From 40d3b8fe793df6508a1ada55d2a00eff33d5f127 Mon Sep 17 00:00:00 2001
From: Oliver Walters <oliver.henry.walters@gmail.com>
Date: Fri, 19 Jun 2026 01:58:07 +0000
Subject: [PATCH] Refactor into generic components

---
 src/backend/InvenTree/InvenTree/api.py | 41 ++++++++++++++++++++++++++
 src/backend/InvenTree/part/api.py      | 34 +++------------------
 2 files changed, 45 insertions(+), 30 deletions(-)

diff --git a/src/backend/InvenTree/InvenTree/api.py b/src/backend/InvenTree/InvenTree/api.py
index 79b080bb1d..a85498596f 100644
--- a/src/backend/InvenTree/InvenTree/api.py
+++ b/src/backend/InvenTree/InvenTree/api.py
@@ -23,6 +23,7 @@ from rest_framework.serializers import ValidationError
 from rest_framework.views import APIView
 
 import InvenTree.config
+import InvenTree.filters
 import InvenTree.permissions
 import InvenTree.version
 from common.settings import get_global_setting
@@ -963,3 +964,43 @@ def meta_path(model, lookup_field: str = 'pk', lookup_field_ref: str = 'pk'):
             lookup_field_ref=lookup_field_ref,
         ),
     )
+
+
+class TreeMixin:
+    """A mixin class for supporting tree-structured data in the API."""
+
+    # Any API view which inherits from this mixin must define a 'model_class' attribute
+    model_class = None
+
+    filter_backends = InvenTree.filters.SEARCH_ORDER_FILTER
+    search_fields = ['name', 'description']
+    ordering_fields = ['level', 'name', 'subcategories']
+    ordering_field_aliases = {'level': ['level', 'name'], 'name': ['name', 'level']}
+    ordering = ['level']
+
+    def filter_queryset(self, queryset):
+        """Filter the queryset, and provide extra support for tree-structured data."""
+        queryset = super().filter_queryset(queryset)
+
+        # If a search term is provided, include all ancestors of matched items in the results
+        if self.request.query_params.get('search', '').strip():
+            ancestors = self.model_class.objects.get_queryset_ancestors(
+                queryset, include_self=True
+            )
+            queryset = queryset | ancestors
+
+        # If a specific ID is provided to "expand_to", include all ancestors and siblings
+        if expand_to := self.request.query_params.get('expand_to'):
+            try:
+                target = self.model_class.objects.get(pk=int(expand_to))
+                target_ancestors = target.get_ancestors(include_self=True)
+                queryset = queryset | target_ancestors
+
+                # We also want to include the "sibling" nodes of the expanded item
+                siblings = target.get_siblings(include_self=True)
+                queryset = queryset | siblings
+
+            except (self.model_class.DoesNotExist, ValueError):
+                pass
+
+        return queryset.distinct()
diff --git a/src/backend/InvenTree/part/api.py b/src/backend/InvenTree/part/api.py
index 7e4e7fde9f..75e71e579b 100644
--- a/src/backend/InvenTree/part/api.py
+++ b/src/backend/InvenTree/part/api.py
@@ -21,6 +21,7 @@ from InvenTree.api import (
     BulkUpdateMixin,
     ListCreateDestroyAPIView,
     ParameterListMixin,
+    TreeMixin,
     meta_path,
 )
 from InvenTree.fields import InvenTreeOutputOption, OutputConfiguration
@@ -304,23 +305,14 @@ class CategoryTreeFilter(FilterSet):
         return queryset.filter(level__lte=value)
 
 
-class CategoryTree(ListAPI):
+class CategoryTree(TreeMixin, ListAPI):
     """API endpoint for accessing a list of PartCategory objects ready for rendering a tree."""
 
+    model_class = PartCategory
     queryset = PartCategory.objects.all()
     serializer_class = part_serializers.CategoryTree
     filterset_class = CategoryTreeFilter
 
-    filter_backends = SEARCH_ORDER_FILTER
-
-    search_fields = ['name', 'description']
-    ordering_fields = ['level', 'name', 'subcategories']
-
-    ordering_field_aliases = {'level': ['level', 'name'], 'name': ['name', 'level']}
-
-    # Order by tree level (top levels first) and then name
-    ordering = ['level']
-
     def get_queryset(self, *args, **kwargs):
         """Return an annotated queryset for the CategoryTree endpoint."""
         queryset = super().get_queryset(*args, **kwargs)
@@ -330,25 +322,7 @@ class CategoryTree(ListAPI):
     def filter_queryset(self, queryset):
         """Filter the queryset, and include all ancestors of matched items when searching."""
         queryset = super().filter_queryset(queryset)
-
-        # If a search term is provided, include all ancestors of matched items in the results
-        if self.request.query_params.get('search', '').strip():
-            ancestors = PartCategory.objects.get_queryset_ancestors(
-                queryset, include_self=True
-            )
-            queryset = (queryset | ancestors).distinct()
-            queryset = part_serializers.CategoryTree.annotate_queryset(queryset)
-
-        # If a specific ID is provided to "expand_to", include all ancestors of that item in the results
-        expand_to = self.request.query_params.get('expand_to')
-        if expand_to:
-            try:
-                target = PartCategory.objects.get(pk=int(expand_to))
-                ancestors = target.get_ancestors(include_self=True)
-                queryset = (queryset | ancestors).distinct()
-                queryset = part_serializers.CategoryTree.annotate_queryset(queryset)
-            except (PartCategory.DoesNotExist, ValueError):
-                pass
+        queryset = part_serializers.CategoryTree.annotate_queryset(queryset)
 
         return queryset