Skip to content

Input Validations

Much inspired by the way graphene-django-cud handles validation, this package provides a similar way to validate your input when the respective input classes are instantiated.

inputs.py
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
@strawberry_django.input(get_user_model())
class UserInput:
    firstname: auto
    lastname: auto

    def validate(self, info):
        if self.firstname == self.lastname:
            raise ValidationError(
                "Firstname and lastname cannot be the same"
            )

    # Or for individual fields    
    def validate_lastname(self, info, value):
        if value == self.firstname:
            raise ValidationError(
                "Firstname and lastname cannot be the same"
            )

When updating an existing object the pk will be available through self.id so you can validate values in comparison to existing ones. Also info is provided in case validations need to be run against the user making the request.

Finally add this to each mutation that needs to run validations:

schema.py
1
2
3
4
5
6
7
8
9
from strawberry_django_extras.field_extensions import with_validation
from strawberry_django import mutations

@strawberry.type
class Mutation:
    create_user: UserType = mutations.create(
        UserInput,
        extensions=[with_validation()]
    )