field added dynamically to a ModelForm at __init__ does not save - django

I'm using Django profiles and was inspired by James Bennett to create a dynamic form (http://www.b-list.org/weblog/2008/nov/09/dynamic-forms/ )
What I need is a company field that only shows up on my user profile form when the user_type is 'pro'.
Basically my model and form look like:
class UserProfile(models.Model):
user_type = models.CharField(...
company_name = models.CharField(...
class UserProfileForm(forms.ModelForm):
class Meta:
model = UserProfile
exclude = ('company_name',)
And I add the company_name field in init like James Bennett showed:
def __init__(self, *args, **kwargs):
super(UserProfileForm, self).__init__(*args,**kwargs)
if (self.instance.pk is None) or (self.instance.user_type == 'pro'):
self.fields['company_name'] = forms.CharField(...
The problem is that, when I try to save() an instance of UserProfileForm, the field 'company_name' is not saved...
I have gone around this by calling the field explicitly in the save() method:
def save(self, commit=True):
upf = super(UserProfileForm, self).save(commit=False)
if 'company_name' in self.fields:
upf.company_name = self.cleaned_data['company_name']
if commit:
upf.save()
return upf
But I am not happy with this solution (what if there was more fields ? what with Django's beauty ? etc.). It kept me up at night trying to make the modelform aware of the new company_name field at init .
And that's the story of how I ended up on stackoverflow posting this...

I would remove this logic from form and move it to factory. If your logic is in factory, you can have two forms:
UserProfileForm
ProUserProfileForm
ProUserProfileForm inherits from UserProfileForm and changes only "exclude" constant.
You will have then following factory:
def user_profile_form_factory(*args, instance=None, **kwargs):
if (self.instance.pk is None) or (self.instance.user_type == 'pro'):
cls = ProUserProfileForm
else:
cls = UserProfileForm
return cls(*args, instance, **kwargs)

It seems I found a solution:
def AccountFormCreator(p_fields):
class AccountForm(forms.ModelForm):
class Meta:
model = User
fields = p_fields
widgets = {
'photo': ImageWidget()
}
return AccountForm
#...
AccountForm = AccountFormCreator( ('email', 'first_name', 'last_name', 'photo', 'region') )
if request.POST.get('acforms', False):
acform = AccountForm(request.POST, request.FILES, instance=request.u)
if acform.is_valid():
u = acform.save()
u.save()
ac_saved = True
else:
acform = AccountForm(instance = request.u)

When are you expecting the user_type property to be set? This seems like something that should be handled by javascript rather than trying to do funny things with the model form.
If you want the company_name field to appear on the client after they've designated themselves as a pro, then you can 'unhide' the field using javascript.
If instead, they've already been designated a pro user, then use another form that includes the company_name field. You can sub-class the original model form in the following manner.
class UserProfileForm(forms.ModelForm):
class Meta:
model = UserProfile
exclude = ('company_name',)
class UserProfileProForm(UserProfileForm):
class Meta:
exclude = None # or maybe tuple() you should test it
Then in your view, you can decide which form to render:
def display_profile_view(request):
if user.get_profile().user_type == 'Pro':
display_form = UserProfileProForm()
else:
display_form = UserProfileForm()
return render_to_response('profile.html', {'form':display_form}, request_context=...)
This would be the preferred way to do it in my opinion. It doesn't rely on anything fancy. There is very little code duplication. It is clear, and expected.
Edit: (The below proposed solution does NOT work)
You could try changing the exclude of the meta class, and hope that it uses the instances version of exclude when trying to determine whether to include the field or not. Given an instance of a form:
def __init__(self, *args, **kwargs):
if self.instance.user_type == 'pro':
self._meta.exclude = None
Not sure if that will work or not. I believe that the _meta field is what is used after instantiation, but I haven't verified this. If it doesn't work, try reversing the situation.
def __init__(self, *args, **kwargs):
if self.instance.user_type != 'pro':
self._meta.exclude = ('company_name',)
And remove the exclude fields altogether in the model form declaration. The reason I mention this alternative, is because it looks like the meta class (python sense of Meta Class) will exclude the field even before the __init__ function is called. But if you declare the field to be excluded afterwards, it will exist but not be rendered.. maybe. I'm not 100% with my python Meta Class knowledge. Best of luck.

