only try to get ip address if necessary

he-ddns

@@ -50,18 +50,22 @@ done
 # shellcheck source=he-ddnsrc
 . "$config" || die $LINENO
 
-ipv4="$(curl -sSL4 "$ip_host")" || die $LINENO
-for domain in "${!DOMAINS4[@]}"; do
-	printf "%s :: " "$domain"
-	key=${DOMAINS4[$domain]}
-	curl -sSL4 "$url" -d "hostname=$domain" -d "password=$key" -d "myip=$ipv4" || die $LINENO
-	echo
-done
+if [[ -n "${DOMAINS4[*]}" ]]; then
+	ipv4="$(curl -sSL4 "$ip_host")" || die $LINENO
+	for domain in "${!DOMAINS4[@]}"; do
+		printf "%s :: " "$domain"
+		key=${DOMAINS4[$domain]}
+		curl -sSL4 "$url" -d "hostname=$domain" -d "password=$key" -d "myip=$ipv4" || die $LINENO
+		echo
+	done
+fi
 
-ipv6="$(curl -sSL6 "$ip_host")" || die $LINENO
-for domain in "${!DOMAINS6[@]}"; do
-	printf "%s :: " "$domain"
-	key=${DOMAINS6[$domain]}
-	curl -sSL6 "$url" -d "hostname=$domain" -d "password=$key" -d "myip=$ipv6" || die $LINENO
-	echo
-done
+if [[ -n "${DOMAINS6[*]}" ]]; then
+	ipv6="$(curl -sSL6 "$ip_host")" || die $LINENO
+	for domain in "${!DOMAINS6[@]}"; do
+		printf "%s :: " "$domain"
+		key=${DOMAINS6[$domain]}
+		curl -sSL6 "$url" -d "hostname=$domain" -d "password=$key" -d "myip=$ipv6" || die $LINENO
+		echo
+	done
+fi