two scripts to set and read default app for url schemes (http, mailto, ssh, etc.) for use with Jamf Pro

getDefaultAppForURL.sh

#!/bin/bash

# this script will return the current default application for a url scheme
# for use as a Jamf Extension attribute

# by Armin Briegel - Scripting OS X

# Permission is granted to use this code in any way you want.
# Credit would be nice, but not obligatory.
# Provided "as is", without warranty of any kind, express or implied.

# the url scheme to check for
# change to check for other url schemes, e.g. `mailto`, `ssh`
urlScheme="http"

# Note that macOS does not allow separate settings for `http` and `https`.
# When a user changes one, it changes both, so it is sufficient to check just one.

currentUser=$( echo "show State:/Users/ConsoleUser" | scutil | awk '/Name :/ { print $3 }' )

# global check if there is a user logged in
if [ -z "$currentUser" ] || [ "$currentUser" = "loginwindow" ]; then
  echo "no user logged in, cannot proceed"
  exit 1
fi
# now we know a user is logged in

# get the current user's UID
uid=$(id -u "$currentUser")

# run a command as the current user
runAsUser() {  
  if [ "$currentUser" != "loginwindow" ]; then
    launchctl asuser "$uid" sudo -u "$currentUser" "$@"
  fi
}

getDefaultAppForScheme() { # $1: scheme, e.g. http, mailto, ...
	local urlScheme="${1?:"arg 1 required: url scheme "}"
	runAsUser osascript -l JavaScript << EndOfScript
		if ($.NSProcessInfo.processInfo.isOperatingSystemAtLeastVersion({majorVersion: 12, minorVersion: 0, patchVersion: 0})) {
            ObjC.import("AppKit")
            const url = $.NSURL.URLWithString(ObjC.wrap("${urlScheme}:"))
            const result = $.NSWorkspace.sharedWorkspace.URLForApplicationToOpenURL(url)
            result.path.js
        } else {
	        ObjC.import("LaunchServices")
            const url = $.NSURL.URLWithString(ObjC.wrap("http:"))
            $.LSCopyDefaultApplicationURLForURL(ObjC.wrap(url), 4294967295, null).path.js  
         }
EndOfScript
}

defaultApp=$(getDefaultAppForScheme "$urlScheme")

# for Jamf extension attributes, wrap in `result` tags
echo "<result>$defaultApp</result>"

# for non Extension Attribute use, comment above line and uncomment bleow:
# echo "$defaultApp"

setDefaultAppForURL.sh

#!/bin/bash

# this script will set the current default application for a url scheme

# by Armin Briegel - Scripting OS X

# IMPORTANT: when changing default app for 'http' user is prompted
# also 'https' will be automatically set when 'http' is changed
# attempting to change 'https' will result in an error

# Permission is granted to use this code in any way you want.
# Credit would be nice, but not obligatory.
# Provided "as is", without warranty of any kind, express or implied.


# get data from arguments

# when running as a Jamf policy, first three args with be target volume, 
# computer name and user name. Target volume will always be `/`, unless 
# you are imaging, which is dead...
# Then we shift the first three args. That way we can run interactively
# from Terminal as well as from a Jamf policy.
if [[ "$1" == "/" ]]; then
    shift 3
fi

urlScheme=${1?:"argument urlScheme required, e.g. 'http'"}
identifier=${2?:"argument bundle identifier required, e.g. 'com.apple.safari'"}

# you can get the identifier for an app with:
# mdls /Applications/Firefox.app -name kMDItemCFBundleIdentifier -raw 

currentUser=$( echo "show State:/Users/ConsoleUser" | scutil | awk '/Name :/ { print $3 }' )

uid=$(id -u "$currentUser")

# global check if there is a user logged in
if [[ -z "$currentUser" || "$currentUser" = "loginwindow" ]]; then
  echo "no user logged in, cannot proceed"
  exit 1
fi
# now we know a user is logged in

# run a command as the current user
runAsUser() {  
  if [ "$currentUser" != "loginwindow" ]; then
    launchctl asuser "$uid" sudo -u "$currentUser" "$@"
  fi
}

setDefaultAppForScheme() {
	local urlScheme=${1?:"arg 1 required: url scheme "}
    local bundleIdentifier=${2?:"arg 2 required: bundle identifier"}
    
	runAsUser osascript -l JavaScript << EndOfScript
    	// create NSURL from scheme string
    	const url = $.NSURL.URLWithString(ObjC.wrap("${urlScheme}:"))
    	if ($.NSProcessInfo.processInfo.isOperatingSystemAtLeastVersion({majorVersion: 12, minorVersion: 0, patchVersion: 0})) {
    		// macOS 12 and higher, use new NSWorkspace API
    		ObjC.import("AppKit")
    		const ws=$.NSWorkspace.sharedWorkspace
    		const appURL = ws.URLForApplicationWithBundleIdentifier(ObjC.wrap("$bundleIdentifier"))
    		ws.setDefaultApplicationAtURLToOpenURLsWithSchemeCompletionHandler(appURL, ObjC.wrap("$urlScheme"), err => {} )
     		delay(1)
    	} else {
    	    // macOS 11 and earlier use deprecated LaunchServices API
    	    ObjC.import("LaunchServices")
            $.LSSetDefaultHandlerForURLScheme(ObjC.wrap("$urlScheme"), ObjC.wrap("$bundleIdentifier"))
    	}
EndOfScript
}

setDefaultAppForScheme "$urlScheme" "$identifier"