How to change display text in django admin foreignkey dropdown - python

I have a task list, with ability to assign users. So I have foreignkey to User model in the database. However, the default display is username in the dropdown menu, I would like to display full name (first last) instead of the username. If the foreignkey is pointing to one of my own classes, I can just change the str function in the model, but User is a django authentication model, so I can't easily change it directly right?
Anyone have any idea how to accomplish this?
Thanks a lot!

You can create a new ModelForm for your Task model, which will display the list of users however you like (code here assumes a model named Task with a 'user' attribute):
def get_user_full_name_choices:
return [(user, user.get_full_name()) for user in User.objects.all()]
class TaskAdminForm(forms.ModelForm):
class Meta:
model = Task
user = forms.ChoiceField(choices=get_user_full_name_choices)
Then, tell your ModelAdmin class to use the new form:
class TaskAdmin(admin.ModelAdmin):
form = TaskAdminForm

There is another choice:
USERS = [(user.id, user.get_full_name()) for user in User.objects.all()]
USERS.insert(0, ('', '----'))
class TaskAdminForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(TaskAdminForm, self).__init__(*args, **kwargs)
self.fields['user'].choices=USERS

A more generic, verbose solution, using a ModelChoiceField as base. Avoids fiddling with querysets, just focusing on modifying the visible value in the dropdown.
create your own formfield:
class CustomLabelChoiceField(forms.ModelChoiceField):
def label_from_instance(self, obj):
return "Howdy {}".format(obj.name)
use it either with formfield_for_dbfield (as in the link), or, more verbose, in your admin form:
class TaskAdminForm(forms.ModelForm):
user = CustomLabelChoiceField(queryset=User.objects.all()
class Meta:
model = Task
# obviously, link it with your admin
class TaskAdmin(admin.ModelAdmin):
form = TaskAdminForm

By overriding formfield_for_foreignkey(), you can display the combination of "first_name" and "last_name" to Django Admin without creating a custom "forms.ModelChoiceField" and a custom "forms.ModelForm" as shown below:
#admin.register(Task)
class TaskAdmin(admin.ModelAdmin):
def formfield_for_foreignkey(self, db_field, request, **kwargs):
formfield = super().formfield_for_foreignkey(db_field, request, **kwargs)
if db_field.name == "user":
formfield.label_from_instance = lambda obj: f'{obj.first_name} ({obj.last_name})'
return formfield

Related

How to change the default labels of a ForeignKey field whose form's widget is a RadioSelect

In my Django app, I have this form:
from django import forms
from main.models import Profile
class ProfileForm(forms.ModelForm):
class Meta:
model = Profile
fields = ['picture']
widgets = {
'picture': forms.RadioSelect(),
}
By default, the labels of the picture field within the template are generated according to the __str__() method of the Picture model. That's because the picture field on my Profile model is actually a ForeignKey field to a Picture model.
However, the value returned by that __str__() method doesn't make much sense in this particular template, and changing it is not possible because it's being used elsewhere.
Therefore, is there a way I might change the default labels for the picture field of my ProfileForm? For instance, changing from the __str__()'s default picture.src + ' (' + picture.description + ')' to something like picture.description only?
I have checked what the docs had to say regarding the label_from_instance, but I didn't understand how to apply it. In fact, I couldn't even understand if that would be a solution for this case.
Some similiar questions here on Stack Overflow also mentioned that link of the docs, but the questions's forms were slightly different than mine, and I ended up not understanding them either.
If you want to use label_from_instance, you should make a specific widget with:
class PictureField(forms.ModelChoiceField):
def label_from_instance(self, obj):
return obj.description
class ProfileForm(forms.ModelForm):
picture = PictureField(Picture.objects)
class Meta:
model = Profile
On another hand, you can use your code and in init function of your form to change the choices attribute of the picture field
It turns out I didn't need to use label_from_instance. I just needed to create a subclass of django.forms.RadioSelect and override its create_option() method, setting the label by giving option['label'] the value I'd like, just like this:
from django import forms
from main.models import Profile
class PictureRadioSelect(forms.RadioSelect):
def create_option(self, name, value, label, selected, index, subindex=None, attrs=None):
option = super().create_option(name, value, label, selected, index, subindex, attrs)
option['label'] = value.instance.description
return option
class ProfileForm(forms.ModelForm):
class Meta:
model = Profile
fields = ['picture']
widgets = {
'picture': PictureRadioSelect(),
}
This section of the docs explains this in greater detail. It actually describes how to override django.forms.Select options, but I tested it with django.forms.RadioSelect and it ran as expected.
By overriding formfield_for_foreignkey(), you can display picture's description to Django Admin without creating a custom "forms.ModelChoiceField" and a custom "forms.ModelForm" as shown below:
#admin.register(Profile)
class ProfileAdmin(admin.ModelAdmin):
def formfield_for_foreignkey(self, db_field, request, **kwargs):
formfield = super().formfield_for_foreignkey(db_field, request, **kwargs)
if db_field.name == "picture":
formfield.label_from_instance = lambda obj: f'{obj.description}'
return formfield

