Using Django 1.11, one of my models is an array stored within a django-jsonfield field.
class MyModel(models.Model)
id = models.AutoField(primary_key=True)
name = models.CharField(max_length=100)
core = JSONField(blank=True, null=True, default=None)
I am using a ModelForm in a couple of views to create and edit new instances. Within the ModelForm I'm borrowing the django.contrib.postgres.forms.SimpleArrayField to parse the input into the field.
Adding a new model is fine, but in the edit version, the array gets pre-populated with what looks like the __str__ representation (eg an array of 1,2,3 becomes ['1','2','3'].
I'm getting around this by parsing the array into initial= for each form but I'd rather do this in one place (DRY) rather than having to repeat it inside each view and form instance.
Are there any hooks or methods (perhaps a custom widget?) that means I can do this just once in the form or somewhere else?
Snippet of the current view with hacky approach using initial=:
def edit_mymodel(id):
current_instance = MyModel.objects.get(pk=id)
if request.method == "GET":
form = MyModelForm(instance=current_instance,
initial={"core": ",".join(current_instance.core)}
)
return render(request, 'network_manager/edit.html',
{'form': form}
)
You can override __init__
class MyModelForm(ModelForm)
def __init__(self, *args, **kwargs):
super(MyModelForm, self).__init__(*args, **kwargs)
self.initial['core'] = ",".join(self.instance.core)
Related
SOLUTION AT THE BOTTOM
Problem: Django form populating with list of objects rather than values
Summary: I have 2 models Entities and Breaks. Breaks has a FK relationship to the entity_id (not the PK) on the Entities model.
I want to generate an empty form for all the fields of Breaks. Generating a basic form populates all the empty fields, but for the FK it generates a dropdown list of all objects of the Entities table. This is not helpful so I have excluded this in the ModelForm below and tried to replace with a list of all the entity_ids of the Entities table. This form renders as expected.
class BreakForm(ModelForm):
class Meta:
model = Breaks
#fields = '__all__'
exclude = ('entity',)
def __init__(self, *args, **kwargs):
super(BreakForm, self).__init__(*args, **kwargs)
self.fields['entity_id'] = ModelChoiceField(queryset=Entities.objects.all().values_list('entity_id', flat=True))
The below FormView is the cbv called by the URL. As the below stands if I populate the form, and for the FK column entity_id choose one of the values, the form will not submit. By that field on the form template the following message appears Select a valid choice. That choice is not one of the available choices.
class ContactFormView(FormView):
template_name = "breaks/test/breaks_form.html"
form_class = BreakForm
My initial thoughts were either that the datatype of this field (string/integer) was wrong or that Django needed the PK of the row in the Entities table (for whatever reason).
So I added a post function to the FormView and could see that the request.body was populating correctly. However I can't work out how to populate this into the ModelForm and save to the database, or overcome the issue mentioned above.
Addendum:
Models added below:
class Entity(models.Model):
pk_securities = models.AutoField(primary_key=True)
entity_id = models.CharField(unique=True)
entity_description = models.CharField(blank=True, null=True)
class Meta:
managed = False
db_table = 'entities'
class Breaks(models.Model):
pk_break = models.AutoField(primary_key=True)
date = models.DateField(blank=True, null=True)
entity = models.ForeignKey(Entity, on_delete= models.CASCADE, to_field='entity_id')
commentary = models.CharField(blank=True, null=True)
active = models.BooleanField()
def get_absolute_url(self):
return reverse(
"item-update", args=[str(self.pk_break)]
)
def __str__(self):
return f"{self.pk_break}"
class Meta:
managed = False
db_table = 'breaks'
SOLUTION
Firstly I got this working by adding the following to the Entity Model class. However I didn't like this as it would have consequences elsewhere.
def __str__(self):
return f"{self.entity_id}"
I found this SO thread on the topic. The accepted answer is fantastic and the comments to it are helpful.
