Python 导入问题：属性错误：'NoneType'对象没有属性'fields'

Question

我正在尝试在带有scapy lib的Linux Embedded 上编写一个小python脚本。在我的 OsX 或 Linux 盒子上，我做这样的事情没有任何问题：

from scapy.all import IP, sniff
from scapy.layers import http
import urllib, re
def process_tcp_packet(packet):
    http_layer = packet.getlayer(http.HTTPRequest)
    ip_layer = packet.getlayer(IP)
    url = str('{1[Path]}'.format(ip_layer.fields, http_layer.fields))
    if url:
        url = urllib.unquote(url).decode('utf8')
        print re.findall(r'(https?://S+lh1)', url)

sniff(filter="tcp and host hostexample.com", prn=process_tcp_packet)

Scapy 文件夹如下所示：

enter code here
/scapy
  __init__.py
  all.py
  ...
  /layers
   __init__.py
   http.py
   dhcp.py
   ...

当我启动脚本时，似乎导入了所有模块，但以下行：

url = str('{1[Path]}'.format(ip_layer.fields, http_layer.fields))

返回错误：

AttributeError: 'NoneType' object has no attribute 'fields'
-->End of Python script error report<--

任何帮助将不胜感激！谢谢！

Answer 1

"print http_layer"在 OsX-Box 上：

GET
PATH: someurl....
Http-Version: HTTP/1.1
Host: hostexample.com
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:37.0)    Gecko/20100101 Firefox/37.0
Accept: image/png,image/*;q=0.8,*/*;q=0.5
Accept-Language: de,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate
Referer: http://hostexample/someurl
Connection: keep-alive

嵌入："无"