AttributeError: 'collections.OrderedDict' object has no attribute 'pk' with Django Rest Framework while adding item to a many to many relationship - django-rest-framework

Question

First question here, so please bear with me. I'm learning Django and the Django Rest Framework, and I'm getting an exception when adding a related object in a many to many relationship. What I do not understand is that the object gets created correctly, and I am getting the error when getting the response.
This is an excerpt of my urls.py:
path('mybox/', views_api.MyBoxList.as_view(), name='mybox-list'),
path('mybox/<int:pk>/', views_api.MyBoxDetail.as_view(), name='mybox-detail'),
path('mybox/<int:pk>/documents/', views_api.DocumentList.as_view(), name='mybox-document-list'),
path('documents/', views_api.DocumentList.as_view(), name='document-list'),
path('documents/<int:pk>/', views_api.DocumentDetail.as_view(), name='document-detail'),
My models.py:
class MyBox(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='boxes')
name = models.CharField(_('name'), max_length=100, default='my_box')
description = models.CharField(_('description'), max_length=250, null=True, blank=True)
time_created = models.DateTimeField(_('time created'), auto_now_add=True)
def __str__(self):
return self.name
def user_folder_doc_path(instance, filename):
# file will be uploaded to MEDIA_ROOT/user_<id>/docs/<filename>
return 'user_{0}/docs/{1}'.format(instance.owner.id, filename)
class Document(models.Model):
owner = models.ForeignKey(User, on_delete=models.CASCADE, related_name='documents')
file = models.FileField(_('file'), upload_to=user_folder_doc_path, null=True, blank=True)
description = models.TextField(_('description'), null=True, blank=True)
time_created = models.DateTimeField(_('time created'), auto_now_add=True)
mybox = models.ManyToManyField(MyBox, related_name='documents', blank=True)
My serializers:
class MyBoxSerializer(serializers.HyperlinkedModelSerializer):
user = serializers.ReadOnlyField(source='user.username')
class Meta:
model = MyBox
fields = ['url', 'id', 'user', 'name', 'description', 'documents']
class DocumentSerializer(serializers.HyperlinkedModelSerializer):
mybox = MyBoxSerializer(many=True, read_only=True)
owner = serializers.ReadOnlyField(source='owner.username')
class Meta:
model = Document
fields = ['url', 'id', 'owner', 'description', 'file', 'mybox']
extra_kwargs = {'mybox': {'required': False}}
And my views.py:
class DocumentList(generics.ListCreateAPIView):
#queryset = Document.objects.all()
serializer_class = DocumentSerializer
permission_classes = [permissions.IsAuthenticated]
def get_queryset(self):
"""
This view should return a list of all the documents
for the currently authenticated user.
"""
owner = self.request.user
mybox_id = self.kwargs.get('pk', None)
if mybox_id:
return Document.objects.filter(mybox=mybox_id, owner=owner)
else:
return Document.objects.filter(owner=owner)
def perform_create(self, serializer):
mybox_id = self.kwargs.get('pk', None)
if mybox_id:
print("Hay ID de MyBox")
mybox = MyBox.objects.get(pk=mybox_id)
serializer = DocumentSerializer(data=self.request.data)
if serializer.is_valid():
document = serializer.save(owner=self.request.user)
mybox.documents.add(document)
else:
print("No hay ID de MyBox")
serializer.save(owner=self.request.user)
I've tried several suggestions I found online, with no luck. I believe the issue is my serializers, and I tried adding this to MyBoxSerializer: documents = serializers.HyperlinkedIdentityField(view_name='mybox-document-list', lookup_field='mybox_id')
But I think I do not understand serializers enough when dealing with M2M relationships.
Just to reiterate, after going to mybox/1/documents/ and creating a new document here, the document gets properly created and the relationship with MyBox id:1 (in this example) is also there, but I never get a response, only the exception
Thanks for any help/suggestions!

Answer 1

So I finally managed to fix the issue, thanks to the solution provided by somebody else. In case anyone gets to this page with a similar issue.
The problem was in the perform_create function, which had a serializer too many and I had to save the document too. This is the correct version that works for me:
def perform_create(self, serializer):
mybox_id = self.kwargs.get('pk', None)
if mybox_id:
mybox = MyBox.objects.get(pk=mybox_id)
if serializer.is_valid():
document = serializer.save(owner=self.request.user)
document.mybox.add(mybox)
document.save()
else:
serializer.save(owner=self.request.user)
I hope this helps