nix-git/modules/print-and-scan.nix

{ config, pkgs, ... }:
{
  # Printing with IPP everywhere capable printers
  #   https://nixos.wiki/wiki/Printing
  # Share printer via AirPrint
  #   https://project-insanity.org/2021/10/12/share-printer-via-airprint-with-nixos/
  #   After following these steps, my manually added Lexmark E460dn was instantly found on an Apple iPad.

  # When adding the Lexmark E460dn printer (via GNOME settings or directly on the CUPS web interface),
  # it is not found lateron. Discovery through the detected URL does not work.
  # Instead, I added it manually.
  # - When adding a printer, select `AppSocket/HP JetDirect` as type.
  # - Then fill in the IP of the printer, e.g. `socket://192.168.178.107:9100`
  # Reference: https://infoserve.lexmark.com/ids/ifc/ids_topic.aspx?root=kb20220119195146366&gid=v54804876&id=v54804875&topic=HO2475&productCode=Lexmark_T642&loc=en_CA

  networking.firewall = {
    allowedTCPPorts = [ 631 ];
    allowedUDPPorts = [ 631 ];
  };

  services.printing = {
    # Enable CUPS to print documents.
    enable = true;
    # HP and Lexmark drivers
    drivers = [ pkgs.hplip pkgs.postscript-lexmark ];
    # Specifies whether shared printers are advertised.
    browsing = true;
    defaultShared = true;
    listenAddresses = [ "*:631" ];
    allowFrom = [ "all" ];
    extraConf = ''
      DefaultPaperSize A4
    '';
  };

  services.avahi = {
    enable = true;
    # Whether to enable the mDNS NSS (Name Service Switch) plug-in.
    # Enabling it allows applications to resolve names in the .local domain by transparently querying the Avahi daemon.
    # -> Discover network printers.
    nssmdns = true;
    # Network printers
    openFirewall = true;
    publish = {
      enable = true;
      userServices = true;
    };
  };

  # Scanning
  #   https://nixos.wiki/wiki/Scanners
  # HP OfficeJet scanning
  #   https://unix.stackexchange.com/questions/518687/how-do-i-set-up-scanning-from-an-hp-officejet-pro-on-nixos/518688
  hardware.sane = {
    enable = true;
    # Optionally, add pkgs.sane-airscan for AirScan.
    extraBackends = [ pkgs.hplip ];
  };

  users.users.yoda = {
    extraGroups = [ "scanner" "lp" ];
    packages = with pkgs; [
      gnome.simple-scan
    ];
  };
}