DRY way to rename ModelSerializer fields without duplicating model/field definitions? - django

Question

Working with a legacy database with an awful schema and want to rename several ModelSerializer fields without having to redefine fields already defined on the model.
Here's an example model:
class LegacyItem(models.Model):
# Note: ignore things that feel "wrong" here (just an example)
legacyitem_id = models.IntegerField(primary_key=True)
legacyitem_notes = models.CharField(max_length=4000, blank=True, null=True)
directory_id = models.ForeignKey('Directory', models.DO_NOTHING)
created_by_directory_id = models.ForeignKey('Directory', models.DO_NOTHING)
created_date = models.DateField(auto_now_add=True)
modified_by_directory_id = models.ForeignKey('Directory', models.DO_NOTHING)
modified_date = models.DateField(auto_now=True)
Here's a working serializer:
class LegacyItemSerializer(serializers.ModelSerializer):
class Meta:
fields = '__all__'
model = LegacyItem
read_only_fields = [
'created_date',
'modified_date',
]
The goal is to bulk rename model fields for the API so we can abstract away the awful schema. Here's a working serializer showing the sort of renaming we want to do:
class LegacyItemSerializer(serializers.ModelSerializer):
created_by = serializers.PrimaryKeyRelatedField(
read_only=True,
source='created_by_directory_id',
)
customer = serializers.PrimaryKeyRelatedField(
queryset=Directory.objects.all(),
source='directory_id',
)
id = serializers.PrimaryKeyRelatedField(
read_only=True,
source='legacyitem_id'
)
modified_by = serializers.PrimaryKeyRelatedField(
read_only=True,
source='modified_by_directory_id',
)
notes = serializers.DateField(source='legacyitem_notes')
class Meta:
fields = [
'id',
'customer',
'notes',
'created_by',
'created_date',
'modified_by',
'modified_date',
]
model = LegacyItem
read_only_fields = [
'created_date',
'modified_date',
]
All we want to do is rename the fields. We don't want to change the validation and would rather keep most of that validation on the model and the model's fields and not also put it into the serializer. We will have to do this sort of thing for a lot of models and it's very tedious and bad practice (IMO) to be duplicating model validation on the serializer just to rename a field.
Is there a DRY way to do this? Maybe something we can put into LegacyItemSerializer.Meta or some method we can override? When working with Django forms, for example, you could do this easily by tweaking labels/widgets in the ModelForm.Meta. You would never have to redefine ModelForm fields/validation.
In a perfect world, maybe something like:
class LegacyItemSerializer(serializers.ModelSerializer):
class Meta:
model = LegacyItem
model_field_args = {
'legacyitem_id': {'name': 'id'},
'directory_id': {'name': 'customer'},
'legacyitem_notes': {'name': 'notes'},
'created_by_directory_id': {'name': 'created_by'},
'modified_by_directory_id': {'name': 'modified_by'},
}