How to get instance values for form in django? - python

I've overridden a detail view so I can render form elements with render_field. However, when rendered they do not show the saved values. I can't set the value in the template because I can't put {{}} within {% %} syntax. How can I access and display the previously saved model instance values? (these are sliders that I want to keep as sliders, and they also have a lot of data attributes that I want to keep consistent, so I can't just write the inputs manually in the template)
In views.py:
class MyDetailEditMixin(SingleObjectMixin):
"""
Hybrid mixin to edit a detail
"""
model = MyModel
form_class = forms.MyForm
raise_execption = True
def get_context_data(self, **kwargs):
"""
expose the form
"""
kwargs.setdefault('form', forms.MyForm)
return super(MyDetailEditMixin, self).get_context_data(**kwargs)
class MyDetailView(MyDetailEditMixin, DetailView):
"""
Shows the details
"""
I feel like I need to explicitly mention the instance somehow? I'm not sure. The inputs render correctly with all their specific data attributes, just no set values.

I tried many different things, but in the end I ditched the mixin and edited MyDetailView with a get_form method (and within that I could tell it to use the instance):
class MyDetailView(DetailView):
"""
Shows the details
"""
form_class = forms.MyForm
def get_form(self):
form = self.form_class(instance=self.object)
return form
def get_context_data(self, **kwargs):
context = super(MyDetailView, self).get_context_data(**kwargs)
context.update({
'form': self.form_class(instance=self.get_object()),
})
return context
The render_field fields have their values filled with the saved instance values and all the attributes they need are there.

Related

Django: tie two redirects to a single Update button depending on where the user came from

So, i have a rather usual "update item" page that is a class-based view which inherits UpdateView. (in views.py it looks like "class ItemUpdateView(UpdateView) and it has method get_success_url(self) defined which contains the redirect url where user will be taken after clicking "Update" button.
My problem is that in my application, there are two different pages that could lead me to this "Update item" page, and depending on the page that user comes from - i want to take the user back to either pageA or pageB upon the successful update of the item.
I wasn't able to find the best-practices of how to handle this anywhere on the web, so - would really appreciate the help.
My guess is that I need to create an additional parameter that will be a part of the url and will contain A or B depending on the pageA or pageB that user came from, i.e. the url itself would be something like '/itemUpdate/int:pk/sourcepage' => '/itemUpdate/45/A'. Does that sound like a correct aproach or is there a better way?
There is a better way that you can check Meta dictionary in request:
write in your views file:
class ItemUpdateView(UpdateView):
previous_url = ''
form_class = UpdateItem
def get(self, request, *args, **kwargs):
self.previous_url = request.META.get('HTTP_REFERER')
print(self.previous_url)
return super().get(request, *args, **kwargs)
def get_initial(self):
initial = super().get_initial()
initial['success_url'] = self.previous_url
return initial
def form_valid(self, form):
self.success_url = form.cleaned_data['success_url']
print(self.success_url)
return super().form_valid(form)
# also you can use get_success_url instead of form_valid()
# def get_success_url(self):
# return super().get_form().cleaned_data['success_url']
and then write a hidden field in your form and name it success_url
class UpdateItem(forms.ModelForm):
success_url = forms.URLField(widget=forms.HiddenInput)
class Meta:
model=Item
fields=['itemName','quantity']
Note you can not use instance in order to get success_url field, because this field belong to form nor your model instance !
refer to documentions

Django contect_object_name is not producing a context dict in view

I am back with more django questions on CBVs. This is about context_object_name. I have the following:
#method_decorator(verified_email_required, name='dispatch')
class Create(CreateView):
model = Profile
context_object_name = 'profileForm'
template_name = 'Members/template_includes/profile/form.html'
form_class = ProfileForm
success_url = '/Members'
form_title = "New Login Profile Information"
def get(self, request, *args, **kwargs):
return render(request, self.template_name, {
'profileTitle': self.form_title,
})
I am using PyCharm and can put a breakpoint in the template_name form and see what the environment knows about. I expect to see a dict named profileForm with all the form members in it plus profileTitle. Instead I see profileTitle as a standalone member. I do not see anything named profileForm or object_list and the expected form members are not being painted in the template.
I suppose that I understand that the extra content in the return render will pass a "naked" profileTitle but I did expect that the default get behaviour would pull in the form info.
Have I missed the point?
You've overridden the get method in your CreateView-subclass and in doing so, you've bypassed the included functionality that a CreateView does to fill your context. If you take a look here you can see that a CreateView would otherwise call return self.render_to_response(self.get_context_data()) (because it inherits from ProcessFormView) and it's within get_context_data() (ref) that those included context variables are set up.