What about removing exclude = ('company_name',) from Meta class? I'd think that it is the reason why save() doesn't save company_name field

Related

Manually filling disabled fields of Django ModelForm

I am facing the following scenario: I have a Django model class called Contact, which looks something like:
class Contact(models.Model):
first_name = models.CharField(max_length=70)
last_name = models.CharField(max_length=70)
company = models.ForeignKey(Company) // should be disabled in user-facing forms
organizations = models.ManyToManyField(Organization) // should be disabled and hidden in user-facing forms
// some other fields not relevant to this question
Both users of the app and administrators should be able to create objects of type Contact and store it in the database. However, for a user this should be restricted in the way that he cannot freely chose the company field of a Contact object. For this, I have created a base ModelForm called ContactForm, intended to be used by administrators, and a restricted user-facing child class called RestrictedContactForm. The code looks as follows:
class ContactForm(forms.modelForm):
class Meta:
model = Contact
fields = ['first_name', 'last_name', 'company', 'organizations']
class RestrictedContactForm(ContactForm):
class Meta(ContactForm.Meta):
widgets = {'organizations': forms.HiddenInput()}
def __init__(self, *args, **kwargs):
super(RestrictedContactForm, self).__init__(*args, **kwargs)
// Maybe populate company and organization here somehow?
self.fields['company'].disabled = True
self.fields['organization'].disabled = True
The RestrictedContactForm is rendered to the user once he decides to create a new contact. Clearly, as both the company and organization fields are mandatory, they need to be manually injected somehow. It is exactly here where my problem lies: I haven't managed to populate these fields by hand.
Below you can find an outline of the view function implementing the logic of a user initiated creation.
def create_contact(request, company_pk):
company = Company.objects.get(pk=company_pk)
organization = Organization.objects.get(...)
if request.method == 'POST':
// Add company.pk and organization.pk to POST here?
// Pass data dictionary manually populated from POST and
// with company.pl and organization.pk to constructor?
contact_form = RestrictedContactForm(request.POST, request.FILES)
// Add company.pk and organization.pk to contact_form.data
// here (after making it mutable)?
if contact_form.is_valid():
contact_form.save()
return redirect(...)
return render(...)
contact_form = ContactForm(initial={'company': company, 'organizations': organization})
I have already tried every suggestion appearing in the comments above. The form simply never validates. My question hence is, what would be the correct way of doing this? Moreover, is the approach outlined at least conceptually right?
The project uses Django 1.9.
If the company and organization fields are not changeable by the user, then they should not be included in the fields list at all in RestrictedContactForm.
What you can do instead is pass the known values for organization and company into the constructor of the form, and then assign them to the object before you actually create it in the database.
class RestrictedContactForm(ContactForm):
class Meta(ContactForm.Meta):
fields = ['first_name', 'last_name', ]
def __init__(self, company, organization, *args, **kwargs):
super(RestrictedContactForm, self).__init__(*args, **kwargs)
self.company = company
self.organization = organization
def save(self, commit=True):
instance = super(RestrictedContactForm, self).save(commit=False)
if not instance.pk:
instance.company = self.company
instance.organization = self.organization
if commit:
instance.save()
return instance
def create_contact(request, company_pk):
# ...
if request.method == 'POST':
company = Company.objects.get(pk=company_pk)
organization = company.organization
contact_form = RestrictedContactForm(company, organization, request.POST, request.FILES)
# ...
# ...
I've always done this using the form_valid method. In this case, in the form_valid method of the child form:
def form_valid(self, form):
form.instance.company = foo
form.instance.organisation = bar
return super().form_valid(form)
This populates the missing field, and then saves the form.

django modelform validation at the form level

I can have custom validators for my django models and what I would like to do is perform validation at the form level where the form elements have dependencies with each other. To illustrate, say I have the following model:
class MyModel(models.Model):
num_average = models.IntegerField(verbose_name='Number of averages',
default=1)
num_values = models.IntegerField(verbose_name='Number of values',
default=3)
The dependency is that num_values = num_average * 3. I know I can set this automatically but for this purposes let us assume we want the user input. I have a form as:
class MyForm(ModelForm):
class Meta:
model = MyModel
fields = ['num_average', 'num_values']
def __init__(self, *args, **kwargs):
super(MyForm, self).__init__(*args, **kwargs)
Is there a way to validate the form as a whole before the submit gets triggered?
Yes, as the form docs point out, this kind of thing is done in a clean method.
class MyForm(ModelForm):
class Meta:
model = MyModel
fields = ['num_average', 'num_values']
def clean(self):
data = self.cleaned_data
if data['num_values'] != data['num_average'] *3:
raise forms.ValidationError('values must be three times average')
As an aside, you shouldn't define __init__ if you're not doing anything with it; overriding a method just to call the superclass method is pointless.