Limit choices and validate django's foreign key to related objects (also in REST)

I have my models.py like this:
class Category(models.Model):
user = models.ForeignKey(User)
name = models.CharField(max_length=256, db_index=True)
class Todo(models.Model):
user = models.ForeignKey(User)
category = models.ForeignKey(Category)
...
And I want to limit choices of Category for Todo to only those ones where Todo.user = Category.user
Every solutuion that I've found was to set queryset for a ModelForm or implement method inside a form. (As with limit_choices_to it is not possible(?))
The problem is that I have not only one model with such limiting problem (e.g Tag, etc.)
Also, I'm using django REST framework, so I have to check Category when Todo is added or edited.
So, I also need functions validate in serializers to limit models right (as it does not call model's clean, full_clean methods and does not check limit_choices_to)
So, I'm looking for a simple solution, which will work for both django Admin and REST framework.
Or, if it is not possible to implement it the simple way, I'm looking for an advice of how to code it the most painless way.
Here what I've found so far:
To get Foreignkey showed right in admin, you have to specify a form in ModelAdmin
class TodoAdminForm(ModelForm):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.fields['category'].queryset = Category.objects.filter(user__pk=self.instance.user.pk)
#admin.register(Todo)
class TodoAdmin(admin.ModelAdmin):
form = TodoAdminForm
...
To get ManyToManyField showed right in InlineModelAdmin (e.g. TabularInline) here comes more dirty hack (can it be done better?)
You have to save your quiring field value from object and then manually set queryset in the field. My through model has two members todo and tag
And I'd like to filter tag field (pointing to model Tag):
class MembershipInline(admin.TabularInline):
model = Todo.tags.through
def get_formset(self, request, obj=None, **kwargs):
request.saved_user_pk = obj.user.pk # Not sure if it can be None
return super().get_formset(request, obj, **kwargs)
def formfield_for_foreignkey(self, db_field, request=None, **kwargs):
if db_field.name == 'tag':
kwargs['queryset'] = Tag.objects.filter(user__pk=request.saved_user_pk)
return super().formfield_for_foreignkey(db_field, request, **kwargs)
And finally, to restrict elements only to related in Django REST framework, I have to implement custom Field
class PrimaryKeyRelatedByUser(serializers.PrimaryKeyRelatedField):
def get_queryset(self):
return super().get_queryset().filter(user=self.context['request'].user)
And use it in my serializer like
class TodoSerializer(serializers.ModelSerializer):
category = PrimaryKeyRelatedByUser(required=False, allow_null=True, queryset=Category.objects.all())
tags = PrimaryKeyRelatedByUser(required=False, many=True, queryset=Tag.objects.all())
class Meta:
model = Todo
fields = ('id', 'category', 'tags', ...)
Not sure if it actually working in all cases as planned. I'll continue this small investigation.
Question still remains. Could it be done simplier?

