Open links with documentation in neovim instead of browser

init.lua

-- Put this somewhere in init.lua
if vim.fn.has"unix" then
  -- Listen for :help call from .desktop python script
  pcall(vim.fn.serverstart, "localhost:" .. (vim.env.NVIM_LISTEN_PORT or 6969))
end

link-opener.desktop

[Desktop Entry]
Type=Application
Name=Opennvimlink
Exec=path/to/script.py %u
Terminal=false

script.py

#!/usr/bin/env python
import os
import sys
from urllib.parse import unquote, urlparse
from pynvim import tcp_session
parsed = urlparse(sys.argv[1])
try:
    if parsed.hostname not in ("vimhelp.org", "neovim.io"):
        raise Exception()
    topic = unquote(parsed.fragment)
    session = tcp_session("localhost", os.getenv("NVIM_LISTEN_PORT", "6969"))
    session.request("nvim_command", f"help {topic}")
    session.request("nvim_command", "wincmd L")
    session.close()
    # Display a notification from kitty; since I use wayland and there isn't
    # any way to manually raise the window, like in wmctrl
    os.system(f"notify-send -a kitty \"neovim: {topic}\"")
except:
    os.system(f"firefox {sys.argv[1]}")