Improved response checking in linux script

Added check that prevents throwing a JSON parsing error when the server is down

resources/templates/scripts/xbackbone_uploader.sh.twig

@@ -30,6 +30,14 @@ EOF
 
 upload() {
     RESPONSE="$(curl -F "token={{ token }}" -F "upload=@${1}" {{ upload_url }})";
+    
+    if jq -e . >/dev/null 2>&1 <<<"$RESPONSE"; then
+        # Response is JSON
+        echo;
+    else
+        notify-send "Error: Uploading returned unexpected response" "Response: ${RESPONSE}";
+        exit 1;
+    fi
 
     if [[ "$(echo "${RESPONSE}" | jq -r '.message')" == "OK." ]]; then
         URL="$(echo "${RESPONSE}" | jq -r '.url')";