How do I save post data using a decorator in Django

I have the following view in my django app.
def edit(request, collection_id):
collection = get_object_or_404(Collection, pk=collection_id)
form = CollectionForm(instance=collection)
if request.method == 'POST':
if 'comicrequest' in request.POST:
c = SubmissionLog(name=request.POST['newtitle'], sub_date=datetime.now())
c.save()
else:
form = CollectionForm(request.POST, instance=collection)
if form.is_valid():
update_collection = form.save()
return redirect('viewer:viewer', collection_id=update_collection.id)
return render(request, 'viewer/edit.html', {'form': form})
It displays a form that allows you to edit a collection of images. The footer of my html contains a form that allows you to request a new image source from the admin. It submits to a different data model than the CollectionForm. Since this is in the footer of every view, I want to extract lines 5-7 of the code and turn it into a decorator. Is this possible and if so how might I go about doing that?
I would make a new view to handle the post of the form. And then stick a blank form instance in a context processor or something, so you can print it out on every page.
If you do want to make a decorator, i would suggest using class based views. That way, you could easily make a base view class that handles the form, and every other view could extend that.
EDIT:
Here's the docs on class based views: https://docs.djangoproject.com/en/dev/topics/class-based-views/intro/
Note, I would still recommend having a separate view for the form POST, but here's what your solution might look like with class based views:
class SubmissionLogFormMixin(object):
def get_context_data(self, **kwargs):
context = super(SubmissionLogFormMixin, self).get_context_data(**kwargs)
# since there could be another form on the page, you need a unique prefix
context['footer_form'] = SubmissionLogForm(self.request.POST or None, prefix='footer_')
return context
def post(self, request, *args, **kwargs):
footer_form = SubmissionLogForm(request.POST, prefix='footer_')
if footer_form.is_valid():
c = footer_form.save(commit=False)
c.sub_date=datetime.now()
c.save()
return super(SubmissionLogFormMixin, self).post(request, *args, **kwargs)
class EditView(SubmissionLogFormMixin, UpdateView):
form_class = CollectionForm
model = Collection
# you can use SubmissionLogFormMixin on any other view as well.
Note, that was very rough. Not sure if it will work perfectly. But that should give you an idea.

