Django ModelForm: change a field value when blank - django

Is there any way to change a field value (related to a foreign key) in a Django ModelForm once the form is initialized and filled by the user (I'm using request.POST). I want to change the value when the user doesn't select any option of the dropdown list. I tried this formulari_mostra.data['pools'] = 1 in views.py after saving the feedback from the form with no result:
def sample_form(request):
formulari_mostra=FormulariMostra()
if request.method=="POST":
formulari_mostra=FormulariMostra(request.POST or None)
if formulari_mostra.is_valid():
feedback = formulari_mostra.save(commit=False)
sample = Sample.objects.all()
feedback.sample = sample
feedback.save()
formulari_mostra.save_m2m()
formulari_mostra.data['pools'] = 1
messages.success(request, 'Mostra enregistrada correctament!')
return render(request, "sample/formulari_mostra.html", {'formulari':formulari_mostra})
I got this message:
This QueryDict instance is immutable
I know I can set an initial (default) before introducing data in the form but I don't want to have the default option highlighted in the dropdown.
My model:
class Sample(models.Model):
id_sample = models.AutoField(primary_key=True)
name = models.CharField(unique=True, max_length=20)
sample_id_sex = models.ForeignKey(Sex, on_delete=models.CASCADE, db_column='id_sex', verbose_name='Sexe')
indexes = models.ManyToManyField(Index, through='SamplePoolIndexCand', through_fields=('sample_id', 'index_id'), blank=True, verbose_name="Índexs")
pools = models.ManyToManyField(Pool, through='SamplePoolIndexCand', through_fields=('sample_id', 'pool_id'), blank=True, verbose_name="Pools")
gene_cand_lists = models.ManyToManyField(GeneCandList, through='SamplePoolIndexCand', through_fields=('sample_id', 'gene_cand_list_id'), blank=True, verbose_name="Llista de gens candidats")
class Meta:
db_table = 'sample'
def __str__(self):
return self.name
My forms.py:
class FormulariMostra(ModelForm):
class Meta:
model = Sample
fields = ("name", "sample_id_sex", "pools",)

first - you are setting the polls property after save() is called, so even if this would work, you are not saving the change.
second - if you want to set the polls property to model, then set it to the model instead of the form (formulari_mostra). I dont know how your models look like, so I can only assume the model which has the pools property is in the variable feedback, so you want to do:
feedback = formulari_mostra.save(commit=False)
feedback.pools = 1
feedback.save()

Related

What is difference between these two method of updating DB using form?

I'm trying update db using form. I want to select title in dropdown, and update 'opening_crawl' field to input from text area.
models.py :
class Movies(models.Model):
episode_nb = models.IntegerField(primary_key=True)
title = models.CharField(max_length=64, unique=True, null=False)
opening_crawl = models.TextField(null=True)
director = models.CharField(max_length=32)
producer = models.CharField(max_length=128)
release_date = models.DateField()
created = models.DateTimeField(auto_now_add=True)
updated = models.DateTimeField(auto_now=True, editable=True)
forms.py:
class TitleDropDownForm(forms.Form):
title = forms.ModelChoiceField(queryset=Movies.objects.only('title'), empty_label=None)
opening_crawl = forms.CharField(widget=forms.Textarea)
views.py:
def update(request):
msg = ''
if request.method == 'POST':
form = TitleDropDownForm(request.POST)
if form.is_valid():
#method 1 : it updates 'opening_crawl' properly, but not 'updated_time'.
movie = form.cleaned_data['title']
movie.opening_crawl = form.cleaned_data['opening_crawl']
movie.save()
#method 2
#h = Movies.objects.get(pk=1)
#h.opening_crawl = 'HAND WRITTEN MESSAGE!'
#h.save()
return redirect(request.META.get('HTTP_REFERER'))
else:
form = TitleDropDownForm()
if not form.fields['title'].queryset:
msg = 'No data available.'
return render(request, 'ex07/update.html', context={'form' : form, 'msg' : msg})
method 1 works with 'opening_crawl' field, but 'updated' datetime field was not changed.
When I tried like method 2, it updates both fields properly.
What is the difference between two method? Is there any misunderstanding?
I suspect it's because you're using .only()
From the Django documentation:
When saving a model fetched through deferred model loading (only() or defer()) only the fields loaded from the DB will get updated. In effect there is an automatic update_fields in this case. If you assign or change any deferred field value, the field will be added to the updated fields.
In your second method, you're getting the entire model, without any deferred fields (i.e. updated)

