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# SPDX-License-Identifier: AGPL-3.0-or-later
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"""
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Method ``http_user_agent``
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--------------------------
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The ``http_user_agent`` method evaluates a request as the request of a bot if
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the User-Agent_ header is unset or matches the regular expression
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:py:obj:`USER_AGENT`.
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.. _User-Agent:
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https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/User-Agent
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"""
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# pylint: disable=unused-argument
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from __future__ import annotations
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import re
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from ipaddress import (
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IPv4Network,
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IPv6Network,
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)
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import flask
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import werkzeug
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from . import config
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from ._helpers import too_many_requests
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USER_AGENT = (
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r'('
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+ r'unknown'
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+ r'|[Cc][Uu][Rr][Ll]|[wW]get|Scrapy|splash|JavaFX|FeedFetcher|python-requests|Go-http-client|Java|Jakarta|okhttp'
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+ r'|HttpClient|Jersey|Python|libwww-perl|Ruby|SynHttpClient|UniversalFeedParser|Googlebot|GoogleImageProxy'
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+ r'|bingbot|Baiduspider|yacybot|YandexMobileBot|YandexBot|Yahoo! Slurp|MJ12bot|AhrefsBot|archive.org_bot|msnbot'
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+ r'|MJ12bot|SeznamBot|linkdexbot|Netvibes|SMTBot|zgrab|James BOT|Sogou|Abonti|Pixray|Spinn3r|SemrushBot|Exabot'
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+ r'|ZmEu|BLEXBot|bitlybot|HeadlessChrome'
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# unmaintained Farside instances
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+ r'|'
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+ re.escape(r'Mozilla/5.0 (compatible; Farside/0.1.0; +https://farside.link)')
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# other bots and client to block
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+ '|.*PetalBot.*'
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+ r')'
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)
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"""Regular expression that matches to User-Agent_ from known *bots*"""
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_regexp = None
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def regexp_user_agent():
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global _regexp # pylint: disable=global-statement
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if not _regexp:
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_regexp = re.compile(USER_AGENT)
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return _regexp
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def filter_request(
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network: IPv4Network | IPv6Network,
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request: flask.Request,
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cfg: config.Config,
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) -> werkzeug.Response | None:
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user_agent = request.headers.get('User-Agent', 'unknown')
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if regexp_user_agent().match(user_agent):
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return too_many_requests(network, f"bot detected, HTTP header User-Agent: {user_agent}")
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return None
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