Create a script file, e.g. /var/nextcloud/.scripts/my-curl-script.sh which contains the desired curl command. As usual use $1, $2, $3, ... to access the command line options which you’ve parsed to the script.
The work flow app use the full path to your script and use, e.g. “%n” to parse the relative nc file path, like e.g.:
Keep in mind that “%n” only contains the relative file path from the Nextcloud data directory, e.g. “/user/files/YourDirectory/20191111_184052.jpg”.
Yes as described in the administrator guide, but this is a different story, isn’t it? The subject of this thread is “Workflow script with cURL” and not “cron.php”?! You should try not to mix-up different things in one thread.