django postgresql json field schema validation

Question

I have a django model with a JSONField (django.contrib.postgres.fields.JSONField) Is there any way that I can validate model data against a json schema file?

Answer 1

I wrote a custom validator using jsonschema in order to do this (Django 1.11, Python 3.6).

project/validators.py

import django
from django.core.validators import BaseValidator
import jsonschema
    

class JSONSchemaValidator(BaseValidator):
    def compare(self, input, schema):
        try:
            jsonschema.validate(input, schema)
        except jsonschema.exceptions.ValidationError:
            raise django.core.exceptions.ValidationError(
                '%(value)s failed JSON schema check', params={'value': input})

project/app/models.py

from django.db import models
from django.contrib.postgres.fields import JSONField

from project.validators import JSONSchemaValidator

MY_JSON_FIELD_SCHEMA = {
    'schema': 'http://json-schema.org/draft-07/schema#',
    'type': 'object',
    'properties': {
        'my_key': {
            'type': 'string'
        }
    },
    'required': ['my_key']
}

class MyModel(models.Model):
    my_json_field = JSONField(
        default=dict,
        validators=[JSONSchemaValidator(limit_value=MY_JSON_FIELD_SCHEMA)]
    )