Moved the user utilities from the "accounting.database" module to the "accounting.utils.users" module, and simplified its use.

src/accounting/utils/user.py

@@ -0,0 +1,116 @@
+# The Mia! Accounting Flask Project.
+# Author: imacat@mail.imacat.idv.tw (imacat), 2023/2/1
+
+#  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 user utilities.
+
+This module should not import any other module from the application.
+
+"""
+import typing as t
+from abc import ABC, abstractmethod
+
+import sqlalchemy as sa
+from flask_sqlalchemy.model import Model
+
+T = t.TypeVar("T", bound=Model)
+
+
+class AbstractUserUtils(t.Generic[T], ABC):
+    """The abstract user utilities."""
+
+    @property
+    @abstractmethod
+    def cls(self) -> t.Type[T]:
+        """Returns the user class.
+
+        :return: The user class.
+        """
+
+    @property
+    @abstractmethod
+    def pk_column(self) -> sa.Column:
+        """Returns the primary key column.
+
+        :return: The primary key column.
+        """
+
+    @property
+    @abstractmethod
+    def current_user(self) -> T:
+        """Returns the current user.
+
+        :return: The current user.
+        """
+
+    @abstractmethod
+    def get_by_username(self, username: str) -> T | None:
+        """Returns the user by her username.
+
+        :return: The user by her username, or None if the user was not found.
+        """
+
+    @abstractmethod
+    def get_pk(self, user: T) -> int:
+        """Returns the primary key of the user.
+
+        :return: The primary key of the user.
+        """
+
+
+__user_utils: AbstractUserUtils
+"""The user utilities."""
+user_cls: t.Type[Model]
+"""The user class."""
+user_pk_column: sa.Column
+"""The primary key column of the user class."""
+
+
+def init_user_utils(utils: AbstractUserUtils) -> None:
+    """Initializes the user utilities.
+
+    :param utils: The user utilities.
+    :return: None.
+    """
+    global __user_utils, user_cls, user_pk_column
+    __user_utils = utils
+    user_cls = utils.cls
+    user_pk_column = utils.pk_column
+
+
+def get_current_user_pk() -> int:
+    """Returns the primary key value of the currently logged-in user.
+
+    :return: The primary key value of the currently logged-in user.
+    """
+    return __user_utils.get_pk(__user_utils.current_user)
+
+
+def has_user(username: str) -> bool:
+    """Returns whether a user by the username exists.
+
+    :param username: The username.
+    :return: True if the user by the username exists, or False otherwise.
+    """
+    return __user_utils.get_by_username(username) is not None
+
+
+def get_user_pk(username: str) -> int:
+    """Returns the primary key value of the user by the username.
+
+    :param username: The username.
+    :return: The primary key value of the user by the username.
+    """
+    return __user_utils.get_pk(__user_utils.get_by_username(username))