How to pass a queryset to a ModelChoiceField using a self.field_value in Django ModelForms

I could explain the whole thing to you but I guess a code speaks clearer than words so:
class Skills(models.Model):
skill = models.ForeignKey(ReferenceSkills)
person = models.ForeignKey(User)
class SkillForm(ModelForm):
class Meta:
model = Skills
fields = ( 'person', 'skill')
(???)skill = forms.ModelChoiceField(queryset= SkillsReference.objects.filter(person = self.person)
I'm just guessing at how I can do it. But I hope you guys understand what I'm trying to do.
You can ovverride a form structure before you create an instance of the form like:
class SkillForm(ModelForm):
class Meta:
model = Skills
fields = ( 'person', 'skill')
In your view:
SkillForm.base_fields['skill'] = forms.ModelChoiceField(queryset= ...)
form = SkillForm()
You can override it anytime you want in your view, impottant part is, you must do it before creating your form instance with
form = SkillForm()
Assuming you are using class-based views, you can pass the queryset in your form kwargs and then replace it on form init method:
# views.py
class SkillUpdateView(UpdateView):
def get_form_kwargs(self, **kwargs):
kwargs.update({
'skill_qs': Skills.objects.filter(skill='medium')
})
return super(self, SkillUpdateView).get_form_kwargs(**kwargs)
# forms.py
class SkillForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
qs = kwargs.pop('skill_ks')
super(self, SkillForm).__init__(*args, **kwargs)
self.fields['skill'].queryset = qs
But, personally I prefer this second approach. I get the form instance on the View and than replace the field queryset before django wrap it on the context:
# views.py
class SkillsUpdateView(UpdateView):
form_class = SkillForm
def get_form(self, form_class=None):
form = super().get_form(form_class=self.form_class)
form.fields['skill'].queryset = Skills.objects.filter(skill='medium')
return form
Your code looks almost ok. Try this SkillForm:
class SkillForm(ModelForm):
skill = forms.ModelChoiceField(queryset= SkillsReference.objects.filter(person = self.person)
class Meta:
model = Skills
fields = ( 'person', 'skill')
The difference is that skill is a form's field, should not be in Meta class
EDITED
The above solution is incorrect, but this link describes how to achieve what you want:
http://www.zoia.org/blog/2007/04/23/using-dynamic-choices-with-django-newforms-and-custom-widgets/

How do I add a Foreign Key Field to a ModelForm in Django?

