searxngRebrandZaclys/searx/plugins/limiter.py
Alexandre Flament fe419e355b The checker requires Redis
Remove the abstraction in searx.shared.SharedDict.
Implement a basic and dedicated scheduler for the checker using a Redis script.
2022-11-05 12:04:50 +01:00

102 lines
3.6 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-or-later
# lint: pylint
# pyright: basic
"""Some bot protection / rate limitation
To monitor rate limits and protect privacy the IP addresses are getting stored
with a hash so the limiter plugin knows who to block. A redis database is
needed to store the hash values.
Enable the plugin in ``settings.yml``:
- ``server.limiter: true``
- ``redis.url: ...`` check the value, see :ref:`settings redis`
"""
import re
from flask import request
from searx.shared import redisdb
from searx.redislib import incr_sliding_window
name = "Request limiter"
description = "Limit the number of request"
default_on = False
preference_section = 'service'
re_bot = re.compile(
r'('
+ r'[Cc][Uu][Rr][Ll]|[wW]get|Scrapy|splash|JavaFX|FeedFetcher|python-requests|Go-http-client|Java|Jakarta|okhttp'
+ r'|HttpClient|Jersey|Python|libwww-perl|Ruby|SynHttpClient|UniversalFeedParser|Googlebot|GoogleImageProxy'
+ r'|bingbot|Baiduspider|yacybot|YandexMobileBot|YandexBot|Yahoo! Slurp|MJ12bot|AhrefsBot|archive.org_bot|msnbot'
+ r'|MJ12bot|SeznamBot|linkdexbot|Netvibes|SMTBot|zgrab|James BOT|Sogou|Abonti|Pixray|Spinn3r|SemrushBot|Exabot'
+ r'|ZmEu|BLEXBot|bitlybot'
+ r')'
)
def is_accepted_request() -> bool:
# pylint: disable=too-many-return-statements
redis_client = redisdb.client()
user_agent = request.headers.get('User-Agent', '')
x_forwarded_for = request.headers.get('X-Forwarded-For', '')
if request.path == '/image_proxy':
if re_bot.match(user_agent):
return False
return True
if request.path == '/search':
c_burst = incr_sliding_window(redis_client, 'IP limit, burst' + x_forwarded_for, 20)
c_10min = incr_sliding_window(redis_client, 'IP limit, 10 minutes' + x_forwarded_for, 600)
if c_burst > 15 or c_10min > 150:
logger.debug("to many request") # pylint: disable=undefined-variable
return False
if re_bot.match(user_agent):
logger.debug("detected bot") # pylint: disable=undefined-variable
return False
if len(request.headers.get('Accept-Language', '').strip()) == '':
logger.debug("missing Accept-Language") # pylint: disable=undefined-variable
return False
if request.headers.get('Connection') == 'close':
logger.debug("got Connection=close") # pylint: disable=undefined-variable
return False
accept_encoding_list = [l.strip() for l in request.headers.get('Accept-Encoding', '').split(',')]
if 'gzip' not in accept_encoding_list and 'deflate' not in accept_encoding_list:
logger.debug("suspicious Accept-Encoding") # pylint: disable=undefined-variable
return False
if 'text/html' not in request.accept_mimetypes:
logger.debug("Accept-Encoding misses text/html") # pylint: disable=undefined-variable
return False
if request.args.get('format', 'html') != 'html':
c = incr_sliding_window(redis_client, 'API limit' + x_forwarded_for, 3600)
if c > 4:
logger.debug("API limit exceeded") # pylint: disable=undefined-variable
return False
return True
def pre_request():
if not is_accepted_request():
return 'Too Many Requests', 429
return None
def init(app, settings):
if not settings['server']['limiter']:
return False
if not redisdb.client():
logger.error("The limiter requires Redis") # pylint: disable=undefined-variable
return False
app.before_request(pre_request)
return True