From 3b00a352a5c71747175f7c5d5eb6c0720592e9b8 Mon Sep 17 00:00:00 2001
From: Konrad Mohrfeldt <konrad.mohrfeldt@farbdev.org>
Date: Thu, 23 Jan 2025 15:52:37 +0100
Subject: [PATCH] feat: add reorder view mixin
This mixin factory makes it easy to create atomic reorder operations for
entities that have a static numeric order criteria that is supposed to
be updated by clients.
---
program/utils.py | 91 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 91 insertions(+)
diff --git a/program/utils.py b/program/utils.py
index ca5e478..b07758f 100644
--- a/program/utils.py
+++ b/program/utils.py
@@ -24,7 +24,13 @@ from datetime import date, datetime, time
from typing import Any, Callable, Dict, Hashable, Optional, Tuple, Union
import requests
+from drf_spectacular.utils import OpenApiExample, extend_schema
+from rest_framework import serializers
+from rest_framework.decorators import action
+from rest_framework.request import Request
+from rest_framework.response import Response
+from django import db
from django.conf import settings
from django.utils import timezone
from program.models import Episode, EpisodeLink, Profile, ProfileLink, Show, ShowLink
@@ -247,3 +253,88 @@ def saves_relationships_to(*field_names):
return wrapper
return relationship_update_decorator
+
+
+def reorder_mixin_factory(
+ order_field_name: str | None = None,
+ id_field_type: type[serializers.Field] = serializers.IntegerField,
+ serializer_class: type[serializers.Serializer] | None = None,
+):
+ """
+ Factory function that creates a mixin for handling bulk reordering of objects in a ViewSet.
+
+ :param order_field_name: the field that stores the ordinal
+ :param id_field_type: the field type that stores the id
+ :param serializer_class: Optional custom response serializer for the endpoint
+ :returns: the parameterized mixin class for the ViewSet
+ """
+
+ class ReorderItemSerializer(serializers.Serializer):
+ id = id_field_type()
+ order = serializers.IntegerField(source=order_field_name)
+
+ def __init__(self, *args, **kwargs):
+ super().__init__(*args, **kwargs)
+ # Get the model from the parent's context if available
+ if self.parent and getattr(self.parent, "context", None):
+ viewset = self.parent.context.get("view")
+ if viewset:
+ self.fields["id"].queryset = viewset.get_queryset()
+
+ class ReorderRequestSerializer(serializers.Serializer):
+ orderings = ReorderItemSerializer(many=True)
+
+ class ReorderMixin:
+ @extend_schema(
+ methods=["patch"],
+ request=ReorderRequestSerializer,
+ responses={200: serializer_class} if serializer_class else {204: None},
+ examples=[
+ OpenApiExample(
+ "Reorder Example",
+ value={
+ "orderings": [
+ {"id": 1, "order": 5},
+ {"id": 2, "order": 2},
+ {"id": 3, "order": 1},
+ ]
+ },
+ description="Example request to reorder multiple objects",
+ )
+ ],
+ description="Reorder multiple objects in a single operation.",
+ summary="Bulk reorder objects",
+ )
+ @action(
+ detail=False,
+ methods=["patch"],
+ url_path="reorder",
+ serializer_class=ReorderRequestSerializer,
+ )
+ def reorder(self, request: Request) -> Response:
+ serializer = ReorderRequestSerializer(data=request.data)
+ serializer.is_valid(raise_exception=True)
+
+ new_orderings = serializer.validated_data["orderings"]
+ requested_obj_ids = [ordering["id"] for ordering in new_orderings]
+ model = self.get_queryset().model
+ obj_ids = model.objects.filter(id__in=requested_obj_ids).values_list("id", flat=True)
+ update_map = {
+ ordering["id"]: ordering["order"]
+ for ordering in new_orderings
+ if ordering["id"] in obj_ids
+ }
+
+ with db.transaction.atomic():
+ objects = model.objects.select_for_update().filter(id__in=update_map.keys())
+
+ for pk, order in update_map.items():
+ objects.filter(id=pk).update(**{order_field_name or "order": order})
+
+ if serializer_class:
+ updated_objects = self.get_queryset().filter(id__in=update_map.keys())
+ response_serializer = serializer_class(updated_objects, many=True)
+ return Response(response_serializer.data)
+ return Response(status=204)
+
+ return ReorderMixin
--
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