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How to give access for a model object to a specific user in Django

I am doing an online classroom project in Django where I created a model named create_course which is accessible by teachers. Now I am trying to design this as the teacher who creates a class only he can see this after login another teacher shouldn't see his classes and how to add students into that particular class I created
the course model
class course(models.Model):
course_name = models.CharField(max_length=200)
course_id = models.CharField(max_length=10)
course_sec = models.IntegerField()
classroom_id = models.CharField(max_length=50,unique=True)
views.py
def teacher_view(request, *args, **kwargs):
form = add_course(request.POST or None)
context = {}
if form.is_valid():
form.save()
return HttpResponse("Class Created Sucessfully")
context['add_courses'] = form
return render(request, 'teacherview.html', context)
forms.py
from django import forms
from .models import course
class add_course(forms.ModelForm):
class Meta:
model = course
fields = ('course_name', 'course_id', 'course_sec', 'classroom_id')

Add one more field in course model that establish relationship with User model. Hence you can get the details about the teacher who has created course.
from django.contrib.auth.models import User
class course(models.Model):
course_name = models.CharField(max_length=200)
course_id = models.CharField(max_length=10)
course_sec = models.IntegerField()
classroom_id = models.CharField(max_length=50,unique=True)
created_by = models.ForeignKey(User, on_delete=models.CASCADE)
In your view function, you can check whether logged in user is same as the created of the requested course.
def teacher_view(request, *args, **kwargs):
# since this is course specific view, you will be passing an identiier or pk of the course as an argument to this function.
course_obj = Course.objects.get(id="identifier")
if request.user == course_obj.created_by:
# logged in user is same as the creator of the course
else:
# redirect
I would prefer creating permissions and having those in specific models. You can give it a try with that too. Let me know, if it doesn't work.

How to access User Profile's friends in ManyToMany field

I am building a simple social media app. AND i am trying to build a feature of adding users into post using ManyToManyField.
I am trying to access profile friends in Post's model instance "add_user" for tagging user.
models.py
class Profile(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE,default='',unique=True)
full_name = models.CharField(max_length=100,default='')
friends = models.ManyToManyField("Profile",blank=True)
class Post(models.Model):
post_owner = models.ForeignKey(User,default='',null=True,on_delete = models.CASCADE)
post_title = models.CharField(max_length=500,default='')
add_user = models.ManyToManyField(User.profile.friends.all())
I am new in django and I have no idea how can i access user's friend in Post's model instance.
Any help would be much Appreciated.
Thank You in Advance.

You can't give a queryset as an argument for a ManyToManyField, just a class name.
add_users = models.ManyToManyField(User.profile.friends.all()) # you can't do this.
add_users = models.ManyToManyField(User) # Do this.
You shouldn't place you logic in your model's definition.
Do that in your views.
EDIT:
I suggest you use a ModelChoiceField and do the filtering logic there:
class AddFriendForm(forms.Form):
def __init__(self, *args, **kwargs):
try:
user = kwargs.pop('user')
except:
user = None
super(AddFriendForm, self).__init__(*args, **kwargs)
self.fields['friend'].queryset = user.profile.friends.all()
friend = forms.ModelChoiceField(queryset=User.objects.none())
And then in your view you initialize it like this:
def your_view(request):
form = AddFriendForm(user=request.user)

You cannot do
add_users = models.ManyToManyField(User.profile.friends.all())`
Because the models is evaluated once, and need to be non mutable values
You need to do :
add_user = models.ManyToManyField("Profile",blank=True)
And dont forget to add on your ManyToManyField:
related_name="XXX", null=True

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?

Saving Form Data with a ForeignKey Field

I want to expand my User Model with a UserProfile model. This UserProfile model includes a ForeignKey Field. In the form, I would like to use a ModelChoiceField to pre-populate this form field.
Whenever I submit the form, I get
ValueError at /accounts/register/
Cannot assign "'13'": "UserProfile.course" must be a "Course" instance.
Any help would be appreciated!
My Code:
models.py
class Course(models.Model):
course_accid = models.CharField(max_length=10)
def __str__(self):
return self.course_accid
class UserProfile(models.Model):
# This line is required. Links UserProfile to a User model instance.
user = models.OneToOneField(User)
website = models.URLField(blank=True)
picture = models.ImageField(upload_to='profile_images', blank=True)
course = models.ForeignKey(Course)
def __unicode__(self):
return self.user.username
def user_registered_callback(sender, user, request, **kwargs):
profile = UserProfile(user = user)
profile.website = request.POST["website"]
profile.course = Course.objects.get(pk=request.POST["course"]),
profile.save()
forms.py
class RegistrationForm(RegistrationForm):
course = forms.ModelChoiceField(queryset=Course.objects.all())
website = forms.URLField()

So, the problem that's occurring is that course needs to be set to a course instance with a step before, on forms.py, before it's a ModelChoiceField. The reason why is because querying it, like you're doing with queryset is really just searching for a string that matches, not the actual object.
If you break it up into two steps,
class = [some_method_for_getting_a_class_object]
UserProfile.class = class
Then it should get rid of that error.

accessing user in django rest framework

i am using django rest framework for my project.
i have a gallery model which has a user field. this field is a Foreign key to the user that created the gallery. and a name field which is gallery's name.
class Gallery(models.Model):
user = models.ForeignKey(User,related_name='galleries')
name = models.CharField(max_length=64)
here is my serializer:
class GallerySerializer(serializers.ModelSerializer):
user = serializers.ReadOnlyField(source='user.username')
def validate_name(self, name):
if len(name) < 3:
raise serializers.ValidationError("name must at least 3 letters")
return name
class Meta:
model = Gallery
fields = ('id', 'user', 'name',)
def create(self, validated_data):
"""
Create and return a new `Gallery` instance, given the validated data.
"""
return Galleries.objects.create(**validated_data)
and here is my views:
class GalleryList(generics.ListCreateAPIView):
queryset = Gallery.objects.all()
serializer_class = GallerySerializer
permission_classes = (permissions.IsAuthenticatedOrReadOnly,
IsOwnerOrReadOnly,)
def perform_create(self, serializer):
serializer.save(user=self.request.user, )
class GalleryDetail(generics.RetrieveUpdateDestroyAPIView):
queryset = Gallery.objects.all()
serializer_class = GallerySerializer
permission_classes = (permissions.IsAuthenticatedOrReadOnly,
IsOwnerOrReadOnly,)
i want to validate post (and put) data, and prevent user from creating two gallery with the same name.(if "user A" has a "gallery A", he can't make a gallery with the same name or rename another gallery to "gallery A". but "user B" is allowed to make a "gallery A")
to do so, i need to check if user.galleries.filter(name=name) exist or not.
but i don't know how to get user in serializer.

You get it from the context that was passed to the serializer. This is done automatically for you, so you can access it like that:
user = self.context['request'].user
If you want to have the ability to specify another user, you can add it to the context yourself:
# This method goes in your view/viewset
def get_serializer_context(self):
context = super().get_serializer_context()
context['user'] = #whatever you want here
return context
That would make the user available as self.context['user']. This is a bit more verbose, but it is more versalite as it allows the serializer to be passed a user different from the one who did the request.