As part of a Form Wizard in my Django view I am using a Formset. The wizard's forms for each step are declared like this:
UserFormSet = modelformset_factory(account_models.MyUser,
form=account_forms.MyUserForm,
extra=5,
max_num=10,
can_delete=True)
FORMS = [('userchoice', UserChoiceForm),
('user', UserFormSet),]
TEMPLATES = {'userchoice': "account/userchoice.html",
'user': "account/user.html",}
What I am trying to achieve is this: In UserChoiceForm (first step) the number of required users can be set. I want to use this value to dynamically set the extra attribute on UserFormSet so that only the required number of Forms gets displayed in the second step.
I am trying to do this by overriding the wizard's get_form() method:
class MyUserWizard(SessionWizardView):
def get_form(self, step=None, data=None, files=None):
form = super(MyUserWizard, self).get_form(step, data, files)
# Determine the step if not given
if step is None:
step = self.steps.current
if step == 'user':
# Return number of forms for formset requested
# in previous step.
userchoice = self.get_cleaned_data_for_step('userchoice')
num_users = userchoice['num_users']
CoFunderFormSet.extra = num_users
return CoFunderFormSet
return form
With this approach I am able to get the right amount of forms displayed for the second step, but when trying to post the Formset I am ending up with this error:
[u'ManagementForm data is missing or has been tampered with']
The POST data has the expected management form fields set, e.g.
form-TOTAL_FORMS u'1'
but I assume the FormWizard is using the Formset that was set in the initial FORMS list and therefore the management forms do not match.
I was wondering if there is a solution to this and if there is a way to tell the FormWizard to use the dynamically generated Formset on POST instead.
You can override get_form_initial, assume you have already set your form_list like this:
form_list = [
(FIRST_STEP, forms.FirstForm),
(SECOND_STEP, modelformset_factory(Second_model, form=forms.SecondForm)),
]
def get_form_initial(self, step):
"""
Set extra parameter for step2, which is from clean data of step1.
"""
if step == self.SECOND_STEP:
form_class = self.form_list[step]
data = self.get_cleaned_data_for_step(self.FIRST_STEP)
if data is not None:
extra = get_extra_count(data) # use cleaned data calculate extra
form_class.extra = extra
return super(PackageWizard, self).get_form_initial(step)
If you get this error message,
[u'ManagementForm data is missing or has been tampered with']
In your template make sure that you have given {{ wizard.form.management_form }}.
Related
I am trying to create a wizard to import several of a model in Django using JSON. I want to be able to:
go to a URL like entries/import/ which will display a textfield
where I can paste in some JSON entries and hit submit
which will then bring me to step 2 of the wizard where I will be presented with a list of model forms
where upon inspecting/changing some data I can hit submit and have all the entries saved
It looks like I want to use a Form Wizard in conjunction with a FormSet. I have steps 1 and 2 complete, but I can't figure out how to get all the models to be presented as forms on step 2 of the wizard.
I've come across this link that shows where I might be able to convert the JSON to a FormSet, but I haven't been able to get it to work as of yet. Below is what I believe to be the relevant code. Can you help me figure out how to get the formset to be passed to step2?
class EntryForm(forms.ModelForm):
class Meta:
model = Entry
fields = ['text', 'tags']
class ImportForm(forms.Form):
json = forms.CharField(widget=forms.Textarea, label='JSON')
class ImportSelectionForm(forms.Form):
entryFormSet = formset_factory(EntryForm)
FORMS = (
("step1", ImportForm),
("step2", ImportSelectionForm),
)
TEMPLATES = {
"step1": "entries/json_form.html",
"step2": "entries/entry_import_form.html",
}
class ImportWizard(SessionWizardView):
def get_template_names(self):
return [TEMPLATES[self.steps.current]]
def get_form_initial(self, step):
current_step = self.storage.current_step
if current_step == 'step2':
# Not getting here for some reason after submitting step1
prev_data = self.storage.get_step_data('step1')
json = prev_data.get('step1-json', '')
models = serializers.deserialize("json", json)
EntryFormSet = formset_factory(EntryForm)
formset = EntryFormSet(self.request.POST, self.request.FILES)
return self.initial_dict.get(step, {'formset': formset})
return self.initial_dict.get(step, {})
def done(self, form_list, **kwargs):
return HttpResponseRedirect(revierse_lazy('entries:index'))
You should just use step parameter passed to get_form_initial method instead of using self.storage.current_step. After testing I've noticed that self.storage.current_step contains previous step.
