Add xlsx_auto_filter option (#115)

* Add xlsx_auto_filter option

Filters can automatically be added to the header row by setting xlsx_auto_filter.

* Reformat with Ruff

* Fix type hint for fixture

* Tweak test for readability

---------

Co-authored-by: Bruno Alla <[email protected]>

Author: nathan-osman

README.md

@@ -235,6 +235,10 @@ By default, headers will use the same 'names' as they are returned by the API. T
 
 Instead of using the field names, the export will use the labels as they are defined inside your Serializer. A serializer field defined as `title = serializers.CharField(label=_("Some title"))` would return `Some title` instead of `title`, also supporting translations. If no label is set, it will fall back to using `title`.
 
+### Auto filter header fields
+
+Filters can automatically be added to the header row by setting `xlsx_auto_filter = True`. The filter will include all header columns in the worksheet.
+
 ### Ignore fields
 
 By default, all fields are exported, but you might want to exclude some fields from your export. To do so, you can set an array with fields you want to exclude: `xlsx_ignore_headers = [<excluded fields>]`.

drf_excel/renderers.py

@@ -94,6 +94,9 @@ def render(self, data, accepted_media_type=None, renderer_context=None):
         # Make column headers
         column_titles = column_header.get("titles", [])
 
+        # Check for auto_filter
+        auto_filter = get_attribute(drf_view, "xlsx_auto_filter", False)
+
         # If we have results, then flatten field names
         if len(results):
             # Set `xlsx_use_labels = True` inside the API View to enable labels.
@@ -216,6 +219,10 @@ def render(self, data, accepted_media_type=None, renderer_context=None):
                 self._make_body(body, row, row_count)
                 row_count += 1
 
+        # Enable auto filters if requested
+        if auto_filter and column_count:
+            self.ws.auto_filter.ref = f"A1:{get_column_letter(column_count)}{row_count}"
+
         # Set sheet view options
         # Example:
         # sheet_view_options = {

tests/conftest.py

@@ -18,9 +18,9 @@ def worksheet(workbook: Workbook) -> Worksheet:
 
 
 @pytest.fixture
-def workbook_reader() -> Callable[[Union[bytes, str]], Workbook]:
-    def reader_func(buffer: Union[bytes, str]) -> Workbook:
+def workbook_reader() -> Callable[[Union[bytes, str], bool], Workbook]:
+    def reader_func(buffer: Union[bytes, str], read_only: bool = True) -> Workbook:
         io_buffer = io.BytesIO(buffer)
-        return load_workbook(io_buffer, read_only=True)
+        return load_workbook(io_buffer, read_only=read_only)
 
     return reader_func

tests/test_viewset_mixin.py

@@ -126,3 +126,16 @@ def test_dynamic_field_viewset(api_client, workbook_reader):
 
     row_1_values = [cell.value for cell in data]
     assert row_1_values == ["YUL", "CDG", "YYZ", "MAR"]
+
+
+def test_auto_filter_viewset(api_client, workbook_reader):
+    ExampleModel.objects.create(title="test 1", description="This is a test")
+
+    response = api_client.get("/auto-filter/")
+    assert response.status_code == 200
+
+    # Note: auto_filter.ref is not available for read-only workbooks
+    wb = workbook_reader(response.content, read_only=False)
+    sheet = wb.worksheets[0]
+
+    assert sheet.auto_filter.ref == "A1:B2"

tests/testapp/views.py

@@ -51,3 +51,11 @@ def list(self, request, *args, **kwargs):
         )
         serializer.is_valid(raise_exception=True)
         return Response(serializer.data)
+
+
+class AutoFilterViewSet(XLSXFileMixin, ReadOnlyModelViewSet):
+    queryset = ExampleModel.objects.all()
+    serializer_class = ExampleSerializer
+    renderer_classes = (XLSXRenderer,)
+
+    xlsx_auto_filter = True

tests/urls.py

@@ -2,6 +2,7 @@
 
 from .testapp.views import (
     AllFieldsViewSet,
+    AutoFilterViewSet,
     DynamicFieldViewSet,
     ExampleViewSet,
     SecretFieldViewSet,
@@ -12,5 +13,6 @@
 router.register(r"all-fields", AllFieldsViewSet)
 router.register(r"secret-field", SecretFieldViewSet)
 router.register(r"dynamic-field", DynamicFieldViewSet, basename="dynamic-field")
+router.register(r"auto-filter", AutoFilterViewSet, basename="auto-filter")
 
 urlpatterns = router.urls