What I would like to do is to display a single form that lets the user:
Enter a document title (from Document model)
Select one of their user_defined_code choices from a drop down list (populated by the UserDefinedCode model)
Type in a unique_code (stored in the Code model)
I'm not sure how to go about displaying the fields for the foreign key relationships in a form. I know in a view you can use document.code_set (for example) to access the related objects for the current document object, but I'm not sure how to apply this to a ModelForm.
My model:
class UserDefinedCode(models.Model):
name = models.CharField(max_length=8)
owner = models.ForeignKey(User)
class Code(models.Model):
user_defined_code = models.ForeignKey(UserDefinedCode)
unique_code = models.CharField(max_length=15)
class Document(models.Model):
title = models.CharField(blank=True, null=True, max_length=200)
code = models.ForeignKey(Code)
active = models.BooleanField(default=True)
My ModelForm
class DocumentForm(ModelForm):
class Meta:
model = Document
In regards to displaying a foreign key field in a form you can use the forms.ModelChoiceField and pass it a queryset.
so, forms.py:
class DocumentForm(forms.ModelForm):
class Meta:
model = Document
def __init__(self, *args, **kwargs):
user = kwargs.pop('user','')
super(DocumentForm, self).__init__(*args, **kwargs)
self.fields['user_defined_code']=forms.ModelChoiceField(queryset=UserDefinedCode.objects.filter(owner=user))
views.py:
def someview(request):
if request.method=='post':
form=DocumentForm(request.POST, user=request.user)
if form.is_valid():
selected_user_defined_code = form.cleaned_data.get('user_defined_code')
#do stuff here
else:
form=DocumentForm(user=request.user)
context = { 'form':form, }
return render_to_response('sometemplate.html', context,
context_instance=RequestContext(request))
from your question:
I know in a view you can use
document.code_set (for example) to
access the related objects for the
current document object, but I'm not
sure how to apply this to a ModelForm.
Actually, your Document objects wouldn't have a .code_set since the FK relationship is defined in your documents model. It is defining a many to one relationship to Code, which means there can be many Document objects per Code object, not the other way around. Your Code objects would have a .document_set. What you can do from the document object is access which Code it is related to using document.code.
edit: I think this will do what you are looking for. (untested)
forms.py:
class DocumentForm(forms.ModelForm):
class Meta:
model = Document
exclude = ('code',)
def __init__(self, *args, **kwargs):
user = kwargs.pop('user','')
super(DocumentForm, self).__init__(*args, **kwargs)
self.fields['user_defined_code']=forms.ModelChoiceField(queryset=UserDefinedCode.objects.filter(owner=user))
self.fields['unique_code']=forms.CharField(max_length=15)
views.py:
def someview(request):
if request.method=='post':
form=DocumentForm(request.POST, user=request.user)
if form.is_valid():
uniquecode = form.cleaned_data.get('unique_code')
user_defined_code = form.cleaned_data.get('user_defined_code')
doc_code = Code(user_defined_code=user_defined_code, code=uniquecode)
doc_code.save()
doc = form.save(commit=False)
doc.code = doc_code
doc.save()
return HttpResponse('success')
else:
form=DocumentForm(user=request.user)
context = { 'form':form, }
return render_to_response('sometemplate.html', context,
context_instance=RequestContext(request))
actually you probably want to use get_or_create when creating your Code object instead of this.
doc_code = Code(user_defined_code=user_defined_code, code=uniquecode)

How to make optionally read-only fields in django forms?

I have a read-only field in a django form that I sometimes want to edit.
I only want the right user with the right permissions to edit the field. In most cases the field is locked, but an admin could edit this.
Using the init function, I am able to make the field read-only or not, but not optionally read-only. I also tried passing an optional argument to StudentForm.init but that turned much more difficult that I expected.
Is there a proper way to do accomplish this?
models.py
class Student():
# is already assigned, but needs to be unique
# only privelidged user should change.
student_id = models.CharField(max_length=20, primary_key=True)
last_name = models.CharField(max_length=30)
first_name = models.CharField(max_length=30)
# ... other fields ...
forms.py
class StudentForm(forms.ModelForm):
class Meta:
model = Student
fields = ('student_id', 'last_name', 'first_name',
# ... other fields ...
def __init__(self, *args, **kwargs):
super(StudentForm, self).__init__(*args, **kwargs)
instance = getattr(self, 'instance', None)
if instance:
self.fields['student_id'].widget.attrs['readonly'] = True
views.py
def new_student_view(request):
form = StudentForm()
# Test for user privelige, and disable
form.fields['student_id'].widget.attrs['readonly'] = False
c = {'form':form}
return render_to_response('app/edit_student.html', c, context_instance=RequestContext(request))
Is that what you are looking for? By modifying your code a little bit:
forms.py
class StudentForm(forms.ModelForm):
READONLY_FIELDS = ('student_id', 'last_name')
class Meta:
model = Student
fields = ('student_id', 'last_name', 'first_name')
def __init__(self, readonly_form=False, *args, **kwargs):
super(StudentForm, self).__init__(*args, **kwargs)
if readonly_form:
for field in self.READONLY_FIELDS:
self.fields[field].widget.attrs['readonly'] = True
views.py
def new_student_view(request):
if request.user.is_staff:
form = StudentForm()
else:
form = StudentForm(readonly_form=True)
extra_context = {'form': form}
return render_to_response('forms_cases/edit_student.html', extra_context, context_instance=RequestContext(request))
So the thing is to check permissions on the views level, and then to pass argument to your form when it is initialized. Now if staff/admin is logged in, fields will be writeable. If not, only fields from class constant will be changed to read only.
It would be pretty easy to use the admin for any field editing and just render the student id in the page template.
I'm not sure if this answers your questions though.