Currently I have 4 classes in a model:
User(models.Model):
....
class Meta:
abstract=True
Sender(User):
....
Owner(User):
....
Report(models.Model):
sender = models.OneToOneField(Sender)
owner = models.OneToOneField(Owner)
The Sender/Owner extends the abstract base class User. I need a one to one relationship between a sender, a report, and an owner.
The problem is that I cannot create the Sender or Owner models because they have no differences in their fields (all the data they need is created in the abstract User model, and I created the subclasses for ease of representation). The solution I have come up with is this:
User(models.Model):
....
user_type = models.CharField(max_length=200)
class Meta:
abstract=True
Report(models.Model):
sender = models.OneToOne(User)
owner = models.OneToOne(User)
However I want to ensure that there is one sender and one owner per report. Is there a way to specify that the User MUST have a user_type of 'sender' or something along those lines? Or is there a better solution to this in general?
I am not a veteran user, so forgive me if I'm in the wrong here, but I don't know that it's good practice to define a new model called User when django.contrib.auth.models provides a base user model also named User. It seems to me like this would set you up for potential conflicts.
Since you want to have two different "types" of user, I would use the old approach of linking back from a related model.
from django.contrib.auth.models import User
from django.db import models
class Sender(models.Model):
user = models.OneToOneField(User, related_name='sender')
is_active = models.BooleanField(default=True)
class Owner(models.Model):
user = models.OneToOneField(User, related_name='owner')
is_active = models.BooleanField(default=True)
Say you create a new User with id=1, then create a new Sender called s keyed to that User. Remember, s is the Sender object, not the User object.
>>s.user
<user: username> #can vary with your own unicode definitions
>>s.user.id
1
>>print hasattr(s.user, 'sender')
True
>>print hasattr(s.user, 'owner')
False
>>print s.is_active
True
>>u = User.objects.get(id=1)
>>u.sender
<Sender: username> #again, what actually displays is controlled by your own 'def __unicode__'
>>print u.sender.is_active
True
>>print hasattr(u, 'sender')
True
>>print hasattr(u, 'owner')
False
Then for the report model:
class Report(models.Model):
sender = models.ForeignKey(Sender, related_name='report_sender')
owner = models.ForeignKey(Owner, related_name='report_owner')
Edit to answer your other question: how do you make sure a User has only a Sender or Owner model, but not both?
I don't know how to accomplish that on the model level. In practice, the easiest way I can think of to prevent this from being an issue would be through some custom form validation when a new Sender/Owner is created. If you're creating a new Sender, as part of validation make sure that the User you're tying it to doesn't already have an Owner model tied to it - and vice versa. Or create both the user and appropriate profile model at the same time.
You could alter your User registration form to have an extra field:
class UserRegistrationForm(UserCreationForm):
CHOICES = (
('s', 'Sender'),
('o', 'Owner'),
)
type = models.ChoiceField(max_length=2, choices=CHOICES)
class Meta: ...
Then when you're processing the form in your view:
...
if form.is_valid():
u = form.save()
type = form.cleaned_data['type']
if type == 's':
Sender.objects.create(user=u)
elif type == 'o':
Owner.objects.create(user=u)
(I apologize, but I am not somewhere I can test this. Please let me know if it doesn't work for you.)
I think the most straightforward way to resolve this is to override the save() method of the Report model and insert (before a super() call) a validation check to enforce your requirements.
Related
In Django : From a Python OO perspective if I want different types of users shouldn't I have a "Teacher" Object Type AND "Student" Object" type extended from AbstractUser?
Looks like all the solutions mention to just extend with all the fields required for both users and only use the fields required for a Teacher or Student at Form time.
Just trying to stay with the OO method which makes sense to me from a newbie perspective.
Having different object types would allow me to test the object for the type instead of looking at an attribute and have only the needed fields for each type defined in the object.
Is there a correct way to do this so I have users of different object types?
Could I just embed an object of type Teacher or Student as a field in the User Model? Just a guess?
Let me know what you can and thanks for your expert polite response and patience.
Is this a good solution?
https://github.com/mishbahr/django-users2
This is the recurring theme I see on the internets...
django best approach for creating multiple type users
This is a bit like assigning a profile to a user. The way I'd do it would be a type field on a custom user model which then created a related model of either Teacher or Student depending on that type.
Looking at the age of the code in django-users2 there, I wouldn't use that with it being 6 or 7 years old. You might read through it & adapt it's concepts, but I wouldn't use it as it is.
