Haketilo

# SPDX-License-Identifier: AGPL-3.0-or-later

"""

A modular "virtual network" proxy,

wrapping the classes in proxy_core.py

"""

# This file is part of Haketilo.

#

# Copyright (C) 2021 jahoti <jahoti@tilde.team>

# Copyright (C) 2021 Wojtek Kosior <koszko@koszko.org>

#

# This program is free software: you can redistribute it and/or modify

# it under the terms of the GNU Affero General Public License as

# published by the Free Software Foundation, either version 3 of the

# License, or (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU Affero General Public License for more details.

#

# You should have received a copy of the GNU Affero General Public License

# along with this program.  If not, see <https://www.gnu.org/licenses/>.

#

#

# I, Wojtek Kosior, thereby promise not to sue for violation of this

# file's license. Although I request that you do not make use of this code

# in a proprietary program, I am not going to enforce this in court.

from pathlib import Path

from urllib.parse import parse_qs

from threading import Thread

import traceback

from .proxy_core import ProxyRequestHandler, ThreadingHTTPServer

from .misc_constants import *

from .world_wide_library import catalog as internet

class RequestHijacker(ProxyRequestHandler):

    def handle_request(self, req_body):

        path_components = self.path.split('?', maxsplit=1)

        path = path_components[0]

        try:

            # Response format: (status_code, headers (dict. of strings),

            #       body as bytes or filename containing body as string)

            if path in internet:

                info = internet[path]

                if type(info) is tuple:

                    status_code, headers, body_file = info

                    resp_body = b''

                    if body_file is not None:

                        if 'Content-Type' not in headers:

                            ext = body_file.suffix[1:]

                            if ext and ext in mime_types:

                                headers['Content-Type'] = mime_types[ext]

                        with open(body_file, mode='rb') as f:

                            resp_body = f.read()

                else:

                    # A function to evaluate to get the response

                    get_params, post_params = {}, {}

                    if len(path_components) == 2:

                        get_params = parse_qs(path_components[1])

                    # Parse POST parameters; currently only supports

                    # application/x-www-form-urlencoded

                    if req_body:

                        post_params = parse_qs(req_body.encode())

                    status_code, headers, resp_body = info(self.command, get_params, post_params)

                    if type(resp_body) == str:

                        resp_body = resp_body.encode()

                if type(status_code) != int or status_code <= 0:

                    raise Exception('Invalid status code %r' % status_code)

                for header, header_value in headers.items():

                    if type(header) != str:

                        raise Exception('Invalid header key %r' % header)

                    elif type(header_value) != str:

                        raise Exception('Invalid header value %r' % header_value)

            else:

                status_code, headers = 404, {'Content-Type': 'text/plain'}

                resp_body = b'Handler for this URL not found.'

        except Exception:

            status_code = 500

            headers     = {'Content-Type': 'text/plain'}

            resp_body   = b'Internal Error:\n' + traceback.format_exc().encode()

        headers['Content-Length'] = str(len(resp_body))

        self.send_response(status_code)

        for header, header_value in headers.items():

            self.send_header(header, header_value)

        self.end_headers()

        if resp_body:

            self.wfile.write(resp_body)

def do_an_internet(certdir=Path.cwd() / 'certs',

                   port=default_proxy_port):

    """Start up the proxy/server"""

    class RequestHijackerWithCertdir(RequestHijacker):

        def __init__(self, *args, **kwargs):

            super().__init__(*args, certdir=certdir, **kwargs)

    httpd = ThreadingHTTPServer(('', port), RequestHijackerWithCertdir)

    Thread(target=httpd.serve_forever).start()

    return httpd