I could not get HEIC previews working correcly when using Nextcloud on FreeBSD. So I made this script to convert them to jpg instead, which works fine for previews.

This Python script uses the WebDAV protocol to convert .heic files in a given Nextcloud folder to .jpg. The script works by finding all .heic files in the specified folder, downloading each file, converting it to .jpg, then re-uploading the new jpg file back to the same location in the Nextcloud server. The original .heic file is subsequently deleted from the server.

Set up the environment variables in a .env file (see from .env.example):

NEXTCLOUD_DAV_ENDPOINT: Your Nextcloud WebDAV endpoint.
NEXTCLOUD_USERNAME: Your Nextcloud username.
NEXTCLOUD_PASSWORD: Your Nextcloud password.
NEXTCLOUD_FOLDER: The path of the Nextcloud folder you wish to convert files in.

You can run the script with Poetry: poetry run nextcloud_heic_converter/main.py

You need imagemagick installed as this script relies on its convert command.