Add new option xlsx_specify_headers

README.md

@@ -235,11 +235,13 @@ 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`.
 
-### 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
@@ -99,7 +100,8 @@ 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.
@@ -277,8 +279,10 @@ 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

@@ -126,3 +126,19 @@ 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_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

@@ -51,3 +51,11 @@ def list(self, request, *args, **kwargs):
         )
         serializer.is_valid(raise_exception=True)
         return Response(serializer.data)
+
+
+class SpecifyHeadersViewSet(XLSXFileMixin, ReadOnlyModelViewSet):
+    queryset = AllFieldsModel.objects.all()
+    serializer_class = AllFieldsSerializer
+    renderer_classes = (XLSXRenderer,)
+
+    xlsx_specify_headers = ['title']

tests/urls.py

@@ -5,12 +5,14 @@
     DynamicFieldViewSet,
     ExampleViewSet,
     SecretFieldViewSet,
+    SpecifyHeadersViewSet,
 )
 
 router = routers.SimpleRouter()
 router.register(r"examples", ExampleViewSet)
 router.register(r"all-fields", AllFieldsViewSet)
 router.register(r"secret-field", SecretFieldViewSet)
 router.register(r"dynamic-field", DynamicFieldViewSet, basename="dynamic-field")
+router.register(r"specify-headers", SpecifyHeadersViewSet, basename="specify-headers")
 
 urlpatterns = router.urls