cloudflare-ddns-update.sh

#!/bin/bash

# Initial data; they need to be filled by the user
## API token
api_token=<api-token>
email=<your-clodflare-email>
zone_name=<root-domain-name>
dns_record=<submdomain> # requires the full sub+domain ex. subdomain.root.com

# Function to log messages with timestamp
log() {
    local type="$1"
    local message="$2"
    echo "$(date '+%Y-%m-%d %H:%M:%S') [$type] $message"
}

log "INFO" "Script started."

# Get the basic data
log "INFO" "Fetching IPv4 and IPv6 addresses."
ipv4=$(curl -s -X GET -4 https://ifconfig.co)
ipv6=$(curl -s -X GET -6 https://ifconfig.co)

log "INFO" "Verifying API token."
user_id=$(curl -s -X GET "https://api.cloudflare.com/client/v4/user/tokens/verify" \
               -H "Authorization: Bearer $api_token" \
               -H "Content-Type:application/json" \
          | jq -r '{"result"}[] | .id')

if [ -z "$user_id" ]; then
    log "ERROR" "Invalid API token or email."
    exit 1
fi

log "INFO" "User ID verified: $user_id"
log "INFO" "Zone name: $zone_name"
log "INFO" "DNS record: $dns_record"
log "INFO" "IPv4: $ipv4"
log "INFO" "IPv6: $ipv6"

# Get the zone ID
log "INFO" "Fetching Zone ID for $zone_name."
zone_id=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones?name=$zone_name&status=active" \
               -H "Content-Type: application/json" \
               -H "X-Auth-Email: $email" \
               -H "Authorization: Bearer $api_token" \
          | jq -r '{"result"}[] | .[0] | .id')

if [ -z "$zone_id" ]; then
    log "ERROR" "Unable to fetch Zone ID. Check if the Zone Name is correct."
    exit 1
fi

log "INFO" "Zone ID fetched: $zone_id"

# Update A record (IPv4)
if [ -n "$ipv4" ]; then
    log "INFO" "Checking current A record for $dns_record."
    dns_record_a_id=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records?type=A&name=$dns_record"  \
                           -H "Content-Type: application/json" \
                           -H "X-Auth-Email: $email" \
                           -H "Authorization: Bearer $api_token")

    dns_record_a_ip=$(echo $dns_record_a_id | jq -r '{"result"}[] | .[0] | .content')
    log "INFO" "Current IPv4 set on Cloudflare (A Record) is: $dns_record_a_ip"

    if [ "$dns_record_a_ip" != "$ipv4" ]; then
        log "INFO" "Updating A record with new IPv4."
        response=$(curl -s -X PUT "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records/$(echo $dns_record_a_id | jq -r '{"result"}[] | .[0] | .id')" \
                     -H "Content-Type: application/json" \
                     -H "X-Auth-Email: $email" \
                     -H "Authorization: Bearer $api_token" \
                     --data "{\"type\":\"A\",\"name\":\"$dns_record\",\"content\":\"$ipv4\",\"ttl\":1,\"proxied\":false}" \
                | jq -r '.errors')

        if [ -z "$response" ]; then
            log "INFO" "A record updated successfully."
        else
            log "ERROR" "Failed to update A record: $response"
        fi
    else
        log "INFO" "The current IPv4 and DNS record IPv4 are the same. No update needed."
    fi
else
    log "WARNING" "Could not get your IPv4. Check your internet connection or https://ifconfig.co"
fi

# Update AAAA record (IPv6)
if [ -n "$ipv6" ]; then
    log "INFO" "Checking current AAAA record for $dns_record."
    dns_record_aaaa_id=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records?type=AAAA&name=$dns_record"  \
                               -H "Content-Type: application/json" \
                               -H "X-Auth-Email: $email" \
                               -H "Authorization: Bearer $api_token")

    dns_record_aaaa_ip=$(echo $dns_record_aaaa_id | jq -r '{"result"}[] | .[0] | .content')
    log "INFO" "Current IPv6 set on Cloudflare (AAAA Record) is: $dns_record_aaaa_ip"

    if [ "$dns_record_aaaa_ip" != "$ipv6" ]; then
        log "INFO" "Updating AAAA record with new IPv6."
        response=$(curl -s -X PUT "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records/$(echo $dns_record_aaaa_id | jq -r '{"result"}[] | .[0] | .id')" \
                     -H "Content-Type: application/json" \
                     -H "X-Auth-Email: $email" \
                     -H "Authorization: Bearer $api_token" \
                     --data "{\"type\":\"AAAA\",\"name\":\"$dns_record\",\"content\":\"$ipv6\",\"ttl\":1,\"proxied\":false}" \
                | jq -r '.errors')

        if [ -z "$response" ]; then
            log "INFO" "AAAA record updated successfully."
        else
            log "ERROR" "Failed to update AAAA record: $response"
        fi
    else
        log "INFO" "The current IPv6 and DNS record IPv6 are the same. No update needed."
    fi
else
    log "WARNING" "Could not get your IPv6. Check your internet connection or https://ifconfig.co"
fi

log "INFO" "Script completed."