Develop Reference

Python - Django - Pass Argument To Form Clean Method

I am trying to pass a variable to a ModelForm clean method using __init__ arguments but have had no success so far - I looked at various posts on StackOverflow but none seemed to help.
My code is the following:
forms.py
class property_booking_form(forms.ModelForm):
check_in_date = forms.DateField(widget=SelectDateWidget)
check_out_date = forms.DateField(widget=SelectDateWidget)
class Meta:
model = Properties_bookings
fields = ['check_in_date', 'check_out_date']
def __init__(self, property_id):
self.property_id = property_id
super(property_booking_form, self).__init__(self, property_id)
def clean(self):
check_in_date = self.cleaned_data.get('check_in_date')
check_out_date = self.cleaned_data.get('check_out_date')
property_min_nights = Properties.objects.get(id=self.property_id).property_minimum_nights
...
views.py
def view(request):
...
if request.method == 'POST':
booking_form = property_booking_form(request.POST, property_id=property_id)
if booking_form.is_valid():
...
else:
booking_form = property_booking_form(property_id=property_id)
return render(...)
This raises the following error:
'property_booking_form' object has no attribute 'get'
Which seems to be related to the widget as per the error description:
Exception Location:
/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/forms/widgets.py in value_from_datadict, line 1058
The form works fine without the overriding __init__.
Does anyone know what would be the underlying cause of this issue?
Thanks.

Your __init__ method should accept *args and **kwargs, you should pass these when you call the superclass' __init__ method, rather than self and property_id.
def __init__(self, property_id, *args, **kwargs):
self.property_id = property_id
super(property_booking_form, self).__init__(*args, **kwargs)
You also need to change the way you instantiate the form in the view, since property_id is the first argument. For example:
if request.method == 'POST':
booking_form = property_booking_form(property_id=property_id, data=request.POST)
Alternatively, you can remove property_id from the signature, and pop it from kwargs. In this case, no changes to the views are required.
def __init__(self, *args, **kwargs):
self.property_id = kwargs.pop('property_id')
super(property_booking_form, self).__init__(*args, **kwargs)

This has been solved by amending __init__ as follows:
def __init__(self, *args, **kwargs):
self.property_id = kwargs.pop('property_id', None)
super(property_booking_form, self).__init__(*args, **kwargs)

Django pass User instance to Forms when form is created

I have a Django form and l would like to pass a user instance when the form is created
First Approach
This is where l create the form and pass the instance of the user:
form = QuestionForm(request.user, request.POST)
And inside the QuestionForm
def __init__(self, user, *args, **kwargs):
super(QuestionForm, self).__init__(*args, **kwargs)
self.data = user
log.info(self)
Study.objects.filter(owner = self.data.id))
Second Approach
This is where l create the form and pass the request:
form = QuestionForm ( ..., request=request)
And inside the QuestionForm
def __init__(self, *args, **kwargs):
self.request = kwargs.pop("request")
super(MyForm, self).__init__(*args, **kwargs)
ref = forms.ModelChoiceField(queryset=Study.objects.filter(owner = self.request.user.id))
Now l am getting an error that self is not define and as such l cannot get the user id to query the Study class
Any help would be much appreciated

If you do this code in field declaration section like
class QuestionForm(forms.Form):
ref = forms.ModelChoiceField(queryset=Study.objects.filter(owner=...)
then it will not work because it still doesn't have self variable.
You can do this in init method like this
class QuestionForm(forms.Form):
ref = forms.ModelChoiceField()
def __init__(self, *args, **kwargs):
super(MyForm, self).__init__(*args, **kwargs)
self.fields['ref'].queryset = Study.objects.filter(owner=request.user)

Passing arguments to a form obtained by 'getattr()'

