基于csv的用户注册和认证

# ############### 1. 基于csv的用户注册和认证 #############
import os
# 文件路径处理
base_dir = os.path.dirname(os.path.abspath(__file__))
db_file_path = os.path.join(base_dir, 'db.csv')
# 用户注册
while True:
    choice = input("是否进行用户注册（Y/N）？")
    choice = choice.upper()
    if choice not in {'Y', 'N'}:
        print('输入格式错误，请重新输入。')
        continue
    if choice == "N":
        break
    with open(db_file_path, mode='a', encoding='utf-8') as file_object:
        while True:
            user = input("请输入用户名（Q/q退出）：")
            if user.upper() == 'Q':
                break
            pwd = input("请输入密码：")
            file_object.write("{},{}\n".format(user, pwd))
            file_object.flush()
    break
# ##################用户登录时########################
print("欢迎使用xx系统，请登录！")
username = input("请输入用户名：")
password = input("请输入密码：")
if not os.path.exists(db_file_path):
    print("用户文件不存在")
else:
    with open(db_file_path, mode='r', encoding='utf-8') as file_object:
        for line in file_object:
            user, pwd = line.strip().split(',')
            if username == user and pwd == password:
                print('登录成功')
                break
        else:
            print("用户名或密码错误")