summaryrefslogtreecommitdiff
path: root/searx/botdetection/http_accept_encoding.py
blob: ae630fd68f1edf2cd7a7804c3666cec791ef4086 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
# SPDX-License-Identifier: AGPL-3.0-or-later
# lint: pylint
"""
Method ``http_accept_encoding``
-------------------------------

The ``http_accept_encoding`` method evaluates a request as the request of a
bot if the Accept-Encoding_ header ..

- did not contain ``gzip`` AND ``deflate`` (if both values are missed)
- did not contain ``text/html``

.. _Accept-Encoding:
   https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Encoding

"""

from typing import Optional, Tuple
import flask


def filter_request(request: flask.Request) -> Optional[Tuple[int, str]]:
    accept_list = [l.strip() for l in request.headers.get('Accept-Encoding', '').split(',')]
    if not ('gzip' in accept_list or 'deflate' in accept_list):
        return 429, "bot detected, HTTP header Accept-Encoding did not contain gzip nor deflate"
    return None