emacs and xdg-open

emacs and xdg-open

[Eric Abrahamsen]

I'm running archlinux, stumpwm and emacs, and have had pretty resounding
success using dired as my only file manager: in dired I've bound 'e' to
a command that passes files to xdg-open, and by dint of copying
/usr/share/applications/mimeinfo.cache into
~/.local/share/applications/default.list, the right external
applications open files out of dired.

The one iffy thing is getting other applications to pass directory
references to emacs (ie clicking the dropbox applet icon in the system
tray and having the dropbox directory open in dired). Pointing
the inode/directory MIME type at emacs works, but starts a new emacs
instance. I created a "emacsclient.desktop" file:

[Desktop Entry]
Name=EmacsClient
MimeType=inode/directory;x-directory/normal
Exec=emacsclient -n %F
Type=Application
Terminal=false

And this nearly works, except that the '-n' flag to the emacsclient exec
doesn't appear to be respected: emacs still tells me "Press C-x # when
you're done editing this file" (this being a dired buffer), and if I
kill the buffer it asks: "Buffer `Dropbox' still has clients; kill it?"

I guess this is a long shot, but does anyone have a guess as to why the
'-n' flag is ignored, and how to fix it? If not, please consider this a
(nearly-functional) tutorial on using emacs as your only file manager on
linux systems without a proper desktop environment. :)

Yrs,
Eric

-- 
GNU Emacs 24.0.92.2 (i686-pc-linux-gnu, GTK+ Version 2.24.8)
 of 2012-01-04 on pellet

Re: emacs and xdg-open

[Philipp Haselwarter]

Eric Abrahamsen <eric@ericabrahamsen.net> writes:

> I'm running archlinux, stumpwm and emacs, and have had pretty resounding
> success using dired as my only file manager: in dired I've bound 'e' to
> a command that passes files to xdg-open, and by dint of copying
> /usr/share/applications/mimeinfo.cache into
> ~/.local/share/applications/default.list, the right external
> applications open files out of dired.

Thanks for sharing, fits my setup quite well!

What command you use to call `xdg-open'?

Some programs (eg. mplayer) exit uncleanly when their stderr and stdout
are closed, which causes xdg-open to reopen the file with the default
application for unknown mime types, as it appears.
And allocating a buffer to every started program....

> The one iffy thing is getting other applications to pass directory
> references to emacs (ie clicking the dropbox applet icon in the system
> tray and having the dropbox directory open in dired). Pointing
> the inode/directory MIME type at emacs works, but starts a new emacs
> instance. I created a "emacsclient.desktop" file:
>
> [Desktop Entry]
> Name=EmacsClient
> MimeType=inode/directory;x-directory/normal
> Exec=emacsclient -n %F
> Type=Application
> Terminal=false
>
> And this nearly works, except that the '-n' flag to the emacsclient exec
> doesn't appear to be respected: emacs still tells me "Press C-x # when
> you're done editing this file" (this being a dired buffer), and if I
> kill the buffer it asks: "Buffer `Dropbox' still has clients; kill it?"
>
> I guess this is a long shot, but does anyone have a guess as to why the
> '-n' flag is ignored, and how to fix it? If not, please consider this a
> (nearly-functional) tutorial on using emacs as your only file manager on
> linux systems without a proper desktop environment. :)
>
> Yrs,
> Eric

I wrote a quick test script, and it looks like it's not Emacs' fault,
arguments are just not passed on.

Actually, it the Exec line seems not to be honored; instead simply the
basename of the .desktop gets executed (ie. just emacsclient).

So in order to make everything work, you need to create a script with a
new name (and also beware of applications that don't call emacsclient
with an argument, it'll fail):

emacsclient_wrapper
#!/bin/sh
[ "$@" ] && emacsclient -n $@ || emacsclient -n ~/

Leave out the -n in the desktop file and rename it accordingly:

emacsclient_wrapper.desktop

-- 
Philipp Haselwarter

Re: emacs and xdg-open

[Eric Abrahamsen]

On Tue, Jan 10 2012, Philipp Haselwarter wrote:

> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
>
>> I'm running archlinux, stumpwm and emacs, and have had pretty resounding
>> success using dired as my only file manager: in dired I've bound 'e' to
>> a command that passes files to xdg-open, and by dint of copying
>> /usr/share/applications/mimeinfo.cache into
>> ~/.local/share/applications/default.list, the right external
>> applications open files out of dired.
>
> Thanks for sharing, fits my setup quite well!

There may also be mimeinfo.cache files in
/usr/local/share/applications/, for packages you've installed yourself.
I could probably figure out why xdg-mime doesn't just read those files
directly, but life is short.