Also notice that for some reason get_form_initial is processed twice, once for previous and once for current step.
Situation
Using Django 1.5, I am using forms.ModelForms to let the user edit database contents. However I can't get the form to update the database upon form.save().
Each of my models correspond to a setting form (the application is a the direct porting of a desktop software in which the user can store several settings). I needed to implement a Reset to default feature, so I thought of having a default object (imported with Django fixtures) which I would use only to reset a second one. The user would only interact with the second model.
pk=1 refers to the base object
pk=2 refers to the custom object
I have several forms on the same page (only foobar here), so basically this what I planned to do:
No POST data
Building form from either pk=1 or pk=2, depending pk=2 has been found or not
Rendering the forms to the template
AJAX request, with POST datas
Getting form content
Checking whether or not the user has permission to edit the model (checksum)
Update the model form POST datas
Returning AJAX response
Code
I have put two debug prints to illustrate the issue I am facing. The form I fetch doesn't seem to be bound to my model.
# Response codes to use in the template
RESPONSES = {
200: {'code':'0xB16B00B5', 'message':'Success'},
400: {'code':'0x8BADF00D', 'message':'Form is not valid'},
403: {'code':'0xBAADF00D', 'message':'No permission to edit the database'},
501: {'code':'0xDEADC0DE', 'message':'POST datas not found'},
}
# Those are the setting labels
TYPES = {
'foobar': {'model':FooBar, 'form':FooBarForm },
}
def index(request):
# Handling form datas
if request.method == 'POST':
response = HttpResponse(simplejson.dumps({'code':RESPONSES[501]['code']}), 'application/json')
for label in TYPES:
# Filtering the right form to handle
if label in request.POST:
model = _fetch_setting(label, mode='model')
form = _fetch_setting(label, mode='form', post=request.POST)
checksum = model.checksum # Somehow, 'form.is_valid()' is altering 'model', need to backup the checksum
if form.is_valid():
# The user has permission to edit the model
if form.cleaned_data['checksum'] == checksum:
if form.has_changed():
print form.cleaned_data['foo'] # Outputs the form data, as expected
form.save()
print model.foo # Outputs the old data
model.checksum = str(uuid4()).replace('-', '')
model.save()
response = HttpResponse(simplejson.dumps({'code':RESPONSES[200]['code']}), 'application/json')
# This one does not
else:
response = HttpResponse(simplejson.dumps({'code':RESPONSES[403]['code']}), 'application/json')
break # We are still inside the label loop
# The form is not valid
else:
response = HttpResponse(simplejson.dumps({'code':RESPONSES[400]['code']}), 'application/json')
# Form not submitted yet, building the HTML forms
else:
forms = {}
label = 'foobar'
for label in TYPES:
forms[label] = _fetch_setting(label, mode='form')
context = {'errors':RESPONSES, 'forms':forms}
response = render(request, 'home/index.html', context)
return response
# Return a setting object (model or form) corresponding to the given label
def _fetch_setting(label, mode='model', post=None):
try:
result = None
default = TYPES[label]['model'].objects.get(pk=1)
try:
model = TYPES[label]['model'].objects.get(pk=2)
except TYPES[label]['model'].DoesNotExist:
model = TYPES[label]['model'].objects.create(
checksum = default.checksum,
foo = default.foo,
bar = default.bar,
)
if mode == 'model':
result = model
if mode == 'form':
print model
result = TYPES[label]['form'](data=post, instance=model) # The 'instance' attribute doesn't seem to be applied
except KeyError:
result = None
finally:
return result
Update
07.10
It does work when I pass the instance to bound with to _fetch_setting. So I guess this issue is coming from the form validation.