Django ModelChoiceField Issue

I've got the following Situation, I have a rather large legacy model (which works nonetheless well) and need one of its fields as a distinct dropdown for one of my forms:
Legacy Table:
class SummaryView(models.Model):
...
Period = models.CharField(db_column='Period', max_length=10, blank=True, null=True)
...
def __str__(self):
return self.Period
class Meta:
managed = False # Created from a view. Don't remove.
db_table = 'MC_AUT_SummaryView'
Internal Model:
class BillCycle(models.Model):
...
Name = models.CharField(max_length=100, verbose_name='Name')
Period = models.CharField(max_length=10, null=True, blank=True)
Version = models.FloatField(verbose_name='Version', default=1.0)
Type = models.CharField(max_length=100, verbose_name='Type', choices=billcycle_type_choices)
Association = models.ForeignKey(BillCycleAssociation, on_delete=models.DO_NOTHING)
...
def __str__(self):
return self.Name
Since I don't want to connect them via a Foreign Key (as the SummaryView is not managed by Django) I tried a solution which I already used quite a few times. In my forms I create a ModelChoiceField which points to my Legacy Model:
class BillcycleModelForm(forms.ModelForm):
period_tmp = forms.ModelChoiceField(queryset=SummaryView.objects.values_list('Period', flat=True).distinct(),
required=False, label='Period')
....
class Meta:
model = BillCycle
fields = ['Name', 'Type', 'Association', 'period_tmp']
And in my view I try to over-write the Period Field from my internal Model with users form input:
def billcycle_create(request, template_name='XXX'):
form = BillcycleModelForm(request.POST or None)
data = request.POST.copy()
username = request.user
print("Data:")
print(data)
if form.is_valid():
initial_obj = form.save(commit=False)
initial_obj.ModifiedBy = username
initial_obj.Period = form.cleaned_data['period_tmp']
initial_obj.Status = 'Creating...'
print("initial object:")
print(initial_obj)
form.save()
....
So far so good:
Drop Down is rendered correctly
In my print Statement in the View ("data") I see that the desired infos are there:
'Type': ['Create/Delta'], 'Association': ['CP'], 'period_tmp': ['2019-12']
Still I get a Select a valid choice. That choice is not one of the available choices. Error in the forms. Any ideas??

Remove option from generic class view in Django

I just started learning Django this week and I'm trying to figure out how I can remove an option from a select menu being rendered in a class based view. The dropdown is for a Foreign Key field that links to my users table.
The functionality here is that I do not want the current user logged into show up on that list (basically I don't want someone to be able to select themself). How can I go about doing this?
View:
class TransferCreateView(CreateView):
model = Transfer
template_name = 'points/transfer_form.html'
fields = ['receiver', 'message', 'amount']
Model:
class Transfer(models.Model):
receiver = models.ForeignKey(User, null=False,
on_delete=models.CASCADE, related_name='receiver')
sender = models.ForeignKey(User, null=False, on_delete=models.CASCADE, related_name='sender')
amount = models.IntegerField(
validators=[
MinValueValidator(1),
MaxValueValidator(1000)],
null=False)
message = models.CharField(max_length=100)
date_sent = models.DateTimeField(default=timezone.now)
Basically, I don't want the person who is the sender (which i was going to set in the code in a form_valid() function) to be an option for 'receiver' in the template when it renders.
Override the get_form method of the CreateView and change the queryset of that field, something like this:
class TransferCreateView(CreateView):
model = Transfer
template_name = 'points/transfer_form.html'
fields = ['receiver', 'message', 'amount']
def get_form(self, form_class):
form = super().get_form(form_class)
form.fields['receiver'].queryset = User.objects.exclude(id=self.request.user.id)
return form

