kraken private API BASH, curl and openssl - bash

Question

I am using bash and curl to operate the Kraken API.
When I try to AddOrder, I get the response :
{"error":["EGeneral:Invalid arguments"]}
When I use the same code to find the Balance, I don't get an error.
The URL I am using looks like so :
https://api.kraken.com/0/private/AddOrder?pair=XXBTZUSD&type=buy&ordertype=limit&price=6000&volume=1&userref=1537588642&validate=1
The code looks like so (with the final openssl and curl command at the very end) :
FUNC="AddOrder"
FN="/tmp/kraken$FUNC.json"
# URL
PRICE=$1
VOL=$2
ORDERTYPE=limit
ID=`date +%s`
URLPATH="/0/private/$FUNC"
URLPATH="$URLPATH?pair=XXBTZUSD&type=buy&ordertype=$ORDERTYPE&price=$PRICE&volume=$VOL&userref=$ID&validate=1"
echo $URLPATH
curlPost $URLPATH $FUNC $FN
curlPost(){
# API Key:
APIKEY=`cat creds.key`
# Private Key:
PRIVATEKEY=`cat creds.private`
URLHOST="https://api.kraken.com"
NONCE=$(date +%s%N)
echo ${1}
echo -n "${1}" > /tmp/kraken.$2.bin
echo -n "${NONCE}nonce=${NONCE}" | openssl sha256 -binary >> /tmp/kraken.$2.bin
PRIVATEKEYHEX=$(echo -n "${PRIVATEKEY}" | base64 -d | hexdump -v -e '/1 "%02X"');
cat /tmp/kraken.$2.bin | openssl sha512 -binary -mac HMAC -macopt hexkey:${PRIVATEKEYHEX} > sign.$2.bin
APISIGN=$(cat sign.$2.bin | base64 -w 0)
curl -X POST -H "Accept: application/json" -H "API-Key: ${APIKEY}" -H "API-Sign: ${APISIGN}" -d "nonce=$NONCE" ${URLHOST}${URLPATH} > $3
}

Answer 1

I have worked out the solution. The curl argumnet -d for data, like so :
URLPATH="/0/private/$FUNC"
DATA="pair=XXBTZUSD&type=buy&ordertype=$ORDERTYPE&price=$PRICE&volume=$VOL&userref=$ID&validate=1"
if [ -z "$DATA" ]; then
curl -X POST -H "Accept: application/json" -H "API-Key: ${APIKEY}" -H "API-Sign: ${APISIGN}" -d "nonce=$NONCE" "${URLHOST}${URLPATH}"
else
curl -d ${DATA} -X POST -H "Accept: application/json" -H "API-Key: ${APIKEY}" -H "API-Sign: ${APISIGN}" -d "nonce=$NONCE" "${URLHOST}${URLPATH}"
fi