An autoupdate-on-launch thing for Discord on Debian

discord

#!/usr/bin/env bash
#
# /usr/local/bin/discord
# Discord autoupdate-on-launch wrapper

update_script="${0/%discord/update-discord.sh}"
[[ ! -x "$update_script" ]] || "$update_script"

exec /usr/bin/discord "$@"

update-discord

# /etc/sudoers.d/update-discord
#
# Lets Discord autoupdate wrapper execute `dpkg -i` as root

username ALL=(root) NOPASSWD: /usr/local/bin/update-discord.sh

update-discord.sh

#!/usr/bin/env bash
#
# /usr/local/bin/update-discord.sh
# Run by /usr/local/bin/discord

api='https://discord.com/api/{}/stable?platform=linux'
chk="${api/{\}/updates}"
dl="${api/{\}/download}"

latest()
{
	local o=$(set +o)
	set +e

	(( UID )) || {
		[[ -z "$1" || ! -f "$1" ]] || {
			local d=$(dirname "$1")
			dpkg -i "$1"
			[[ -z "$d" || ! -d "$d" ]] || rm -fr "$d"
		}
		eval "$o"
		return 0
	}

	set -o pipefail

	local a b
	! a=$(dpkg-query -Wf'${Version}' discord 2>/dev/null) || [[ ! "$a" ]] ||
	! b=$(curl -Ss "$chk" | jq -er .name) || [[ ! "$b" || "$b" == "$a" ]]

	b=$?
	eval "$o"
	return "$b"
}

update()
{
	local d
	! d=$(mktemp -dp /tmp .update-discord-XXXXXXXX) || [[ ! -d "$d" ]] || {
		local f="$d/discord.deb"
		! curl -Ss --follow --output="$f" "$dl" ||
		[[ ! -f "$f" ]] || exec sudo "$1" "$f"
		rm -fr "$d/"
	}
}

latest "$1" || update "$0"