feat(users): Add deleted attribute to users.

This allows us to filter out deleted users which could not be deleted and
had to be soft-deleted.
Meaning: users which still had foreign keys on the database,
from e.g. disabled plugins.

flaschengeist/controller/userController.py

@@ -12,6 +12,7 @@ from flaschengeist.database import db
 from flaschengeist.models.notification import Notification
 from flaschengeist.utils.hook import Hook
 from flaschengeist.utils.datetime import from_iso_format
+from flaschengeist.utils.foreign_keys import merge_references
 from flaschengeist.models.user import User, Role, _PasswordReset
 from flaschengeist.controller import imageController, messageController, sessionController
 
@@ -33,10 +34,6 @@ def _generate_password_reset(user):
     return reset
 
 
-def install():
-    pass
-
-
 def login_user(username, password):
     logger.info("login user {{ {} }}".format(username))
 
@@ -125,23 +122,24 @@ def modify_user(user, password, new_password=None):
         messageController.send_message(messageController.Message(user, text, subject))
 
 
-def get_users():
-    return User.query.all()
+def get_users(deleted=False):
+    return User.query.filter(User.deleted == deleted).all()
 
 
 def get_user_by_role(role: Role):
     return User.query.join(User.roles_).filter_by(role_id=role.id).all()
 
 
-def get_user(uid):
+def get_user(uid, deleted=False):
     """Get an user by userid from database
     Args:
         uid: Userid to search for
+        deleted: Set to true to also search deleted users
     Returns:
         User fround
     Raises:
         NotFound if not found"""
-    user = User.query.filter(User.userid == uid).one_or_none()
+    user = User.query.filter(User.userid == uid, User.deleted == deleted).one_or_none()
     if not user:
         raise NotFound
     return user
@@ -184,9 +182,19 @@ def delete_user(user: User):
     user.roles_.clear()
     user.sessions_.clear()
     user.reset_requests_.clear()
-    db.session.commit()
+    # Now move all other references to the DELETED_USER
+    try:
+        deleted_user = get_user("__deleted_user__", True)
+    except NotFound:
+        deleted_user = User(
+            userid="__deleted_user__", firstname="USER", lastname="DELETED", display_name="DELETED USER", deleted=True
+        )
+        db.session.add(user)
+        db.session.flush()
+    merge_references(user, deleted_user)
+    db.session.commit()
+    # Now try to delete the user for real
     try:
-        # Delete the user
         db.session.delete(user)
         db.session.commit()
     except exc.IntegrityError:
@@ -196,6 +204,7 @@ def delete_user(user: User):
         user.display_name = "DELETED USER"
         user.firstname = ""
         user.lastname = ""
+        user.deleted = True
         user.birthday = None
         user.mail = None
         db.session.commit()

flaschengeist/models/user.py

@@ -57,8 +57,9 @@ class User(db.Model, ModelSerializeMixin):
     display_name: str = db.Column(db.String(30))
     firstname: str = db.Column(db.String(50), nullable=False)
     lastname: str = db.Column(db.String(50), nullable=False)
-    mail: str = db.Column(db.String(60))
+    deleted: bool = db.Column(db.Boolean(), default=False)
     birthday: Optional[date] = db.Column(db.Date)
+    mail: str = db.Column(db.String(60))
     roles: list[str] = []
     permissions: Optional[list[str]] = None
 

flaschengeist/plugins/auth_plain/__init__.py

@@ -15,7 +15,7 @@ from flaschengeist import logger
 
 class AuthPlain(AuthPlugin):
     def post_install(self):
-        if User.query.first() is None:
+        if User.query.filter(User.deleted == False).count() == 0:
             logger.info("Installing admin user")
             role = Role.query.filter(Role.name == "Superuser").first()
             if role is None:

flaschengeist/plugins/users/__init__.py

@@ -22,10 +22,6 @@ class UsersPlugin(Plugin):
     blueprint = Blueprint(name, __name__)
     permissions = permissions.permissions
 
-    def install(self):
-        userController.install()
-        return super().install()
-
 
 @UsersPlugin.blueprint.route("/users", methods=["POST"])
 def register():
@@ -93,7 +89,9 @@ def get_user(userid, current_session):
         JSON encoded `flaschengeist.models.user.User` or if userid is current user also containing permissions or HTTP error
     """
     logger.debug("Get information of user {{ {} }}".format(userid))
-    user: User = userController.get_user(userid)
+    user: User = userController.get_user(
+        userid, True
+    )  # This is the only API point that should return data for deleted users
     serial = user.serialize()
     if userid == current_session.user_.userid:
         serial["permissions"] = user.get_permissions()

flaschengeist/utils/foreign_keys.py

@@ -0,0 +1,51 @@
+# Borrowed from https://github.com/kvesteri/sqlalchemy-utils
+# Modifications see: https://github.com/kvesteri/sqlalchemy-utils/issues/561
+# LICENSED under the BSD license, see upstream https://github.com/kvesteri/sqlalchemy-utils/blob/master/LICENSE
+
+import sqlalchemy as sa
+from sqlalchemy.orm import object_session
+
+
+def get_foreign_key_values(fk, obj):
+    mapper = sa.inspect(obj.__class__)
+    return dict(
+        (
+            fk.constraint.columns.values()[index],
+            getattr(obj, element.column.key)
+            if hasattr(obj, element.column.key)
+            else getattr(obj, mapper.get_property_by_column(element.column).key),
+        )
+        for index, element in enumerate(fk.constraint.elements)
+    )
+
+
+def get_referencing_foreign_keys(mixed):
+    tables = [mixed]
+    referencing_foreign_keys = set()
+
+    for table in mixed.metadata.tables.values():
+        if table not in tables:
+            for constraint in table.constraints:
+                if isinstance(constraint, sa.sql.schema.ForeignKeyConstraint):
+                    for fk in constraint.elements:
+                        if any(fk.references(t) for t in tables):
+                            referencing_foreign_keys.add(fk)
+    return referencing_foreign_keys
+
+
+def merge_references(from_, to, foreign_keys=None):
+    """
+    Merge the references of an entity into another entity.
+    """
+    if from_.__tablename__ != to.__tablename__:
+        raise TypeError("The tables of given arguments do not match.")
+
+    session = object_session(from_)
+    foreign_keys = get_referencing_foreign_keys(from_.__table__)
+
+    for fk in foreign_keys:
+        old_values = get_foreign_key_values(fk, from_)
+        new_values = get_foreign_key_values(fk, to)
+        session.query(from_.__mapper__).filter(*[k == old_values[k] for k in old_values]).update(
+            new_values, synchronize_session=False
+        )