Update your Public IP on your cloudflare domains automatically

updatecloudflare.sh

#/bin/bash

# https://theawesomegarage.com/blog/godaddy-terminated-my-free-dns-management-api-now-what

# This script will retrieve your Public IP, and if the service IP is different from last time
# the script will attempt to call Cloudflare's specific API endpoint for DNS updates.
# I suggest calling the script from crontab like this, for example every minute:
# */1 * * * * /mnt/web/scripts/updatecloudflare.sh /mnt/web/scripts/theawesomegarage.org.cfg >> /var/log/dns-updates.log 

# You will have to give a .cfg-file for each domain you want to update, formatted like this (without the comments, obviously):
#TOKEN="*****************"
#ZONE_ID="*****************"
#DNS_RECORD_ID="***************"
#NAME="@"
#PROXIED="true"
#TYPE="A"
#COMMENT="IP changed at ISP"
#TTL=600

# Create your token here to Edit DNS: https://dash.cloudflare.com/profile/api-tokens
# Zone ID: You find it on the *Overview* page for your zone/domain to the right
# Zone Record ID - you need to call a CloudFlare API to find it: 
# curl --request GET --url https://api.cloudflare.com/client/v4/zones/ZONE_ID_HERE/dns_records --header 'Content-Type: application/json' -H "Authorization: Bearer TOKEN_HERE"


# Check if a configuration file is provided as an argument
if [ -z "$1" ]; then
  echo "Usage: $0 <config_file>"
  exit 1
fi

# Source the configuration file
CONFIG_FILE="$1"
source "$CONFIG_FILE"

record_cache=/tmp/.cloudflareDNS.$TYPE.$ZONE_ID.$NAME.addr
[ -e $record_cache ] && old_record_ip=`cat $record_cache`


# A=IPv4 or AAAA=IPv6 
if [ $TYPE = "AAAA" ]; then
  public_ip=$(ip -6 addr list scope global $device | grep -v " fd" | sed -n 's/.*inet6 \([0-9a-f:]\+\).*/\1/p' | head -n 1)
else

  public_cache=/tmp/.myPublicIP
  [ -e $public_cache ] && public_ip=`cat $public_cache`

  # Check if the IPv4 cached public ip address matches the IPv4 pattern
  if ! [[ $public_ip =~ ^([0-9]{1,3}\.){3}[0-9]{1,3}$ ]]; then
    echo "$TYPE.$ZONE_ID.$NAME: $(date): Invalid Public IP Cache"
    exit 1
  fi
fi

# Re-validate that we got an IPv4 or IPv6 address
if [ -z "$public_ip" ]; then
  echo "$TYPE.$ZONE_ID.$NAME: $(date): Empty IP. Exiting."
  exit 1
fi

# Check cache ip, if matched, program exit
if [ "$old_record_ip" = "$public_ip" ]; then
  #echo "$TYPE.$ZONE_ID.$NAME: $(date): Still $public_ip. Exiting."
  exit
else
  echo "$TYPE.$ZONE_ID.$NAME: $(date): New IP $public_ip. Updating..."
  CONTENT=$public_ip
  # Define the API URL
  API_URL="https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records/$DNS_RECORD_ID"
  # Define the JSON payload
  JSON_PAYLOAD=$(cat <<EOF 
{ 
  "content": "$CONTENT", 
  "name": "$NAME", 
  "proxied": $PROXIED, 
  "type": "$TYPE", 
  "comment": "$COMMENT", 
  "ttl": $TTL
}
EOF
)
  nresult=$(curl -o /dev/null -s -w "%{http_code}" \
                 --request PUT \
                 --url "$API_URL" \
                 --header "Content-Type: application/json" \
                 --header "Authorization: Bearer $TOKEN" \
                 --data "$JSON_PAYLOAD")

  if [ "$nresult" = "200" ]; then
    echo "$TYPE.$ZONE_ID.$NAME: $(date): OK $nresult"
    echo $public_ip > $record_cache
  else
    echo "$TYPE.$ZONE_ID.$NAME: $(date): NOT OK $nresult"
  fi
fi