Django JSONField to have particular keys

Question

My class looks like this:

class Foo(models.Model):
  known_by = JSONField()

My data looks like this

{ "known_by" : [
                {'by':'name1', 'value':['def']},
                {'by':'name2', 'value':['bar']}
               ]
}

Is there any way for me to enforce that the Jsonfield needs to follow the format of by,value[] dict. I know how to do this using serialiazers

Any other cleaner way to enforce this(in the model definition itself)? Thanks

Answer 1

You can add a validator to the model field, like this:

 class Foo(models.Model):
     known_by = ArrayField(JSONField(max_length=100), size=4, validators=[a_json_array_validator])

And the validator is:

def a_json_array_validator(value):
    if any([not is_json_valid(entry) for entry in value]):
        raise ValidationError(
            _('%(value) is not a valid json'),
            params={'value': value},
         )

(The actual json validation is up to you) ;-) Note that validators receive python objects so its actually a dict.

Answer 2

You could implement it this way:

from django.db import models

class Bar(models.Model):
    by = models.CharField()
    value = models.ArrayField()


class Foo(models.Model):
    known_by = models.ForeignKey(Bar, on_delete=models.CASCADE)