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# SPDX-License-Identifier: AGPL-3.0-or-later
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# lint: pylint
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# pyright: basic
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"""Some bot protection / rate limitation
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To monitor rate limits and protect privacy the IP addresses are getting stored
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with a hash so the limiter plugin knows who to block. A redis database is
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needed to store the hash values.
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Enable the plugin in ``settings.yml``:
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- ``server.limiter: true``
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- ``redis.url: ...`` check the value, see :ref:`settings redis`
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"""
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import re
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from flask import request
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from searx import redisdb
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from searx.redislib import incr_sliding_window
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name = "Request limiter"
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description = "Limit the number of request"
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default_on = False
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preference_section = 'service'
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re_bot = re.compile(
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r'('
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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'
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+ r')'
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)
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def is_accepted_request() -> bool:
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# pylint: disable=too-many-return-statements
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redis_client = redisdb.client()
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user_agent = request.headers.get('User-Agent', '')
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x_forwarded_for = request.headers.get('X-Forwarded-For', '')
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if request.path == '/image_proxy':
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if re_bot.match(user_agent):
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return False
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return True
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if request.path == '/search':
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c_burst = incr_sliding_window(redis_client, 'IP limit, burst' + x_forwarded_for, 20)
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c_10min = incr_sliding_window(redis_client, 'IP limit, 10 minutes' + x_forwarded_for, 600)
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if c_burst > 15 or c_10min > 150:
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logger.debug("to many request") # pylint: disable=undefined-variable
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return False
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if re_bot.match(user_agent):
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logger.debug("detected bot") # pylint: disable=undefined-variable
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return False
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if len(request.headers.get('Accept-Language', '').strip()) == '':
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logger.debug("missing Accept-Language") # pylint: disable=undefined-variable
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return False
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if request.headers.get('Connection') == 'close':
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logger.debug("got Connection=close") # pylint: disable=undefined-variable
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return False
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accept_encoding_list = [l.strip() for l in request.headers.get('Accept-Encoding', '').split(',')]
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if 'gzip' not in accept_encoding_list and 'deflate' not in accept_encoding_list:
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logger.debug("suspicious Accept-Encoding") # pylint: disable=undefined-variable
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return False
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if 'text/html' not in request.accept_mimetypes:
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logger.debug("Accept-Encoding misses text/html") # pylint: disable=undefined-variable
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return False
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if request.args.get('format', 'html') != 'html':
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c = incr_sliding_window(redis_client, 'API limit' + x_forwarded_for, 3600)
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if c > 4:
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logger.debug("API limit exceeded") # pylint: disable=undefined-variable
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return False
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return True
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def pre_request():
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if not is_accepted_request():
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return 'Too Many Requests', 429
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return None
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def init(app, settings):
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if not settings['server']['limiter']:
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return False
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if not redisdb.client():
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logger.error("The limiter requires Redis") # pylint: disable=undefined-variable
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return False
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app.before_request(pre_request)
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return True
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