Limit values in the modelformset field

I've been trying to solve this problem for a couple of days now, getting quite desperate. See the commented out code snippets for some of the things I've tried but didn't work.
Problem: How can I limit the values in the category field of the IngredientForm to only those belonging to the currently logged in user?
views.py
#login_required
def apphome(request):
IngrFormSet = modelformset_factory(Ingredient, extra=1, fields=('name', 'category'))
# Attempt #1 (not working; error: 'IngredientFormFormSet' object has no attribute 'fields')
# ingrformset = IngrFormSet(prefix='ingr', queryset=Ingredient.objects.none())
# ingrformset.fields['category'].queryset = Category.objects.filter(user=request.user)
# Attempt #2 (doesn't work)
# ingrformset = IngrFormSet(prefix='ingr', queryset=Ingredient.objects.filter(category__user_id = request.user.id))
models.py:
class Category(models.Model):
name = models.CharField(max_length=30, unique=True)
user = models.ForeignKey(User, null=True, blank=True)
class Ingredient(models.Model):
name = models.CharField(max_length=30, unique=True)
user = models.ForeignKey(User, null=True, blank=True)
category = models.ForeignKey(Category, null=True, blank=True)
counter = models.IntegerField(default=0)
forms.py:
class IngredientForm(ModelForm):
class Meta:
model = Ingredient
fields = ('name', 'category')
UPDATE: I've made some progress but the solution is currently hard-coded and not really usable:
I found out I can control the categoryform field via form class and then pass the form in the view like this:
#forms.py
class IngredientForm(ModelForm):
category = forms.ModelChoiceField(queryset = Category.objects.filter(user_id = 1))
class Meta:
model = Ingredient
fields = ('name', 'category')
#views.py
IngrFormSet = modelformset_factory(Ingredient, form = IngredientForm, extra=1, fields=('name', 'category'))
The above produces the result I need but obviously the user is hardcoded. I need it to be dynamic (i.e. current user). I tried some solutions for accessing the request.user in forms.py but those didn't work.
Any ideas how to move forward?
You don't need any kind of custom forms. You can change the queryset of category field as:
IngrFormSet = modelformset_factory(Ingredient, extra=1, fields=('name', 'category'))
IngrFormSet.form.base_fields['category'].queryset = Category.objects.filter(user__id=request.user.id)
Category.objects.filter(user=request.user)
returns a list object for the initial value in your form which makes little sense.
Try instead
Category.objects.get(user=request.user)
or
Category.objects.filter(user=request.user)[0]