def _fetch_setting(label, mode='model', post=None, instance=None):
# ...
if mode == 'form':
if instance:
model = instance
result = TYPES[label]['form'](data=post, instance=model)
# ...
As I commented in my code, form.is_valid() seems to alter the object.
Will flag as answered if no one come with a clean solution.
The issue is, you are creating a new model object with each form.save()
You need to update the same model object with commit=False
if form.cleaned_data['checksum'] == checksum:
if form.has_changed():
print form.cleaned_data['foo'] # Outputs the form data, as expected
model = form.save(commit=False)
model.checksum = str(uuid4()).replace('-', '')
model.save()
From the fabulous manual:
The first time you call is_valid() or access the errors attribute of a ModelForm triggers form validation as well as model validation. This has the side-effect of cleaning the model you pass to the ModelForm constructor. For instance, calling is_valid() on your form will convert any date fields on your model to actual date objects. If form validation fails, only some of the updates may be applied. For this reason, you’ll probably want to avoid reusing the model instance passed to the form, especially if validation fails.
Say I have a form that looks like this:
forms.py
class CreateASomethingForm(ModelForm):
class Meta:
model = Something
fields = ['field2', 'field3', 'field4']
I want the form to have these three fields. However my Somethingclass also has field1. My question is - how do I add data to field1, if I am not using the ModelForm to collect the data. I tried doing something like this, but it isn't working and I am unsure on the proper way to solve this:
views.py
def create_something_view(request):
if (request.method == 'POST'):
# Create an object of the form based on POST data
obj = CreateASomething(request.POST)
# ** Add data into the blank field1 ** (Throwing an error)
obj['field1'] = request.user
# ... validate, save, then redirect
The error I receive is:
TypeError: 'CreateAClassForm' object does not support item assignment
In Django, what is the proper way to assign data to a ModelForm object before saving?
form = CreateASomething(request.POST)
if form.is_valid():
obj = form.save(commit=False)
obj.field1 = request.user
obj.save()
Sometimes, the field might be required which means you can't make it past form.is_valid(). In that case, you can pass a dict object containing all fields to the form.
if request.method == 'POST':
data = {
'fields1': request.user,
'fields2': additional_data,
}
form = CreateASomethingForm(data)
if form.is_valid():
form.commit(save)
There are two ways given by Django official
LINK : https://docs.djangoproject.com/en/3.0/topics/forms/modelforms/
Method 1]
author = Author(title='Mr')
form = PartialAuthorForm(request.POST, instance=author)
form.save()
Method 2]
form = PartialAuthorForm(request.POST)
author = form.save(commit=False)
author.title = 'Mr'
author.save()
Here is a more suitable way to add data especially used during testing:
First convert an existing entry into a dictionary with the model_to_dict function
from django.forms.models import model_to_dict
...
valid_data = model_to_dict(entry)
Then add the new data into this dictionary
valid_data['finish_time'] = '18:44'
This works better than setting the value in the form
update_form.finish_time = '18:44'
Create the form with the valid data and the instance
update_form = UserEntryForm(valid_data, instance=entry)
Do any assertions you require:
self.assertTrue(update_form.is_valid())
entry = update_form.save()
self.assertEqual(
entry.status,
1
)
I have a modelform that will either create a new model or edit an existing one - this is simple and should work, but for some reason I'm getting a new instance every time.
