The full Dockerfile adds dependencies for all optional packages suggested by nextcloud that may be needed for some features (e.g. Video Preview Generation), as stated in the Administration Manual.
NOTE: The Dockerfile does not install the LibreOffice package (line is commented), because it would increase the generated Image size by approximately 500 MB. In order to install it, simply uncomment the 13th line of the Dockerfile.
NOTE: Per default, only previews for BMP, GIF, JPEG, MarkDown, MP3, PNG, TXT, and XBitmap Files are generated. The configuration of the preview generation can be done in config.php, as explained in the Administration Manual
NOTE: Nextcloud recommends disabling preview generation for high security deployments, as preview generation opens your nextcloud instance to new possible attack vectors.
The required steps for each optional/recommended package that is not already in the Nextcloud image are listed here, so that the Dockerfile can easily be modified to only install the needed extra packages. Simply remove the steps for the unwanted packages from the Dockerfile.
docker-php-ext-install bz2
apt install libmagickwand-dev
pecl install imagick
docker-php-ext-enable imagick
apt install libc-client-dev libkrb5-dev
docker-php-ext-configure imap --with-kerberos --with-imap-ssl
docker-php-ext-install imap
apt install libgmp3-dev
docker-php-ext-install gmp
apt install smbclient libsmbclient-dev
pecl install smbclient
docker-php-ext-enable smbclient
apt install ffmpeg