Added the "accounting.report.reports.csv_export" module to handle the CSV export in one place.

src/accounting/report/reports/utils/csv_export.py

@@ -0,0 +1,54 @@
+# The Mia! Accounting Flask Project.
+# Author: imacat@mail.imacat.idv.tw (imacat), 2023/3/7
+
+#  Copyright (c) 2023 imacat.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+"""The utility to export the report as CSV for download.
+
+"""
+import csv
+from abc import ABC, abstractmethod
+from decimal import Decimal
+from io import StringIO
+
+from flask import Response
+
+
+class BaseCSVRow(ABC):
+    """The base CSV row."""
+
+    @property
+    @abstractmethod
+    def values(self) -> list[str | Decimal | None]:
+        """Returns the values of the row.
+
+        :return: The values of the row.
+        """
+
+
+def csv_download(filename: str, rows: list[BaseCSVRow]) -> Response:
+    """Exports the data rows as a CSV file for download.
+
+    :param filename: The download file name.
+    :param rows: The data rows.
+    :return: The response for download the CSV file.
+    """
+    with StringIO() as fp:
+        writer = csv.writer(fp)
+        writer.writerows([x.values for x in rows])
+        fp.seek(0)
+        response: Response = Response(fp.read(), mimetype="text/csv")
+        response.headers["Content-Disposition"] \
+            = f"attachment; filename={filename}"
+        return response