If you’re using the fantastic Nextcloud and like to feel comfortable browsing all your auto-uploaded photos like once upon a time you did in some proprietary Picasa or so, you can benefit from Preview Generator, which will take care of pre-rendering the thumbnails.
As it states you must add some cron magic to get it working and the Nextcloud folks asked for a tutorial, here’s how to do it with cron or (my preference) with systemd timers.
- we need to setup the job as the system user running Nextcloud (e.g.
httpd, … - depends on your distribution). You can find out by looking at the owner of the nextcloud files using
- we need to use the absolut path to the
- we need to use the absolut path to Nextclouds
occfile, depends in which folder your Nextcloud has been installed (e.g.
Add or create a new cronjob for the Nextcloud user:
crontab -e -u www-data
Using your favourite editor, add something like this, which will run the job at 04:00:
0 4 * * * /usr/bin/php -f /var/www/nextcloud/occ preview:pre-generate
Systemd also has the possibility to run specific tasks at specific times or events. called Timers. You need to create 2 unit files:
[Unit] Description=Nextcloud Preview Generator [Service] Type=oneshot User=www-data ExecStart=/usr/bin/php -f /var/www/nextcloud/occ preview:pre-generate [Install] WantedBy=basic.target
[Unit] Description=Run Nextcloud Preview Generator daily at 04:00 [Timer] OnCalendar=*-*-* 4:00:00 Persistent=true [Install] WantedBy=timers.target
- systemd reload
- activate the timer
systemctl enable nextcloud-preview-generator.timer
- start the timer
systemctl start nextcloud-preview-generator.timer