From 687bf9924b80f10e852d69eaa78c291c3dd99763 Mon Sep 17 00:00:00 2001
From: Tom Hacohen <tom@stosb.com>
Date: Thu, 16 Apr 2020 16:37:26 +0300
Subject: [PATCH] API: change how pagination and stoken are done

---
 django_etesync/paginators.py | 36 ----------------------------
 django_etesync/views.py      | 46 +++++++++++++++++++++++++++++++-----
 2 files changed, 40 insertions(+), 42 deletions(-)
 delete mode 100644 django_etesync/paginators.py

diff --git a/django_etesync/paginators.py b/django_etesync/paginators.py
deleted file mode 100644
index 6d55599..0000000
--- a/django_etesync/paginators.py
+++ /dev/null
@@ -1,36 +0,0 @@
-# Copyright © 2017 Tom Hacohen
-#
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU Affero General Public License as
-# published by the Free Software Foundation, version 3.
-#
-# This library is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program. If not, see <http://www.gnu.org/licenses/>.
-
-from rest_framework import pagination
-from rest_framework.response import Response
-
-
-class LinkHeaderPagination(pagination.LimitOffsetPagination):
-    def get_paginated_response(self, data):
-        next_url = self.get_next_link()
-        previous_url = self.get_previous_link()
-
-        if next_url is not None and previous_url is not None:
-            link = '<{next_url}>; rel="next", <{previous_url}>; rel="prev"'
-        elif next_url is not None:
-            link = '<{next_url}>; rel="next"'
-        elif previous_url is not None:
-            link = '<{previous_url}>; rel="prev"'
-        else:
-            link = ''
-
-        link = link.format(next_url=next_url, previous_url=previous_url)
-        headers = {'Link': link} if link else {}
-
-        return Response(data, headers=headers)
diff --git a/django_etesync/views.py b/django_etesync/views.py
index 6c2faf3..df22068 100644
--- a/django_etesync/views.py
+++ b/django_etesync/views.py
@@ -24,8 +24,8 @@ from rest_framework import parsers
 from rest_framework.decorators import action as action_decorator
 from rest_framework.response import Response
 
-from . import app_settings, paginators
-from .models import Collection, CollectionItem
+from . import app_settings
+from .models import Collection, CollectionItem, CollectionItemRevision
 from .serializers import (
         CollectionSerializer,
         CollectionItemSerializer,
@@ -61,8 +61,9 @@ class CollectionViewSet(BaseViewSet):
     serializer_class = CollectionSerializer
     lookup_field = 'uid'
 
-    def get_queryset(self):
-        queryset = type(self).queryset
+    def get_queryset(self, queryset=None):
+        if queryset is None:
+            queryset = type(self).queryset
         return self.get_collection_queryset(queryset)
 
     def get_serializer_context(self):
@@ -89,10 +90,24 @@ class CollectionViewSet(BaseViewSet):
         return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
 
     def list(self, request):
+        stoken = request.GET.get('stoken', None)
+        limit = int(request.GET.get('limit', 50))
+
         queryset = self.get_queryset()
 
+        if stoken is not None:
+            last_rev = get_object_or_404(CollectionItemRevision.objects.all(), uid=stoken)
+            queryset = queryset.filter(items__revisions__id__gt=last_rev.id)
+
+        queryset = queryset[:limit]
+
         serializer = self.serializer_class(queryset, context=self.get_serializer_context(), many=True)
-        return Response(serializer.data)
+
+        new_stoken = serializer.data[-1]['stoken'] if len(serializer.data) > 0 else stoken
+        ret = {
+            'data': serializer.data,
+        }
+        return Response(ret, headers={'X-EteSync-SToken': new_stoken})
 
 
 class CollectionItemViewSet(BaseViewSet):
@@ -100,7 +115,6 @@ class CollectionItemViewSet(BaseViewSet):
     permission_classes = BaseViewSet.permission_classes
     queryset = CollectionItem.objects.all()
     serializer_class = CollectionItemSerializer
-    pagination_class = paginators.LinkHeaderPagination
     lookup_field = 'uid'
 
     def get_queryset(self):
@@ -148,6 +162,26 @@ class CollectionItemViewSet(BaseViewSet):
         # FIXME: implement, or should it be implemented elsewhere?
         return Response(status=status.HTTP_405_METHOD_NOT_ALLOWED)
 
+    def list(self, request, collection_uid=None):
+        stoken = request.GET.get('stoken', None)
+        limit = int(request.GET.get('limit', 50))
+
+        queryset = self.get_queryset()
+
+        if stoken is not None:
+            last_rev = get_object_or_404(CollectionItemRevision.objects.all(), uid=stoken)
+            queryset = queryset.filter(revisions__id__gt=last_rev.id)
+
+        queryset = queryset[:limit]
+
+        serializer = self.serializer_class(queryset, context=self.get_serializer_context(), many=True)
+
+        new_stoken = serializer.data[-1]['content']['uid'] if len(serializer.data) > 0 else stoken
+        ret = {
+            'data': serializer.data,
+        }
+        return Response(ret, headers={'X-EteSync-SToken': new_stoken})
+
     @action_decorator(detail=True, methods=['GET'])
     def revision(self, request, collection_uid=None, uid=None):
         col = get_object_or_404(self.get_collection_queryset(Collection.objects), uid=collection_uid)