Nextcloud allows you to create aliases for mimetypes, so that you can display custom icons for files. For example, you might want a nice audio icon for audio files instead of the default file icon.
By default Nextcloud is distributed with
Do not modify this file, as it will be replaced when Nextcloud is updated.
Instead, create your own
file with your custom aliases. Use the same syntax as in
Once you have made changes to your
mimetypealiases.json, use the
command to propagate the changes through the system. This example is for
$ sudo -u www-data php occ maintenance:mimetype:update-js
See Using the occ command to learn more about
Some common mimetypes that may be useful in creating aliases are:
- Generic image
- Vector image
- Generic audio file
- Word processed document
- Generic text document
- Source code
Nextcloud allows administrators to specify the mapping of a file extension to a
mimetype. For example files ending in
mp3 map to
then in turn allows Nextcloud to show the audio icon.
By default Nextcloud comes with
mimetypemapping.dist.json. This is a
simple json array.
Administrators should not update this file as it will get replaced on upgrades
of Nextcloud. Instead the file
mimetypemapping.json should be created and
modified, this file has precedence over the shipped file.
When an icon is retrieved for a mimetype, if the full mimetype cannot be found, the search will fallback to looking for the part before the slash. Given a file with the mimetype ‘image/my-custom-image’, if no icon exists for the full mimetype, the icon for ‘image’ will be used instead. This allows specialised mimetypes to fallback to generic icons when the relevant icons are unavailable.