Encode string as html in eXist-db / XQuery - xquery

Question

I'm trying to generate a treeview from a collection (filesystem). Unfortunately some Files have special characters like ü ä and ö. And I'd like to have them html encoded as &­auml;
When I get them from the variable, they are URL encoded. First I decode them to UTF-8 and then .... i don't know how to go further.
<li>{util:unescape-uri($child, "UTF-8")}
The function util:parse is doing the exact opposite from that what I want.
Here is the recursive function:
xquery version "3.0";
declare namespace ls="ls";
declare option exist:serialize "method=html media-type=text/html omit-xml-declaration=yes indent=yes";
declare function ls:ls($collection as xs:string, $subPath as xs:string) as element()* {
if (xmldb:collection-available($collection)) then
(
for $child in xmldb:get-child-collections($collection)
let $path := concat($collection, '/', $child)
let $sPath := concat($subPath, '/', $child)
order by $child
return
<li>{util:unescape-uri($child, "UTF-8")}
<ul>
{ls:ls($path,$sPath)}
</ul>
</li>,
for $child in xmldb:get-child-resources($collection)
let $sPath := concat($subPath, '/', $child)
order by $child
return
<li> {util:unescape-uri($child, "UTF-8")}</li>
)
else ()
};
let $collection := request:get-parameter('coll', '/db/apps/ebner-online/resources/xss/xml')
return
<ul>{ls:ls($collection,"")}</ul>

Answer 1

Rather than util:unescape-uri(), I would suggest using xmldb:encode-uri() and xmldb:decode-uri(). Use the encode version on a collection or document name when creating/storing it. Use the decode version when displaying the collection or document name. See the function documentation for the xmldb module.
As to forcing ä instead of ü, this is an even trickier serialization issue. Both, along with ä, are equivalent representations of the same UTF-8 character. Why not just let the character through as ü?