geolocate is a fast, self-contained, country-level GeoIP resolver that you can include as a drop-in in your project and use immediately, without the need for a separate server and database files.

Features

Simple. This is a single file exporting a single geolocate function that does a single job, match an IP to a country.

Lookups are fast. Averages to 4.6μs per lookup, or about 220k lookups per second, even on my feeble laptop.

Self-contained. No need to spawn up an entire server and an SQLite database just to make a couple of queries. No outside request to a geolocation API. No dependencies.

Usage

const geolocate = require("./geolocate");

geolocate("8.8.8.8");        // {code: 'US', name: 'United States'}
geolocate("160.106.123.29"); // {code: 'CA', name: 'Canada'}
geolocate("103.28.251.187"); // {code: 'NZ', name: 'New Zealand'}
geolocate("54.222.60.218");  // {code: 'CN', name: 'China'}
geolocate("127.0.0.1");      // undefined

About the data

This is designed to work with the GeoLite2 Country IPv4 database. However, MaxMind Inc also provides city-level and IPv6 databases, and you can probably make it work on those instead with a couple of tweaks.

Getting started

What's actually included is the build script that will generate an up-to-date geolocate.js, rather than the script itself.
And because I know you're lazy, here's a three-liner that does everything for you ; fetch the GeoLite db, run build.js, and clean up, leaving a freshly generated geolocate.js:

curl "http://geolite.maxmind.com/download/geoip/database/GeoLite2-Country-CSV.zip" | tar -x --strip-components=1 --include "*/GeoLite2-Country-Blocks-IPv4.csv" "*/GeoLite2-Country-Locations-en.csv"
curl "https://raw.githubusercontent.com/npny/geolocate/master/build.js" | node;
rm GeoLite2-Country-Blocks-IPv4.csv GeoLite2-Country-Locations-en.csv

License

The GeoLite2 databases are distributed under the Creative Commons BY-SA 4.0 license.
geolocate is released under the MIT license. Pierre Boyer, 2016.