lately override them in get method.
class FeedbackSection(View):
"""
Feedback section for different objects.
This is something like 'generic' view, so I implement it that it will find
the model and feedbacks for this model by having only slug.
"""
template_name = 'feedbacks/feedback-section.html'
form_class = CreateFeedbackForm
slug = None
model_instance = None
context = None
def get(self, request, *args, **kwargs):
self.slug = kwargs.get('slug')
self.model_instance = get_model_instance(self.slug)
self.context = get_feedback_section_context(self.slug, self.form_class, self.model_instance)
return render(request, self.template_name, self.context)
#method_decorator(login_required)
def post(self, request, *args, **kwargs):
form = self.form_class(request.POST)
if form.is_valid():
# will create feedback object and update model[Advert, Company] rating.
end_feedback_post_logic(self.request.user, form, self.model_instance)
return render(request, self.template_name, self.context)
The attributes(slug, model_instance and context), when post method is in runtime are equivalent to None.
The problem is that this implementation was working fine yesterday, but today it's not.
I know I can use my functions again, but in post method. I don't want to do this. Because it will multiple DB Queries by two.
We need to override the setup method of the View class and define those attributes there.
def setup(self, request, *args, **kwargs):
self.slug = kwargs.get('slug')
self.model_instance = get_model_instance(self.slug)
self.context = get_feedback_section_context(
self.slug,
self.form_class,
self.model_instance
)
return super().setup(request, *args, **kwargs)
I have RetrieveUpdateDestroyAPIView view like this.
class TaskRetrieveUpdateDestroyAPIView(RetrieveUpdateDestroyAPIView):
lookup_field = 'id'
serializer_class = TasksSerializer
def get_queryset(self):
query_set=Task.objects.get(id=self.kwargs['id'])
def get(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
def put(self, request, *args, **kwargs):
return self.update(request, *args, **kwargs)
def patch(self, request, *args, **kwargs):
return self.partial_update(request, *args, **kwargs)
def delete(self, request, *args, **kwargs):
return self.destroy(request, *args, **kwargs)
and my urls like this
path('task_detail/<int:id>', TaskRetrieveUpdateDestroyAPIView.as_view(), name="get_task"),
I am trying to PUT , PATCH , GET but getting same error
{
"detail": "Not found.",
"status_code": 404
}
The issue is in the function get_queryset, It expects a queryset but yours returns a single object, that's what the get function does as described here. So, you need to either set the queryset class field or use the get_queryset function.
You don't need to look up the task object yourself, that's what the generic view does for you. also you don't have to specify the method handlers(get, post, i.e.) yourself, they are already generated because you use RetrieveUpdateDestroyAPIView class. Also, since the lookup field defaults to the primary key(id), so, you could omit that, too
Try this code
class TaskRetrieveUpdateDestroyAPIView(RetrieveUpdateDestroyAPIView):
queryset = Task.objects.all()
serializer_class = TasksSerializer
and use pk instead of id
path('task_detail/<int:pk>', TaskRetrieveUpdateDestroyAPIView.as_view(), name="get_task")
or you could leave the lookup field as id and use it in the path function. It's pretty much the same thing, just saving some code
Hey I want to add if statement and according to it decide if to delete the object or not.
I could not find it online.
In general how can I add if statements to any CBV including Update for example..
This is my DeleteView func:
class PostDeleteView(LoginRequiredMixin, DeleteView):
model = Post
success_url = reverse_lazy('TheApp:post_list')
EDIT! THE SOLUTION THAT WORKED FOR ME:(Thanks to AKX)
def delete(self, request, *args, **kwargs):
if (Post.author == request.user.username):
return super().delete(request, *args, **kwargs)
else:
return HttpResponse('You are not the owner of this Post! You can not delete it!')
Well, as you know, CBVs' methods map to HTTP methods, so just override delete() and add your condition:
class SomeView(..., DeleteView, ...):
def delete(self, request, *args, **kwargs):
if request.GET.get('really') != 'true':
return HttpResponse('I knew you were just kidding!')
return super().delete(request, *args, **kwargs)
I have a url mapping that looks like this:
url(r'^(?P<lang>[a-z][a-z])/$', MyTemplateView.as_view()),
There are only a few values that I accept for the lang capture group, that is: (1) ro and (2) en. If the user types http://server/app/fr/, I want to redirect it to the default http://server/app/en/.
How can I do this since MyTemplateView only has a method that is expected to return a dictionary?
def get_context_data(self, **kwargs):
return { 'foo': 'blah' }
I know this question is old, but I've just done this myself. A reason you may think you want to do it in get_context_data is due to business logic, but you should place it in dispatch.
def dispatch(self, request, *args, **kwargs):
if not request.user.is_authenticated():
return redirect('home')
return super(MyTemplateView, self).dispatch(request, *args, **kwargs)
Keep your business logic in your dispatch and you should be golden.
