python连接telnet服务

import telnetlib


def main(host, port, username, password):
    login_hints = [b'login', b'Login']
    login_failed_status = [b"Login incorrect", b'Login failed', b'Login Failed']
    password_hints = [b"Password", b"password"]
    username_flag = False
    password_flag = False

    try:
        tn = telnetlib.Telnet(host=host, port=port, timeout=10)
        while True:
            if username_flag:
                break
						
            # 如果这里使用decode的话，不同的操作系统可能会因为不兼容导致报错。
            std_out = tn.read_eager().strip(b'\r\n')

            if not std_out:
                continue

            for login_hint in login_hints:
                if login_hint in std_out:
                    tn.write(username.encode() + b'\r\n')
                    username_flag = True
                    break

        while True:
            if password_flag:
                break

            std_out = tn.read_eager().strip(b'\r\n')

            if not std_out:
                continue

            for password_hint in password_hints:
                if password_hint in std_out:
                    tn.write(password.encode() + b'\r\n')
                    password_flag = True
                    break

        while True:
            std_out = tn.read_very_eager().strip(b'\r\n')

            if not std_out:
                continue

            for failed_status in login_failed_status:
                if failed_status in std_out:
                    return False
            tn.close()
            return True

    except Exception as e:
        print(e)
        return False