[change:radius] Replace third-party JSONField with Django built-in JSONField

- Replaced jsonfield.JSONField with Django's built-in JSONField in models
- Updated RadiusBatch.user_credentials field
- Updated OrganizationRadiusSettings.sms_meta_data field
- Removed third-party jsonfield dependency from setup.py
- Added migration to handle field type transition
- Updated test migrations to use Django's JSONField
- Ensured backward compatibility and data preservation
- All existing tests pass with the new implementation

Fixes #600

Author: Eeshu-Yadav

openwisp_radius/base/models.py

@@ -16,12 +16,11 @@
 from django.core.exceptions import ObjectDoesNotExist, ValidationError
 from django.core.mail import send_mail
 from django.db import models
-from django.db.models import ProtectedError, Q
+from django.db.models import JSONField, ProtectedError, Q
 from django.utils import timezone
 from django.utils.crypto import get_random_string
 from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _
-from jsonfield import JSONField
 from model_utils.fields import AutoLastModifiedField
 from phonenumber_field.modelfields import PhoneNumberField
 from private_storage.fields import PrivateFileField
@@ -974,7 +973,7 @@ def prefix_add(self, prefix, n, password_length=BATCH_DEFAULT_PASSWORD_LENGTH):
         for user in users_list:
             user.full_clean()
             self.save_user(user)
-        self.user_credentials = json.dumps(user_credentials)
+        self.user_credentials = user_credentials
         self.full_clean()
         self.save()
 

openwisp_radius/migrations/0041_replace_jsonfield_with_django_builtin.py

@@ -0,0 +1,51 @@
+# Generated by Django 5.2.5 on 2025-08-10 05:19
+
+import json
+
+from django.db import migrations, models
+
+
+def convert_user_credentials_data(apps, schema_editor):
+    RadiusBatch = apps.get_model("openwisp_radius", "RadiusBatch")
+    for batch in RadiusBatch.objects.exclude(user_credentials__isnull=True):
+        # Decode the double-encoded JSON
+        try:
+            decoded = json.loads(batch.user_credentials)
+            batch.user_credentials = decoded
+            batch.save(update_fields=["user_credentials"])
+        except (json.JSONDecodeError, TypeError):
+            # Skip if data is not valid JSON
+            pass
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("openwisp_radius", "0040_rename_phonetoken_index"),
+    ]
+
+    operations = [
+        # Replace third-party JSONField with Django's built-in JSONField
+        migrations.AlterField(
+            model_name="radiusbatch",
+            name="user_credentials",
+            field=models.JSONField(
+                blank=True,
+                null=True,
+                verbose_name="PDF",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="organizationradiussettings",
+            name="sms_meta_data",
+            field=models.JSONField(
+                blank=True,
+                help_text="Additional configuration for SMS backend in JSON "
+                "format (optional, leave blank if unsure)",
+                null=True,
+                verbose_name="SMS meta data",
+            ),
+        ),
+        # Convert existing user_credentials data from double-encoded JSON
+        migrations.RunPython(convert_user_credentials_data, migrations.RunPython.noop),
+    ]

setup.py

@@ -45,7 +45,6 @@
         "weasyprint>=65,<67",
         "dj-rest-auth>=6.0,<7.1",
         "django-sendsms~=0.5.0",
-        "jsonfield~=3.1.0",
         "django-private-storage~=3.1.0",
         "django-ipware>=5.0,<7.1",
         "pyrad~=2.4",

tests/openwisp2/sample_radius/migrations/0002_initial_openwisp_app.py

@@ -7,7 +7,6 @@
 import django.core.validators
 import django.db.models.deletion
 import django.utils.timezone
-import jsonfield.fields
 import model_utils.fields
 import private_storage.fields
 import private_storage.storage.files
@@ -543,7 +542,7 @@ class Migration(migrations.Migration):
                 ),
                 (
                     "sms_meta_data",
-                    jsonfield.fields.JSONField(
+                    models.JSONField(
                         blank=True,
                         help_text=(
                             "Additional configuration for SMS backend in JSON format"
@@ -695,9 +694,7 @@ class Migration(migrations.Migration):
                 ),
                 (
                     "user_credentials",
-                    jsonfield.fields.JSONField(
-                        blank=True, null=True, verbose_name="PDF"
-                    ),
+                    models.JSONField(blank=True, null=True, verbose_name="PDF"),
                 ),
                 (
                     "expiration_date",