The scenario is this is the first step in an ecommerce order. The user must fill out some info describing the order (which is stored in the model). I create the model, save it, then redirect to the next view for the user to enter their cc info. I stick the model in the session so I don't have to do a DB lookup in the next view. There is a link in the template for the second (cc info) view that lets the user go back to the first view to edit their order.
# forms.py
class MyForm(forms.ModelForm):
class Meta:
fields = ('field1', 'field2')
model = MyModel
# views.py
def create_or_update(request):
if request.method == 'POST':
form = MyForm(request.POST)
if form.is_valid():
m = form.save(commit=False)
# update some other fields that aren't in the form
m.field3 = 'blah'
m.field4 = 'blah'
m.save()
request.session['m'] = m
return HttpResponseRedirect(reverse('enter_cc_info'))
# invalid form, render template
...
else:
# check to see if we're coming back to edit an existing model
# this part works, I get an instance as expected
m = request.session.get('m', None)
if m:
instance = get_object_or_None(MyModel, id=m.id)
if instance:
form = MyForm(instance=instance)
else:
# can't find it in the DB, but it's in the session
form = MyForm({'field1': m.field1, 'field2': m.field2})
else:
form = MyForm()
# render the form
...
If I step through in the debugger when I go back to the view to edit an order that the form is created with the instance set to the previously created model, as expected. However, when the form is processed in the subsequent POST, it creates a new instance of the model when form.save() is called.
I believe this is because I've restricted the fields in the form, so there is nowhere in the rendered HTML to store the id (or other reference) to the existing model. However, I tried adding both a 'pk' and an 'id' field (not at the same time), but then my form doesn't render at all.
I suspect I'm making this more complicated than it needs to be, but I'm stuck at the moment and could use some feedback. Thanks in advance.
This is interesting. Here is my stab at it. Consider this line:
form = MyForm(request.POST)
Can you inspect the contents of request.POST? Specifically, check if there is any information regarding which instance of the model is being edited. You'll find that there is none. In other words, each time you save the form on POST a new instance will be created.
Why does this happen? When you create a form passing the instance=instance keyword argument you are telling the Form class to return an instance for an instance of the model. However when you render the form to the template, this information is used only to fill in the fields. That is, the information about the specific instance is lost. Naturally when you post pack there is way to connect to the old instance.
How can you prevent this? A common idiom is to use the primary key as part of the URL and look up an instance on POST. Then create the form. In your case this would mean:
def create_or_update(request, instance_id):
# ^^^^^
# URL param
if request.method == 'POST':
instance = get_object_or_None(Model, pk = instance_id)
# ^^^^^
# Look up the instance
form = MyForm(request.POST, instance = instance)
# ^^^^^^^
# pass the instance now.
if form.is_valid():
....
I created a view which returns a form including a contact form and two phone_number forms, following this example:
multiple forms
The phone number forms should only be validated if the user inserts at least a value for one field in a phone number form. For example: a phone number has a type and a number. If the user is selecting the type, the number is required.
Now I'm wondering how i can check in the view whether the user inserted a value / selected a type or inserted a number. It should work like in the admin for inline editing a model.
my view looks like this:
def contact_add(request):
user = request.user
if request.method == 'POST':
cform = ContactForm(request.POST)
pforms = [PhoneNumberForm(request.POST, prefix=str(x)) for x in range(0,3)]
if cform.is_valid() and all([pf.is_valid() for pf in pforms]):
new_contact = cform.save(commit=False)
new_contact.created_by = user
new_contact.save()
for pf in pforms:
new_phone_number = pf.save(commit=False)
new_phone_number.contact = new_contact
new_phone_number.save()
request.user.message_set.create(message='Contact %s has been added.' % new_contact.__str__())
return HttpResponseRedirect("/crm/contacts/?oby=1")
else:
cform = ContactForm()
pforms = [PhoneNumberForm(prefix=str(x)) for x in range(0,3)]
return render_to_response(
'crm/contact_add.html',
{'cform': cform, 'pforms': pforms,},
context_instance = RequestContext(request),
)
Edit after first response below:
I tried to accomplish this task with custom validation but did not come to a satisfying end. To ease my task I changed the use-case a bit. I create a form which includes one Contact Form and one Address Form. The Address Form should only be validated if at least one field of the Address Form is filled in, since it should be possible to create a contact without creating a corresponding Address.
