Cloudflare DDNS

cfddns.sh

#!/bin/bash

# cloudflare api v4
# https://gist.github.com/benkulbertis/fff10759c2391b6618dd

# 
# user-defined variables
# 
CFUSER="[email protected]"
CFKEY="cloudflare_globalkey"
ZONE_NAME="domain.com"
REC_NAMES="*.domain.com sub.domain.com"
# DISCORD_WEBHOOK="if you want to get notification via discord"

# 
# system variables
# 
hostname=`cat /etc/hostname`
script_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null && pwd )"
script_file=$(basename "$0")
ip_file="${script_dir}/${script_file%.*}.ip"
id_file="${script_dir}/${script_file%.*}.id"
ip=`wget http://ipinfo.io/ip -qO -`

# 
# functions
# 
send_message() {
curl -X POST $DISCORD_WEBHOOK \
    -H "Content-Type: application/json" \
	-d@- << EOF
{
	"username": "DDNS",
	"avatar_url": "https://www.cloudflare.com/img/cf-facebook-card.png",
    "embeds": [{
        "title": "${1}",
        "description": "${2}",
        "footer": {
            "text": "${3}"
        }
    }]
}    
EOF
}

update_record () {
	# $1=$zone_id
	# $2=$rec_name
	# $3=$rec_id
	# $4=$ip
	curl -s -X PUT "https://api.cloudflare.com/client/v4/zones/$1/dns_records/$3" \
		-H "Content-Type:application/json" \
		-H "X-Auth-Key:${CFKEY}" \
		-H "X-Auth-Email:${CFUSER}" \
		--data '{"id": "'"$1"'", "type": "A", "name": "'"$2"'", "content": "'"$4"'"}'
}

# early termination
if [ -f $ip_file ]; then
	old_ip=`cat "$ip_file"`
	if [ $ip == $old_ip ]; then
		echo "No Changes in IP Adddress: ${old_ip}"
		exit 0
	fi
fi

# get zone_id
if [ -f $id_file ] && grep -qF "zone $ZONE_NAME" $id_file; then
	zone_id=$(grep -F "zone $ZONE_NAME" $id_file | cut -d " " -f 3)
else
	zone_id=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones?name=$ZONE_NAME" -H "X-Auth-Email: $CFUSER" -H "X-Auth-Key: $CFKEY" -H "Content-Type: application/json" | grep -Po '(?<="id":")[^"]*' | head -1 )
	echo "zone $ZONE_NAME $zone_id" >> $id_file
fi

# get rec_id
for rec_name in $REC_NAMES; do
	if ! grep -qF "record $rec_name" $id_file; then
		rec_id=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records?name=$rec_name" -H "X-Auth-Email: $CFUSER" -H "X-Auth-Key: $CFKEY" -H "Content-Type: application/json"  | grep -Po '(?<="id":")[^"]*')
		echo "record $rec_name $rec_id" >> $id_file
	fi
done

echo "IP has changed: $ip"

for rec_name in $REC_NAMES; do
	rec_id=$(grep -F "record $rec_name" $id_file | cut -d " " -f 3)
	update=$(update_record $zone_id $rec_name $rec_id $ip)
	if [[ $update == *"\"success\":false"* ]]; then
		echo -e "Update failed: ${rec_name}\n$update"
	else
		echo "Update successful: ${rec_name}"
	fi
done

# notification
if [ ! -z $DISCORD_WEBHOOK ]; then
	if [ -z $old_ip ]; then
		send_message "Back online" "$ip" "detected on '$hostname'" &> /dev/null
	else
		send_message "IP changed" "$ip" "detected on '$hostname'" &> /dev/null
	fi
fi

# save updated ip for comparison
echo $ip > "$ip_file"

exit 0

Usage

1. Save this script to the preferred location.

2. Edit user-defined variables: CFUSER, CFKEY, ZONE_NAME, REC_NAMES, DISCORD_WEBHOOK(Optional)

3. Add to crontab, like */30 * * * * /home/username/ddns/cfddns.sh >/dev/null 2>&1