The solution is to subclass ModelChoiceField and override the label_from_instance
class EntityChoiceField(ModelChoiceField):
def label_from_instance(self, obj):
return obj.entity_id
I think your problem is two fold, first is not rendering the dropdown correctly and second is form is not saving. For first problem, you do not need to do any changes in ModelChoiceField queryset, instead, add to_field_name:
class BreakForm(ModelForm):
class Meta:
model = Breaks
#fields = '__all__'
def __init__(self, *args, **kwargs):
super(BreakForm, self).__init__(*args, **kwargs)
self.fields['entity_id'] = ModelChoiceField(queryset=Entities.objects.all(), to_field_name='entity_id')
Secondly, if you want to save the form, instead of FormView, use CreateView:
class ContactFormView(CreateView):
template_name = "breaks/test/breaks_form.html"
form_class = BreakForm
model = Breaks
In Django, the request object passed as parameter to your view has an attribute called "method" where the type of the request is set, and all data passed via POST can be accessed via the request. POST dictionary. The view will display the result of the login form posted through the loggedin. html.
I am working on a project which is administered by a super admin who puts in data for different companies.
Lets say, I have these models:
class Company(models.Model):
name = models.CharField(max_length=100)
class ContactPerson(models.Model):
name = models.CharField(max_length=100)
company = models.ForeignKey(Company)
class Item(models.Model):
company = models.ForeignKey(Company)
contact_person = models.ForeignKey(ContactPerson)
I need to ensure that I (in django admin) in the edit mode I only see contact persons which belong to the selected company.
Being not in the year 2005 anymore I want to avoid writing loads of super ugly jQuery code.
I guess I could overwrite the admin form for Item. But still I had to make the contact_person optional, so when I create a new Item, the list of contact persons need to be empty. Then I'd select a company, save it and go back to edit. Now the contact_person list would be filled and I could add somebody. But if I now change the comany, I'd have to remove all selected contact persons. Sure, I could to this in the form... but it looks SO hacky and not like a nice django solution.
Anybody got some fancy ideas?
Actually, django provided me with a neat solution.
When you look at the UserAdmin class within the django code, you'll find a built-in way to handle a two-step creation process.
#admin.register(User)
class UserAdmin(admin.ModelAdmin):
...
add_form = UserCreationForm
...
def get_form(self, request, obj=None, **kwargs):
"""
Use special form during user creation
"""
defaults = {}
if obj is None:
defaults['form'] = self.add_form
defaults.update(kwargs)
return super().get_form(request, obj, **defaults)
When the attribute add_form is set and the object has no id yet (= we are creating it), it takes a different form than usual.
I wrapped this idea in an admin mixin like this:
class AdminCreateFormMixin:
"""
Mixin to easily use a different form for the create case (in comparison to "edit") in the django admin
Logic copied from `django.contrib.auth.admin.UserAdmin`
"""
add_form = None
def get_form(self, request, obj=None, **kwargs):
defaults = {}
if obj is None:
defaults['form'] = self.add_form
defaults.update(kwargs)
return super().get_form(request, obj, **defaults)
Now, when I have dependent fields, I create a small form, containing all values independent of - in my case - company and a regular form containing everything.
#admin.register(Item)
class ItemAdmin(AdminCreateFormMixin, admin.ModelAdmin):
form = ItemEditForm
add_form = ItemAddForm
...
Now I can customise the querysets of the dependent field in my edit form:
class ItemEditForm(forms.ModelForm):
class Meta:
model = Item
exclude = ()
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.fields['contact_person'].queryset = ContactPerson.objects.filter(company=self.instance.company)
The only drawback is, that all dependent fields need to be nullable for the database. Otherwise you wouldn't be able to save it in the creation process.
Luckily, you can tell django that a field is required in the form but not on database level with blank=False, null=True in the model declaration.
Hope this helps somebody else as well!
There are several questions on stackoverflow related to this topic but none of them explains whats happening neither provides working solution.
I need to pass user's first name as an argument to Django ModelForm when rendering template with this form.
I have some basic form:
class MyForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
self.first_name = ???
super(MyForm, self).__init__(*args, **kwargs)
class Meta:
model = MyModel
fields = [***other fields***, 'first_name']
Here's my sample class-based view:
class SomeClassBasedView(View):
def get(self, request):
user_first_name = request.user.first_name
form = MyForm(user_first_name)
return render(request, 'my_template.html', {'form': form})
What do I pass to MyForm when initialising it and how do I access this value inside the __init__ method?
