API updates

- Fix options for model_type
- Add API filters

src/backend/InvenTree/common/api.py

@@ -772,7 +772,7 @@ class ParameterTemplateFilter(FilterSet):
         """Metaclass options."""
 
         model = common.models.ParameterTemplate
-        fields = ['name', 'units', 'checkbox']
+        fields = ['model_type', 'name', 'units', 'checkbox']
 
     has_choices = rest_filters.BooleanFilter(
         method='filter_has_choices', label='Has Choice'
@@ -794,6 +794,18 @@ class ParameterTemplateFilter(FilterSet):
 
         return queryset.filter(Q(units=None) | Q(units='')).distinct()
 
+    for_model = rest_filters.CharFilter(method='filter_for_model', label='For Model')
+
+    def filter_for_model(self, queryset, name, value):
+        """Filter queryset to include only ParameterTemplates which apply to the given model.
+
+        Note that this varies from the 'model_type' filter, in that ParameterTemplates
+        with a blank 'model_type' are considered to apply to all models.
+        """
+        return queryset.filter(
+            Q(model_type__iexact=value) | Q(model_type__isnull=True) | Q(model_type='')
+        ).distinct()
+
 
 class ParameterTemplateMixin:
     """Mixin class for ParameterTemplate views."""

src/backend/InvenTree/common/models.py

@@ -72,21 +72,14 @@ class RenderMeta(enums.ChoicesMeta):
     """Metaclass for rendering choices."""
 
     choice_fnc = None
-    allow_blank: bool = False
-    blank_label: str = '------'
 
     @property
     def choices(self):
         """Return a list of choices for the enum class."""
         fnc = getattr(self, 'choice_fnc', None)
         if fnc:
-            options = fnc()
-        options = []
-
-        if self.allow_blank:
-            options.insert(0, ('', self.blank_label))
-
-        return options
+            return fnc()
+        return []
 
 
 class RenderChoices(models.TextChoices, metaclass=RenderMeta):  # type: ignore
@@ -2395,8 +2388,7 @@ class ParameterTemplate(
     class ModelChoices(RenderChoices):
         """Model choices for parameter templates."""
 
-        allow_blank = True
-        choice_fnc = common.validators.parameter_model_options
+        choice_fnc = common.validators.parameter_template_model_options
 
     @staticmethod
     def get_api_url() -> str:

src/backend/InvenTree/common/serializers.py

@@ -724,13 +724,13 @@ class ParameterTemplateSerializer(
         if len(self.fields['model_type'].choices) == 0:
             self.fields[
                 'model_type'
-            ].choices = common.validators.attachment_model_options()
+            ].choices = common.validators.parameter_template_model_options()
 
     # Note: The choices are overridden at run-time on class initialization
     model_type = serializers.ChoiceField(
         label=_('Model Type'),
         default='',
-        choices=common.validators.attachment_model_options(),
+        choices=common.validators.parameter_template_model_options(),
         required=False,
         allow_blank=True,
         allow_null=True,

src/backend/InvenTree/common/validators.py

@@ -29,6 +29,14 @@ def parameter_model_options():
     ]
 
 
+def parameter_template_model_options():
+    """Return a list of options for models which support parameter templates.
+
+    Note: This includes a blank option at the start, since ParameterTemplate.model_type may be blank.
+    """
+    return [('', _('Any model type')), *parameter_model_options()]
+
+
 def validate_parameter_model_type(value: str):
     """Ensure that the provided parameter model is valid."""
     model_names = [el[0] for el in parameter_model_options()]

src/backend/InvenTree/part/models.py

@@ -410,6 +410,7 @@ class PartReportContext(report.mixins.BaseReportContext):
 @cleanup.ignore
 class Part(
     InvenTree.models.PluginValidationMixin,
+    InvenTree.models.InvenTreeParameterMixin,
     InvenTree.models.InvenTreeAttachmentMixin,
     InvenTree.models.InvenTreeBarcodeMixin,
     InvenTree.models.InvenTreeNotesMixin,