Develop Reference

Django: Create object with ForeignKey from url

I am working on a Django project with two models linked by a ForeignKey. The parent model, Composition, is linked to the child model, NoteObject, by the id of Composition.
in models.py
class Composition(models.Model):
id = models.AutoField(primary_key=True)
...
class NoteObject(models.Model):
id = models.AutoField(primary_key=True)
composition = models.ForeignKey(Composition, on_delete=models.CASCADE)
...
Once a composition is created, the user needs to be able to create NoteObjects that belong to that composition. The notes are created with the following method:
in views.py
class NoteCreateView(CreateView):
model = NoteObject
template_name = 'entry.html'
fields = ['duration', 'pitch', 'accidental', 'octave']
success_url = reverse_lazy('compositions')
def get_context_data(self, **kwargs):
kwargs['notes'] = NoteObject.objects.filter(
composition=self.kwargs['composition'])
return super(NoteCreateView, self).get_context_data(**kwargs)
The get_context_data method is there to display only the notes for the current composition. The current composition comes from the id of the composition that is part of the url where <composition> is the id of the composition.
in urls.py
path('entry/<composition>/', views.NoteCreateView.as_view(), name='entry')
When I save a NoteObject, what do I need to do in order to set the value of the ForeignKey to be the value within <composition>?
in models.py
def save(self, *args, **kwargs):
composition_id = ????????
self.composition_id = composition_id
super(NoteObject, self).save(*args, **kwargs)
How do I get the value of kwarg in the CreateView to be the ForeignKey when the object is created?

I think you can do it by over-riding form_valid method as mentioned in docs here.
class NoteCreateView(CreateView):
model = NoteObject
template_name = 'entry.html'
fields = ['duration', 'pitch', 'accidental', 'octave']
success_url = reverse_lazy('compositions')
def form_valid(self, form):
form.instance.composition = self.kwargs['composition']
return super(NoteCreateView, self).form_valid(form)

In order to make this work, you need to override the dispatch function as well.
def dispatch(self, request, *args, **kwargs):
self.composition = Composition.objects.values_list(
'id').filter(pk=kwargs['composition'])
return super().dispatch(request, *args, **kwargs)
def form_valid(self, form):
form.instance.composition_id = self.composition
return super().form_valid(form)
I used this solution and modified it slightly: CreateView Set ForeignKey from Url Parameter.

Django - Multiple custom models on the same form

I'm using Django 2.1 and PostgreSQL.
My problem is that I'm trying to create a form to edit two different models at the same time. This models are related with a FK, and every example that I see is with the user and profile models, but with that I can't replicate what I really need.
My models simplified to show the related information about them are:
# base model for Campaigns.
class CampaignBase(models.Model):
....
project = models.ForeignKey(Project, on_delete=models.CASCADE)
creation_date = models.DateTimeField(auto_now_add=True)
start_date = models.DateTimeField(null=True, blank=True)
end_date = models.DateTimeField(null=True, blank=True)
....
# define investment campaign made on a project.
class InvestmentCampaign(models.Model):
....
campaign = models.ForeignKey(CampaignBase, on_delete=models.CASCADE, null=True, blank=True)
description = models.CharField(
blank=True,
max_length=25000,
)
....
And the form that I want to create is one that includes the end_date of the FK CampaignBase, and the Description from the InvestmentCampaign.
Now I have this UpdateView to edit the InvestmentCampaign, and I need to adapt to my actual needs, that are also update the CampaignBase model:
class ProjectEditInvestmentCampaignView(LoginRequiredMixin, SuccessMessageMixin, generic.UpdateView):
template_name = 'webplatform/project_edit_investment_campaign.html'
model = InvestmentCampaign
form_class = CreateInvestmentCampaignForm
success_message = 'Investment campaign updated!'
def get_success_url(self):
return reverse_lazy('project-update-investment-campaign', args=(self.kwargs['project'], self.kwargs['pk']))
# Make the view only available for the users with current fields
def dispatch(self, request, *args, **kwargs):
self.object = self.get_object()
# here you can make your custom validation for any particular user
if request.user != self.object.campaign.project.user:
raise PermissionDenied()
return super().dispatch(request, *args, **kwargs)
# Set field as current user
def form_valid(self, form):
campaign = InvestmentCampaign.objects.get(pk=self.kwargs['campaign'])
form.instance.campaign = campaign
form.instance.history_change_reason = 'Investment campaign updated'
return super(ProjectEditInvestmentCampaignView, self).form_valid(form)
def get_context_data(self, **kwargs):
project = Project.objects.get(pk=self.kwargs['project'])
context = super(ProjectEditInvestmentCampaignView, self).get_context_data(**kwargs)
context['project'] = project
return context
My forms are:
class CreateCampaignBaseForm(forms.ModelForm):
class Meta:
model = CampaignBase
fields = ('end_date',)
widgets = {
'end_date': DateTimePickerInput(),
}
def __init__(self, *args, **kwargs):
# first call parent's constructor
super(CreateCampaignBaseForm, self).__init__(*args, **kwargs)
# evade all labels and help text to appear when using "as_crispy_tag"
self.helper = FormHelper(self)
self.helper.form_show_labels = False
self.helper._help_text_inline = True
class CreateInvestmentCampaignForm(forms.ModelForm):
class Meta:
model = InvestmentCampaign
fields = ('description')
widgets = {
'description': SummernoteWidget(attrs={'summernote': {
'placeholder': 'Add some details of the Investment Campaign here...'}}),
}
def __init__(self, *args, **kwargs):
# first call parent's constructor
super(CreateInvestmentCampaignForm, self).__init__(*args, **kwargs)
# evade all labels and help text to appear when using "as_crispy_tag"
self.helper = FormHelper(self)
self.helper.form_show_labels = False
self.helper._help_text_inline = True
I've read everywhere that the best way of doing this is using function based views, and call each of the forms that I have and then do the validation. the thing is that I don't know how can I populate the fields with the right object in both forms, and also, I don't know how to do the equivalent of the get_context_data nor getting the self arguments to do the equivalent of the get_success_url (because with function based views I only have the request attr so I can't access the kwargs).
I've seen some people using the django-betterforms, but again, the only examples are with the auth and profile models and I don't see the way to replicate that with my own models.
Thank you very much.

