mod_fileiri implements http IRIs for directories/files, i.e.
if accepts URIs with non-ASCII characters encoded in UTF-8 and
converts them to the legacy encoding used in the file system
(which can be specified per directory, or even finer if necessary
(although that's a real hack)).

What is more, it continues to accept requests in the legacy
encoding specified, and redirects them to the correct UTF-8
form, which then returns the actual document (without looping).

There is also a backwards mode, which does redirects from
URIs in a specified legacy encoding to UTF-8 if the directory/
filenames are in UTF-8.