The way I create profiles associated with a user is through a signal like this;
from django.contrib.auth import get_user_model
from django.db.models.signals import post_save
from django.dispatch import receiver
from ..models import Profile
#receiver(post_save, sender=get_user_model())
def auto_create_profile(instance, **kwargs):
"""
Anytime a User object is created, create the associated Profile object
alongside it
"""
if kwargs.get('created', False):
Profile.objects.create(
user=instance
)
So you might adapt that to check the type as well;
if kwargs.get('created', False):
if instance.type == 'teacher':
Teacher.objects.create(
user=instance
)
Then your models just need a link to the user, which makes sense as a OneToOneField;
class Profile(models.Model):
"""
Profile model
"""
class Meta:
"""
Metadata
"""
app_label = 'accounts'
verbose_name = _('User profile')
verbose_name_plural = _('User profiles')
user = models.OneToOneField(
verbose_name=_('User'),
to=settings.AUTH_USER_MODEL,
related_name='profile',
on_delete=models.CASCADE
)
So I know that Django has a built in system with the User, and it contains things like Username, e-mail, password, and first and last name. I want to know how I can utilise this in my site.
So I have a first_name and last_name field in the models.py file, and they are CharFields. I want to know how to connect them to the already existing UserForm that comes with Django.
I have tried a few things already, such as doing this with the models.py file.
class UserProfileInfo(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
first_name = models.OneToOneField(User, on_delete=models.CASCADE)
Here is some code for the form.py file.
class UserForm(forms.ModelForm):
password = forms.CharField(widget=forms.PasswordInput())
class Meta():
model = User
fields = ('username','email','password','first_name')
As you can see from the form, I added the first_name attribute, and in the models.py file, I have the first_name connected with the forms.py one. I am now getting this error.
HINT: Add or change a related_name argument to the definition for 'UserProfileInfo.user' or 'UserProfileInfo.first_name'.
So I added a related name field to the model, as shown here
first_name = models.OneToOneField(User, on_delete=models.CASCADE,related_name='first_name')
But, wouldn't you know it, I got yet another error:
ValueError: Cannot assign "''": "User.first_name" must be a "UserProfileInfo" instance.
I don't really know what is going on here.
So I expected to get no errors, just like the user field. Instead I got this error. Any help would be greatly appreciated :)
Your code is setting a OneToOne to the User model for both the user and first_name fields. So this means the related field will be User.id for both.
To specify that you want UserProfileInfo.first_name to map to User.first_name you will need to set to_field=first_name
class UserProfileInfo(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
first_name = models.OneToOneField(User, on_delete=models.CASCADE, to_field='first_name', related_name='user_profile_first_name')
However, this will still cause an issue as you can only set a OneToOne relationship to a unique field. As User.first_name is not unique, you cannot set a OneToOne relationship to it.
If both the OneToOne relationships are referencing the same object, one of the relationships is redundant as you can access the fields on that object through the other relationship. It would be better to have a method on UserProfileInfo that gets the first name through the user field.
class UserProfileInfo(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
def get_first_name(self):
return user.first_name
You will also need to set signals to create/update UserProfileInfo when User is created/updated. Have a look at this article.
There are also other ways to extend the User model in Django. Have a look at this article or this answer for suggestions.
But if you're not adding any extra fields to the User model, it may be better just to use it directly.
I have a model with two entities, Person and Code. Person is referenced by Code twice, a Person can be either the user of the code or the approver.
What I want to achieve is the following:
if the user provides an existing Person.cusman, no further action is needed.
if the user provides an unknown Person.cusman, a helper code looks up other attributes of the Person (from an external database), and creates a new Person entity.
I have implemented a function triggered by pre_save signal, which creates the missing Person on the fly. It works fine as long as I use python manage.py shell to create a Code with nonexistent Person.
However, when I try to add a new Code using the admin form or a CreateView descendant I always get the following validation error on the HTML form:
Select a valid choice. That choice is not one of the available choices.