Dynamically setting the queryset of a ModelMultipleChoiceField to a custom recordset

I've seen all the howtos about how you can set a ModelMultipleChoiceField to use a custom queryset and I've tried them and they work. However, they all use the same paradigm: the queryset is just a filtered list of the same objects.
In my case, I'm trying to get the admin to draw a multiselect form that instead of using usernames as the text portion of the , I'd like to use the name field from my account class.
Here's a breakdown of what I've got:
# models.py
class Account(models.Model):
name = models.CharField(max_length=128,help_text="A display name that people understand")
user = models.ForeignKey(User, unique=True) # Tied to the User class in settings.py
class Organisation(models.Model):
administrators = models.ManyToManyField(User)
# admin.py
from django.forms import ModelMultipleChoiceField
from django.contrib.auth.models import User
class OrganisationAdminForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
from ethico.accounts.models import Account
self.base_fields["administrators"] = ModelMultipleChoiceField(
queryset=User.objects.all(),
required=False
)
super(OrganisationAdminForm, self).__init__(*args, **kwargs)
class Meta:
model = Organisation
This works, however, I want queryset above to draw a selectbox with the Account.name property and the User.id property. This didn't work:
queryset=Account.objects.all().order_by("name").values_list("user","name")
It failed with this error:
'tuple' object has no attribute 'pk'
I figured that this would be easy, but it's turned into hours of dead-ends. Anyone care to shed some light?
You can use a custom widget, override its render method. Here's what I had done for a text field :
class UserToAccount(forms.widgets.TextInput):
def render(self, name, value, attrs=None):
if isinstance(value, User) :
value = Account.objects.get(user=value).name
return super (UserToAccount, self).render(name, value, attrs=None)
Then of course, use the widget parameter of your administrator field, in order to use your custom widget.
I don't know if it can be adapted for a select, but you can try out.
The queryset needs to be a QuerySet, when you do values_list you get a list so that won't work.
If you want to change the default display of models, just override __unicode__. See http://docs.djangoproject.com/en/dev/ref/models/instances/#unicode
For example:
def __unicode__(self):
return u"%s for %s" % (self.name, self.user)
Django will use __unicode__ whenever you asks it to print a model. For testing you can just load up a model in the shell and do print my_instance.
Taking a queue from sebpiq, I managed to figure it out:
class OrganisationAdminForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
from django.forms import MultipleChoiceField
from ethico.accounts.models import Account
self.base_fields["administrators"] = MultipleChoiceField(
choices=tuple([(a.user_id, a.name) for a in Account.objects.all().order_by("name")]),
widget=forms.widgets.SelectMultiple,
required=False
)
super(OrganisationAdminForm, self).__init__(*args, **kwargs)
class Meta:
model = Organisation
class OrganisationAdmin(admin.ModelAdmin):
form = OrganisationAdminForm
admin.site.register(Organisation, OrganisationAdmin)
The key was abandoning the queryset altogether. Once I went with a fixed choices= parameter, everything just worked. Thanks everyone!