Why only get_context_data?
Just set up your get handler to do a redirect if necessary.
def get(self, request, lang):
if lang == 'fr':
return http.HttpResponseRedirect('../en')
return super(MyTemplateView, self).get(request, lang)
A note from the future: it's now possible and probably simpler just to use RedirectView.
This worked for me using an UpdateView class in Django 3.1:
def get(self, request, *args, **kwargs):
if 1 == 1:
return HttpResponseRedirect(reverse_lazy("view_name_here"))
else:
return super().get(request, *args, **kwargs)
To determine this, I analyzed its base class (Cmd+Click in PyCharm), where I found the base method:
def get(self, request, *args, **kwargs):
self.object = self.get_object()
return super().get(request, *args, **kwargs)
You can find this and other methods in the Django source code: django/views/generic/edit.py
In Django's ModelAdmin, I need to display forms customized according to the permissions a user has. Is there a way of getting the current user object into the form class, so that i can customize the form in its __init__ method?
I think saving the current request in a thread local would be a possibility but this would be my last resort because I'm thinking it is a bad design approach.
Here is what i did recently for a Blog:
class BlogPostAdmin(admin.ModelAdmin):
form = BlogPostForm
def get_form(self, request, **kwargs):
form = super(BlogPostAdmin, self).get_form(request, **kwargs)
form.current_user = request.user
return form
I can now access the current user in my forms.ModelForm by accessing self.current_user
EDIT: This is an old answer, and looking at it recently I realized the get_form method should be amended to be:
def get_form(self, request, *args, **kwargs):
form = super(BlogPostAdmin, self).get_form(request, *args, **kwargs)
form.current_user = request.user
return form
(Note the addition of *args)
Joshmaker's answer doesn't work for me on Django 1.7. Here is what I had to do for Django 1.7:
class BlogPostAdmin(admin.ModelAdmin):
form = BlogPostForm
def get_form(self, request, obj=None, **kwargs):
form = super(BlogPostAdmin, self).get_form(request, obj, **kwargs)
form.current_user = request.user
return form
For more details on this method, please see this relevant Django documentation
This use case is documented at ModelAdmin.get_form
[...] if you wanted to offer additional fields to superusers, you could swap in a different base form like so:
class MyModelAdmin(admin.ModelAdmin):
def get_form(self, request, obj=None, **kwargs):
if request.user.is_superuser:
kwargs['form'] = MySuperuserForm
return super().get_form(request, obj, **kwargs)
If you just need to save a field, then you could just override ModelAdmin.save_model
from django.contrib import admin
class ArticleAdmin(admin.ModelAdmin):
def save_model(self, request, obj, form, change):
obj.user = request.user
super().save_model(request, obj, form, change)
I think I found a solution that works for me: To create a ModelForm Django uses the admin's formfield_for_db_field-method as a callback.
So I have overwritten this method in my admin and pass the current user object as an attribute with every field (which is probably not the most efficient but appears cleaner to me than using threadlocals:
def formfield_for_dbfield(self, db_field, **kwargs):
field = super(MyAdmin, self).formfield_for_dbfield(db_field, **kwargs)
field.user = kwargs.get('request', None).user
return field
Now I can access the current user object in the forms __init__ with something like:
current_user=self.fields['fieldname'].user
stumbled upon same thing and this was first google result on my page.Dint helped, bit more googling and worked!!
Here is how it works for me (django 1.7+) :
class SomeAdmin(admin.ModelAdmin):
# This is important to have because this provides the
# "request" object to "clean" method
def get_form(self, request, obj=None, **kwargs):
form = super(SomeAdmin, self).get_form(request, obj=obj, **kwargs)
form.request = request
return form
class SomeAdminForm(forms.ModelForm):
class Meta(object):
model = SomeModel
fields = ["A", "B"]
def clean(self):
cleaned_data = super(SomeAdminForm, self).clean()
logged_in_email = self.request.user.email #voila
if logged_in_email in ['abc#abc.com']:
raise ValidationError("Please behave, you are not authorised.....Thank you!!")
return cleaned_data
Another way you can solve this issue is by using Django currying which is a bit cleaner than just attaching the request object to the form model.
from django.utils.functional import curry
class BlogPostAdmin(admin.ModelAdmin):
form = BlogPostForm
def get_form(self, request, **kwargs):
form = super(BlogPostAdmin, self).get_form(request, **kwargs)
return curry(form, current_user=request.user)
This has the added benefit making your init method on your form a bit more clear as others will understand that it's being passed as a kwarg and not just randomly attached attribute to the class object before initialization.
class BlogPostForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
self.current_user = kwargs.pop('current_user')
super(BlogPostForm, self).__init__(*args, **kwargs)