If the only thing you want to change is one field end_date on BaseCampaign, then you should use just one form. Just add end_date as an additional field (e.g. forms.DateTimeField()) on your CreateInvestmentCampaignForm and in your form.valid() method, after saving the form, set the value on the associated campaign:
def form_valid(self, form):
inv_campaign = form.save(commit=False)
inv_campaign.campaign.end_date = form.cleaned_data['end_date']
inv_campaign.campaign.save()
inv_campaign.history_change_reason = ...
return super().form_valid(form)
Here's how to add end_date to your form and initialize it correctly:
class CreateInvestmentCampaignForm(ModelForm):
end_date = forms.DateTimeField(blank=True)
class Meta:
model = InvestmentCampaign
fields = ('description')
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
if self.instance.campaign:
self.fields['end_date'].initial = self.instance.campaign.end_date

Based on the conversation on the answer of #dirkgroten, I've developed what worked for me and what I'm actually using, but I market his answer as correct because his code is also functional.
So, meanwhile he is initiating the values on the form, I'm using the view to do that by adding a def get_initial(self): and also adding the validation on the def form_valid(self, form)::
On the view:
...
def get_initial(self):
"""
Returns the initial data to use for forms on this view.
"""
initial = super(ProjectEditInvestmentCampaignView, self).get_initial()
initial['end_date'] = self.object.campaign.end_date
return initial
...
# Set field as current user
def form_valid(self, form):
form.instance.history_change_reason = 'Investment campaign updated'
is_valid = super(ProjectEditInvestmentCampaignView, self).form_valid(form)
if is_valid:
# the base campaign fields
campaign = form.instance.campaign
campaign.end_date = form.cleaned_data.get("end_date")
campaign.save()
return is_valid
And on the form I just added the end_date field:
class CreateInvestmentCampaignForm(forms.ModelForm):
end_date = forms.DateTimeField()
class Meta:
model = InvestmentCampaign
fields = ('description',)
widgets = {
'description': SummernoteWidget(attrs={'summernote': {
'placeholder': 'Add some details of the Investment Campaign here...'}}),
'end_date': DateTimePickerInput(), # format='%d/%m/%Y %H:%M')
}
def __init__(self, *args, **kwargs):
# first call parent's constructor
super(CreateInvestmentCampaignForm, self).__init__(*args, **kwargs)
# evade all labels and help text to appear when using "as_crispy_tag"
self.helper = FormHelper(self)
self.helper.form_show_labels = False
self.helper._help_text_inline = True

Django Admin - Filter ManyToManyField with through model

How can I filter a queryset inside the Admin page of an object that has a ManyToManyField relation with a manually defined through model?
Given models.py
class Foo(models.Model):
foo_field1 = models.CharField(max_length=50)
class Main(models.Model):
main_field1 = models.CharField(max_length=50)
m2mfield = models.ManyToManyField(Foo, through="FooBar")
class FooBar(models.Model):
main = models.ForeignKey(Main, on_delete=models.CASCADE)
foo = models.ForeignKey(Foo, on_delete=models.CASCADE)
new_field = models.CharField(max_length=50)
Inside admin.py
class M2MInlineAdmin(admin.TabularInline):
model = Main.m2mfield.through
extra = 1
class MainAdmin(admin.ModelAdmin):
inlines = [M2MInlineAdmin,]
...
def formfield_for_manytomany(self, db_field, request, **kwargs):
print('called formfield_for_manytomany')
return super().formfield_for_manytomany(db_field, request, **kwargs)
def get_field_queryset(self, db, db_field, request):
print('called get_field_queryset')
return super().get_field_queryset(db, db_field, request)
I try to access both of these methods, but none of them are called if I specify a through table. However, they do get called if the ManyToMany relation is simply defined as like this:
class Main(models.Model):
main_field1 = models.CharField(max_length=50)
m2mfield = models.ManyToManyField(Foo)
Is there a method to filter the queryset when a through table is specified (while being able to access the request context)?
EDIT:
The methods are indeed called when the ManyToManyField has a through model specified, only if there are no fieldsets specified inside the modelAdmin class.
How to access these methods when fieldsets are defined?

