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User Follower model on Django. Cannot use add() on a ManyToManyField which specifies an intermediary model. Use accounts.Contact's Manager instead

I am new to Django, Please forgive any silly mistakes in code or logic,
Intro: I am trying to create a user follower model in Django. Where users can follow and unfollow other users on the sites
Error: I have made the models for my follow/unfollow I have also made the views I am getting this error
AttributeError at /accounts/admin/follow/
Cannot use add() on a ManyToManyField which specifies an intermediary model. Use accounts.Contact's Manager instead.
The obj.followers.add(user) is highlighted in the traceback as the origin of the error
Below are my models.py
from django.contrib.auth.models import User
class Profile(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
city = models.CharField(max_length=100)
country = models.CharField(max_length=100)
def get_absolute_url(self):
return reverse('accounts:profile', kwargs={'username': self.user.username})
class Contact(models.Model):
user_from = models.ForeignKey(User, related_name='suppporter')
user_to = models.ForeignKey(User, related_name='leader')
def __str__(self):
return '{} follows {}'.format(self.user_from, self.user_to)
User.add_to_class('following',
models.ManyToManyField('self', through=Contact, related_name='followers', symmetrical=False))
I think the models.py may be good. The fault I believe is in my views.
Below is my view.py
class FollowToggle(LoginRequiredMixin, RedirectView):
def get_redirect_url(self, *args, **kwargs):
username = self.kwargs.get('username')
print(username + " This is the user who will be followed") # This prints correct
profile = get_object_or_404(Profile, user__username=username)
print(profile) # This prints correct
obj = get_object_or_404(User, username=username)
print(obj) # This prints correct
url_ = profile.get_absolute_url()
print(url_) # This prints correct
user = self.request.user
print(user) # This prints correct
if user.is_authenticated():
if user in obj.followers.all(): # I know this is the source of the error.
obj.followers.remove(user)
else:
obj.followers.add(user)
return url_
Below are the Urls.py just in case
url(r'^(?P<username>[-\w]+)/follow/$', views.FollowToggle.as_view(), name='follow'),

You cannot use add and remove method for manytomany relation defined through third model. From the docs:
Unlike normal many-to-many fields, you can’t use add(), create(), or set() to create relationships
Instead you should use Contact manager:
if user.is_authenticated():
if user in obj.followers.all(): # I know this is the source of the error.
Contact.objects.filter(user_to=obj, user_from=user).delete()
else:
Contact.objects.create(user_to=obj, user_from=user)

In Django 2.2 you can use add, remove and set methods (Docs)
You can also use add(), create(), or set() to create relationships, as long as your specify through_defaults for any required fields

ValueError: Lookup failed for model referenced by field

I have made Custom User model in my Django project. Here it is:
class CustomUser(User):
avatar = models.ImageField(upload_to='avatars')
about_myself = models.TextField(max_length=300)
USERNAME_FIELD = 'username'
def __str__(self):
return self.username
def is_author(self):
return 'blog.change_post' and 'blog.add_post' in self.get_all_permissions()
And after it, I changed all Foreign Keys of user to new CustomUser model. It works OK. But I make one new migration and django cause error, when I want to migrate it:
ValueError: Lookup failed for model referenced by field blog.Comment.author: main.CustomUser
My blog.Comment model:
class Comment(models.Model):
content = models.TextField()
author = models.ForeignKey(CustomUser)
date_create = models.DateTimeField(auto_now_add=True)
post = models.ForeignKey(Post)
What should I do?
Thanks!

Judging from the code you posted, you might be might be better served by extending the user model rather than replacing it. This pattern is usually called a profile model and works via a one-to-one relationship with User.
Profiles provides application specific fields and behaviors, while allowing User to go about it's usual business unchanged. It doesn't require you to muck around with rewriting auth or even necessarily change your foreign keys.
Here's an example of your code written as a profile:
class Profile(models.Model):
# Link to user :
user = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
avatar = models.ImageField(upload_to='avatars')
about_myself = models.TextField(max_length=300)
def __str__(self):
return self.user.username
def is_author(self):
return 'blog.change_post' and 'blog.add_post' in self.user.get_all_permissions()
Comment model:
class Comment(models.Model):
content = models.TextField()
author = models.ForeignKey(settings.AUTH_USER_MODEL)
date_create = models.DateTimeField(auto_now_add=True)
post = models.ForeignKey(Post)
# How to access the profile:
def check_author(self):
self.author.profile.is_author()
You'll also want to add a signal to create a new profile when a user is registered:
#receiver(post_save, sender=settings.AUTH_USER_MODEL)
def create_profile_for_new_user(sender, created, instance, **kwargs):
if created:
profile = Profile(user=instance)
profile.save()
Django docs on extending users.
If a profile approach doesn't work for you, try inheriting from AbstractUser or AbstractBaseUser instead of User. The abstract models provide the same basic functionality as User and are the preferred technique for recent Django versions.
There are a handful of additional steps however, check out the docs on creating custom users for a run down.

