Add new option xlsx_specify_headers

README.md

@@ -239,11 +239,13 @@ Instead of using the field names, the export will use the labels as they are def
 
 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
+### Specify or 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>]`.
+By default, all fields are exported. However, this behavior can be changed.
 
-This also works with nested fields, separated with a dot (i.e. `icon.url`).
+To include only a specified list of fields, provide them with: `xlsx_specify_headers = [<fields to include>]`. Conversely, to exclude certain fields from your export, provide them with: `xlsx_ignore_headers = [<excluded fields>]`.
+
+These both work with nested fields, separated with a dot (i.e. `icon.url`).
 
 ### Date/time and number formatting
 Formatting for cells follows [openpyxl formats](https://openpyxl.readthedocs.io/en/stable/_modules/openpyxl/styles/numbers.html).

drf_excel/renderers.py

@@ -42,6 +42,7 @@ class XLSXRenderer(BaseRenderer):
     format = "xlsx"  # Reserved word, but required by BaseRenderer
     combined_header_dict = {}
     fields_dict = {}
+    specify_headers = None
     ignore_headers = []
     boolean_display = None
     column_data_styles = None
@@ -102,7 +103,8 @@ def render(self, data, accepted_media_type=None, renderer_context=None):
             # Set `xlsx_use_labels = True` inside the API View to enable labels.
             use_labels = getattr(drf_view, "xlsx_use_labels", False)
 
-            # A list of header keys to ignore in our export
+            # A list of header keys to use or ignore in our export
+            self.specify_headers = getattr(drf_view, "xlsx_specify_headers", None)
             self.ignore_headers = getattr(drf_view, "xlsx_ignore_headers", [])
 
             # Create a mapping dict named `xlsx_boolean_labels` inside the API View.
@@ -284,8 +286,13 @@ def _get_label(parent_label, label_sep, obj):
         _fields = serializer.fields
         for k, v in _fields.items():
             new_key = f"{parent_key}{key_sep}{k}" if parent_key else k
-            # Skip headers we want to ignore
-            if new_key in self.ignore_headers or getattr(v, "write_only", False):
+            # Skip headers that weren't in the list (if present) or were specifically ignored
+            if (
+                self.specify_headers is not None
+                and new_key not in self.specify_headers
+                or new_key in self.ignore_headers
+                or getattr(v, "write_only", False)
+            ):
                 continue
             # Iterate through fields if field is a serializer. Check for labels and
             # append if `use_labels` is True. Fallback to using keys.

tests/test_viewset_mixin.py

@@ -139,3 +139,19 @@ def test_auto_filter_viewset(api_client, workbook_reader):
     sheet = wb.worksheets[0]
 
     assert sheet.auto_filter.ref == "A1:B2"
+
+
+def test_specify_headers(api_client, workbook_reader):
+    AllFieldsModel.objects.create(title="Hello", age=36)
+
+    response = api_client.get("/specify-headers/")
+    assert response.status_code == 200
+
+    wb = workbook_reader(response.content)
+    sheet = wb.worksheets[0]
+
+    header, data = list(sheet.rows)
+
+    assert len(header) == 1
+    assert len(data) == 1
+    assert header[0].value == "title"

tests/testapp/views.py

@@ -59,3 +59,11 @@ class AutoFilterViewSet(XLSXFileMixin, ReadOnlyModelViewSet):
     renderer_classes = (XLSXRenderer,)
 
     xlsx_auto_filter = True
+
+
+class SpecifyHeadersViewSet(XLSXFileMixin, ReadOnlyModelViewSet):
+    queryset = AllFieldsModel.objects.all()
+    serializer_class = AllFieldsSerializer
+    renderer_classes = (XLSXRenderer,)
+
+    xlsx_specify_headers = ["title"]

tests/urls.py

@@ -6,6 +6,7 @@
     DynamicFieldViewSet,
     ExampleViewSet,
     SecretFieldViewSet,
+    SpecifyHeadersViewSet,
 )
 
 router = routers.SimpleRouter()
@@ -14,5 +15,6 @@
 router.register(r"secret-field", SecretFieldViewSet)
 router.register(r"dynamic-field", DynamicFieldViewSet, basename="dynamic-field")
 router.register(r"auto-filter", AutoFilterViewSet, basename="auto-filter")
+router.register(r"specify-headers", SpecifyHeadersViewSet, basename="specify-headers")
 
 urlpatterns = router.urls