How to save a ManyToMany relationship from a ModelForm in Django

I'm not sure to save my ManyToMany relationship. I found my exact problem in this thread: Django embedded ManyToMany form, except instead of Sales and Products models, I have models that make up a movie.
I tried the solution, but I receive a syntax error. I don't understand how Django should link the EquipmentModel, LightModel, and ActorModel to the ManyToMany relationship in MovieModel. So far (before trying the other thread's solution), the CharFields that are displayed on the form for LightModel, EquipmentModel, and ActorModel are not linked to the ManyToManyField in MovieModel. So when I save the forms and try to access a particular Movie's actors, all I see is a blank list. The solution from the other thread seems to make sense since it tries to link the models to the ManyToMany relationship in MovieModel, but I don't understand how Django knows which MovieModel to add to (how does it get the correct movieID?).
On a side note, is there a way to check for duplicate movies when the user presses the 'Submit' button on the form? I want to avoid creating duplicates.
views.py:
def add_movie(request, movieID=""):
if request.method == "POST":
form = MovieModelForm(request.POST)
eform = EquipmentModelForm(request.POST)
lform = LightModelForm(request.POST)
aform = ActorModelForm(request.POST)
print 'checking form'
print request.POST.items()
if form.is_valid() and eform.is_valid() and lform.is_valid() and aform.is_valid():
print 'form is valid'
movie_to_add = form.save()
e = eform.save()
l = lform.save()
a = aform.save()
movie_to_add.actors.add(a)
movie_to_add.lights.add(l)
movie_to_add.equipments.add(e)
# return HttpResponseRedirect('/data')
else:
# code for create forms ....
return render_to_response('add_movie.html', {'form':form, 'eform':eform,'lform':lform, 'aform':aform,}, context_instance=RequestContext(request))
Other code that may help:
forms.py
class LightModelForm(forms.ModelForm):
class Meta:
model = LightModel
class ActorModelForm(forms.ModelForm):
class Meta:
model = ActorModel
class EquipmentModelForm(forms.ModelForm):
class Meta:
model = EquipmentModel
class MovieModelForm(forms.ModelForm):
class Meta:
model = MovieModel
fields = ("title", "rank")
models.py
class EquipmentModel(models.Model):
equip = models.CharField(max_length=20)
class ActorModel(models.Model):
actor = models.CharField(max_length=20)
class LightModel(models.Model):
light = models.CharField(max_length=20)
class MovieModel(models.Model):
rank = models.DecimalField(max_digits=5000, decimal_places=3)
title = models.CharField(max_length=20)
equipments = models.ManyToManyField(EquipmentModel, blank=True, null=True)
actors = models.ManyToManyField(ActorModel, blank=True, null=True)
lights = models.ManyToManyField(LightModel, blank=True, null=True)
def __str__(self):
return self.title
Edit: removed unnecessary init and fields thanks to DTing
Edit2: Fixed!
There is a whole lot of stuff going wrong here in addition to what spulec said.
Your models.py look okay.
class EquipmentModel(models.Model):
equip = models.CharField(max_length=20)
class ActorModel(models.Model):
actor = models.CharField(max_length=20)
class LightModel(models.Model):
light = models.CharField(max_length=20)
class MovieModel(models.Model):
rank = models.DecimalField(max_digits=5000, decimal_places=3)
title = models.CharField(max_length=20)
equipments = models.ManyToManyField(EquipmentModel, blank=True, null=True)
actors = models.ManyToManyField(ActorModel, blank=True, null=True)
lights = models.ManyToManyField(LightModel, blank=True, null=True)
def __str__(self):
return self.title
You don't need to override the __init__ method on forms if you are not changing anything on init. You also don't need to be explicit about the fields if you want to include them all.
class LightModelForm(forms.ModelForm):
class Meta:
model = LightModel
class ActorModelForm(forms.ModelForm):
class Meta:
model = ActorModel
class EquipmentModelForm(forms.ModelForm):
class Meta:
model = EquipmentModel
class MovieModelForm(forms.ModelForm):
class Meta:
model = MovieModel
fields = ("title", "rank")
your view doesn't really make sense unless for every movie you are trying to add you also want to:
add a new movie to the db using the submitted post data
create one actor object and add to db
create one light object and add to db
create one equipment object and add to db
take those three objects and add them to another movie's m2m relationships.
This other movie is some movie that you pulled from the urlconf and passed to your view, not the one you just created.
This all seems a little strange.
what i think you want to do is create all the equipment, actors and lights objects so they are in your db already, and use the default m2m formfield widget to select them when adding a movie.
so:
forms.py
class MovieModelForm(forms.ModelForm):
class Meta:
model = MovieModel
urls.py:
url(r'^add_movie/$', add_movie)
views.py:
def add_movie(request):
if request.method=='POST':
form = MovieModelForm(request.POST)
if form.is_valid():
form.save()
return HttpResponse('success')
else:
form = MovieModelForm()
context = {'form':form }
return render_to_response('some_template.html', context,context_instance=RequestContext(request))
you could combine adding actors, lights, and equipment into the same form but that's a bit much for me to write out right now.
As far as modifying your original code to add those lights, actors, and equipment to the movie you just created, you could do this:
if form.is_valid() and eform.is_valid() and lform.is_valid() and aform.is_valid():
new_movie = form.save()
e = eform.save()
l = lform.save()
a = aform.save()
new_movie.actors.add(a)
new_movie.lights.add(l)
new_movie.equipments.add(e)
Change it to:
movie_to_add = get_object_or_404(MovieModel, id=movieID)