Django NOT NULL constraint failed userprofile.user_id in case of uploading a file

I am trying to practice a simple project: A user registers (using Django registration-redux), uploads some file, and then s/he is provided with a list of her files, being downloadable. Here are my models.py, forms.py, and views respectively:
models.py
class UserProfile(models.Model):
user = models.ForeignKey(User, related_name='uploaded_by')
names = models.CharField(max_length=40)
lastname = models.CharField(max_length=50)
email = models.EmailField()
uploads = models.FileField(upload_to= 'blablabla')
def __str__(self):
return self.email
forms.py
class UserProfileForm(forms.ModelForm):
class Meta:
model = UserProfile
fields = ['names', 'uploads']
view.py
from .forms import UserProfileForm
from .models import UserProfile
#login_required()
def new(request):
form = UserProfileForm(request.POST or None, request.FILES or None)
if form.is_valid():
form.save()
context = {'title': 'welcome', 'form': form}
return render(requst, 'upform.html', context)
however when I login with a user and try to upload a file I get the error: IntegrityError at /new
NOT NULL constraint failed: _userprofile.user_id
After digging a lot I noticed someone suggested the reason of the error is because the user is not included anyhow in the process of posting the form, so I tried whatever came to my mind and the case in which I added the user field to the forms.py worked:
forms.py
class UserProfileForm(forms.ModelForm):
class Meta:
model = UserProfile
fields = ['names', 'uploads']
the problem however is that the form shown in the browser now includes a drop-down list containing all the registered users. I tried to associate the logged-in user with the form in the views by I kept seeing different errors.
My question is: How can I associate the uploads with the logged-in user in a transparent manner.
sorry if the question is too newbie-liked

Keep the user out of the form and add it on save:
if form.is_valid():
profile = form.save(commit=False)
profile.user = request.user
profile.save()
I must say your model looks a bit odd; you have multiple profiles for each user, each with a single upload. Seems more likely you want a single profile, with a OneToOne relationship to User, than a separate Uploads model with a ForeignKey to UserProfile.

I added the user field to the forms.py worked:
This probably also opens up a security hole, because you could then set the user from outside of your application, overriding the logged-in user.
After digging a lot I noticed someone suggested the reason for the error is because the user is not included anyhow in the process of posting the form.
You figured that quite right. If the user is not a field, the form never knows how to fill the user field of UserProfile. Since you cannot save a UserProfile without a filled in user foreign key, you get the error.
There are various ways around this:
One way to solve the problem is to use save(commit=False) on the form, patch the user into the unsaved instance and manually saving the object to the database:
if form.is_valid():
profile = form.save(commit=False)
profile.user = request.user
profile.save()
This slightly violates the encapsulation because you now handle the database save outside of the form.
You are also able to provide a initial "template" instance to the form:
form = UserProfileForm(
request.POST,
request.FILES,
instance=UserProfile(user=self.request.user)
)
You probably want to do so, anyway because the form also allows to edit an existing userprofile. Currently you are saving a new UserProfile each time and since user is not unique=True in your model class, you will get multiple profiles per user.
If you do not want this to be possible, check Daniel Roseman's answer, because then you probably want UserProfile.user to be a OneToOne field.
In this case, we can simplify to
profile, created = UserProfile.objects.get_or_create(user=request.user)
form = UserProfileForm(
request.POST,
request.FILES,
instance=profile
)
Note also that I removed the or None as it is not necessary. BaseForm (which ModelForm derives from) does this check for you (it actually does self.data = data or {}) which essentially undoes the prior none-ification)

You can do following the advice of Daniel.
class UserProfile(models.Model):
user = models.OneToOneField(User, related_name='uploaded_by')
names = models.CharField(max_length=40)
lastname = models.CharField(max_length=50)
email = models.EmailField()
class UserFiles(models.Model):
user = models.ForeignKey(UserProfile)
file = models.FileField(upload_to= 'blablabla')
Remember OneToOneField is similar a ForeignKey with the attribute unique=True.