Obviously there's a validation happening between clicking on the Save button and the Code.save() method, but I can't figure out which is it. Can you help me which method should I override to accept invalid foreign keys until pre_save creates the referenced entity?
models.py
class Person(models.Model):
cusman = models.CharField(
max_length=10,
primary_key=True)
name = models.CharField(max_length=30)
email = models.EmailField()
def __unicode__(self):
return u'{0} ({1})'.format(self.name, self.cusman)
class Code(models.Model):
user = models.ForeignKey(
Person,
on_delete=models.PROTECT,
db_constraint=False)
approver = models.ForeignKey(
Person,
on_delete=models.PROTECT,
related_name='approves',
db_constraint=False)
signals.py
#receiver(pre_save, sender=Code)
def create_referenced_person(sender, instance, **kwargs):
def create_person_if_doesnt_exist(cusman):
try:
Person = Person.objects.get(pk=cusman)
except Person.DoesNotExist:
Person = Person()
cr = CusmanResolver()
Person_details = cr.get_person_details(cusman)
Person.cusman = Person_details['cusman']
Person.name = Person_details['name']
Person.email = Person_details['email']
Person.save()
create_Person_if_doesnt_exist(instance.user_id)
create_Person_if_doesnt_exist(instance.approver_id)
views.py
class CodeAddForm(ModelForm):
class Meta:
model = Code
fields = [
'user',
'approver',
]
widgets = {
'user': TextInput,
'approver': TextInput
}
class CodeAddView(generic.CreateView):
template_name = 'teladm/code_add.html'
form_class = CodeAddForm
You misunderstood one thing: You shouldn't use TextField to populate ForeignKey, because django foreign keys are populated using dropdown/radio button to refer to the id of the object in another model. The error you got means you provided wrong information that doesn't match any id in another model(Person in your case).
What you can do is: not using ModelForm but Form. You might have some extra work to do after you call form.is_valid(), but at least you could code up your logic however you want.
I need to implement the following:
The user shall be presented with a form that will have a drop down choice menu consisting of property names. There are two types of properties: general properties, i.e. properties common for all users and custom properties, i.e. properties that each user has defined prior to that. The models would look something like that:
class GeneralPropertyName(models.Model):
name = models.CharField(max_length=20)
class CustomPropertyName(models.Model):
user = models.ForeignKey(User)
name = models.CharField(max_length=20)
The drop down menu should have all general properties and only those custom properties that pertain to the user.
First question: how to define such a model?
I need to: 1. somehow unify both properties, 2. take only those items from CustomPropertyName that pertain to the user
class SpecData(models.Model):
user = models.ForeignKey(User)
selection_title = models.CharField(max_length=20)
property = ForeignKey(GeneralPropertyName) ??UNIFY??? ForeignKey(CustomPropertyName)
Second, is there anything special that needs to be done with ModelForm?
class SpecDataForm(ModelForm):
class Meta:
model = SpecData
And the 3rd question is what needs to be done in the view? I will need to use inline formsets since I will have a few dynamic forms like that.
def index(request):
user = User.objects.get(username=request.user.username)
specdataFormSet = inlineformset_factory(User, SpecData, form=SpecDataForm, extra=30)
...
specdata_formset = specdataFormSet(instance=user, prefix='specdata_set')
...
Thanks.
EDIT: Adjusted juliocesar's suggestion to include formsets. Somehow I am getting the following error message: Cannot resolve keyword 'property' into field. Choices are: id, name, selection_title, user
def index(request):
user = User.objects.get(username=request.user.username)
user_specdata_form = UserSpecDataForm(user=user)
SpecdataFormSet = inlineformset_factory(User, SpecData, form=user_specdata_form, extra=30)
You can use a GenericForeignKey to handle it, but you still need more to solve your further questions about forms and view.
I have made an example of how you solve your problem (logged user can select from General properties and his Custom properties, non-logged user only can select General properties). I used model inheritance for the properties (In your sample code it seems that a CustomPropertyName is a PropertyName with other fields). I think inheritance is an easier and a more basic concept than ContentTypes and it fits to your needs.
NOTE: I remove some code like imports to simplify the code.
1) models.py file:
class PropertyName(models.Model):
name = models.CharField(max_length=20)
def __unicode__(self):
return self.name
class CustomPropertyName(PropertyName): # <-- Inheritance!!
user = models.ForeignKey(User)
def __unicode__(self):
return self.name
class SpecData(models.Model):
user = models.ForeignKey(User)
selection_title = models.CharField(max_length=20)
property = models.ForeignKey(PropertyName)
NOTES: The field SpecData.property points to PropertyName since all properties are saved in the PropertyName's database table.
2) forms.py file:
from django import forms
from django.db.models import Q
from models import SpecData, PropertyName
def UserSpecDataForm(user=None):
UserPropertiesQueryset = PropertyName.objects.filter(Q(custompropertyname__user=None) | Q(custompropertyname__user__id=user.id))
class SpecDataForm(forms.ModelForm):
property = forms.ModelChoiceField(queryset=UserPropertiesQueryset)
class Meta:
model = SpecData
exclude = ('user',)
return SpecDataForm
NOTES: The trick here is to generate the form SpecDataForm dynamically, by filtering properties according the user specified in the parameter.
