django: how to access current request user in ModelForm? - django

Question

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?

Answer 1

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']

Answer 2

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

Answer 3

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)

Answer 4

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

Answer 5

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']