Override save_model on Django InlineModelAdmin

I have a model that has a user field that needs to be auto-populated from the currently logged in user. I can get it working as specified here if the user field is in a standard ModalAdmin, but if the model I'm working with is in an InlineModelAdmin and being saved from the record of another model inside the Admin, it won't take.
Here's what I think is the best solution. Took me a while to find it... this answer gave me the clues: https://stackoverflow.com/a/24462173/2453104
On your admin.py:
class YourInline(admin.TabularInline):
model = YourInlineModel
formset = YourInlineFormset
def get_formset(self, request, obj=None, **kwargs):
formset = super(YourInline, self).get_formset(request, obj, **kwargs)
formset.request = request
return formset
On your forms.py:
class YourInlineFormset(forms.models.BaseInlineFormSet):
def save_new(self, form, commit=True):
obj = super(YourInlineFormset, self).save_new(form, commit=False)
# here you can add anything you need from the request
obj.user = self.request.user
if commit:
obj.save()
return obj
I know I'm late to the party, but here's my situation and what I came up with, which might be useful to someone else in the future.
I have 4 inline models that need the currently logged in user.
2 as a created_by type field. (set once on creation)
and the 2 others as a closed_by type field. (only set on condition)
I used the answer provided by rafadev and made it into a simple mixin which enables me to specify the user field name elsewhere.
The generic formset in forms.py
from django.forms.models import BaseInlineFormSet
class SetCurrentUserFormset(forms.models.BaseInlineFormSet):
"""
This assume you're setting the 'request' and 'user_field' properties
before using this formset.
"""
def save_new(self, form, commit=True):
"""
This is called when a new instance is being created.
"""
obj = super(SetCurrentUserFormset, self).save_new(form, commit=False)
setattr(obj, self.user_field, self.request.user)
if commit:
obj.save()
return obj
def save_existing(self, form, instance, commit=True):
"""
This is called when updating an instance.
"""
obj = super(SetCurrentUserFormset, self).save_existing(form, instance, commit=False)
setattr(obj, self.user_field, self.request.user)
if commit:
obj.save()
return obj
Mixin class in your admin.py
class SetCurrentUserFormsetMixin(object):
"""
Use a generic formset which populates the 'user_field' model field
with the currently logged in user.
"""
formset = SetCurrentUserFormset
user_field = "user" # default user field name, override this to fit your model
def get_formset(self, request, obj=None, **kwargs):
formset = super(SetCurrentUserFormsetMixin, self).get_formset(request, obj, **kwargs)
formset.request = request
formset.user_field = self.user_field
return formset
How to use it
class YourModelInline(SetCurrentUserFormsetMixin, admin.TabularInline):
model = YourModel
fields = ['description', 'closing_user', 'closing_date']
readonly_fields = ('closing_user', 'closing_date')
user_field = 'closing_user' # overriding only if necessary
Be careful...
...as this mixin code will set the currently logged in user everytime for every user. If you need the field to be populated only on creation or on specific update, you need to deal with this in your model save method. Here are some examples:
class UserOnlyOnCreationExampleModel(models.Model):
# your fields
created_by = # user field...
comment = ...
def save(self, *args, **kwargs):
if not self.id:
# on creation, let the user field populate
self.date = datetime.today().date()
super(UserOnlyOnCreationExampleModel, self).save(*args, **kwargs)
else:
# on update, remove the user field from the list
super(UserOnlyOnCreationExampleModel, self).save(update_fields=['comment',], *args, **kwargs)
Or if you only need the user if a particular field is set (like boolean field closed) :
def save(self, *args, **kwargs):
if self.closed and self.closing_date is None:
self.closing_date = datetime.today().date()
# let the closing_user field set
elif not self.closed :
self.closing_date = None
self.closing_user = None # unset it otherwise
super(YourOtherModel, self).save(*args, **kwargs) # Call the "real" save() method.
This code could probably be made way more generic as I'm fairly new to python but that's what will be in my project for now.
Only the save_model for the model you're editing is executed, instead you will need to use the post_save signal to update inlined data.
(Not really a duplicate, but essentially the same question is being answered in Do inline model forms emmit post_save signals? (django))
I had a similar issue with a user field I was trying to populate in an inline model. In my case, the parent model also had the user field defined so I overrode save on the child model as follows:
class inline_model:
parent = models.ForeignKey(parent_model)
modified_by = models.ForeignKey(User,editable=False)
def save(self,*args,**kwargs):
self.modified_by = self.parent.modified_by
super(inline_model,self).save(*args,**kwargs)
The user field was originally auto-populated on the parent model by overriding save_model in the ModelAdmin for the parent model and assigning
obj.modified_by = request.user
Keep in mind that if you also have a stand-alone admin page for the child model you will need some other mechanism to keep the parent and child modified_by fields in sync (e.g. you could override save_model on the child ModelAdmin and update/save the modified_by field on the parent before calling save on the child).
I haven't found a good way to handle this if the user is not in the parent model. I don't know how to retrieve request.user using signals (e.g. post_save), but maybe someone else can give more detail on this.
Does the other model save the user? In that case you could use the post_save signal to add that information to the set of the inlined model.
Have you tried implementing custom validation in the admin as it is described in the documentation? Overriding the clean_user() function on the model form might do the trick for you.
Another, more involved option comes to mind. You could override the admin template that renders the change form. Overriding the change form would allow you to build a custom template tag that passes the logged in user to a ModelForm. You could then write a custom init function on the model form that sets the User automatically. This answer provides a good example on how to do that, as does the link on b-list you reference in the question.

