CloudFlare Dynamic DNS Shell Script - Abandonware! Use ddclient instead!

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 v4 API
# https://www.cloudflare.com/docs/client-api.html#s5.2
#
# Use with cron jobs etc.
#
# e.g.
#
# manually run:
# cloudflare_dyn_dns.sh -key 404613183ab3971a2118ae5bf03d63e032f9e -email [email protected] -zone example.com -name extra
#
# cronjob entry to run every 5 minutes:
# */5 * * * * /path/to/cloudflare_dyn_dns.sh -key 404613183ab3971a2118ae5bf03d63e032f9e -email [email protected] -zone 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 key

key=
email=
zone=
zone_id=
type=A
rec_id=
name=
content=
ttl=1
proxied=false

while [ "$1" != "" ]; do
    case $1 in
        -key )     shift
                   key=$1
                   ;;
        -email )   shift
                   email=$1
                   ;;
        -zone )    shift
                   zone=$1
                   ;;
        -zone_id ) shift
                   zone_id=$1
                   ;;
        -type )    shift
                   type=$1
                   ;;
        -rec_id )  shift
                   rec_id=$1
                   ;;
        -name )    shift
                   name=$1
                   ;;
        -content ) shift
                   content=$1
                   ;;
        -ttl )     shift
                   ttl=$1
                   ;;
        -proxied ) shift
                   proxied=$1
                   ;;
        * )        echo "unknown parameter $1"
                   exit 1
    esac
    shift
done

if [ "$content" = "" ]
then
    content=`curl -s http://myexternalip.com/raw`
    if [ "$content" = "" ]
    then
        date
        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 [ "$zone" = "" ]
then
    echo "You must provide the domain you wish to change."
    exit 1
fi

if [ "$name" = "$zone" ]
then
    hostname="$name"
else
    hostname="$name.$zone"
fi

command -v host > /dev/null 2>&1
if [ "$?" = "1" ]
then
    command -v nslookup > /dev/null 2>&1
    if [ "$?" = "1" ]
    then
        echo "Cannot find a way to check existing $type record for $hostname"
        exit 1
    fi
    existing_content=`nslookup -type=$type $hostname | awk -F 'Address: ' 'NR==6 { print $2 }'`
else
    existing_content=`host -t $type $hostname | sed -E 's/.+?\s+([^\s]+)$/\1/'`
fi

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

if [ "$key" = "" ]
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 zone id for the entry we're trying to change if it's not provided
if [ "$zone_id" = "" ]
then
    zone_response_json=`curl -X GET "https://api.cloudflare.com/client/v4/zones?name=$zone" -H "X-Auth-Email: $email" -H "X-Auth-Key: $key" -H "Content-Type: application/json"`
    zone_id=`echo $zone_response_json | sed -E "s/.+\"result\":\[\{\"id\":\"([a-f0-9]+)\"[^\}]+$zone.+/\1/g"`
    if [ "$zone_id" = "" ]
    then
        echo "Cloudflare DNS Zone id could not be found, please make sure it exists"
        exit 1
    fi
fi

# Get the record id for the entry we're trying to change if it's not provided
if [ "$rec_id" = "" ]
then
    rec_response_json=`curl -X GET "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records?name=$hostname" -H "X-Auth-Email: $email" -H "X-Auth-Key: $key" -H "Content-Type: application/json"`
    rec_id=`echo $rec_response_json | sed -E "s/.+\"result\":\[\{\"id\":\"([a-f0-9]+)\"[^\}]+\"type\":\"$type\"[^\}]+$hostname.+/\1/g"`
    if [ "$rec_id" = "" ]
    then
        echo "Cloudflare DNS Record id could not be found, please make sure it exists"
        exit 1
    fi
fi

# Update the DNS record
update_response=`curl -X PUT "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records/$rec_id" -H "X-Auth-Email: $email" -H "X-Auth-Key: $key" -H "Content-Type: application/json" --data "{\"id\":\"$rec_id\",\"type\":\"$type\",\"name\":\"$hostname\",\"content\":\"$content\",\"ttl\":$ttl,\"proxied\":$proxied}"`

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

@chappy84 thank you for reply. I use your scripts cannot get record_id, I just do a little of optimization. thanks again for your method that use sed to parse json.

@0neday Regular expressions shouldn't be used to parse JSON (similar to the reasons why you shouldn't parse X/HTML with RegEx). This script is a perfect example of why not, as it relies on the order of the properties in the object, which the JSON spec specifically defines as incorrect. If cloudflare have switched / do switch to a server-side technology that doesn't always output the properties in that specific order, then this will break.
As in my last response, by hacking around with that regex, you're masking the issue, and potentially creating a far worse issue by updating the wrong records. Please consider using a much better solution, i.e. not bash, and use something like ddclient instead.

Anyone coming to this, please consider this script "abandonware".
I've not maintained it, or used it myself, in years, instead switching to ddclient. It was a quick hacky script that's purpose can be much better served, as mentioned above, by using ddclient, now that they support cloudflare, which they didn't when I wrote this script.
If I could archive it (like you can projects on github), I would, but they've not ported that feature to gists yet.

N/B: Comments after this will be deleted to make this more obvious, so it's not lost in a sea of comments.