Django register extended user

I'm trying to create and manage a custom user in django.
I saw there are two possibilities, and i've chosen to extend (not create a new auth).
Models
models.py
class Artists(models.Model):
user = models.OneToOneField(User)
artist_image = models.ImageField(null=True, blank=True, upload_to="/artist_image/")
def __str__(self):
return 'Profil de {0}'.format(self.username)
def get_absolute_url(self):
return reverse('artist-details', kwargs={'pk': self.pk})
As i read in doc, I just make a OneToOne field with the User class of django auth models, so I can access method and properties, such as username, email, on my own user (here Artists).
form.py
class CreateArtistForm(UserCreationForm):
class Meta:
model = User
fields = ('username', 'email')
def save(self, commit=True):
user = super(CreateArtistForm, self).save(commit=False)
user.email = self.cleaned_data['email']
if commit:
user.save()
return user
Here I extend UserCreationForm to prepare a form a little different (I want to have email field on my register form).
But here is my question : I first tried with
class Meta:
model = Artists
fields = ('user.username', 'user.email')
But I the error fields unknown in model Artist.
So I tried just with username and email and same error.
So I changed the model = Artists to User, and it works fine.
But now how i register my Artist Object when the user is saved?
Do I have to make something like (in save()):
artist = Artists()
artist.user = user
artist.save()
Or override create_user()?
I'm quite lost here and i'm looking docs and questions not able to find something because most of example people define their own auth.
Thanks in advance
Besta
edit : i'm using django 1.8.2 and python 3.4

not saving custom fields to django-allauth - no luck from previous posts

I am trying to create custom fields for users to enter on signup with django-allauth. I have referred to several posts about this, but I am not able to get my custom form to save to my database. I do get a combined form on my signup.html page with username, password1 and 2, email and my extra fields of city and school, but I am not able to save the extra fields to the database. I have run syncdb and can see my User Profile table in the admin area.
This advice is the closest I have come to the answer but I do not understand how to implement it: "You can't use UserProfileForm to the allauth.SIGNUP_FORM_CLASS. You need to extend it from SignUpForm and write a save method which will accept the newly created user as the only parameter," from this post:
Custom registration form for use with django-allauth
I have also attempted to integrate advice on this form these posts:
Django Allauth not saving custom form
How to customize user profile when using django-allauth
This is my code:
Models.py
from django.db import models
from django.contrib.auth.models import User
class UserProfile(models.Model):
# A required line - links a UserProfile to User.
user = models.OneToOneField(User)
# The additional attributes we wish to include.
school = models.CharField(max_length=128)
city = models.CharField(max_length=128)
def __unicode__(self):
return self.user.username
Forms.py
from django import forms
from django.contrib.auth.models import User
from myapp.models import UserProfile
from django.forms.widgets import HiddenInput
class UserProfileForm(forms.ModelForm):
class Meta:
model = UserProfile
fields = ('city', 'school')
def signup(self, request, user):
user=User.objects.get(email=request.email)
city=request.POST.get('city','')
school=request.POST.get('school','')
userprofile_obj = UserProfile(user=user,city=city,school=school)
userprofile_obj.save()
Settings.py
ACCOUNT_SIGNUP_FORM_CLASS = 'myapp.forms.UserProfileForm'
My template is the basic Signup.html from the django-allauth templates and I do not have a view made for this, although I attempted to make one from the tangowithdjango user authentication section register view, and this gave similar behavior (not saving to the database).
Thanks,
Kelly

Not sure if this is still an active question/issue for the original poster: if so, and for anyone else who comes across this, a few things to correct to at least move in the right direction:
I don't see an __init__() method that calls the superclass? E.g.:
def __init__(self, *args, **kwargs):
super(SignupForm, self).__init__(*args, **kwargs)
use the user parameter to the signup method. It should be populated; don't reload it.
Ensure the two objects are linking correctly (I didn't use Django to build my profile table so YMMV but I set user.profile = Profile(...); then execute user.profile.save() at the end of my signup() method.
get the values to place into the profile from the form cleaned_data (e.g. self.cleaned_data['city'] not the POST.
Then start debugging: is your signup() method firing? What does it get? What happens when you execute the profile.save() method?