formfield_for_manytomany method seems to be called only when default form is used. When fieldsets is defined, it is using a different form which is why above method is not getting called.
Since you are using tabular admin for many to many field, you can override get_queryset to filter with field.
class M2MInlineAdmin(admin.TabularInline):
model = Main.fruits.through
extra = 1
def get_queryset(self, request):
qs = super(M2MInlineAdmin, self).get_queryset(request)
qs = qs.filter(some_arg=some_value)
return qs
Alternatively, you can write a custom model form and use it in admin instead of default form.
class MainAdminForm(forms.ModelForm):
class Meta:
model = Main
fields = '__all__'
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
# custom setup
class MainAdmin(admin.ModelAdmin):
form = MainAdminForm

You can use the formfield_for_foreignkey() method on the inline class.
class M2MInlineAdmin(admin.TabularInline):
model = Main.m2mfield.through
extra = 1
def formfield_for_foreignkey(self, db_field, request, **kwargs):
if db_field.name == "car":
kwargs["queryset"] = Car.objects.filter(owner=request.user)
return super().formfield_for_foreignkey(db_field, request, **kwargs)

Django: Use post() in UpdateView to populate form's fields with instance's existing field values

I have trouble getting the current instance's fields on my UpdateView. How do I get the specific instance based on its id?
views.py
class ShowUpdate(UpdateView):
model = Show
fields = ['description', 'season', 'episode']
def post(self, request, **kwargs):
request.POST = request.POST.copy()
request.POST['description'] = "how to get instance description?" # problem here
request.POST['season'] = 2
return super(ShowUpdate, self).post(request, **kwargs)
models.py
class Show(models.Model):
owner = models.ForeignKey(User, null=True, default=True, related_name='o')
title = models.CharField(max_length=100)
description = models.TextField(default='N/A', blank=True, max_length=250)
season = models.IntegerField(default=0)
episode = models.IntegerField(default=0)
def get_absolute_url(self):
return reverse('show:index')
def __str__(self):
return self.title

Look to the UpdateView docs
This View has method get_object(self, queryset=None)
In you case just need to call it in POST method something like this:
class ShowUpdate(UpdateView):
model = Show
fields = ['description', 'season', 'episode']
def post(self, request, **kwargs):
self.object = self.get_object()
request.POST = request.POST.copy()
request.POST['description'] = self.object.description
request.POST['season'] = 2
return super(ShowUpdate, self).post(request, **kwargs)

How to assign the User object to save method in Django

I am trying to log the activities during save operation to track all the changes to user model. my approach is as follows.
class User(AbstractUser):
undergrad_college = models.CharField(max_length=20, choices=COLLEGE_CHOICES)
undergrad_degree = models.CharField(max_length=20, choices=COLLEGE_DEGREES)
postgrad_college = models.CharField(max_length=20, choices=COLLEGE_CHOICES)
postgrad_degree = models.CharField(max_length=20, choices=COLLEGE_DEGREES)
currently_working_on = models.TextField()
previous_work_experience = models.TextField()
previous_internship_experience = models.TextField()
def __str__(self):
return self.username
def save(self, *args, **kwargs):
Log(user=User, actions="Updated profile",
extra={"undergrad_college": self.undergrad_college,
"undergrad_degree": self.undergrad_degree,
"postgrad_college": self.postgrad_college,
"postgrad_degree": self.postgrad_degree,
"currently_working_on": self.currently_working_on,
"previous_work_experience": self.previous_work_experience,
"previous_internship_experience": self.previous_internship_experience
})
super(User, self).save(args, **kwargs)
my views are like this for handling the logging.
class ActivityMixin(LoginRequiredMixin):
def get_context_data(self, **kwargs):
context = super(ActivityMixin, self).get_context_data(**kwargs)
context['activities'] = Log.objects.filter(user=self.request.user)
return context
class IndexListView(ActivityMixin, ListView):
template_name = 'pages/home.html'
model = User
I get this error while performing the update action.
Cannot assign "<class 'users.models.User'>": "Log.user" must be a "User" instance.
Update view is as follows
class UserUpdateView(LoginRequiredMixin, UpdateView):
form_class = UserForm
# we already imported User in the view code above, remember?
model = User
# send the user back to their own page after a successful update
def get_success_url(self):
return reverse("users:detail",
kwargs={"username": self.request.user.username})
def get_object(self, **kwargs):
# Only get the User record for the user making the request
return User.objects.get(username=self.request.user.username)
How to assign the User model instance to the Log function. I cant get this working. I am Django newbie.

Looks like pretty straightforward, replace User with self:
Log(user=User, ...
Log(user=self, ...