I want to use 'first_name' value as a value for one of the fields in template by updating self.fields[***].widget.attrs.update({'value': self.first_name}).
The solution is as simple as passing initial data dictionary to MyForm for fields you need to set initial value.
This parameter, if given, should be a dictionary mapping field names to initial values. So if MyModel class has a field my_field and you want to set its initial value to foo_bar then you should create MyForm object with initial parameters as follows:
form = MyForm(initial={'my_field': 'foo_bar'})
A link to Django documentation on this topic.
You can pass the parameter instance to your form like this:
obj = MyModel(...)
form = MyForm(instance=obj)
If obj has a user first name it will be attached to your form.
I have two separate class-based views and would like to keep their functionality, and have the two CBVs point to the same template (I'm trying to bring two separate forms into a single page).
More specifically, I am trying to subclass/combine this email view, and this password change view, so that I can have them point to the same template, as I ultimately would like both forms on the same page.
I've attempted to do this by subclassing them into my own views:
class MyEmailUpdateView(LoginRequiredMixin, EmailView):
template_name = 'account/account_settings'
success_url = reverse_lazy('settings')
def form_valid(self, form):
return super(SettingsUpdateView, self).form_valid(form)
class MyPasswordUpdateView(LoginRequiredMixin, PasswordChangeView):
template_name = 'account/account_settings'
success_url = reverse_lazy('settings')
def form_valid(self, form):
return super(SettingsUpdateView, self).form_valid(form)
But I am now finding out due to errors, one by one, that it appears nothing from the parent class is actually transferred over to my custom class unless I manually bring it in(success_url, methods, etc). Even then, the code from the original classes that I am subclassing is pointing elsewhere.
SO, when combining these two views, do I need to copy all of the original code into my custom subclass views?
Is this the proper way to accomplish it? How can I combine these two views? I'm ultimately looking for a way to have both of their forms on a single page in my own app. Is there possibly a simpler way to accomplish this using the library's provided templates?
You can use Django Multi Form View to combine many forms in view
After install you can use it like below:
class MultiFView(MultiFormView):
form_classes = {
'email_form' : AddEmailForm,
'change_password_form' : ChangePasswordForm
}
record_id = None
template_name = 'web/multi.html'
def forms_valid(self, forms):
email = forms['email_form'].save(commit=False)
email.save()
return super(MultiFView, self).forms_valid(forms)
and in template:
{{ forms.email_form.as_p }}
{{ forms.change_password_form.as_p }}
I think You can use the default class in django to a achieve the same result.
As far as i understood i got the scenario like this we have two django forms and we need it to be used in same template if that is the scenario we can use the LoginView from django.contrib.auth.views which has several customizable option like you can give the additional form like this
class LoginUserView(LoginView):
authentication_form = LoginForm
extra_context = {"register_form": RegistrationForm}
template_name = 'accounts/index.html'
it will be using the get context data method to update the form which you will be able to get in the template and use accordingly .If you are not wishing to use the code like this you can still use it like this
class MyEmailUpdateView(LoginRequiredMixin, EmailView):
form_class = EmailForm
template_name = 'account/account_settings'
success_url = reverse_lazy('settings')
def get_context_data(self, **kwargs):
context = super(MyEmailUpdateView, self).get_context_data(**kwargs)
context['password_reset_form'] = ResetPasswordForm
return context
def form_valid(self, form):
return super(MyEmailUpdateView, self).form_valid(form)
Then you can handle your post in the form valid accordingly as your requirement.
Hope that helps get back if you need any additional requirement.
This can be solved by implementing a (kind of) partial update method for your view.
Tools:
First protect your sensitive data:
sensitive_variables decorator:
If a function (either a view or any regular callback) in your code uses local variables susceptible to contain sensitive information, you may prevent the values of those variables from being included in error reports using the sensitive_variables decorator
sensitive_post_parameters() decorator:
If one of your views receives an HttpRequest object with POST parameters susceptible to contain sensitive information, you may prevent the values of those parameters from being included in the error reports using the sensitive_post_parameters decorator
Create some code after:
Use ModelForm to create a form with specific fields of interest for your view. Don't include the password field, because we will add it in a different way to suit our needs:
myapp/forms.py:
class PartialUpdateForm(forms.ModelForm):
new_password = forms.CharField(
required=False, widget=forms.widgets.PasswordInput
)
class Meta:
model = MyUser
fields = ('email', 'other_fields',...)