First I tried to use custome validation, which looked like this:
class AddressForm(forms.ModelForm):
class Meta:
model = Address
exclude = ('contact',)
def clean(self):
cleaned_data = self.cleaned_data
street = cleaned_data.get("street")
postal_code = cleaned_data.get("postal_code")
city = cleaned_data.get("city")
country = cleaned_data.get("country")
if not street and not postal_code and not city and not country:
#searching a better idea here
return 0
else:
return cleaned_data
But this does not really help, since this way I do not get rid of the validation errors.
This lead me to the idea that the clean method is the wrong place to do this validation, I think I have to check already in the POST.request whether all values for the Address Form are missing. And if they are missing, I do not call is_valid() for the Address Form and just ignore it. If at least one value is available, I just do the normal validation of the Address Form, without overriding the clean() method..
Good or bad idea?
If it is a good idea, how can I easily check the POST request for the values of my Address Form.
Probably I`m thinking way to complicated :-)
Edit: The solution using FormSets:
#login_required
def contact_add(request):
user = request.user
if request.method == 'POST':
cform = ContactForm(request.POST)
phonenumberformset = PhoneNumberFormSet(request.POST)
if cform.is_valid() and classificationformset.is_valid() and addressformset.is_valid() and phonenumberformset.is_valid():
new_contact = cform.save(commit=False)
new_contact.created_by = user
new_contact.save()
new_phonenumber_instances = phonenumberformset.save(commit=False)
for new_phonenumber in new_phonenumber_instances:
new_phonenumber.contact = new_contact
new_phonenumber.save()
request.user.message_set.create(message='Contact %s has been added.' % new_contact.__str__())
return HttpResponseRedirect("/crm/contacts/?oby=1")
else:
cform = ContactForm()
#By default, when you create a formset from a model, the formset will use
#a queryset that includes all objects in the model (e.g., Author.objects.all()).
#Here we want to present an empty formset in order to add a new object
phonenumberformset = PhoneNumberFormSet(queryset=PhoneNumber.objects.none())
return render_to_response(
'crm/contact_add.html',
{'cform': cform, 'phonenumberformset': phonenumberformset,},
context_instance = RequestContext(request),
)
Please note that this can also be accomplished using an inlineformset_factory, see my other post for more details: link
Note that if you are using FormSets you have to include a management_form for each form_set in your template. docs
Otherwise you get this error:
[u'ManagementForm data is missing or has been tampered with']
Using a formset inside a view is as easy as using a regular Form class. The only thing you will want to be aware of is making sure to use the management form inside the template.
{{ context.phonenumberformset.management_form }}
You should be using formsets rather than messing around with dynamic prefixes for your PhoneNumber subform - it will make everything much easier, and this is indeed how the admin manages inline forms (see also the model formsets documentation).
Formsets are intelligent enough that if no information is entered in one form of the formset, it does not enforce the required elements - but if one element is filled, it will enforce all the validation requirements. This sounds like it should solve your problem.
What you want to do is define custom validation on the form.
class PhoneNumberForm(forms.Form):
# Everything as before.
...
def clean(self):
cleaned_data = self.cleaned_data
phone1 = cleaned_data.get("phone1")
if phone1:
# validate manually, and if it doesn't pass:
self._errors["phone1"] = ErrorList(["Hey, this field is wrong."])
del cleaned_data["phone1"]
# Always return the full collection of cleaned data.
return cleaned_data
Then in the view, you want to rely on Django's built-in error form validation error handling:
{{ pforms.phone1 }}
{{ pforms.phone1.errors }}