> What command you use to call `xdg-open'?

I modified something I found on the internet that originally used
gnome-open:

--8<---------------cut here---------------start------------->8---
(defun dired-xdg-open-file ()
  "Opens the current file in a Dired buffer."
  (interactive)
  (xdg-open-file (dired-get-file-for-visit)))

(defun xdg-open-file (filename)
  "xdg-opens the specified file."
  (interactive "fFile to open: ")
  (let ((process-connection-type nil))
    (start-process "" nil "/usr/bin/xdg-open" filename)))

;;'e' usually does 'dired-find-file, same as RET, rebinding it here
(add-hook 'dired-mode-hook
	  (lambda ()
	    (define-key dired-mode-map (kbd "e") 'dired-xdg-open-file)))

(setq image-dired-external-viewer "/usr/bin/xdg-open")
--8<---------------cut here---------------end--------------->8---


> Some programs (eg. mplayer) exit uncleanly when their stderr and stdout
> are closed, which causes xdg-open to reopen the file with the default
> application for unknown mime types, as it appears.
> And allocating a buffer to every started program....
>
>> The one iffy thing is getting other applications to pass directory
>> references to emacs (ie clicking the dropbox applet icon in the system
>> tray and having the dropbox directory open in dired). Pointing
>> the inode/directory MIME type at emacs works, but starts a new emacs
>> instance. I created a "emacsclient.desktop" file:
>>
>> [Desktop Entry]
>> Name=EmacsClient
>> MimeType=inode/directory;x-directory/normal
>> Exec=emacsclient -n %F
>> Type=Application
>> Terminal=false
>>
>> And this nearly works, except that the '-n' flag to the emacsclient exec
>> doesn't appear to be respected: emacs still tells me "Press C-x # when
>> you're done editing this file" (this being a dired buffer), and if I
>> kill the buffer it asks: "Buffer `Dropbox' still has clients; kill it?"
>>
>> I guess this is a long shot, but does anyone have a guess as to why the
>> '-n' flag is ignored, and how to fix it? If not, please consider this a
>> (nearly-functional) tutorial on using emacs as your only file manager on
>> linux systems without a proper desktop environment. :)
>>
>> Yrs,
>> Eric
>
> I wrote a quick test script, and it looks like it's not Emacs' fault,
> arguments are just not passed on.
>
> Actually, it the Exec line seems not to be honored; instead simply the
> basename of the .desktop gets executed (ie. just emacsclient).
>
> So in order to make everything work, you need to create a script with a
> new name (and also beware of applications that don't call emacsclient
> with an argument, it'll fail):
>
> emacsclient_wrapper
> #!/bin/sh
> [ "$@" ] && emacsclient -n $@ || emacsclient -n ~/
>
> Leave out the -n in the desktop file and rename it accordingly:
>
> emacsclient_wrapper.desktop

This worked, by god, thank you! Just for the record, it seems the "Exec"
line in the desktop file *is* honored, it just drops command-line
arguments (perhaps the whole line could be wrapped in quotes or
something?). Just naming the desktop file the same as my
emacsclient-wrapper script wasn't enough, I had to point the Exec line
at the script itself (I know because when I misspelled that line the
whole thing stopped working). And a good thing too—how bizarre would it
be to have an Exec line that did nothing? Dropping command line
parameters seems weird enough, though…

Anyway, thanks for getting me the rest of the way there!

Eric

-- 
GNU Emacs 24.0.92.2 (i686-pc-linux-gnu, GTK+ Version 2.24.8)
 of 2012-01-04 on pellet

Re: emacs and xdg-open

[Philipp Haselwarter]

Eric Abrahamsen <eric@ericabrahamsen.net> writes:

> On Tue, Jan 10 2012, Philipp Haselwarter wrote:
>
>> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
>>
---8<---[snipped 13 lines]---8<---
>
>> What command you use to call `xdg-open'?
>
> I modified something I found on the internet that originally used
> gnome-open:
>
> (defun dired-xdg-open-file ()
>   "Opens the current file in a Dired buffer."
>   (interactive)
>   (xdg-open-file (dired-get-file-for-visit)))
>
> (defun xdg-open-file (filename)
>   "xdg-opens the specified file."
>   (interactive "fFile to open: ")
>   (let ((process-connection-type nil))
>     (start-process "" nil "/usr/bin/xdg-open" filename)))
>
> ;;'e' usually does 'dired-find-file, same as RET, rebinding it here
> (add-hook 'dired-mode-hook
> 	  (lambda ()
> 	    (define-key dired-mode-map (kbd "e") 'dired-xdg-open-file)))
>
> (setq image-dired-external-viewer "/usr/bin/xdg-open")
>
>
>> Some programs (eg. mplayer) exit uncleanly when their stderr and stdout
>> are closed, which causes xdg-open to reopen the file with the default
>> application for unknown mime types, as it appears.
>> And allocating a buffer to every started program....
>>
remains unsolved

