Added the base report class to ensure that the reports can both be shown on the page and downloaded as CSV.

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

@@ -0,0 +1,40 @@
+# The Mia! Accounting Flask Project.
+# Author: imacat@mail.imacat.idv.tw (imacat), 2023/3/8
+
+#  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 base report.
+
+"""
+from abc import ABC, abstractmethod
+
+from flask import Response
+
+
+class BaseReport(ABC):
+    """The base report class."""
+
+    @abstractmethod
+    def csv(self) -> Response:
+        """Returns the report as CSV for download.
+
+        :return: The response of the report for download.
+        """
+
+    @abstractmethod
+    def html(self) -> str:
+        """Composes and returns the report as HTML.
+
+        :return: The report as HTML.
+        """