Populate formset with information from db

I have a view where the user should be able to update an instance of a model, and also update or create new instances of a model related to the first one. I tryied using formsets to do this, and it works perfeclty for creating new objects, but i'm not finding a way to show the objects that already have been created. My problem is that i don't know how to populate the formsets with the existing data, so that i can put it in the context
So this are my models:
class Order(Model):
...
class invoice(Model):
order = models.ForeignKey(Order)
...
And my view is something like this:
class OrderDetailView(UpdateView):
invoice_form_class = InvoiceForm
def get_context_data(self, **kwargs):
context = super(OrderDetailView, self).get_context_data(**kwargs)
if not 'invoice_formset' in context:
context['invoice_formset'] = formset_factory(self.invoice_form_class, extra=3, can_delete=True, formset=BaseFormSet)
return context
There's probably an easy way to do this, but i'm not finding it anywhere
EDIT:
Thanks to #mariodev, i've learned about the inline_formsetfactory, and i'm using it. Now i can fill the formsets with the existing data, and i can create and alter existing ones, but when i try to delete them, nothing happens.
So now i'm defining this formset:
InvoiceFormset = inlineformset_factory(Order, Invoice, fields=('code',), can_delete=True, extra=0)
and my view looks like:
class OrderDetailView(UpdateView):
invoice_form_class = InvoiceForm
def get_context_data(self, **kwargs):
context = super(OrderDetailView, self).get_context_data(**kwargs)
if not 'invoice_formset' in context:
context['invoice_formset'] = InvoiceFormset(instance=self.get_object())
return context
def post(self, *args, **kwargs):
data = self.request.POST
order = self.get_object()
form = self.form_class(data)
invoice_formset = InvoiceFormset(data, instance=order)
if form.is_valid() and invoice_formset.is_valid():
self.object = form.save(order)
for f in invoice_formset:
f.save(self.object)
return HttpResponseRedirect(reverse('order_detail', kwargs={'order_id': self.get_object().order_id}))
I could add some extra lines in the post() to check if i have to delete the form, but it doesn't seem right for me to do it in the view. Is there something else i'm missing?
EDIT AGAIN:
Ended up finding this link which fix exactly this last problem i was having, so now it's all good!
I think it's better use normal function based views (FBV) for this. Understand what's going on first and then gradually move to CBV if you really need to.
This will help you with FBV:
http://catherinetenajeros.blogspot.com/2013/03/inline-formset-saving-and-updating-two.html
This may help you with CBV:
django class-based views with inline model-form or formset

Django: ListView with post() method?

I am trying to process two forms in a Django class based view. The site contains a form called form (based on GET) for narrowing the list results of the ListView and the second form status_form (based on POST).
Both forms are required since the ListView returns a list of items. Form lets the user restrict the choices and status_forms lets the user flag incorrect items via a modal form (therefore it needs to be in the same template).
My trouble is that ListView does not come with the method post, however FormView does. My class List inherits from both classes, but when I execute the class I get the error message:
Attribute Error: 'List' object has no attribute 'status_form'
How should I change my implementation to allow the second form been processed via the post method?
class List(PaginationMixin, ListView, FormMixin):
model = ListModel
context_object_name = 'list_objects'
template_name = 'pages/list.html'
paginate_by = 10 #how may items per page
def get(self, request, *args, **kwargs):
self.form = ListSearchForm(self.request.GET or None,)
return super(List, self).get(request, *args, **kwargs)
def post(self, request, *args, **kwargs):
self.status_form = StatusForm(self.request.POST or None)
if self.status_form.is_valid():
...
else:
return super(List, self).post(request, *args, **kwargs)
def get_queryset(self):
# define the queryset
...
# when done, pass to object_list
return object_list
def get_context_data(self, **kwargs):
context = super(List, self).get_context_data(**kwargs)
context.update(**kwargs)
context['form'] = self.form
context['status_form'] = self.status_form # Django is complaining that status_form is not existing, result since the post method is not executed
return context
# Django is complaining that status_form does not exist,
# result since the post method is not executed
context['status_form'] = self.status_form
Because you didn't define self.status_from in the first place.
You have defined it in get_context_data, and it's accessible from there.
You can access you object from get_context_data in your post method;
context = self.get_context_data(**kwargs)
status_form = context['status_form']
Also consider that you can define your status_form directly in post method itself without getting it from self or get_context_data.
Redesign you views to separate each Form processing in separate Views then tight them with each-other.
Views redesign:
In nutshell, let each view to do one job. You can create a View just for processing your status_form and name it like StatusFormProcessView then on your List view return it on its post method
class List(ListView);
def post(self, request, *args, **kwargs):
return StatusFormView.as_view()(request) # What ever you need be pass to you form processing view
This is just an example of it, need more work to be real.
For another example; On my website index page I have a search form. when user POST or GET the search form, The processing of searching doesn't exist in my IndexView, instead I handle the whole form stuff in separate view, If form should process on GET method, I'll override get() method, If form should process on POST, I'll override post() method to send search_form data to the view that is responsible for handling of processing the search_form.
Comments response
status_form = context['status_form']
shouldn't it be
context['status_form'] = status_form
after I created it ?
You want to get status_form from context, So you need to
status_form = context['status_form']
Anyway, your form data are available on self.request.POST

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