How do I restrict foreign keys choices to related objects only in django

I have a two way foreign relation similar to the following
class Parent(models.Model):
name = models.CharField(max_length=255)
favoritechild = models.ForeignKey("Child", blank=True, null=True)
class Child(models.Model):
name = models.CharField(max_length=255)
myparent = models.ForeignKey(Parent)
How do I restrict the choices for Parent.favoritechild to only children whose parent is itself? I tried
class Parent(models.Model):
name = models.CharField(max_length=255)
favoritechild = models.ForeignKey("Child", blank=True, null=True, limit_choices_to = {"myparent": "self"})
but that causes the admin interface to not list any children.
I just came across ForeignKey.limit_choices_to in the Django docs.
Not sure yet how it works, but it might be the right thing here.
Update: ForeignKey.limit_choices_to allows one to specify either a constant, a callable or a Q object to restrict the allowable choices for the key. A constant obviously is of no use here, since it knows nothing about the objects involved.
Using a callable (function or class method or any callable object) seems more promising. However, the problem of how to access the necessary information from the HttpRequest object remains. Using thread local storage may be a solution.
2. Update: Here is what has worked for me:
I created a middleware as described in the link above. It extracts one or more arguments from the request's GET part, such as "product=1", and stores this information in the thread locals.
Next there is a class method in the model that reads the thread local variable and returns a list of ids to limit the choice of a foreign key field.
#classmethod
def _product_list(cls):
"""
return a list containing the one product_id contained in the request URL,
or a query containing all valid product_ids if not id present in URL
used to limit the choice of foreign key object to those related to the current product
"""
id = threadlocals.get_current_product()
if id is not None:
return [id]
else:
return Product.objects.all().values('pk').query
It is important to return a query containing all possible ids if none was selected so that the normal admin pages work ok.
The foreign key field is then declared as:
product = models.ForeignKey(
Product,
limit_choices_to={
id__in=BaseModel._product_list,
},
)
The catch is that you have to provide the information to restrict the choices via the request. I don't see a way to access "self" here.
The 'right' way to do it is to use a custom form. From there, you can access self.instance, which is the current object. Example --
from django import forms
from django.contrib import admin
from models import *
class SupplierAdminForm(forms.ModelForm):
class Meta:
model = Supplier
fields = "__all__" # for Django 1.8+
def __init__(self, *args, **kwargs):
super(SupplierAdminForm, self).__init__(*args, **kwargs)
if self.instance:
self.fields['cat'].queryset = Cat.objects.filter(supplier=self.instance)
class SupplierAdmin(admin.ModelAdmin):
form = SupplierAdminForm
The new "right" way of doing this, at least since Django 1.1 is by overriding the AdminModel.formfield_for_foreignkey(self, db_field, request, **kwargs).
See http://docs.djangoproject.com/en/1.2/ref/contrib/admin/#django.contrib.admin.ModelAdmin.formfield_for_foreignkey
For those who don't want to follow the link below is an example function that is close for the above questions models.
class MyModelAdmin(admin.ModelAdmin):
def formfield_for_foreignkey(self, db_field, request, **kwargs):
if db_field.name == "favoritechild":
kwargs["queryset"] = Child.objects.filter(myparent=request.object_id)
return super(MyModelAdmin, self).formfield_for_manytomany(db_field, request, **kwargs)
I'm only not sure about how to get the current object that is being edited. I expect it is actually on the self somewhere but I'm not sure.
This isn't how django works. You would only create the relation going one way.
class Parent(models.Model):
name = models.CharField(max_length=255)
class Child(models.Model):
name = models.CharField(max_length=255)
myparent = models.ForeignKey(Parent)
And if you were trying to access the children from the parent you would do
parent_object.child_set.all(). If you set a related_name in the myparent field, then that is what you would refer to it as. Ex: related_name='children', then you would do parent_object.children.all()
Read the docs http://docs.djangoproject.com/en/dev/topics/db/models/#many-to-one-relationships for more.
If you only need the limitations in the Django admin interface, this might work. I based it on this answer from another forum - although it's for ManyToMany relationships, you should be able to replace formfield_for_foreignkey for it to work. In admin.py:
class ParentAdmin(admin.ModelAdmin):
def get_form(self, request, obj=None, **kwargs):
