Fix validation for ListSerializer #8979
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…ect list object instead of the entire list when validating ListSerializer
saadullahaleem
changed the title
…code#8986) * Fix Django Docs url in reverse.md Django URLs of the documentation of `reverse` and `reverse_lazy` were wrong. * Update reverse.md
* fix URLPathVersioning reverse fallback * add test for URLPathVersioning reverse fallback * Update tests/test_versioning.py --------- Co-authored-by: Jorn van Wier <[email protected]> Co-authored-by: Asif Saif Uddin <[email protected]>
* Make set_value a static method for Serializers As an alternative to encode#7671, let the method be overridden if needed. As the function is only used for serializers, it has a better place in the Serializer class. * Set `set_value` as an object (non-static) method * Add tests for set_value() These tests follow the examples given in the method.
…ect list object instead of the entire list when validating ListSerializer
* Make set_value a static method for Serializers As an alternative to encode#7671, let the method be overridden if needed. As the function is only used for serializers, it has a better place in the Serializer class. * Set `set_value` as an object (non-static) method * Add tests for set_value() These tests follow the examples given in the method.
…ect list object instead of the entire list when validating ListSerializer
…ect list object instead of the entire list when validating ListSerializer
…ect list object instead of the entire list when validating ListSerializer
Co-authored-by: Sergei Shishov <[email protected]>
Co-authored-by: Sergei Shishov <[email protected]>
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| instance = kwargs.get('instance', []) | ||
| data = kwargs.get('data', []) | ||
| if instance and data: | ||
| assert len(data) == len(instance), 'Data and instance should have same length' | ||
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The lengths might be different in some use cases. Let's say we want the list serializer to delete from queryset all elements that are not provided in the data during an update. The queryset will be bigger than the data in this case.
This update breaks serializers like:
class BankBulkUpdateSerializer(serializers.ListSerializer):
"""Bank bulk update serializer."""
def update(
self,
instance: models.QuerySet[Bank],
validated_data: list[OrderedDict],
) -> list[Bank]:
"""Bulk update banks."""
bank_dict = {bank.pk: bank for bank in instance}
banks_to_create: list[Bank] = []
banks_to_update: list[Bank] = []
banks_created: list[Bank] = []
banks_updated: list[Bank] = []
bank_pks_to_keep: list[int] = []
for bank_data in validated_data:
bank_id = bank_data.get("id")
bank = bank_dict.get(bank_id) if bank_id is not None else None
if bank is not None:
for attr, value in bank_data.items():
setattr(bank, attr, value)
banks_to_update.append(bank)
bank_pks_to_keep.append(bank.pk)
else:
bank = Bank(**bank_data)
banks_to_create.append(bank)
with db_transaction.atomic():
instance.exclude(pk__in=bank_pks_to_keep).delete()
if banks_to_update:
update_fields = ["name", "compe", "ispb", "website"]
Bank.objects.bulk_update(banks_to_update, update_fields)
banks_updated = banks_to_update
if banks_to_create:
banks_created: list[Bank] = Bank.objects.bulk_create(
banks_to_create
)
return sorted(banks_created + banks_updated, key=lambda a: a.name)Instead of indexing, it's better to relate the elements by id:
self.child.instance = self.instance.filter(id=item['id']).first() if self.instance else None
self.child.initial_data = item
validated = self.child.run_validation(item)We could add a "pk_field" to the serializer Meta to make it more flexible.
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would you mind come with an improvement in another PR and ping me?
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@saadullahaleem @sshishov we got a PR here #9244, suggesting a better design choice. although not complete, we might need to improve the current implementation instead and make sure it is flexible. otherwise might be we have to revert it for a while |
@auvipy I am okay with any route/solution. Our goal is to improve the functionality of the package and if there is better design then we should try to use/apply it. The approach mentioned in #9244 PR used for bulk actions is valid, we are also using similar approach to create/update objects inside same PATCH request. In the original issue it wa proposed to use |
Description
This PR fixes #8926. It makes the instance variable of child serializer point to the correct list object instead of the entire list when validating ListSerializer.
Problem
As mentioned in #8926, when calling
is_validon a serializer that has been initialized withmany=True, theinstancevariable within anyvalidate_method points to the list of multiple model instances instead of the relevant single model instance.Solution
When a serializer is initialized with
many=True, the returned serializer is actually an instance ofListSerializerwith the intended serializer set as thechildof theListSerializer. This PR dynamically sets the correctinstanceon the child serializer when iterating over all provided objects in thedatalist.If both
dataandinstanceare passed to a serializer withmany=True, the serializer raises an assertion error if their lengths are different.Assumptions
It is assumed that the objects within
dataandinstancecorrespond to each other based on the index.Further Work
We could also add the ability to pass a
keyorfieldvalue that matches objects withindataandinstance. Moreover, the API would be clearer ifinstancewas actually renamed toinstancesbut that might cause backwards compatibility issues.