cloudflare_dyn_dns.sh

#!/bin/sh
# 
# CloudFlare Dynamic DNS
# 
# Updates CloudFlare records with the current public IP address
# 
# Takes the same basic arguments as A/CNAME updates in the CloudFlare API
# https://www.cloudflare.com/docs/client-api.html#s5.2
# 
# Use with cron jobs etc.
# 
# e.g.
# 
# manually run:
# cloudflare_dyn_dns.sh -tkn 404613183ab3971a2118ae5bf03d63e032f9e -email [email protected] -z example.com -name extra
#
# cronjob entry to run every 5 minutes:
# */5 * * * * /path/to/cloudflare_dyn_dns.sh -tkn 404613183ab3971a2118ae5bf03d63e032f9e -email [email protected] -z example.com -name extra >> /path/to/cloudflare_dyn_dns.log
# 
# will both set the type A DNS record for extra.example.com to the current public IP address for user [email protected] with the provided API tkn

tkn=
email=
z=
type=A
id=
name=
content=
ttl=1
service_mode=0

while [ "$1" != "" ]; do
    case $1 in
        -tkn )     shift
                   tkn=$1
                   ;;
        -email )   shift
                   email=$1
                   ;;
        -z )       shift
                   z=$1
                   ;;
        -type )    shift
                   type=$1
                   ;;
        -id )      shift
                   id=$1
                   ;;
        -name )    shift
                   name=$1
                   ;;
        -content ) shift
                   content=$1
                   ;;
        -ttl )     shift
                   ttl=$1
                   ;;
        -service_mode ) shift
                        service_mode=$1
                        ;;
        * )        echo "unknown parameter $1"
                   exit 1
    esac
    shift
done

if [ "$content" = "" ] 
then
    echo "Attempting to get current public IP Address for content."
    content=`curl -s http://myexternalip.com/raw`
    if [ "$content" = "" ]
    then
        echo "No IP address to set record value with." 
        exit 1
    fi
fi

if [ "$name" = "" ]
then
    echo "You must provide the name of the record you wish to change." 
    exit 1
fi

if [ "$z" = "" ]
then
    echo "You must provide the domain you wish to change."
    exit 1
fi

existing_content=`host -t $type $name.$z | grep -oE '((1?[0-9][0-9]?|2[0-4][0-9]|25[0-5])\.){3}(1?[0-9][0-9]?|2[0-4][0-9]|25[0-5])'`

if [ "$content" = "$existing_content" ]
then
    echo "Existing record value $existing_content is the same as provided content $content. Exiting."
    exit
fi

if [ "$tkn" = "" ]
then
    echo "You must provide your user API token."
    exit 1
fi

if [ "$email" = "" ]
then
    echo "You must provide your user email."
    exit 1
fi

# Get the record id for the entry we're trying to change if it's not provided
if [ "$id" = "" ]
then
    response_json=`curl -s https://www.cloudflare.com/api_json.html -d 'a=rec_load_all' -d "tkn=$tkn" -d "email=$email" -d "z=$z"`
    id=`echo $response_json | sed -E "s/.+\{\"rec_id\":\"([0-9]+)\"[^\}]+$name.$z.+/\1/g"`
    if [ "$id" = "" ]
    then
        echo "DNS Record ID could not be found, please make sure it exists"
        exit 1
    fi
fi

# Update the DNS record
update_response=`curl -s https://www.cloudflare.com/api_json.html -d 'a=rec_edit' -d "tkn=$tkn" -d "id=$id" -d "email=$email" -d "z=$z" -d "type=$type" -d "name=$name" -d "content=$content" -d "service_mode=$service_mode" -d "ttl=$ttl"`

success_val=`echo $update_response | sed -E "s/.+\"result\":\"([^\"]+)\".+/\1/g"`
if [ "$success_val" = "success" ]
then
    echo "Record Updated."
else
    echo "Record update failed."
    exit 1
fi