Webhook Notifications: Support the owner field

[Maffooch]

Attempting to supply a user under the notification webhook form produced the following exception. The solution is to create a sub template for the user model that is similar to the way the product type sub template was implemented.

[06/Aug/2025 19:50:58] ERROR [django.request:253] Internal Server Error: /notifications/webhooks/add
Traceback (most recent call last):
  File "/usr/local/lib/python3.11/site-packages/django/core/handlers/exception.py", line 55, in inner
    response = get_response(request)
               ^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/core/handlers/base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/views/generic/base.py", line 105, in view
    return self.dispatch(request, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/views/generic/base.py", line 144, in dispatch
    return handler(request, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/dojo/notifications/views.py", line 260, in post
    request, success = self.process_form(request, context)
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/dojo/notifications/views.py", line 217, in process_form
    self.get_webhook_manager_instance()._test_webhooks_notification(form.instance)
  File "/app/dojo/notifications/helper.py", line 548, in _test_webhooks_notification
    res = self._webhooks_notification_request(
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/dojo/notifications/helper.py", line 538, in _webhooks_notification_request
    headers, data = self._generate_request_details(endpoint, event=event, **kwargs)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/dojo/notifications/helper.py", line 522, in _generate_request_details
    yaml_data = self._create_notification_message(
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/dojo/notifications/helper.py", line 166, in _create_notification_message
    notification_message = render_to_string(
                           ^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/loader.py", line 62, in render_to_string
    return template.render(context, request)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/backends/django.py", line 107, in render
    return self.template.render(context)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/base.py", line 171, in render
    return self._render(context)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/base.py", line 163, in _render
    return self.nodelist.render(context)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/base.py", line 1008, in render
    return SafeString("".join([node.render_annotated(context) for node in self]))
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/base.py", line 1008, in <listcomp>
    return SafeString("".join([node.render_annotated(context) for node in self]))
                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/base.py", line 969, in render_annotated
    return self.render(context)
           ^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/loader_tags.py", line 210, in render
    return template.render(context)
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/base.py", line 173, in render
    return self._render(context)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/base.py", line 163, in _render
    return self.nodelist.render(context)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/base.py", line 1008, in render
    return SafeString("".join([node.render_annotated(context) for node in self]))
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/base.py", line 1008, in <listcomp>
    return SafeString("".join([node.render_annotated(context) for node in self]))
                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/base.py", line 969, in render_annotated
    return self.render(context)
           ^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/base.py", line 1067, in render
    output = self.filter_expression.resolve(context)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/django/template/base.py", line 745, in resolve
    new_obj = func(obj, *arg_vals)
              ^^^^^^^^^^^^^^^^^^^^
  File "/app/dojo/templatetags/as_json.py", line 16, in as_json_no_html_esc
    return mark_safe(json.dumps(value))
                     ^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/json/__init__.py", line 231, in dumps
    return _default_encoder.encode(obj)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/json/encoder.py", line 200, in encode
    chunks = self.iterencode(o, _one_shot=True)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/json/encoder.py", line 258, in iterencode
    return _iterencode(o, 0)
           ^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/json/encoder.py", line 180, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type Dojo_User is not JSON serializable

[dryrunsecurity]

No vulnerability summary was generated for this pull request.

---

All finding details can be found in the DryRun Security Dashboard.

[kiblik]

Can we add unittests for this, please?