Merge pull request #1258 from pyriku/delete-signals-destroy-model-mixin

Adds pre_delete and post_delete hooks on `DestroyModelMixin`

docs/api-guide/generic-views.md

@@ -163,12 +163,14 @@ For example:
             return 20
         return 100
 
-**Save hooks**:
+**Save / deletion hooks**:
 
 The following methods are provided as placeholder interfaces.  They contain empty implementations and are not called directly by `GenericAPIView`, but they are overridden and used by some of the mixin classes.
 
 * `pre_save(self, obj)` - A hook that is called before saving an object.
 * `post_save(self, obj, created=False)` - A hook that is called after saving an object.
+* `pre_delete(self, obj)` - A hook that is called before deleting an object.
+* `post_delete(self, obj)` - A hook that is called after deleting an object.
 
 The `pre_save` method in particular is a useful hook for setting attributes that are implicit in the request, but are not part of the request data.  For instance, you might set an attribute on the object based on the request user, or based on a URL keyword argument.
 

rest_framework/generics.py

@@ -344,6 +344,18 @@ class GenericAPIView(views.APIView):
         """
         pass
 
+    def pre_delete(self, obj):
+        """
+        Placeholder method for calling before deleting an object.
+        """
+        pass
+
+    def post_delete(self, obj):
+        """
+        Placeholder method for calling after saving an object.
+        """
+        pass
+
     def metadata(self, request):
         """
         Return a dictionary of metadata about the view.

rest_framework/mixins.py

@@ -192,5 +192,7 @@ class DestroyModelMixin(object):
     """
     def destroy(self, request, *args, **kwargs):
         obj = self.get_object()
+        self.pre_delete(obj)
         obj.delete()
+        self.post_delete(obj)
         return Response(status=status.HTTP_204_NO_CONTENT)