学生信息系统登录注册改良版

import file_manager
import student_system
#=================注册
"""
[
    {'user_name':'password'}  改良了格式
]
保存到userinfo.json中
"""

file_name = 'user_info.json'
def login():
    user_name=input('请输入用户名:')
    password=input('请输入密码:')
    all_user = get_all_user()
    for user in all_user:
        for key in user:
            if key == user_name:
                if user[key] == password:
                    print('登录成功')
                    return user_name
                else:
                    print('密码错误,登录失败')
                    return None
    print('没有注册,登录失败!')
    return None


def get_all_user():
    all_user = file_manager.read_json_file(file_name)
    if all_user == None:
        return []
    return all_user


def register():

    while True:
        username = input('请输入一个用户名(3-10位):')
        if not 3<=len(username)<=10:
            print('输入有误,请重新输入')
            continue
        all_user = file_manager.read_json_file(file_name)
        if not all_user:
            all_user = []
        for user in all_user:
            for key in user:
                if key == username:
                    print('%s,已经注册过,请重新输入'%username)
                    return register() #运用回调函数重新返回输入用户名

        print('用户名可用')
        break

    while True:
        password = input('请输入密码(6-16位):')
        if not 6<=len(password)<=16:
            print('密码输入有误,请重新输入')
            continue
        re_password = input('确认密码:')
        if password != re_password:
            print('和第一次输入的密码不一样,请重新输入')
            continue
        break

    all_user = get_all_user()
    all_user.append({username:password})
    re = file_manager.write_json_file(file_name,all_user)
    if re:
        print('注册成功')
    else:
        print('注册失败')

#==================主页
def show_main_page():
    while True:
        print(file_manager.read_file('login.txt'))
        value = input('请选择(1-3):')

        if value == '3':
            break
        elif value == '2':
            register()
        elif value == '1':
            user_name = login()
            if user_name:
                student_system.user_name = user_name
                student_system.main_page()
        else:
            print('输入有误!')

if __name__ == '__main__':

    show_main_page()