self.instance = obj
return super(ParentAdmin, self).get_form(request, obj=obj, **kwargs)
def formfield_for_foreignkey(self, db_field, request=None, **kwargs):
if db_field.name == 'favoritechild' and self.instance:
kwargs['queryset'] = Child.objects.filter(myparent=self.instance.pk)
return super(ChildAdmin, self).formfield_for_foreignkey(db_field, request=request, **kwargs)
#Ber: I have added validation to the model similar to this
class Parent(models.Model):
name = models.CharField(max_length=255)
favoritechild = models.ForeignKey("Child", blank=True, null=True)
def save(self, force_insert=False, force_update=False):
if self.favoritechild is not None and self.favoritechild.myparent.id != self.id:
raise Exception("You must select one of your own children as your favorite")
super(Parent, self).save(force_insert, force_update)
which works exactly how I want, but it would be really nice if this validation could restrict choices in the dropdown in the admin interface rather than validating after the choice.
I'm trying to do something similar. It seems like everyone saying 'you should only have a foreign key one way' has maybe misunderstood what you're trying do.
It's a shame the limit_choices_to={"myparent": "self"} you wanted to do doesn't work... that would have been clean and simple. Unfortunately the 'self' doesn't get evaluated and goes through as a plain string.
I thought maybe I could do:
class MyModel(models.Model):
def _get_self_pk(self):
return self.pk
favourite = models.ForeignKey(limit_choices_to={'myparent__pk':_get_self_pk})
But alas that gives an error because the function doesn't get passed a self arg :(
It seems like the only way is to put the logic into all the forms that use this model (ie pass a queryset in to the choices for your formfield). Which is easily done, but it'd be more DRY to have this at the model level. Your overriding the save method of the model seems a good way to prevent invalid choices getting through.
Update
See my later answer for another way https://stackoverflow.com/a/3753916/202168
Do you want to restrict the choices available in the admin interface when creating/editing a model instance?
One way to do this is validation of the model. This lets you raise an error in the admin interface if the foreign field is not the right choice.
Of course, Eric's answer is correct: You only really need one foreign key, from child to parent here.
An alternative approach would be not to have 'favouritechild' fk as a field on the Parent model.
Instead you could have an is_favourite boolean field on the Child.
This may help:
https://github.com/anentropic/django-exclusivebooleanfield
That way you'd sidestep the whole problem of ensuring Children could only be made the favourite of the Parent they belong to.
The view code would be slightly different but the filtering logic would be straightforward.
In the admin you could even have an inline for Child models that exposed the is_favourite checkbox (if you only have a few children per parent) otherwise the admin would have to be done from the Child's side.
A much simpler variation of #s29's answer:
Instead of customising the form,
You can simply restrict the choices available in form field from your view:
what worked for me was:
in forms.py:
class AddIncomingPaymentForm(forms.ModelForm):
class Meta:
model = IncomingPayment
fields = ('description', 'amount', 'income_source', 'income_category', 'bank_account')
in views.py:
def addIncomingPayment(request):
form = AddIncomingPaymentForm()
form.fields['bank_account'].queryset = BankAccount.objects.filter(profile=request.user.profile)
from django.contrib import admin
from sopin.menus.models import Restaurant, DishType
class ObjInline(admin.TabularInline):
def __init__(self, parent_model, admin_site, obj=None):
self.obj = obj
super(ObjInline, self).__init__(parent_model, admin_site)
class ObjAdmin(admin.ModelAdmin):
def get_inline_instances(self, request, obj=None):
inline_instances = []
for inline_class in self.inlines:
inline = inline_class(self.model, self.admin_site, obj)
if request:
if not (inline.has_add_permission(request) or
inline.has_change_permission(request, obj) or
inline.has_delete_permission(request, obj)):
continue
if not inline.has_add_permission(request):
inline.max_num = 0
inline_instances.append(inline)
return inline_instances
class DishTypeInline(ObjInline):
model = DishType
def formfield_for_foreignkey(self, db_field, request=None, **kwargs):
field = super(DishTypeInline, self).formfield_for_foreignkey(db_field, request, **kwargs)
if db_field.name == 'dishtype':
if self.obj is not None:
field.queryset = field.queryset.filter(restaurant__exact = self.obj)
else:
field.queryset = field.queryset.none()
return field
class RestaurantAdmin(ObjAdmin):
inlines = [
DishTypeInline
]

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