.. _searx filtron: ========================== How to protect an instance ========================== .. sidebar:: further reading - :ref:`filtron.sh` - :ref:`nginx searx site` .. contents:: Contents :depth: 2 :local: :backlinks: entry .. _filtron: https://github.com/asciimoo/filtron Searx depends on external search services. To avoid the abuse of these services it is advised to limit the number of requests processed by searx. An application firewall, filtron_ solves exactly this problem. Filtron is just a middleware between your web server (nginx, apache, ...) and searx, we describe such infratructures in chapter: :ref:`architecture`. filtron & go ============ .. _Go: https://golang.org/ .. _filtron README: https://github.com/asciimoo/filtron/blob/master/README.md Filtron needs Go_ installed. If Go_ is preinstalled, filtron_ is simply installed by ``go get`` package management (see `filtron README`_). If you use filtron as middleware, a more isolated setup is recommended. To simplify such an installation and the maintenance of, use our script :ref:`filtron.sh`. Sample configuration of filtron =============================== .. sidebar:: Tooling box - :origin:`/etc/filtron/rules.json ` An example configuration can be find below. This configuration limits the access of: - scripts or applications (roboagent limit) - webcrawlers (botlimit) - IPs which send too many requests (IP limit) - too many json, csv, etc. requests (rss/json limit) - the same UserAgent of if too many requests (useragent limit) .. code:: json [ { "name": "search request", "filters": [ "Param:q", "Path=^(/|/search)$" ], "interval": "", "limit": "", "subrules": [ { "name": "roboagent limit", "interval": "", "limit": "", "filters": [ "Header:User-Agent=(curl|cURL|Wget|python-requests|Scrapy|FeedFetcher|Go-http-client)" ], "actions": [ { "name": "log"}, { "name": "block", "params": { "message": "Rate limit exceeded" } } ] }, { "name": "botlimit", "limit": 0, "stop": true, "filters": [ "Header:User-Agent=(Googlebot|bingbot|Baiduspider|yacybot|YandexMobileBot|YandexBot|Yahoo! Slurp|MJ12bot|AhrefsBot|archive.org_bot|msnbot|MJ12bot|SeznamBot|linkdexbot|Netvibes|SMTBot|zgrab|James BOT)" ], "actions": [ { "name": "log"}, { "name": "block", "params": { "message": "Rate limit exceeded" } } ] }, { "name": "IP limit", "interval": "", "limit": "", "stop": true, "aggregations": [ "Header:X-Forwarded-For" ], "actions": [ { "name": "log"}, { "name": "block", "params": { "message": "Rate limit exceeded" } } ] }, { "name": "rss/json limit", "interval": "", "limit": "", "stop": true, "filters": [ "Param:format=(csv|json|rss)" ], "actions": [ { "name": "log"}, { "name": "block", "params": { "message": "Rate limit exceeded" } } ] }, { "name": "useragent limit", "interval": "", "limit": "", "aggregations": [ "Header:User-Agent" ], "actions": [ { "name": "log"}, { "name": "block", "params": { "message": "Rate limit exceeded" } } ] } ] } ] .. _filtron route request: Route request through filtron ============================= Filtron can be started using the following command: .. code:: sh $ filtron -rules rules.json It listens on ``127.0.0.1:4004`` and forwards filtered requests to ``127.0.0.1:8888`` by default. Use it along with ``nginx`` with the following example configuration. .. code:: nginx location / { proxy_pass http://127.0.0.1:4004/; proxy_set_header Host $http_host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header X-Scheme $scheme; } Requests are coming from port 4004 going through filtron and then forwarded to port 8888 where a searx is being run. For a complete setup see: :ref:`nginx searx site`.