TastyPie: related resource returns NULL

Question

I have UserProfile model which extends Django's User model:

class UserProfile(models.Model):
    user = models.OneToOneField(User, related_name="profile")
    avatar = models.CharField(max_length=40, default='0')
    activation_key = models.CharField(max_length=40, blank=True)
    key_expires = models.DateTimeField(default=django.utils.timezone.now)

    def __str__(self):
        return self.user.username

    class Meta:
        verbose_name_plural = u'User profiles'

I have two resources:

class UserProfileResource(ModelResource):
    class Meta:
        queryset = UserProfile.objects.all()
        resource_name = 'profile'
        allowed_methods = ['get']

and

class UserResource(ModelResource):
    profile = fields.ToOneField('api.api.UserProfileResource',
                                'profile', full=True, null=True)
    class Meta:
        queryset = User.objects.all()
        #fields = ['first_name', 'last_name', 'email', 'date_joined', 'profile']
        fields = [ 'profile' ]
        allowed_methods = ['get', 'post']
        resource_name = 'user'
        authentication = SessionAuthentication()
        authorization = DjangoAuthorization()
        detail_uri_name = 'username'

    def obj_create(self, bundle, **kwargs):
        return super(UserResource, self).obj_create(bundle, user=bundle.request.user)

    def authorized_read_list(self, object_list, bundle):
        return object_list.filter(user=bundle.request.user)

I trying to make a GET request:

http://localhost:8000/api/v1/user/<some_username>

And I receive:

Object { profile: null, resource_uri: "/api/v1/user/<some_username>/" }

It's correct that the profile is NULL, because I have an attribute null=True in my UserResource. The response is empty, that is why I receive NULL. But how I can solve this problem? What is wrong?

Maybe it's because of the structure of the project? The resources file is:

<project_name>/api/api.py

Answer 1

Accidentally I found the decision. Model:

class UserProfile(models.Model):
    user = models.OneToOneField(User)
    avatar = models.CharField(max_length=40, default='0')
    activation_key = models.CharField(max_length=40, blank=True)
    key_expires = models.DateTimeField(default=django.utils.timezone.now)

    def __str__(self):
        return self.user.username

    class Meta:
        verbose_name_plural = u'User profiles'

Resources:

class UserProfileResource(ModelResource):

    class Meta:
        queryset = UserProfile.objects.all()
        authentication = SessionAuthentication()
        authorization = DjangoAuthorization()
        allowed_methods = ['get', 'post']
        resource_name = 'profile'
        include_resource_uri = False

class UserResource(ModelResource):
    userprofile = fields.ToOneField(UserProfileResource, 'userprofile', null=True, full=True)

    class Meta:
        queryset = User.objects.all()
        fields = ['first_name', 'last_name', 'email', 'date_joined', 'userprofile']
        allowed_methods = ['get', 'post']
        resource_name = 'user'
        detail_uri_name = 'username'
        authentication = SessionAuthentication()
        authorization = DjangoAuthorization()

As you can see, this line is important:

userprofile = fields.ToOneField(UserProfileResource, 'userprofile', null=True, full=True)

The name of this property (userprofile) should be equal to the name of the model (UserProfile).

GET request:

http://localhost:8000/api/v1/user/<some_username>

Response:

{
    "date_joined": "2016-03-01T08:22:40", 
    "email": "[email protected]", 
    "first_name": "Ivan", 
    "last_name": "Ivan", 
    "resource_uri": "/api/v1/user/<some_username>/", 
    "userprofile": {
        "activation_key": "...", 
        "avatar": "...", 
        "id": 22, 
        "key_expires": "2016-03-14T17:11:01"
    }
}