3) views.py file:
from forms import UserSpecDataForm
def index(request):
if request.POST:
form = UserSpecDataForm(request.user)(request.POST) # instance=user
if form.is_valid():
spec_data = form.save(commit=False)
spec_data.user = request.user
spec_data.save()
else:
form = UserSpecDataForm(request.user)()
return render_to_response('properties.html', {'form': form}, context_instance=RequestContext(request))
NOTES: Nothing special here, just a call to form.UserSpecDataForm(request.user) that returns the form class and then instantiate. Also setted the logged-in user to the object returned on save since It was excluded in the form to not show in front-end.
Following this basic example you can do the same with formsets if you need it.
UPDATE:
Formset can be used by adding following code to the view:
user_specdata_form = UserSpecDataForm(user=request.user)
SpecdataFormSet = inlineformset_factory(User, SpecData, form=user_specdata_form, extra=30)
The complete project sample can be downloaded from http://ge.tt/904Wg7O1/v/0
Hope this helps
1a) have you looked into django's ContentType framework this will allow you to have generic foreign keys and you can put restrictions on what types of models are acceptable to store in.
1b) I think that the validation for accepting what type of foreign key is acceptable shouldn't be in your model but should be part of your form validation before saving.
2) If you do use a model form you're going to have to define your own custom widget for the propery field. This means you're probably going to have to write you're own render function to render the html from the field. You should also define your own validation function on the form to make sure that only the appropriate data is acceptable to save.
3) I don't think you'll have to do anything you aren't already doing in the views
Use GenericForeignKey:
class SpecData(models.Model):
user = models.ForeignKey(User)
selection_title = models.CharField(max_length=20)
content_type = models.ForeignKey(ContentType)
object_id = models.PositiveIntegerField()
property = GenericForeignKey('content_type', 'object_id')
You can use this to combine the two fields(type & id) into a single choice field.
One way is that you have only one model, make user nullable:
class PropertyName(models.Model):
user = models.ForeignKey(User, null=True, blank=True)
name = models.CharField(max_length=20)
class SpecData(models.Model):
user = models.ForeignKey(User)
selection_title = models.CharField(max_length=20)
property = ForeignKey(PropertyName)
So, if user is not set, it is a general property. If it is set, it is related to this user.
However, please note that if you need unique property names, that NULL != NULL.
Of course, the suggested GenericForeignKey solution is better for some cases.
Also, you can easily make the normal (non-model) form with that you describe and separate form logic from model logic.
I am extending the Django User model to include a foreign key pointing at another model like so (just like it says in the Django docs):
models.py:
class Ward(models.Model):
name = models.CharField(max_length=100)
def __unicode__(self):
return self.name
# Extending the user model
class WardMember(models.Model):
user = models.OneToOneField(User)
ward = models.ForeignKey(Ward)
def __unicode__(self):
return self.ward.name
admin.py:
class WardMemberInline(admin.StackedInline):
model = WardMember
can_delete = False
verbose_name_plural = 'ward member'
# Define a new User admin
class UserAdmin(UserAdmin):
inlines = (WardMemberInline, )
admin.site.register(Ward)
# Re-register UserAdmin to get WardMember customizations
admin.site.unregister(User)
admin.site.register(User, UserAdmin)
When I create a new user in the admin interface I want this new WardMember.ward extension to be required. Currently it's not enforcing that. Here's what happens:
Create user succeeds without a ward
Create other records as user succeed
Edit user now won't let me save unless there is a ward selected
I'd really like #1 above to fail.
I've tried figuring out how to override save() for User using a proxy object but that's not working. I looked into the pre_save signal but the docs explicitly say that's not for vetoing saves.
What is the right approach?
Additional information:
I'm using 1.4. I see that in 1.5 I can extend the user class but I'm not in a position to update to 1.5 just yet.
I ended up forging ahead with Django 1.5, but I'll leave this here in case someone has a final answer to contribute that works with 1.4.
In django 1.3.1 I use this code and works fine:
from django.contrib.auth.models import User
class FilterSearchQueries(models.Model):
title = models.CharField(max_length=250)
owner = models.ForeignKey(User)
place = models.CharField(max_length=250)
query = models.TextField()