DAP reads data using an input plugin, transforms it through a series of filters, and prints it out again using an output plugin. Every record is treated as a document (aka: hash/dict) and filters are used to reduce, expand, and transform these documents as they pass through. Think of DAP as a mashup between sed, awk, grep, csvtool, and jq, with map/reduce capabilities.

A gem for interacting with the GeoIP2 webservices and databases. MaxMind provides geolocation data as downloadable databases as well as through a webservice.

Embargoed blocks all visitors from Russia from your Rails application, displaying a pro-Ukraine message instead.

Trackdown is a Ruby gem that easily allows you to geolocate IP addresses. It's a simple, convenient wrapper on top of the MaxMind database. Plug your MaxMind license key and you're good to go. It keeps your MaxMind database updated regularly, and it offers a handy API for Rails applications to fetch country, city, and emoji flag information for any IP address.

An offline GeoIP CLI filter for Apache (common, combined) logs. It's like grep but with a knowledge about what data an ip holds. Requires MaxMind's GeoLite2 DB (GeoLite2-City.mmdb) installed.

Logstash Filter Plugin for IPinfoDb

Somewhat more radical filters designed to decimate malicious requests during a denial-of-service (DoS) attack by chopping their connection well before your Rack app wastes any significant resources on them – ouch! The filters have been proven to work against certain DoS attacks, however, they might also block IPs behind proxies or VPNs. Make sure you have understood how the filters are triggered and consider this middleware a last resort only to be enabled during an attack.