Unable to open Thunderbird as default calendar app

[John Boxall]

I am trying to launch Thunderbird as my calendar application when
opening a webcal link. Though I have updated all appropriate
gnome-mimeapps.list and mimeapps.list files and used xdg-mime to query
and set the default calendar application, my user session wants to open
Evolution. The GNOME defaults for mail and calendar were already set to
Thunderbird. If I remove Evolution, the dialog opens but specifies
xdg-open and there are no options to choose another application.

This happens in both Chrome and Firefox.

I am running Debian 10/Buster with all of the latest updates.

The following files have been updated to point to Thunderbird:

~/.config/gnome-mimeapps.list
~/.config/mimeapps.list
/etc/xdg/gnome-mimeapps.list
/etc/xdg/mimeapps.list
~/.local/share/applications/gnome-mimeapps.list
~/.local/share/applications/mimeapps.list
/usr/local/share/applications/gnome-mimeapps.list
/usr/local/share/applications/mimeapps.list
/usr/share/applications/gnome-mimeapps.list
/usr/share/applications/mimeapps.list

I would appreciate if someone could point me to the missing puzzle piece.

--
Regards,

John Boxall

[Max Nikulin]

On 29/03/2023 05:01, John Boxall wrote:
> I am trying to launch Thunderbird as my calendar application when
> opening a webcal link.

Your description is too general, it lacks details. E.g. you did not
provide exact commands and their output that you use to check that
defaults are set properly.

> This happens in both Chrome and Firefox.

Open web development tools, switch to the network tab, click on the
link, check MIME type in server response headers.

In Firefox check application associations in preferences (settings).

If you save link target to disk, can you open the downloaded file by
thunderbird directly and by xdg-open? What is MIME type reported by the
"file" utility?

> I am running Debian 10/Buster with all of the latest updates.

Behavior might depend on your desktop environment.

> The following files have been updated to point to Thunderbird:
>

> ~/.config/mimeapps.list

It is hard to reason whether it should work without details what you
have added to this file.

Check entries related to evolution in this file and MIME types specified
in its .desktop file.

[John Boxall]

On 2023-03-29 00:21, Max Nikulin wrote:
> Your description is too general, it lacks details. E.g. you did not
> provide exact commands and their output that you use to check that
> defaults are set properly.
>

Max, though I queried several of the mime types (via "xdg-mime query
default *****), the one I missed was "x-scheme-handler/webcal" which was
still set to Evolution.

"xdg-mime query default x-scheme-handler/webcal
org.gnome.Evolution.desktop"

>
> In Firefox check application associations in preferences (settings).
>

I was able to change the application association in Firefox which
allowed me to select the Thunderbird launch script in /usr/bin and then
process the URL.

Chrome does not have the same capability as Firefox for application
associations and relies on the system file associations.

> If you save link target to disk, can you open the downloaded file by
> thunderbird directly and by xdg-open? What is MIME type reported by the
> "file" utility?
>

Yes, saving the file would have worked.

file "appointments (4).ics"
appointments (4).ics: vCalendar calendar file

>
> Behavior might depend on your desktop environment.
>

GNOME desktop.

>
> It is hard to reason whether it should work without details what you
> have added to this file.

These were queried (via xdg-mime) then added or changed in the files listed:

text/calendar=thunderbird.desktop
text/x-vcard=thunderbird.desktop
application/mbox=thunderbird.desktop
message/rfc822=thunderbird.desktop
x-scheme-handler/mailto=thunderbird.desktop

>
> Check entries related to evolution in this file and MIME types specified
> in its .desktop file.
>

I missed the x-scheme-handler/webcal mime type which was the root of my
problem.

Thank you for the help and push to look closer.

--
Regards,

John Boxall

[Max Nikulin]

On 30/03/2023 08:01, John Boxall wrote:
>     "xdg-mime query default x-scheme-handler/webcal
> org.gnome.Evolution.desktop"

To express it explicitly: handling of "text/calendar" .ics files and
webcal: (webcals:) URI schemes are configured independently. From your
original message it was unclear for me if you mean a https: link to an
.ics file or not.

Alternative command that actually calls xdg-mime:

xdg-settings get default-url-scheme-handler webcal
thunderbird.desktop

Both commands may set handlers.

>> In Firefox check application associations in preferences (settings).
>
> I was able to change the application association in Firefox which
> allowed me to select the Thunderbird launch script in /usr/bin and then
> process the URL.

When associations are properly added to ~/.config/mimeapps.list, firefox
should offer thunderbird directly without necessity to browse filesystem
for the executable.

> Chrome does not have the same capability as Firefox for application
> associations and relies on the system file associations.

Chrome invokes xdg-open that should execute "gio open". Gnome either
uses default handler or display a dialog with alternatives.

>     file "appointments (4).ics"
>     appointments (4).ics: vCalendar calendar file

file --mime
uid.ics: text/calendar; charset=us-ascii

is more relevant for configuration of MIME types

>     text/calendar=thunderbird.desktop

Such entry is present in thunderbird.desktop, so additional
configuration should not be necessary.

> I missed the x-scheme-handler/webcal mime type which was the root of my
> problem.

For some reason posting content of ~/.config/mimeapps.list you missed
section headers.

[Added Associations]
x-scheme-handler/webcal=thunderbird.desktop
x-scheme-handler/webcals=thunderbird.desktop

should be enough for Gnome to add Thunderbird to open dialog. Unsure if
x-scheme-handler/webcals is really necessary. To set thunderbird *by
default*:

[Default Applications]
x-scheme-handler/webcal=thunderbird.desktop
x-scheme-handler/webcals=thunderbird.desktop

and check that it is not overridden. You posted a lot of files and some
of them might have higher priority for backward compatibility.

Ubuntu has x-scheme-handler/webcal in thunderbird.desktop. You may
submit a request to https://bugs.debian.org similar to the mid:
(Message-ID) URI scheme https://bugs.debian.org/1008159

The following pages describe how to configure associations of MIME types
and applications, unfortunately URI schemes are not mentioned:

https://help.gnome.org/admin/system-admin-guide/stable/mime-types-application.html.en
Override the default registered application for all users

https://help.gnome.org/admin/system-admin-guide/stable/mime-types-application-user.html.en
Override the default registered application for individual users

I am unaware of Debian docs, however an example of setting scheme
handler may be found in https://wiki.debian.org/DefaultWebBrowser The
following page looks too general https://wiki.debian.org/MimeTypesSupport

[John Boxall]

On 2023-03-29 23:18, Max Nikulin wrote:

Thank you for the insights Max. Updating the default mime type for
webcal resolved my problem.
--
Regards,

John Boxall