context in nested serializers django rest framework
Ok i found a working solution. I replaced the ChildSerializer assignment in the Parent class with a SerializerMethodField which adds the context. This is then passed to the get_fields method in my CustomModelSerializer:
class ChildSerializer(CustomModelSerializer):
class Meta:
fields = ('c_name', )
model = Child
class ParentSerializer(CustomModelSerializer):
child = serializers.SerializerMethodField('get_child_serializer')
class Meta:
model = Parent
fields = ('p_name', 'child')
def get_child_serializer(self, obj):
serializer_context = {'request': self.context.get('request') }
children = Child.objects.all().filter(parent=obj)
serializer = ChildSerializer(children, many=True, context=serializer_context)
return serializer.data
and in my CustomModelSerializer:
class CustomModelSerializer(rest_serializer_classes.HyperlinkedModelSerializer):
def __init__(self, *args, **kwargs):
"""
Make sure a user is coupled to the serializer (needed for permissions)
"""
super().__init__(*args, **kwargs)
if not self.context:
self._context = getattr(self.Meta, 'context', {})
try:
self.user = self.context['request'].user
except KeyError:
self.user = None
def get_fields(self):
ret = OrderedDict()
if not self.user:
print("No user associated with object")
return ret
fields = super().get_fields()
# Bypass permission if superuser
if self.user.is_superuser:
return fields
for f in fields:
if has_right(self.user, self.Meta.model.__name__.lower(), f, "read"):
ret[f] = fields[f]
return ret
This seems to work fine, and fields of the child are discarded in the serializer when i either revoke read-rights on Child.c_name or on Parent.child
If you can not change the nature of you child serializer, as in @Kirill Cherepanov and @Robin van Leeuwen answers, a light but not full-integrated solution would be to manually pass the context in __init__()
function :
class ChildSerializer(CustomModelSerializer):
class Meta:
fields = ('c_name', )
model = Child
class ParentSerializer(CustomModelSerializer):
child = ChildSerializer(many=True, read_only=True)
class Meta:
model = Parent
fields = ('p_name', 'child')
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
# We pass the "upper serializer" context to the "nested one"
self.fields['child'].context.update(self.context)