Add delete member

backend/src/rest_api.py

@@ -139,3 +139,18 @@ def register() -> flask.Response:
             return flask.Response("Mail taken")
         return flask.Response("Phone/ pin code wrong", 400)
     return flask.Response()
+
+
+@app.post("/delete-member")
+def delete_member() -> flask.Response:
+    try:
+        user_id = flask.session["user_id"]
+    except KeyError:
+        return flask.Response("Not logged in", 428)
+    try:
+        utils.UserHandler.delete_member(flask.request.form["mail"], user_id)
+    except AssertionError:
+        return flask.Response("User doesn't exist", 404)
+    except KeyError as e:
+        return flask.Response("mail doesn't exist", 422)
+    return flask.Response()

backend/src/utils/user.py

@@ -121,8 +121,7 @@ class UserHandler:
                 """,
                 (user_id, )
         ).fetchall()
-        if not users:
-            raise KeyError(f"{user_id} does not exist!")
+        assert users, f"{user_id} does not exist!"
         user = users[0]
         return User(
                 user[0],
@@ -187,3 +186,13 @@ class UserHandler:
                 password.encode("utf-8"), 
                 users[0][0]
         )
+
+    @classmethod
+    def delete_member(cls, mail: str, leader_id: int) -> None:
+        assert cls.get_user_by_id(leader_id).team_id == cls.get_user_by_mail(mail).team_id
+        cls.__cursor.execute(
+                f"""
+                DELETE FROM users WHERE mail=?
+                """, (mail, )
+        )
+        cls.__connection.commit()