Merge pull request projectcaluma#470 from open-dynaMIX/offset_pagination

feat(pagination): implement offset pagination

Author: open-dynaMIX

caluma/core/filters.py

@@ -171,9 +171,23 @@ def __init__(self, label, *args, fields=tuple(), **kwargs):
         )
 
 
+class IntegerFilter(Filter):
+    field_class = forms.IntegerField
+
+
 class FilterSet(GrapheneFilterSetMixin, FilterSet):
     created_by_user = CharFilter()
     created_by_group = CharFilter()
+    offset = IntegerFilter(method="filter_offset")
+    limit = IntegerFilter(method="filter_limit")
+
+    @staticmethod
+    def filter_offset(queryset, name, value):
+        return queryset[value:]
+
+    @staticmethod
+    def filter_limit(queryset, name, value):
+        return queryset[:value]
 
     @classmethod
     def filter_for_lookup(cls, field, lookup_type):

caluma/core/tests/test_pagination.py

@@ -0,0 +1,28 @@
+def test_offset_pagination(db, schema_executor, document_factory):
+    document_factory(meta={"position": 0})
+    document_factory(meta={"position": 1})
+    document_factory(meta={"position": 2})
+    document_factory(meta={"position": 3})
+    document_factory(meta={"position": 4})
+
+    query = """
+        query AllDocumentsQuery {
+          allDocuments(limit: 2, offset: 2) {
+            totalCount
+            edges {
+              node {
+                id
+                meta
+              }
+            }
+          }
+        }
+    """
+
+    result = schema_executor(query)
+
+    assert not result.errors
+    assert len(result.data["allDocuments"]["edges"]) == 2
+    assert result.data["allDocuments"]["totalCount"] == 2
+    assert result.data["allDocuments"]["edges"][0]["node"]["meta"]["position"] == 2
+    assert result.data["allDocuments"]["edges"][1]["node"]["meta"]["position"] == 3