I'm creating a view which loads differents forms according to an argument given using the getattr() function:
form = getattr(forms, service.form)
but in the form I need my username to filter my files, so I have this:
class MyForm(forms.Form):
filename = forms.MultipleChoiceField(widget=forms.CheckboxSelectMultiple)
K = forms.CharField(label='K', max_length=1)
fullOut = forms.CharField(label='fullOut', max_length=1)
def __init__(self, *args, **kwargs):
super(MyForm, self).__init__(*args, **kwargs)
self.user = kwargs.pop('user', None)
self.fields['filename'].queryset = userFile.objects.filter(self.user)
The problem is that I don't know how to pass the 'request.user' in my getattr() funtion. I know that if it was static it should be something like:
form = MyForm(user=request.user)
But I have tried somethings like:
form = getattr(forms, service.form, user=request.user)
And it doesn't work.I'm trying this but any idea of how list user files in a form will be welcomed.
Thanks in advance.

This doesn't have anything to do with you using getattr, the problem is in your __init__ method. You need to pop user before calling super().
def __init__(self, *args, **kwargs):
self.user = kwargs.pop('user', None)
super(MyForm, self).__init__(*args, **kwargs)
You should instantiate the form as you usually do:
form = MyForm(user=request.user)
It doesn't matter whether MyForm is declared in the same module:
class MyForm(forms.Form):
my_field = forms.CharField()
form = MyForm(user=request.user)
or if you get the form class dynamically using getattr
MyForm = getattr(forms, service.form)
form = MyForm(user=request.user)

django: subclass FormView twice and override form_class

Im trying to build a FormView for an app that needs to be subclassed afterwards. Sadly I was not able to set the formclass by the subclass.
My Code:
class EventCreateView(FormView):
template_name='Events/add_event_form.html'
success_url = reverse_lazy('events_list')
form_class = None # replaced by __init__ function
def __init__(self, *args, **kwargs):
self.form_class=EventForm
return super(EventCreateView, self).__init__(*args, **kwargs)
#other functions, not shown here ..
class TrainingCreateView(EventCreateView):
def __init__(self, *args, **kwargs):
self.form_class=TrainingForm
return super(TrainingCreateView, self).__init__(*args, **kwargs)
urls.py:
urlpatterns = patterns('',
url(r'event/event/add/$', EventCreateView.as_view(), name='event_add'),
url(r'event/training/add/$', TrainingCreateView.as_view(), name='training_add'),
)
What am I doing wrong?

Try this instead:
class EventCreateView(FormView):
template_name='Events/add_event_form.html'
success_url = reverse_lazy('events_list')
form_class = EventForm
...
class TrainingCreateView(EventCreateView):
form_class = TrainingForm

This doesn't work for the TrainingCreateView because the __init__ view does the following
It sets self.form_class = TrainingForm
super(TrainingCreateView, self).__init__(*args, **kwargs) calls the __init__ of EventCreateView ...
Which sets self.formclass = EventForm
You can get around this by changing the order of your __init_ method. Note that the method doesn't have to return anything.
class TrainingCreateView(EventCreateView):
def __init__(self, *args, **kwargs):
super(TrainingCreateView, self).__init__(*args, **kwargs)
self.form_class = TrainingForm
However, from the code you've written, it is not clear why you need to set self.form_class in the __init__ method, rather than just setting it as a class attribute. If you need to set it dynamically, a better option might be to override get_form_class instead.

Automatically passing extra attributes to Widget

I have a custom model fields, that can have 'chain' argument.
from django.db import models
class ChainField(object):
def __init__(self, *args, **kwargs):
chain = kwargs.get('chain', False)
if chain:
self.chain = chain
del kwargs['chain']
super(self.__class__.__mro__[2], self).__init__(*args, **kwargs)
class DateTimeField(ChainField, models.DateTimeField):
pass
And now the question: how I can automatically pass 'chain' argument of model field to widget class when initializing ModelForm? I neen that in html it become 'class="chainxxx"' attribute of form field.

Override __init__ of the ModelForm like this:
class MyClass(ModelForm):
def __init__(self, *args, **kwargs):
super(MyClass, self).__init__(*args, **kwargs)
chain_value = self.fields['name_of_the_field'].chain
self.fields['name_of_the_field'].widget = CustomWidget(chain=chain_value)