Here you can use exclude instead of fields if you want to keep every other field except the password: ex. exclude = ('password',)
Use an UpdateView to handle the hustle and override it's form_valid method to handle the partial update:
myapp/views.py:
class MyUpdateView(UpdateView):
template_name = 'account/account_settings'
form_class = PartialUpdateForm
success_url = reverse_lazy('settings')
#sensitive_variables('new_password')
#sensitive_post_parameters('new_password')
def form_valid(self, form):
clean = form.cleaned_data
new_password = clean.get('new_password')
if new_password:
form.instance.password = hash_password(new_password)
return super().form_valid(form)
Finally, create a url for that view:
myapp/urls.py:
...
url(r'^your/pattern/$', MyUpdateView.as_view()),
This way you can handle:
Email AND password update at the same time
Only email update.
Only password update.
Using code from this solution: Django: Only update fields that have been changed in UpdateView
I'm having trouble getting ModelMultipleChoiceField to display the initial values of a model instance. I haven't been able to find any documentation about the field, and the examples I've been reading are too confusing. Django: ModelMultipleChoiceField doesn't select initial choices seems to be similar, but the solution that was given there is not dynamic to the model instance.
Here is my case (each database user is connected to one or more projects):
models.py
from django.contrib.auth.models import User
class Project(Model):
users = ManyToManyField(User, related_name='projects', blank=True)
forms.py
from django.contrib.admin.widgets import FilteredSelectMultiple
class AssignProjectForm(ModelForm):
class Meta:
model = User
fields = ('projects',)
projects = ModelMultipleChoiceField(
queryset=Project.objects.all(),
required=False,
widget=FilteredSelectMultiple('projects', False),
)
views.py
def assign(request):
if request.method == 'POST':
form = AssignProjectForm(request.POST, instance=request.user)
if form.is_valid():
form.save()
return HttpResponseRedirect('/index/')
else:
form = AssignProjectForm(instance=request.user)
return render_to_response('assign.html', {'form': form})
The form that it returns is not selecting the instance's linked projects (it looks like: Django multi-select widget?). In addition, it doesn't update the user with any selections made when the form is saved.
Edit: Managed to solve this using the approach here: http://code-blasphemies.blogspot.com/2009/04/dynamically-created-modelmultiplechoice.html
Here's a solution that is better than the older ones, which really don't work.
You have to both load the existing related values from the database when creating the form, and save them back when saving the form. I use the set() method on the related name (manager) which does all the work for you: taking away existing relations that are not selected anymore, and adding new ones which have become selected. So you don't have to do any looping or checking.
class AssignProjectForm(ModelForm):
def __init__(self, *args, **kwargs):
super(AssignProjectForm, self).__init__(*args, **kwargs)
# Here we fetch your currently related projects into the field,
# so that they will display in the form.
self.fields['projects'].initial = self.instance.projects.all(
).values_list('id', flat=True)
def save(self, *args, **kwargs):
instance = super(AssignProjectForm, self).save(*args, **kwargs)
# Here we save the modified project selection back into the database
instance.projects.set(self.cleaned_data['projects'])
return instance
Aside from simplicity, using the set() method has another advantage that comes into play if you use Django signals (eg. post_save etc) on your m2m relation: If you add and remove entries one at a time in a loop, you'll get signals for each object. But if you do it in one operation using set(), you'll get just one signal with a list of objects. If the code in your signal handler does significant work, this is a big deal.
ModelForm's don't automatically work for reverse relationships.
Nothing is happening on save() because a ModelForm only knows what to do with its own fields - projects is not a field on the User model, it's just a field on your form.
You'll have to tell your form how to save itself with this new field of yours.
def save(self, *args, **kwargs):
for project in self.cleaned_data.get('projects'):
project.users.add(self.instance)
return super(AssignProjectForm, self).save(*args, **kwargs)