--8<---------------cut here---------------start------------->8---
(eval-after-load 'dired
  '(progn
    (define-key dired-mode-map "E" 'my-dired-xdg-open)
    (define-key dired-mode-map [tool-bar my-dired-xdg-open]
      `(menu-item "ext" my-dired-xdg-open
                  :help "Open file(s) with xdg-open"
                  :image ,(find-image
                           '((:type xpm :file "right-arrow.xpm")))))))

(defun my-dired-xdg-open (arg)
  "Open files from `dired-get-marked-files' with `my-xdg-open-file'"
  (interactive "P")
  (mapcar 'my-xdg-open-file (dired-get-marked-files nil arg)))

(defun dired-xdg-open-file ()
  "Opens the current file in a Dired buffer."
  (interactive)
  (xdg-open-file (dired-get-file-for-visit)))
--8<---------------cut here---------------end--------------->8---

The only annoyance left is that opening multiple files calls the program
several times as xdg-open accepts only one file. I'd glad to hear ideas
how to solve this!

---8<---[snipped 53 lines]---8<---
>
> Anyway, thanks for getting me the rest of the way there!
>
> Eric

Glad it works; usually I have {tool,menu,scroll}-bar-mode turned off but
I kind of like them for a file manager.
Here's what I ended up with:

--8<---------------cut here---------------start------------->8---
#!/bin/sh
[ "$1" ] || set "`pwd`"

OPT='((tool-bar-lines . 1) (menu-bar-lines . 1) (vertical-scroll-bars . right))'
emacsclient -n -c -F "$OPT" "$@"
--8<---------------cut here---------------end--------------->8---


-- 
Philipp Haselwarter

Re: emacs and xdg-open

[Eric Abrahamsen]

On Wed, Jan 11 2012, Philipp Haselwarter wrote:

> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
>
>> On Tue, Jan 10 2012, Philipp Haselwarter wrote:
>>
>>> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
>>>
> ---8<---[snipped 13 lines]---8<---
>>

[...]

>>> Some programs (eg. mplayer) exit uncleanly when their stderr and stdout
>>> are closed, which causes xdg-open to reopen the file with the default
>>> application for unknown mime types, as it appears.
>>> And allocating a buffer to every started program....
>>>
> remains unsolved

I've never really seen this problem, so I'm not sure how to address it…


[...]

>
> The only annoyance left is that opening multiple files calls the program
> several times as xdg-open accepts only one file. I'd glad to hear ideas
> how to solve this!

I think the only solution here is to look inside xdg-open and see what
it uses to determine the proper default applications. Then, inside
emacsclient-wrapper, don't use xdg-open itself, but do what it does to
figure out the proper application, and then pass multiple files
directly to that application. I'll admit it never even occurred to me to
open multiple files this way (though it should have!), so I hadn't
thought about it.

Assuming you have no desktop environment, the relevant function inside
xdg-open is open_generic_xdg_mime, which starts at line 408 in my
installation. The following lines make it work:

# get the mime type, and the .desktop file of the program that
# should open it
--8<---------------cut here---------------start------------->8---
filetype=`xdg-mime query filetype "$1" | sed "s/;.*//"`
default=`xdg-mime query default "$filetype"`
--8<---------------cut here---------------end--------------->8---

# then it finds the .desktop file, puts it in $file, and gets the actual
# executable from it, this is why the command line flags are dropped!

--8<---------------cut here---------------start------------->8---
command="`grep -E "^Exec(\[[^]=]*])?=" "$file" | cut -d= -f 2- | first_word`"
command_exec=`which $command 2>/dev/null`
--8<---------------cut here---------------end--------------->8---

# execute command
--8<---------------cut here---------------start------------->8---
$command_exec "$1"
--8<---------------cut here---------------end--------------->8---

So you could use any or all of the above bits to make a shell script
which does basically what xdg-open does, except which can also handle
multiple files (and can also preserve command line flags for the
executable).

Hope that's useful,

Eric

-- 
GNU Emacs 24.0.92.2 (i686-pc-linux-gnu, GTK+ Version 2.24.8)
 of 2012-01-04 on pellet