cups: Add defaultShared, browsing and webInterace config option

nixos/modules/services/printing/cupsd.nix

···
         '';
       };
 
+      defaultShared = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Specifies whether local printers are shared by default.
+        '';
+      };
+
+      browsing = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Specifies whether shared printers are advertised.
+        '';
+      };
+
+      webInterface = mkOption {
+        type = types.bool;
+        default = true;
+        description = ''
+          Specifies whether the web interface is enabled.
+        '';
+      };
+
       cupsdConf = mkOption {
         type = types.lines;
         default = "";
···
 
         SetEnv PATH ${bindir}/lib/cups/filter:${bindir}/bin:${bindir}/sbin
 
-        Browsing On
+        DefaultShared ${if cfg.defaultShared then "Yes" else "No"}
+
+        Browsing ${if cfg.browsing then "Yes" else "No"}
+
+        WebInterface ${if cfg.webInterface then "Yes" else "No"}
 
         DefaultAuthType Basic
 

nixos/tests/printing.nix

···
       { config, pkgs, ... }:
       { services.printing.enable = true;
         services.printing.listenAddresses = [ "*:631" ];
+        services.printing.defaultShared = true;
         services.printing.extraConf =
           ''
             <Location />