Django: pass data from CBV form view to form CBV - django

I have Form with a ModelChoiceField, which is being used as the form_class in a FormView.
The choice field has to be populated with information bound to the request object.
Let's summarize:
class MyFormView(FormView):
# I need to pass `request.user` and a value
# derived from `request.GET['pk']` to the form
form_class = MyForm
class MyForm(Form):
choices = ModelChoiceField(queryset=MyChoice.objects.none())
def __init__(self, user, number, *args, **kwargs):
super(MyForm, self).__init__(*args, **kwargs)
self.fields['choices'] = MyChoice.objects(number=number, owner=user)
What would I need to do to pass that data to the form when its instance is created?
I tried overriding get_form but I am unsure this is the proper way of doing this:
def get_form(self, form_class):
user = self.request.user
number = SomeModel.objects.get(self.GET['pk']).number
return form_class(user, number, **self.get_form_kwargs())

Overriding get_form would work, but a better approach would be to override get_form_kwargs, so that you don't have to duplicate code from the get_form method.
class MyFormView(FormView):
form_class = MyForm
def get_form_kwargs(self):
kwargs = super(MyFormView, self).get_form_kwargs()
kwargs['user'] = self.request.user
kwargs['number'] = SomeModel.objects.get(self.GET['pk']).number
return kwargs

Related

django SetPasswordForm and AdminPasswordChangeForm

hi im trying to use the above forms - but i get
__init__() takes at least 2 arguments (1 given)
i get to the form that it should show but it never save me the new password
i also needed to change the:
def __init__(self, user, *args, **kwargs):
self.user = user
super(AdminPasswordChangeForm, self).__init__(*args, **kwargs)
to:
def __init__(self, *args, **kwargs):
super(AdminPasswordChangeForm, self).__init__(*args, **kwargs)
since it doesnt get a user arg.
any ideas why?
thx
============================ edit =============================================
class set(FormView):
model = User
form_class = AdminPasswordChangeForm
template_name = 'set.html'
def dispatch(self, request, *args, **kwargs):
return super(set, self).dispatch(request, *args, **kwargs)
def get_form_kwargs(self):
kwargs = super(set, self).get_form_kwargs()
kwargs['user_to_update'] = the user
return kwargs
the init:
def __init__(self, *args, **kwargs):
self.user = kwargs['user_to_update']
kwargs.pop('user_to_update')
super(AdminPasswordChangeForm, self).__init__(*args, **kwargs)
Use the existing form. Overide the view's get_form_kwargs method to pass the expected arguments to the form, instead of changing the __init__ method, which will break other things.
In order to save the password, you need to override the form_valid method and call form.save().
For create and update views, you don't always need to override form_valid, because the default behaviour is to save the form and redirect. For FormView, the default behaviour is simply to redirect, so you do have to override it to get it to do anything useful.
class SetPasswordView(FormView):
form_class = AdminPasswordChangeForm
template_name = 'set.html'
success_url = '/thanks/'
def get_form_kwargs(self):
kwargs = super(set, self).get_form_kwargs()
kwargs['user_to_update'] = the user
return kwargs
def form_valid(self, form):
form.save()
return super(SetPasswordView, self).form_valid(form)

How to override form field in CreateView

In model form I can override form field like so
class waypointForm(forms.ModelForm):
def __init__(self, user, *args, **kwargs):
super(waypointForm, self).__init__(*args, **kwargs)
self.fields['waypoints'] = forms.ModelChoiceField(queryset=Waypoint.objects.filter(user=user))
How can I use the same functionality in class based view CreateView, so that I can override form field?
I tried get_form_kwargs and get_form but all in vain. Do I need to create a model form?
You can override the get_form_kwargs and pass the user to kwargs dictionary. Then in your __init__() method, set your field on the form.
views.py
Pass the user in kwargs by overriding the get_form_kwargs().
class MyCreateView(CreateView):
form_class = waypointForm
def get_form_kwargs(self):
kwargs = super(MyCreateView, self).get_form_kwargs()
kwargs['user'] = self.request.user # pass the 'user' in kwargs
return kwargs
forms.py
Now, override the __init__() method. In that, pop the user key from kwargs and use that value to create your field.
class waypointForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
user = kwargs.pop('user', None) # pop the 'user' from kwargs dictionary
super(waypointForm, self).__init__(*args, **kwargs)
self.fields['waypoints'] = forms.ModelChoiceField(queryset=Waypoint.objects.filter(user=user))
To use your model form in your view, set form_class. In your case, you need to override get_form_kwargs as well, so that you can pass user to the form.
def CreateWaypointView(CreateView):
...
form_class = WaypointForm
def get_form_kwargs(self):
kwargs = super(CreateWaypointView, self).get_form_kwargs()
kwargs['user'] = self.request.user
return kwargs

Save custom field in Django ModelForm

I am having trouble saving a custom field in a ModelForm. The field in question is a ModelChoiceField.
I have added a save() method as shown in this question. However, when I use it I get an error:
ImproperlyConfigured
No URL to redirect to. Either provide a url or define a get_absolute_url method on the Model.
When I remove my custom save() method it works ok but doesn't save the custom field. What am I missing?
class NewStoryForm(forms.ModelForm):
class Meta:
model = Story
fields = ['title', 'story_text']
#custom field
about = forms.ModelChoiceField(queryset=None)
#initialise custom field
def __init__(self, user, *args, **kwargs):
super(NewStoryForm, self).__init__(*args, **kwargs)
self.fields['about'] = forms.ModelChoiceField(queryset=Experience.objects.filter(user=user))
#save custom field
def save(self, commit=True):
self.instance.about = self.cleaned_data['about']
super(NewStoryForm, self).save(commit=commit)
class NewStoryView(CreateView):
form_class = NewStoryForm
template_name = 'story/story_form.html'
#Send user to NewStoryForm to initialise custom field
def get_form_kwargs(self):
kwargs = super(NewStoryView, self).get_form_kwargs()
kwargs['user'] = self.request.user
return kwargs
#save author as current user
def form_valid(self, form):
form.instance.author = self.request.user
return super(NewStoryView, self).form_valid(form)
You should return the saved object from the save() method:
return super(NewStoryForm, self).save(commit=commit)

django: how to access current request user in ModelForm?

