Fixes netbox-community#16782: Add object filtering for custom fields

docs/customization/custom-fields.md

@@ -74,6 +74,8 @@ If a default value is specified for a selection field, it must exactly match one
 
 An object or multi-object custom field can be used to refer to a particular NetBox object or objects as the "value" for a custom field. These custom fields must define an `object_type`, which determines the type of object to which custom field instances point.
 
+By default, an object choice field will make all objects of that type available for selection in the drop-down. The list choices can be filtered to only show objects with certain values by providing a `query_params` dict in the Related Object Filter field, as a JSON value. More information about `query_params` can be found [here](./custom-scripts.md#objectvar)
+
 ## Custom Fields in Templates
 
 Several features within NetBox, such as export templates and webhooks, utilize Jinja2 templating. For convenience, objects which support custom field assignment expose custom field data through the `cf` property. This is a bit cleaner than accessing custom field data through the actual field (`custom_field_data`).

netbox/extras/api/serializers_/customfields.py

@@ -62,7 +62,7 @@ class Meta:
         fields = [
             'id', 'url', 'display_url', 'display', 'object_types', 'type', 'related_object_type', 'data_type',
             'name', 'label', 'group_name', 'description', 'required', 'search_weight', 'filter_logic', 'ui_visible',
-            'ui_editable', 'is_cloneable', 'default', 'weight', 'validation_minimum', 'validation_maximum',
+            'ui_editable', 'is_cloneable', 'default', 'related_object_filter', 'weight', 'validation_minimum', 'validation_maximum',
             'validation_regex', 'validation_unique', 'choice_set', 'comments', 'created', 'last_updated',
         ]
         brief_fields = ('id', 'url', 'display', 'name', 'description')

netbox/extras/forms/model_forms.py

@@ -67,7 +67,7 @@ class CustomFieldForm(forms.ModelForm):
         FieldSet(
             'search_weight', 'filter_logic', 'ui_visible', 'ui_editable', 'weight', 'is_cloneable', name=_('Behavior')
         ),
-        FieldSet('default', 'choice_set', name=_('Values')),
+        FieldSet('default', 'choice_set', 'related_object_filter', name=_('Values')),
         FieldSet(
             'validation_minimum', 'validation_maximum', 'validation_regex', 'validation_unique', name=_('Validation')
         ),

netbox/extras/migrations/0116_customfield_related_object_filter.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.0.7 on 2024-07-19 07:31
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('extras', '0115_convert_dashboard_widgets'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='customfield',
+            name='related_object_filter',
+            field=models.JSONField(blank=True, null=True),
+        ),
+    ]

netbox/extras/models/customfields.py

@@ -154,6 +154,14 @@ class CustomField(CloningMixin, ExportTemplatesMixin, ChangeLoggedModel):
             'Default value for the field (must be a JSON value). Encapsulate strings with double quotes (e.g. "Foo").'
         )
     )
+    related_object_filter = models.JSONField(
+        blank=True,
+        null=True,
+        help_text=_(
+            'Filter the object selection choices using a query_params dict (must be a JSON value).'
+            'Encapsulate strings with double quotes (e.g. "Foo").'
+        )
+    )
     weight = models.PositiveSmallIntegerField(
         default=100,
         verbose_name=_('display weight'),
@@ -511,7 +519,8 @@ def to_form_field(self, set_initial=True, enforce_required=True, enforce_visibil
             field = field_class(
                 queryset=model.objects.all(),
                 required=required,
-                initial=initial
+                initial=initial,
+                query_params=self.related_object_filter
             )
 
         # Multiple objects
@@ -522,6 +531,7 @@ def to_form_field(self, set_initial=True, enforce_required=True, enforce_visibil
                 queryset=model.objects.all(),
                 required=required,
                 initial=initial,
+                query_params=self.related_object_filter
             )
 
         # Text

netbox/extras/tests/test_filtersets.py

@@ -23,7 +23,7 @@
 class CustomFieldTestCase(TestCase, ChangeLoggedFilterSetTests):
     queryset = CustomField.objects.all()
     filterset = CustomFieldFilterSet
-    ignore_fields = ('default',)
+    ignore_fields = ('default', 'related_object_filter')
 
     @classmethod
     def setUpTestData(cls):

netbox/templates/extras/customfield.html

@@ -52,6 +52,10 @@ <h5 class="card-header">{% trans "Custom Field" %}</h5>
           <th scope="row">{% trans "Default Value" %}</th>
           <td>{{ object.default }}</td>
         </tr>
+        <tr>
+          <th scope="row">{% trans "Related object filter" %}</th>
+          <td>{{ object.related_object_filter }}</td>
+        </tr>
       </table>
     </div>
     <div class="card">