first commit

searx/botdetection/http_accept_encoding.py

@@ -0,0 +1,40 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""
+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 __future__ import annotations
+from ipaddress import (
+    IPv4Network,
+    IPv6Network,
+)
+
+import werkzeug
+
+from searx.extended_types import SXNG_Request
+
+from . import config
+from ._helpers import too_many_requests
+
+
+def filter_request(
+    network: IPv4Network | IPv6Network,
+    request: SXNG_Request,
+    cfg: config.Config,  # pylint: disable=unused-argument
+) -> werkzeug.Response | None:
+
+    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 too_many_requests(network, "HTTP header Accept-Encoding did not contain gzip nor deflate")
+    return None