Issue
Im quite new to django but i cant find the solution in the docs
My question:
I have a model with 2 OneToOne relations:
class Slotting(ICSBaseMixin):
# database fields
article = models.OneToOneField(
"ics_stock.Article",
on_delete=models.CASCADE,
related_name="slotting",
null=False
)
article_location = models.OneToOneField(
"ics_stock.ArticleLocation",
on_delete=models.CASCADE,
null=False,
related_name="slotting"
)
def __str__(self):
return str(self.record_id)
class Meta:
db_table = "ICS_Stock_Slotting"
verbose_name = "Slotting"
verbose_name_plural = "Slottings" # noqa
I want to create and save a new instance through a serializer.
serializer:
class SlottingCreateUpdateSerializer(serializers.ModelSerializer):
def update(self, instance, validated_data):
article = validated_data.pop("article")
instance.article_id = article
article_location = validated_data.pop("article_location")
instance.article_location_id = article_location
instance.save()
return instance
def create(self, validated_data):
article_id = validated_data.pop("article")
article = get_object_or_404(
Article,
record_id=article_id
)
article_location_id = validated_data.pop("article_location")
article_location = get_object_or_404(
ArticleLocation,
record_id=article_location_id
)
slotting = Slotting()
slotting.article_location = article_location,
slotting.article = article
slotting.save()
return slotting
Now when trying to serialize and save i get the following error:
raceback (most recent call last):
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\db\models\fields\__init__.py", line 1988, in get_prep_value
return int(value)
TypeError: int() argument must be a string, a bytes-like object or a number, not 'Article'
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\core\handlers\exception.py", line 55, in inner
response = get_response(request)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\core\handlers\base.py", line 197, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\views\decorators\csrf.py", line 54, in wrapped_view
return view_func(*args, **kwargs)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\views\generic\base.py", line 84, in view
return self.dispatch(request, *args, **kwargs)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\rest_framework\views.py", line 509, in dispatch
response = self.handle_exception(exc)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\rest_framework\views.py", line 469, in handle_exception
self.raise_uncaught_exception(exc)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\rest_framework\views.py", line 480, in raise_uncaught_exception
raise exc
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\rest_framework\views.py", line 506, in dispatch
response = handler(request, *args, **kwargs)
File "C:\000 Projects\Applications\ICS_Django_core\ics_stock\api\views\slotting.py", line 44, in post
instance = validated_data.save()
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\rest_framework\serializers.py", line 212, in save
self.instance = self.create(validated_data)
File "C:\000 Projects\Applications\ICS_Django_core\ics_stock\api\serializers\slotting.py", line 40, in create
article = get_object_or_404(
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\shortcuts.py", line 85, in get_object_or_404
return queryset.get(*args, **kwargs)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\db\models\query.py", line 482, in get
clone = self._chain() if self.query.combinator else self.filter(*args, **kwargs)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\db\models\query.py", line 1071, in filter
return self._filter_or_exclude(False, args, kwargs)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\db\models\query.py", line 1089, in _filter_or_exclude
clone._filter_or_exclude_inplace(negate, args, kwargs)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\db\models\query.py", line 1096, in _filter_or_exclude_inplace
self._query.add_q(Q(*args, **kwargs))
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\db\models\sql\query.py", line 1502, in add_q
clause, _ = self._add_q(q_object, self.used_aliases)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\db\models\sql\query.py", line 1532, in _add_q
child_clause, needed_inner = self.build_filter(
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\db\models\sql\query.py", line 1448, in build_filter
condition = self.build_lookup(lookups, col, value)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\db\models\sql\query.py", line 1273, in build_lookup
lookup = lookup_class(lhs, rhs)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\db\models\lookups.py", line 27, in __init__
self.rhs = self.get_prep_lookup()
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\db\models\lookups.py", line 85, in get_prep_lookup
return self.lhs.output_field.get_prep_value(self.rhs)
File "C:\000 Projects\Applications\ICS_Django_core\venv\lib\site-packages\django\db\models\fields\__init__.py", line 1990, in get_prep_value
raise e.__class__(
TypeError: Field 'record_id' expected a number but got <Article: test article>.
Now im googling and looking for a whole day but i still dont know what im doing wrong.
What do i need to refactor to be able to fix the bug.
Solution
I created a serializer class to inherrit from that uses a dict input from the Meta class.
class RelatedModelSerializer(serializers.ModelSerializer):
"""
serializes all relationship based models
added field for Meta class
- relationships: dict[str:Model]
Create and update method adds all fields from relationships with the primary key with from model described in relationships dict and saves and raises HTTP404 when object not found
- Arjen Keller
"""
class Meta:
relationships = {}
model = None
def create(self, validated_data):
for key in frozenset(validated_data):
if self.Meta.relationships and key in self.Meta.relationships:
validated_data[f"{key}_id"] = get_object_or_404(
self.Meta.relationships[key],
record_id=validated_data.pop(key).id
).id
return self.Meta.model.objects.create(**validated_data)
def update(self, instance, validated_data):
for key in frozenset(validated_data):
setattr(
instance, f"{key}_id",
validated_data.pop(key)
) if self.Meta.relationships and key in self.Meta.relationships and get_object_or_404(
self.Meta.relationships[key],
record_id=validated_data[key].id
).id else setattr(
instance,
f"{key}",
validated_data.pop(key)
)
instance.save(**validated_data)
return instance
i hope it helps somebody.
Answered By – ArjenKellerICS
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