From ece1c7d60baefe849fb5527cd6d3f01e49edd5ec Mon Sep 17 00:00:00 2001
From: Daniel Langbein <daniel@systemli.org>
Date: Thu, 12 Oct 2023 17:57:08 +0200
Subject: [PATCH] share printers

---
 modules/print-and-scan.nix | 58 ++++++++++++++++++++++++++++++--------
 1 file changed, 47 insertions(+), 11 deletions(-)

diff --git a/modules/print-and-scan.nix b/modules/print-and-scan.nix
index a8af7bf..ab81d44 100644
--- a/modules/print-and-scan.nix
+++ b/modules/print-and-scan.nix
@@ -1,20 +1,56 @@
 { config, pkgs, ... }:
 {
   # Printing with IPP everywhere capable printers
-  # https://nixos.wiki/wiki/Printing
+  #   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.
 
-  # Enable CUPS to print documents.
-  services.printing.enable = true;
-  # HP and Lexmark drivers
-  services.printing.drivers = [ pkgs.hplip pkgs.postscript-lexmark ];
-  services.avahi.enable = true;
-  services.avahi.nssmdns = true;
-  # WiFi printers
-  services.avahi.openFirewall = true;
+  # 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
-  # https://unix.stackexchange.com/questions/518687/how-do-i-set-up-scanning-from-an-hp-officejet-pro-on-nixos/518688
+  #   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.