mitmproxy代码方式忽略特定主机报错问题求助

用mitmproxy创建代理拦截请求，代理本身可正常运行，但配置ignore_hosts忽略特定主机时，持续抛出re.error: nothing to repeat at position 0错误。

现有代码 #

import asyncio
from mitmproxy import options
from mitmproxy.tools import dump


class RequestLogger:
    def request(self, flow):
        print(flow.request.host)


ig = ['localhost', '127.0.0.0/8', '10.0.0.0/8', '192.168.0.0/16', '172.16.0.0/12' , '*.localdomain.com' ]

async def start_proxy(host,port):
    opts = options.Options()
    opts.update(listen_host=host, listen_port=port, ignore_hosts=ig)
    master = dump.DumpMaster(opts,with_termlog=True,with_dumper=True)
    master.addons.add(RequestLogger())
    
    await master.run()
    return master

if __name__ == '__main__':
    asyncio.run(start_proxy("0.0.0.0",8080))

报错信息 #

[21:12:58.880] Addon error: nothing to repeat at position 0
Traceback (most recent call last):
  File "c:\Users\PhenomAmd\AppData\Local\pypoetry\Cache\virtualenvs\proxylsf-Ra9sO3Vd-py3.11\Lib\site-packages\mitmproxy\addons\next_layer.py", line 111, in next_layer
    nextlayer.layer = self._next_layer(
                      ^^^^^^^^^^^^^^^^^
  File "c:\Users\PhenomAmd\AppData\Local\pypoetry\Cache\virtualenvs\proxylsf-Ra9sO3Vd-py3.11\Lib\site-packages\mitmproxy\addons\next_layer.py", line 133, in _next_layer
    if self._ignore_connection(context, data_client, data_server):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\PhenomAmd\AppData\Local\pypoetry\Cache\virtualenvs\proxylsf-Ra9sO3Vd-py3.11\Lib\site-packages\mitmproxy\addons\next_layer.py", line 244, in _ignore_connection
    return any(
           ^^^^
  File "c:\Users\PhenomAmd\AppData\Local\pypoetry\Cache\virtualenvs\proxylsf-Ra9sO3Vd-py3.11\Lib\site-packages\mitmproxy\addons\next_layer.py", line 245, in <genexpr>
    re.search(rex, host, re.IGNORECASE)
  File "C:\Python\Lib\re\__init__.py", line 176, in search
    return _compile(pattern, flags).search(string)
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python\Lib\re\__init__.py", line 294, in _compile
    p = _compiler.compile(pattern, flags)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python\Lib\re\_compiler.py", line 745, in compile
    p = _parser.parse(p, flags)
        ^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python\Lib\re\_parser.py", line 989, in parse
    p = _parse_sub(source, state, flags & SRE_FLAG_VERBOSE, 0)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python\Lib\re\_parser.py", line 464, in _parse_sub
    itemsappend(_parse(source, state, verbose, nested + 1,
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python\Lib\re\_parser.py", line 691, in _parse
    raise source.error("nothing to repeat",
re.error: nothing to repeat at position 0
[21:12:59.006] Addon error: nothing to repeat at position 0
Traceback (most recent call last):
  File "c:\Users\PhenomAmd\AppData\Local\pypoetry\Cache\virtualenvs\proxylsf-Ra9sO3Vd-py3.11\Lib\site-packages\mitmproxy\addons\next_layer.py", line 111, in next_layer
    nextlayer.layer = self._next_layer(
                      ^^^^^^^^^^^^^^^^^
  File "c:\Users\PhenomAmd\AppData\Local\pypoetry\Cache\virtualenvs\proxylsf-Ra9sO3Vd-py3.11\Lib\site-packages\mitmproxy\addons\next_layer.py", line 133, in _next_layer
    if self._ignore_connection(context, data_client, data_server):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\PhenomAmd\AppData\Local\pypoetry\Cache\virtualenvs\proxylsf-Ra9sO3Vd-py3.11\Lib\site-packages\mitmproxy\addons\next_layer.py", line 244, in _ignore_connection
    return any(
           ^^^^
  File "c:\Users\PhenomAmd\AppData\Local\pypoetry\Cache\virtualenvs\proxylsf-Ra9sO3Vd-py3.11\Lib\site-packages\mitmproxy\addons\next_layer.py", line 245, in <genexpr>
    re.search(rex, host, re.IGNORECASE)
  File "C:\Python\Lib\re\__init__.py", line 176, in search
    return _compile(pattern, flags).search(string)
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python\Lib\re\__init__.py", line 294, in _compile
    p = _compiler.compile(pattern, flags)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python\Lib\re\_compiler.py", line 745, in compile
    p = _parser.parse(p, flags)
        ^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python\Lib\re\_parser.py", line 989, in parse
    p = _parse_sub(source, state, flags & SRE_FLAG_VERBOSE, 0)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python\Lib\re\_parser.py", line 464, in _parse_sub
    itemsappend(_parse(source, state, verbose, nested + 1,
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python\Lib\re\_parser.py", line 691, in _parse
    raise source.error("nothing to repeat",
re.error: nothing to repeat at position 0

也曾尝试以下写法，但问题未解决：

ignore=[]
hosts = ['host1','host2','host3']
for host in hosts:
    ignore.append(host)

opts.update(listen_host=host, listen_port=port, ignore_hosts=ignore)

错误根源是ignore_hosts中的*.localdomain.com被mitmproxy当作正则表达式解析，而*在正则中是特殊字符（表示重复前一个元素0或多次），但它前面没有可重复的内容，导致正则编译失败。

有两种修正方法：

1. 直接改用合法正则：将*.localdomain.com替换为.*\.localdomain\.com，其中.*匹配任意前缀，\.转义.避免其被当作正则通配符。
2. 用fnmatch.translate()转换shell通配符：该方法可将*.xxx.com这类shell风格通配符自动转换成合法正则表达式，无需手动处理特殊字符。

修正后的完整代码示例：

import asyncio
import fnmatch
from mitmproxy import options
from mitmproxy.tools import dump


class RequestLogger:
    def request(self, flow):
        print(flow.request.host)


ig = [
    'localhost',
    '127.0.0.0/8',
    '10.0.0.0/8',
    '192.168.0.0/16',
    '172.16.0.0/12',
    fnmatch.translate('*.localdomain.com')
]

async def start_proxy(host,port):
    opts = options.Options()
    opts.update(listen_host=host, listen_port=port, ignore_hosts=ig)
    master = dump.DumpMaster(opts,with_termlog=True,with_dumper=True)
    master.addons.add(RequestLogger())
    
    await master.run()
    return master

if __name__ == '__main__':
    asyncio.run(start_proxy("0.0.0.0",8080))

注：mitmproxy的ignore_hosts支持CIDR格式（如你使用的IP段）、纯字符串匹配（如host1），这些格式无需额外处理。

内容的提问来源于stack exchange，提问作者Minioua