A basic script to run on your self hosted server to update DNS on porkbun

autodns.sh

#!/bin/bash
# usage secretapikey=sk1_xxx apikey=pk1_xxx ./autodns.sh
set -eo pipefail
IFS=$'\n\t'
# passed as env var, see usage
readonly secretapikey=$secretapikey
readonly apikey=$apikey
set -u
MY_DOMAIN_NAME_RECORD='domainname.com/ID'

# checks

if [ -z "${secretapikey}" ];then
 echo 'missing secretapikey'
 exit 1
fi
if [ -z "${apikey}" ];then
 echo 'missing apikey'
 exit 1
fi

SCRIPT_DIRECTORY="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"

myIp=$(ip addr show scope global | grep inet6 | grep --invert-match "mngtmpaddr" | egrep --only-matching  "[[:alnum:]:]{8,39}")

prevIp=$(<"$SCRIPT_DIRECTORY/myip.txt")
if [[ "$prevIp" == "$myIp" ]];then
	echo "same IP: $myIp"
	exit 0
fi

echo "new IP: $myIp, old IP: $prevIp"

curl "https://porkbun.com/api/json/v3/dns/edit/$MY_DOMAIN_NAME_RECORD" --data "{\"secretapikey\":\"$secretapikey\",\"apikey\":\"$apikey\", \"type\": \"AAAA\",\"content\": \"$myIp\"}"


echo "$myIp" > "$SCRIPT_DIRECTORY/myip.txt"