在'expect'中使用条件语句

Question

我需要使用expect自动登录到TELNET会话,但我需要为同一个用户名处理多个密码.

这是我需要创建的流程:

1. 打开到IP的TELNET会话
2. 发送用户名
3. 发送密码
4. 密码错误？再次发送相同的用户名,然后输入不同的密码
5. 此时应该已成功登录...

对于它的价值,这是我到目前为止所得到的:

#!/usr/bin/expect
spawn telnet 192.168.40.100
expect "login:"
send "spongebob\r"
expect "password:"
send "squarepants\r"
expect "login incorrect" {
  expect "login:"
  send "spongebob\r"
  expect "password:"
  send "rhombuspants\r"
}
expect "prompt\>" {
  send_user "success!\r"
}
send "blah...blah...blah\r"

不用说这不起作用,也不是很漂亮.从我与谷歌的冒险预期似乎是暗艺术的东西.在此事先感谢任何人的帮助!

Answer 1

必须为所有期望程序员推荐Exploring Expect书籍 - 非常宝贵.

我重写了你的代码:(未经测试)

proc login {user pass} {
    expect "login:"
    send "$user\r"
    expect "password:"
    send "$pass\r"
}

set username spongebob 
set passwords {squarepants rhombuspants}
set index 0

spawn telnet 192.168.40.100
login $username [lindex $passwords $index]
expect {
    "login incorrect" {
        send_user "failed with $username:[lindex $passwords $index]\n"
        incr index
        if {$index == [llength $passwords]} {
            error "ran out of possible passwords"
        }
        login $username [lindex $passwords $index]
        exp_continue
    }
    "prompt>" 
}
send_user "success!\n"
# ...

exp_continue 循环回到expect块的开头 - 它就像一个"重做"语句.

注意send_user结束时\n没有\r

您不必>在提示符中转义字符:它对Tcl并不特殊.

Answer 2

经过一番抨击,我找到了解决方案.事实证明,期望使用我并不熟悉的TCL语法:

#!/usr/bin/expect
set pass(0) "squarepants"
set pass(1) "rhombuspants"
set pass(2) "trapezoidpants"
set count 0
set prompt "> "
spawn telnet 192.168.40.100
expect {
  "$prompt" {
    send_user "successfully logged in!\r"
  }
  "password:" {
    send "$pass($count)\r"
    exp_continue
  }
  "login incorrect" {
    incr count
    exp_continue
  }
  "username:" {
    send "spongebob\r"
    exp_continue
  }
}
send "command1\r"
expect "$prompt"
send "command2\r"
expect "$prompt"
send "exit\r"
expect eof
exit

希望这对其他人有用.