JNAP DeviceList Lua API for Nginx

This script publishes ISC DHCPD active leases as a Linksys JNAP JSON endpoint (/JNAP/) responding to
http://linksys.com/jnap/devicelist/GetDevices.

Why This Is Useful

This allows homeassistant.components.linksys_smart (the Linksys Smart device tracker) to work seamlessly with a non-Linksys router, such as a self-hosted Linux system running ISC DHCPD.
In short: it makes your self-hosted DHCP server act like a Linksys router for Home Assistant device presence tracking.

Installation

1. Install dependencies:

apt install nginx libnginx-mod-http-lua lua-cjson

2. Copy the Lua script:

mkdir -p /etc/nginx/lua
cp jnap-devicelist.lua /etc/nginx/lua/

3. Enable in your Nginx configuration:

lua_package_path "/etc/nginx/lua/?.lua;;";

location /JNAP/ {
  content_by_lua_file /etc/nginx/lua/jnap-devicelist.lua;
}

4. Reload:

nginx -t && systemctl reload nginx

Usage

Query the endpoint:

curl -X POST http://router.local/JNAP/
-H "Content-Type: application/json"
-d '{"action": "http://linksys.com/jnap/devicelist/GetDevices"}'

Expected response format:

{
  "responses": [{
    "output": {
      "devices": [{
        "knownMACAddresses": ["11:22:33:44:55:66"],
        "connections": true,
        "properties": {"userDeviceName": "Donald's iPhone"}
      }]
    }
  }]
}

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Developed with assistance from Perplexity AI.