python 3次登录

#!/usr/bin/env python
#-*- encoding: utf-8 -*-

import sys
import os
import getpass
import platform


# 全局变量
retry_limit = 3        # 登录重试次数
retry_count = 0        # 计数器

account_file = 'account.txt'
lock_file = 'account_lock.txt'

def lock(user):
    lock_check = open(lock_file, 'r')        # 打开account_lock.txt，检查用户是否已经存在文件中

    for line in lock_check.readlines():    # 循环读取文件内容
        if user == line.strip('\n'):        # 去掉指定字符，并且判断是用户名是否和文件中的文件名一致
            sys.exit('\033[35mUser %s is locked!!!\033[0m' % user)    # 存在则直接退出并打印输出提示

    lock_check.close()        # 关闭打开的文件流
    

def login(user, passwd):
    global retry_count        # 函数内要改变全局变量的值 "retry_count += 1"，需要加上global 关键字

    file = open(account_file, 'r')
    match_flag = False

    for line in file.readlines():
        username, password = line.strip('\n').split()

        if user == username and passwd == password:
            print 'hello, %s !!' % username
            match_flag = True
            break

    file.close()

    if match_flag == False:
        print 'sorry,%s is unmatched' % username
        retry_count += 1
    else:
        print 'wlecome login my learning system!'
        sys.exit(0)


def main():

    # 清屏操作，判断当前运行环境在什么平台下
    if platform.system() != 'Windows':
        os.system('clear')
    else:
        os.system('cls')


    while retry_count < retry_limit:
        username = raw_input('username: ')
        lock(username)
        password = getpass.getpass('password: ')    # 用getpass模块中的getpass方法来实现输入密码时和Linux一样
        login(username, password)
    else:
        print "you account %s is locked!!!" % username
        g = open(lock_file,'a')
        g.write(username)
        g.write('\n')
        g.close()

if __name__ == '__main__':
    main()