Using a secondary browser as Messenger for MS Teams only (open all links in other browser)

README.md

How to use a secondary browser as MS Teams messenger only

Linux:

1. download files:
   • save browser.desktop as ~/.local/share/applications/browser.desktop
   • save browser.sh as /usr/local/bin/browser.sh
     • if you want to use a specific browser for your links, replace xdg-open with that browsers executable
2. install protocols:
   • run xdg-mime default browser.desktop x-scheme-handler/browser for http
   • run xdg-mime default browser.desktop x-scheme-handler/browsers for https
3. install Tampermonkey and external-teams-links.user.js:
   • download Tampermonkey for chrome or Firefox
   • install external-teams-links.user.js by clicking the "Raw" button above it and pressing "install" in the prompt
4. to hide the tab bar, run your browser in app mode:
   • for Chrome: chromium --app="https://teams.microsoft.com"
     • desktop file provided below
   • for Firefox: firefox --kiosk https://teams.microsoft.com for fullscreen or the Add-On Web App Mode
   • for Edge: main menu -> "Apps" -> "Install this site as an app"

Windows:

1. save browser.bat as C:\usr\browser.bat
2. register URL handlers by running the two .reg-files
   • if you want to store browser.bat somewhere else, change the path in the last line of your reg files
3. Continue with steps 3 and 4 from the instructions for Linux

browser.bat

@echo off
set arg1=%1
start "" %arg1:*browser=http%

browser.desktop

[Desktop Entry]
Type=Application
Name=Browser Scheme Handler
Exec=browser.sh %u
StartupNotify=false
MimeType=x-scheme-handler/browser;
MimeType=x-scheme-handler/browsers;

browser.reg

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\browser]
@="URL:browser"
"URL Protocol"=""

[HKEY_CLASSES_ROOT\browser\shell]

[HKEY_CLASSES_ROOT\browser\shell\open]

[HKEY_CLASSES_ROOT\browser\shell\open\command]
@="\"C:\\usr\\browser.bat\" \"%1\""

browser.sh

#!/bin/bash

xdg-open "http${1#"browser"}"

browsers.reg

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\browsers]
@="URL:browsers"
"URL Protocol"=""

[HKEY_CLASSES_ROOT\browsers\shell]

[HKEY_CLASSES_ROOT\browsers\shell\open]

[HKEY_CLASSES_ROOT\browsers\shell\open\command]
@="\"C:\\usr\\browser.bat\" \"%1\""

external-teams-links.user.js

// ==UserScript==
// @name         external-teams-links
// @namespace    https://mstaff.de/
// @version      0.1
// @description  replace links in MS Teams to have chrome act like a messenger only
// @author       Max Staff <max.staff@gmx.de>
// @match        https://teams.microsoft.com/*
// @icon         data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    function run() {
        document.querySelectorAll("a[target=_blank]").forEach(linkElement => {
            linkElement.href = (linkElement.href ?? linkElement.innerHTML).replace("http", "browser");
            linkElement.removeAttribute("target");
        });
    }

    window.setInterval(run, 1000);
})();

teams.desktop

#!/usr/bin/env xdg-open
[Desktop Entry]
Version=1.0
Terminal=false
Type=Application
Name=MS Teams
Exec=/usr/bin/chromium --app="https://teams.microsoft.com"
Icon=/home/max/.local/share/icons/teams.svg

Issues:

• Pictures cannot be displayed when this is activated.
• sent links cannot be opened by clicking

One can fix the issue of Pictures not being displayed by adding following quick and dirty guard inside the forEach loop:
Someone can probably figure out a more robust pattern than this.

if (linkElement.href && linkElement.href.includes("teams.microsoft.com/")) {
    return
}

@hterik sorry I should have updated this earlier: You can run ms teams in chrome in app mode (see step 4) and use the chrome extension Open in Firefox to open all links that do not belong to teams in Firefox. If you use a different Browser there's also Add-Ons for that. That way you don't need Tampermonkey and you don't need steps 1 and 2.