Update BOM API to allow filtering by "uses"

InvenTree/InvenTree/version.py

@@ -12,11 +12,16 @@ import common.models
 INVENTREE_SW_VERSION = "0.6.0 dev"
 
 # InvenTree API version
-INVENTREE_API_VERSION = 17
+INVENTREE_API_VERSION = 18
 
 """
 Increment this API version number whenever there is a significant change to the API that any clients need to know about
 
+v18 -> 2021-11-15
+    - Adds the ability to filter BomItem API by "uses" field
+    - This returns a list of all BomItems which "use" the specified part
+    - Includes inherited BomItem objects
+
 v17 -> 2021-11-09
     - Adds API endpoints for GLOBAL and USER settings objects
     - Ref: https://github.com/inventree/InvenTree/pull/2275

InvenTree/part/api.py

@@ -832,18 +832,6 @@ class PartList(generics.ListCreateAPIView):
 
         queryset = super().filter_queryset(queryset)
 
-        # Filter by "uses" query - Limit to parts which use the provided part
-        uses = params.get('uses', None)
-
-        if uses:
-            try:
-                uses = Part.objects.get(pk=uses)
-
-                queryset = queryset.filter(uses.get_used_in_filter())
-
-            except (ValueError, Part.DoesNotExist):
-                pass
-
         # Exclude specific part ID values?
         exclude_id = []
 
@@ -1211,6 +1199,54 @@ class BomList(generics.ListCreateAPIView):
             except (ValueError, Part.DoesNotExist):
                 pass
 
+        """
+        Filter by 'uses'?
+
+        Here we pass a part ID and return BOM items for any assemblies which "use" (or "require") that part.
+
+        There are multiple ways that an assembly can "use" a sub-part:
+
+        A) Directly specifying the sub_part in a BomItem field
+        B) Specifing a "template" part with inherited=True
+        C) Allowing variant parts to be substituted
+        D) Allowing direct substitute parts to be specified
+
+        - BOM items which are "inherited" by parts which are variants of the master BomItem
+        """
+        uses = params.get('uses', None)
+
+        if uses is not None:
+
+            try:
+                # Extract the part we are interested in
+                uses_part = Part.objects.get(pk=uses)
+
+                # Construct the database query in multiple parts
+
+                # A) Direct specification of sub_part
+                q_A = Q(sub_part=uses_part)
+
+                # B) BomItem is inherited and points to a "parent" of this part
+                parents = uses_part.get_ancestors(include_self=False)
+
+                q_B = Q(
+                    inherited=True,
+                    sub_part__in=parents
+                )
+
+                # C) Substitution of variant parts
+                # TODO
+
+                # D) Specification of individual substitutes
+                # TODO
+
+                q = q_A | q_B
+
+                queryset = queryset.filter(q)
+
+            except (ValueError, Part.DoesNotExist):
+                pass
+
         if self.include_pricing():
             queryset = self.annotate_pricing(queryset)