python - "KeyError: '(插入 IP )'"是什么意思？

Question

我正在使用 Violent Python 这本书，但有一个错误阻止我完成第一个 nmap 构建(第 40-41 页)。在 VM 上使用 Ubuntu 14.04。我在终端中输入“python nmapScan.py -H 10.50.60.125 -p 21, 1720”。

import nmap
import optparse

def nmapScan(tgtHost,tgtPort):
    nmScan = nmap.PortScanner()
    nmScan.scan(tgtHost,tgtPort)
    state=nmScan[tgtHost]['tcp'][int(tgtPort)]['state']
    print "[*] " + tgtHost + " tcp/"+tgtPort +" "+state

def main():
    parser = optparse.OptionParser('usage %prog '+\
                                   '-H <target host> -p <target port>')
    parser.add_option('-H', dest='tgtHost', type='string',\
                      help='specify target host')
    parser.add_option('-p', dest='tgtPort', type='string',\
                      help='specify target port[s] separated by comma')

    (options, args) = parser.parse_args()

    tgtHost = options.tgtHost
    tgtPorts = str(options.tgtPort).split(',')

    if (tgtHost == None) | (tgtPorts[0] == None):
        print parser.usage
        exit(0)
    for tgtPort in tgtPorts:
        nmapScan(tgtHost, tgtPort)


if __name__ == '__main__':
    main()

这里是错误:

File "nmapScan.py", line 24, in <module>
    main()
File "nmapScan.py", line 21, in main
    nmapScan(tgtHost, tgtPort)
File "nmapScan.py", line 7, in nmapScan
    state = nmScan[tgtHost]['tcp'][int(tgtPort)]['state']
File "build/bdist.linux-x86_64/egg/nmap/nmap.py", line 567, in __getitem__
KeyError:'10.50.60.125'

Answer 1

nmap 中的 KeyError 表示 ip 无法访问。您应该验证 ip 是否确实可用。

如果您不确定主机是否启动，您需要一个try/except:

try:
    state = nmScan[tgtHost]['tcp'][int(tgtPort)]['state']
except KeyError as e:
   print(e)
   return