python - 为什么满足条件时我的函数不执行？

Question

我正在尝试为我的服务器应用程序制作一个登录表单，但偶然发现了一个看不见的错误(最糟糕的错误)。我有一个 tries 变量，每当用户错误输入用户名时，该变量就会增加 1。当tries变量达到3时，程序应该执行block()函数。我的问题是事实并非如此。

我的所有 .txt 文件都是空白的，因此没有错误，一切看起来都很好。请帮忙，因为我正在拔头发!

代码如下:

import socket
import time
import sys
import os

tries = 0

def server():

    def block():

        #get host ip
        ipBlock = socket.gethostbyname(socket.gethostname())

        #create black list
        ipBlackList = open("ipBlackList.txt", "w")
        ipBlackList.close()

        #read black list
        ipBlackList = open("ipBlackList.txt", "r")
        isBlocked = ipBlackList.readlines()
        ipBlackList.close()

        #disable account for 60 seconds
        if ipBlock in isBlocked:
            def countdown(t):
                while t:
                    mins, secs = divmod(t, 60)
                    timer = '{:02d}:{:02d}'.format(mins, secs)
                    print('Your account has been temporarily disabled. Please 
                    try again in '+timer, end=" seconds.\r")
                    time.sleep(1)
                    t -= 1
                    os.remove('ipBlackList.txt')
                    print('\nYour account has been re-enabled. You may log in 
                    now.')
                    time.sleep(2)
                t = 60
                countdown(int(t))
    block()

    print("Enter administrator login details: ")

    def usernameLogin():
        #global vars
        global tries

        if tries == 3:
            #read black list
            ipBlackList = open("ipBlackList.txt", "r")
            isBlocked = ipBlackList.readlines()
            ipBlackList.close()

            #get host ip
            ipBlock = socket.gethostbyname(socket.gethostname())

            if ipBlock not in isBlocked:
                ipBlackList = open("ipBlackList.txt", "w")
                ipBlackList.write(ipBlock)
                ipBlackList.close()
                block()

        username = input("\nUsername: ")

        #check if username exists
        usernames = open("usernames.txt", "r")
        checkUser = usernames.readlines()
        usernames.close()

        if username not in checkUser:
            print("That username doesn't exist. Please try again.")
            tries += 1
            print(tries)
            time.sleep(2)
            usernameLogin()

        print("im in")
        time.sleep(3)

    usernameLogin()
server()

Answer 1

事实上，您的代码确实在 tries==3 时执行 block() 函数，但在 block() 的开头> 您重新创建黑名单文件，然后读取空文件，结果条件 if ipBlock in isBlocked: 始终为 false。

因此，我已将创建文件的命令置于 block() 之外。另外，我更改了 countdown() 函数中黑名单文件的 remove 并重新创建但不删除它，因为您的代码在重新启动时会尝试再次读取它询问用户名。另外，当 block() 结束时，我设置了 tries == 0 。此外，countdown() 末尾的缩进不正确。

import socket
import time
import sys
import os

tries = 0

def server():

    def block():

        #get host ip
        ipBlock = socket.gethostbyname(socket.gethostname())

        #read black list
        ipBlackList = open("ipBlackList.txt", "r")
        isBlocked = ipBlackList.readlines()
        ipBlackList.close()

        #disable account for 60 seconds

        if ipBlock in isBlocked:
            def countdown(t):
                while t:
                    mins, secs = divmod(t, 60)
                    timer = '{:02d}:{:02d}'.format(mins, secs)
                    print('Your account has been temporarily disabled. Please \
                    try again in '+timer, end=" seconds.\r")
                    time.sleep(1)
                    t -= 1

                #os.remove('ipBlackList.txt')
                # Recreate an empty black list file
                ipBlackList = open("ipBlackList.txt", "w")
                ipBlackList.close()

                print('\nYour account has been re-enabled. You may log in \
                now.')
                time.sleep(2)
            t = 6
            countdown(int(t))

    #create black list file (empty)
    ipBlackList = open("ipBlackList.txt", "w")
    ipBlackList.close()
    block()

    print("Enter administrator login details: ")

    def usernameLogin():
        #global vars
        global tries

        if tries == 3:
            #read black list
            ipBlackList = open("ipBlackList.txt", "r")
            isBlocked = ipBlackList.readlines()
            ipBlackList.close()

            #get host ip
            ipBlock = socket.gethostbyname(socket.gethostname())
            if ipBlock not in isBlocked:
                ipBlackList = open("ipBlackList.txt", "w")
                ipBlackList.write(ipBlock)
                ipBlackList.close()
                block()

            tries = 0

        username = input("\nUsername: ")

        #check if username exists
        usernames = open("/test/usernames.txt", "r")
        checkUser = usernames.readlines()
        usernames.close()

        if username not in checkUser:
            print("That username doesn't exist. Please try again.")
            tries += 1
            print(tries)
            time.sleep(2)
            usernameLogin()

        print("im in")
        time.sleep(3)

    usernameLogin()
server()