[Linux] [Firefox] Open link in browser, which is in current workspace

README.md

I use separate Firefox profiles for work and personal stuff. To distinguish those I place them on different workspaces.

• Workspace 0: firefox --no-remote -P MyJob
• Workspace 1: firefox --no-remote -P default

I have also company Slack on Workspace 0. Which usually contains links to some work stuff.

The problem

When I open a link in Slack, it opens a new tab in Firefox at Workspace 1. But I want it to open in Firefox at Workspace 0!

In general, I want it to open links in current workspace. The algorithm which FF uses to determine which window to open new tab in, is bad.

The reason

Slack opens link with xdg-open. So I have to fix xdg-open to make Slack links work. The xdg-open uses gio tool, which detects MIME type of an argument and uses default application for that MIME type. The MIME mappings stay in ~/.config/mimeapps.list config file.

$ grep https ~/.config/mimeapps.list 
x-scheme-handler/https=firefox.desktop
x-scheme-handler/https=org.gnome.Epiphany.desktop;firefox.desktop

So in my case xdg-open https://google.com fires firefox.desktop with https://google.com argument. The mentioned desktop icon looks like this (I use NixOS distro):

$ cat /home/danbst/.nix-profile/share/applications/firefox.desktop
[Desktop Entry]
Type=Application
Exec=firefox %U    # <----
Terminal=false
Name=Firefox
Categories=Application;Network;WebBrowser;
Icon=firefox
Comment=
GenericName=Web Browser
MimeType=text/html;text/xml;application/xhtml+xml;application/vnd.mozilla.xul+xml;x-scheme-handler/http;x-scheme-handler/https;x-scheme-handler/ftp

I've highlighted the Exec line, which searches $PATH envvar for a given executable.

In the end, when I click a link in Slack, it runs a command firefox https://..., which opens a new tab in a window with default profile. When no default profile found or all windows are opened with default profile, it uses previously focused Firefox window. So if you did some Facebook lurk on Workspace 1, and then suddenly react to Slack message (on Workspace 0) and click a link, it will open URL in Firefox Workspace 1.

The solution

We have to create a wrapper around firefox, which should detect current workspace, find Firefox there, focus it and open a new tab. We also have to create a .desktop file, which will run this wrapper and set it as default.

I'm attaching the wrapper script and Nix-script to build this mini-package. After installing into current profile with nix-env -if ., you should reload Gnome Shell (Alt-F2 r Enter) and change things in ~/.config/mimeapps.list:

$ grep http ~/.config/mimeapps.list 
x-scheme-handler/http=UrlLauncher.desktop
x-scheme-handler/https=UrlLauncher.desktop
x-scheme-handler/https=org.gnome.Epiphany.desktop;firefox.desktop;UrlLauncher.desktop

Now xdg-open https://google.com will use url-launcher tool to open links.

NOTE: if you want to use this script outside NixOS, you should have xdotool and wmctrl tools installed.

default.nix

with import <nixpkgs> {};
stdenv.mkDerivation rec {
    name = "url-launcher";

    desktopItem = makeDesktopItem {
        name = "UrlLauncher";
        exec = "@out@/bin/url-launcher %U";
        comment = "Run URL in browser in current workspace";
        desktopName = "UrlLauncher";
        genericName = "Browser launcher";
        categories = "Application;Network;WebBrowser;";
        mimeType = "text/html;text/xml;application/xhtml+xml;application/vnd.mozilla.xul+xml;x-scheme-handler/http;x-scheme-handler/https;x-scheme-handler/ftp";
    };

    nativeBuildInputs = [ makeWrapper ];

    buildInputs = [ xdotool wmctrl ];

    buildCommand = ''
        mkdir -p \
           $out/bin \
           $out/share/applications
        cp ${./url-launcher.sh} $out/bin/url-launcher
        chmod +x $out/bin/url-launcher
        wrapProgram $out/bin/url-launcher --prefix PATH : "${lib.makeBinPath buildInputs}"
        cp $desktopItem/share/applications/* $out/share/applications
        substitute $desktopItem/share/applications/* $out/share/applications/UrlLauncher.desktop --subst-var out
    '';
}

url-launcher.sh

#! /usr/bin/env bash
desktop=$(xprop -root -notype _NET_CURRENT_DESKTOP | cut -d\  -f3)
ff_raw=$(wmctrl -lp | grep "  $desktop " | grep Firefox | head -n1)
[ -z "$ff_raw" ] && xdg-open "$1"
echo $ff_raw
ff_wid=$(echo $ff_raw | awk '{print $1}')

wmctrl -i -a $ff_wid
xdotool key ctrl+t
xdotool getwindowfocus windowfocus --sync type "$1"
xdotool key KP_Enter