In my implementation of ModelForm, I would like to perform different types of validation checks based on whether current user is superuser. How can I access the current request user?
If you're using Class Based Views (CBVs) then passing an extra argument in the form constructor (e.g. in get_forms_class) or in form_class will not work, as <form> object is not callable will be shown.
The solution for CBVs is to use get_form_kwargs(), e.g.:
views.py:
class MyUpdateView(UpdateView):
model = MyModel
form_class = MyForm
# Sending user object to the form, to verify which fields to display/remove (depending on group)
def get_form_kwargs(self):
kwargs = super(MyUpdateView, self).get_form_kwargs()
kwargs.update({'user': self.request.user})
return kwargs
forms.py:
class MyForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
self.user = kwargs.pop('user') # To get request.user. Do not use kwargs.pop('user', None) due to potential security hole
super(MyForm, self).__init__(*args, **kwargs)
# If the user does not belong to a certain group, remove the field
if not self.user.groups.filter(name__iexact='mygroup').exists():
del self.fields['confidential']
you can pass the user object as an extra argument in the form constructor.
e.g.
f = MyForm(user=request.user)
and the constructor will look like:
class MyForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
self.user = kwargs.pop('user',None)
super(MyForm, self).__init__(*args, **kwargs)
and then use user in the clean_XX forms as you wish
My small addition,
I had a requirement where one of the model choice fields of the form is dependent on the request.user, and it took a while to take my head around.
The idea is that
you need to have a __init__ method in the model form class,
and you access the request or other parameters from the arguments of the __init__ method,
then you need to call the super constructor to new up the form class
and then you set the queryset of the required field
code sample
class CsvUploadForm(forms.Form):
def __init__(self, *args, **kwargs):
user = kwargs.pop('user')
super(CsvUploadForm, self).__init__(*args, **kwargs)
self.fields['lists'].queryset = List.objects.filter(user=user)
lists = forms.ModelChoiceField(queryset=None, widget=forms.Select, required=True)
as you can see, the lists variable is dependent on the current user, which is available via request object, so we set the queryset of the field as null, and its assigned dynamically from the constructor later.
Take a look into the order of the statements in the above code
you can pass the user variable like this from the view file
form = CsvUploadForm(user=request.user)
or with other POST, FILE data like below
form = CsvUploadForm(request.POST, request.FILES, user=request.user)
You may reference the user object using the instance attribute within the instance it self.
Ex; self.instance.user
class StatusForm(ModelForm):
# def __init__(self, *args, **kwargs):
# self.user = kwargs.pop('user', None)
# super(StatusForm, self).__init__(*args, **kwargs)
class Meta:
model = Status
fields = [
'user',
'content',
'image'
]
def clean_content(self):
content = self.cleaned_data.get("content", None)
if len(content) > 240:
raise ValidationError(f"Hey {self.instance.user.username}, the content is too long")
return content
This worked for me, when I am not sending form in context explicitly in get_context_data:
views.py
class MyView(FormView):
model = MyModel
form_class = MyForm
def get_form_kwargs(self):
kwargs = super(MyView, self).get_form_kwargs()
kwargs.update({'user': self.request.user})
return kwargs
form.py
class MyForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
self.user = kwargs.pop('user')
super(MyForm, self).__init__(*args, **kwargs)
if not self.user.groups.filter(name__iexact='t1_group').exists():
del self.fields['test_obj']
When sending form explicitly in get_context_data we can use and this is forms.Form :
views.py
class MyView(FormView):
model = MyModel
form_class = MyForm
def get_context_data(self, **kwargs):
context = super(MyView, self).get_context_data(**kwargs)
context['form'] = self.form_class(self.request.user)
return context
forms.py
class MyForm(forms.Form):
def __init__(self, user,*args, **kwargs):
super(MyForm, self).__init__(*args, **kwargs)
if not user.groups.filter(name__iexact='t1_group').exists():
del self.fields['test_obj']

Passing a user, request to forms

How would I pass a user object or a request to my form for validation?
For example, I want to be able to do something like this --
class Form(forms.Form):
...
def clean(self)
user = request.user # how to get request.user here?
user = User # how to pass the actual User object?
Thank you.
Just pass it into the constructor and store it as an instance variable:
class MyForm(forms.Form):
def __init__(self, *args, **kwargs):
self.request = kwargs.pop("request")
super(MyForm, self).__init__(*args, **kwargs)
def clean(self):
print self.request.user
...
In your view:
form = MyForm(..., request=request)
And if using a class-based view (a CreateView in this example):
class MyCreateView(CreateView):
...
def get_form_kwargs(self):
kwargs = super(MyCreateView, self).get_form_kwargs()
kwargs.update({'request': self.request})
return kwargs