[tip] Create and Insert a public Nextcloud/Owncloud link

[Juan Manuel Macías]

Hi all,

One of the few things that I miss from a desktop environment like Gnome
Shell or KDE Plasma (currently I use EXWM), is the good integration
these environments had with Nextcloud, as I am a heavy user of
Nextcloud. Many times I need to create and share a public link to a file
in my local folder. In the Nextcloud forum I learned how it can be done
from the command line using curl, so starting from that, it wasn’t very
difficult to write this function in Elisp to insert a public link at
point. It can be inserted in two ways: literally or as an Org bracket
link, with description.

For the function to work we must have: a) a folder within our local
Nextcloud directory dedicated exclusively to public files; b) a line
with our personal data in the ~/.authinfo file. Assuming, for example,
that we use a third-party Nextcloud service like Disroot, the necessary
line in authinfo would be:

machine cloud.disroot.org login <my-user-name> password <my-password>

And let’s go with the function. Before I have defined these three
variables:

┌────
│ (defvar nextcloud-url "https://cloud.disroot.org";)
│ (defvar nextcloud-public-folder "~/disroot/Public/")
│ (defvar nextcloud-public-folder-name "Public")
└────

And the function itself (caveat: the function is not asynchronous):

┌────
│ (defun insert-nextcloud-link ()
│   (interactive)
│   (let* ((file-name (read-file-name "File: "
│                                   nextcloud-public-folder))
│        (file (if (directory-name-p
│                   file-name)
│                  (replace-regexp-in-string
│                   (expand-file-name
│                    nextcloud-public-folder)
│                   ""
│                   file-name)
│                (file-name-nondirectory file-name)))
│        (desc
│         (read-from-minibuffer
│          "Link description (enter = no description): "))
│        (auth
│         (nth 0
│              (auth-source-search
│               :host "cloud.disroot.org"
│               :requires '(user secret))))
│        (my-username (plist-get auth :user))
│        (my-passwd (funcall (plist-get auth :secret)))
│        (result-raw (shell-command-to-string
│                     (concat "curl -u "
│                             "\""
│                             my-username
│                             ":"
│                             my-passwd
│                             "\""
│                             " -H \"OCS-APIRequest: true\" -X POST "
│                             nextcloud-url
│                             "/ocs/v1.php/apps/files_sharing/api/v1/shares -d 
path="
│                             "\""
│                             nextcloud-public-folder-name
│                             "/"
│                             file
│                             "\""
│                             " -d shareType=3"
│                             " -d permissions=1")))
│        (result (with-temp-buffer
│                  (insert result-raw)
│                  (goto-char (point-min))
│                  (re-search-forward "<url>" nil t)
│                  (let ((desde (point)))
│                    (re-search-forward "<" nil t)
│                    (narrow-to-region desde (- (point) 1))
│                    (buffer-string)))))
│     (if (string= desc "")
│       (insert result)
│       (insert (format "[[%s][%s]]" result desc)))))
└────

Best regards,

Juan Manuel