Resolve #159 -- Add custom JSONEncoder support via setting

django_select2/conf.py

@@ -198,6 +198,32 @@ class Select2Conf(AppConf):
     ``settings.DJANGO_SELECT2_I18N`` refers to :attr:`.I18N_PATH`.
     """
 
+    """
+    Custo JSON encoder class used for encoding JSON response used in ModelSelect2Widget, ModelSelect2MultipleWidget 
+    and ModelSelect2TagWidget.
+    Useful when your models uses some special proxy fields and 
+    you get error: Object of type <field> is not JSON serializable 
+
+    Default value is: django.core.serializers.json.DjangoJSONEncoder
+
+    For example:
+
+    If you use django-hashid-field package, you'll get an Object of type Hashid is not JSON serializable when you try
+    to use ModelSelect2Widget.
+    Just extend DjangoJSONEncoder:
+        from django.core.serializers.json import DjangoJSONEncoder
+        from hashid_field import Hashid
+
+        class HashidJSONEncoder(DjangoJSONEncoder):
+            def default(self, o):
+                if isinstance(o, Hashid):
+                    return str(o)
+                return super().default(o)
+
+    And set SELECT2_JSON_ENCODER to 'app_name.econders.HashidJSONEncoder' in settings.py of your project.
+    """
+    JSON_ENCODER = 'django.core.serializers.json.DjangoJSONEncoder'
+
     class Meta:
         """Prefix for all Django-Select2 settings."""
 

django_select2/views.py

@@ -3,6 +3,7 @@
 from django.core.signing import BadSignature
 from django.http import Http404, JsonResponse
 from django.views.generic.list import BaseListView
+from django.utils.module_loading import import_string
 
 from .cache import cache
 from .conf import settings
@@ -43,7 +44,8 @@ def get(self, request, *args, **kwargs):
                     for obj in context["object_list"]
                 ],
                 "more": context["page_obj"].has_next(),
-            }
+            },
+            encoder=import_string(settings.SELECT2_JSON_ENCODER)
         )
 
     def get_queryset(self):