feeds: include "title" in the output OPML -- when it exists

hosts/common/feeds.nix

@@ -41,6 +41,8 @@ let
       );
     } // lib.optionalAttrs (raw.is_podcast or false) {
       format = "podcast";
+    } // lib.optionalAttrs (raw.title or "" != "") {
+      title = lib.mkDefault raw.title;
     };
 
   podcasts = [

modules/feeds.nix

@@ -16,6 +16,10 @@ let
         type = types.enum [ "text" "image" "podcast" ];
         default = "text";
       };
+      title = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+      };
       url = mkOption {
         type = types.str;
         description = ''

modules/lib/feeds.nix

@@ -12,8 +12,24 @@ rec {
   # transform a list of feeds into an attrs mapping cat => [ feed0 feed1 ... ]
   partitionByCat = feeds: builtins.groupBy (f: f.cat) feeds;
 
+  xmlTag = tag: close: attrs:
+    let
+      fmt-attrs = builtins.concatStringsSep
+        " "
+        (lib.mapAttrsToList (name: value: ''${lib.escapeXML name}="${lib.escapeXML value}"'') attrs);
+      fmt-close = if close then "/" else "";
+    in
+      ''<${tag} ${fmt-attrs} ${fmt-close}>'';
+
   # represents a single RSS feed.
-  opmlTerminal = feed: ''<outline xmlUrl="${feed.url}" type="rss"/>'';
+  opmlTerminal = feed: xmlTag "outline" true (
+    {
+      xmlUrl = feed.url;
+      type = "rss";
+    } // lib.optionalAttrs (feed.title != null) {
+      title = feed.title;
+    }
+  );
   # a list of RSS feeds.
   opmlTerminals = feeds: lib.concatStringsSep "\n" (builtins.map opmlTerminal feeds);
   # one node which packages some flat grouping of terminals.