python3代位模块中的错误..。包嗅探器

Question

我正在使用python-3.7构建一个嗅探工具，当我试图使用scapy_http模块时，我得到了这个错误。

它在python-2.x中运行得很好。对象类型为packetscapy.Raw.load

代码：

#!usr/bin/env python
import scapy.all as scapy
from scapy.layers import http

def sniff(interface):
    scapy.sniff(iface=interface, store=False, prn=process_sniffed_packet)
    #store=Flase(does not store the output in memory)
    #prn= call another  function after one packet or any data is sniffed is sniffed

def process_sniffed_packet(packet):
    if packet.haslayer(http.HTTPRequest):
        if packet.haslayer(scapy.Raw):
            load = packet[scapy.Raw].load
            if "username" in load:
                print(load)
sniff("eth0")

错误：

 File "packet_sniffer.py", line 16, in <module>
    sniff("eth0")
  File "packet_sniffer.py", line 6, in sniff
    scapy.sniff(iface=interface, store=False, prn=process_sniffed_packet)
  File "/usr/local/lib/python3.8/site-packages/scapy/sendrecv.py", line 1036, in sniff
    sniffer._run(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/scapy/sendrecv.py", line 989, in _run
    session.on_packet_received(p)
  File "/usr/local/lib/python3.8/site-packages/scapy/sessions.py", line 82, in on_packet_received
    result = self.prn(pkt)
  File "packet_sniffer.py", line 14, in process_sniffed_packet
    if "username" in load:
****TypeError: a bytes-like object is required, not 'str'****

Answer 1

packet[scapy.Raw].load使用来自scapy.packet.Raw类的load。您正在要求python确定字符串是否位于字节对象的内部，正如它所说的那样，这是一个类型错误。复制此错误很容易：

>>> if "word" in b"word":
...     pass
...
Traceback (most recent call last):
  File "<console>", line 1, in <module>
TypeError: a bytes-like object is required, not 'str'

试着在第14行中使用if "username" in str(load):或if b"username" in load:，这样就不会出现类型错配。

注意到：由于使用import scapy.all as scapy，类层次结构很混乱，因此scapy.Raw与代码片段中的scapy.Packet.Raw相同。