Some ideas for this sort of function (or perhaps a few related functions):

* Allow OS-independent handling of the path. E.g. the CGI server still has to check if each segment is a CGI script, the rest becomes PATH_INFO. Perhaps return a sequence of path segments rather than a string.
* Allow easy conversion to a valid OS path (or perhaps a pathlib object)
* Ensure that invalid and special OS filenames trigger an error (e.g. "NUL" or unsupported characters, including backslashes \, on Windows). Like a stricter version of pathlib’s is_reserved().
* Handle percent decoding

Also, see the SimpleHTTPRequestHandler.translate_path() method, and Issue 14567. There seems to be a lot of redundancy.