Merge branch 'process-elts-cursor-pagination' into 'master'

Custom cursor pagination for process elements

See merge request !1043

arkindex/dataimport/api.py

@@ -13,7 +13,7 @@ from rest_framework.views import APIView
 from rest_framework.response import Response
 from rest_framework import status
 from rest_framework.exceptions import ValidationError
-from arkindex.project.mixins import CorpusACLMixin, SelectionMixin, DeprecatedMixin
+from arkindex.project.mixins import CorpusACLMixin, SelectionMixin, DeprecatedMixin, CustomPaginationViewMixin
 from arkindex.project.permissions import IsVerified
 from arkindex.project.openapi import AutoSchema
 from arkindex.documents.models import Corpus, ElementType, Element, ClassificationState
@@ -861,7 +861,7 @@ class ImportTranskribus(CreateAPIView):
         self.dataimport.start(thumbnails=True)
 
 
-class ListProcessElements(ListAPIView):
+class ListProcessElements(CustomPaginationViewMixin, ListAPIView):
     """
     List all elements for a specific process
     """
@@ -966,4 +966,4 @@ class ListProcessElements(ListAPIView):
         if dataimport.mode not in (DataImportMode.Elements, DataImportMode.Workers):
             return Element.objects.none()
 
-        return self.retrieve_elements(dataimport).order_by('id')
+        return self.retrieve_elements(dataimport)

arkindex/dataimport/tests/test_workflows_api.py

@@ -338,7 +338,7 @@ class TestWorkflows(FixtureAPITestCase):
         response = self.client.get(reverse('api:process-elements-list', kwargs={'pk': dataimport.id}))
         self.assertEqual(response.status_code, status.HTTP_200_OK)
         data = response.json()
-        self.assertEqual(data['count'], 1)
+        self.assertEqual(len(data['results']), 1)
         self.assertEqual(data['results'][0]['id'], str(page.id))
 
     @override_settings(ARKINDEX_FEATURES={'selection': False})

arkindex/project/mixins.py

@@ -8,6 +8,7 @@ from arkindex.documents.models import Corpus, Right
 from arkindex.documents.serializers.search import SearchQuerySerializer
 from arkindex.project.elastic import ESQuerySet
 from arkindex.project.openapi import AutoSchema, SearchAutoSchema
+from arkindex.project.pagination import CustomCursorPagination
 
 
 class CorpusACLMixin(object):
@@ -158,3 +159,22 @@ class CachedViewMixin(object):
                 self.cache_timeout,
                 key_prefix=self.cache_prefix,
             )(self.dispatch)
+
+
+class CustomPaginationViewMixin(object):
+    """
+    A custom cursor pagination mixin
+    Elements count can be retrieved with the `with_count` parameter if there is no cursor
+    """
+    pagination_class = CustomCursorPagination
+
+    @property
+    def paginator(self):
+        if not hasattr(self, '_paginator'):
+            params = self.request.query_params
+            with_count = (
+                not params.get('cursor')
+                and params.get('with_count') not in (None, '', 'false', '0')
+            )
+            self._paginator = self.pagination_class(with_count=with_count)
+        return self._paginator

arkindex/project/pagination.py

@@ -26,3 +26,53 @@ class PageNumberPagination(pagination.PageNumberPagination):
             'example': 123,
         }
         return schema
+
+
+class CustomCursorPagination(pagination.CursorPagination):
+    """
+    A custom cursor pagination class
+    Count attribute and ordering may be updated when instanciating the class
+    """
+    count = None
+    page_size = 20
+    page_size_query_param = 'page_size'
+    max_page_size = 1000
+
+    def __init__(self, *args, **kwargs):
+        self.with_count = kwargs.pop('with_count', False)
+        self.ordering = kwargs.pop('ordering', 'id')
+        super().__init__(*args, **kwargs)
+
+    def paginate_queryset(self, queryset, *args, **kwargs):
+        if self.with_count:
+            self.count = queryset.count()
+        return super().paginate_queryset(queryset, *args, **kwargs)
+
+    def get_paginated_response(self, data):
+        return Response(OrderedDict([
+            ('next', self.get_next_link()),
+            ('previous', self.get_previous_link()),
+            ('count', self.count),
+            ('results', data)
+        ]))
+
+    def get_schema_operation_parameters(self, view):
+        parameters = super().get_schema_operation_parameters(view)
+        parameters.append({
+            'name': 'with_count',
+            'required': False,
+            'in': 'query',
+            'description': 'Count the total number of elements. Incompatible with `cursor` parameter.',
+            'schema': {
+                'type': 'boolean',
+            }
+        })
+        return parameters
+
+    def get_paginated_response_schema(self, schema):
+        schema = super().get_paginated_response_schema(schema)
+        schema['properties']['count'] = {
+            'type': 'integer',
+            'example': None,
+        }
+        return schema