true (default), handle If-modified-since and send
modification time.false) and, in addition to the plain
file, there is a .gz file that is not older than the
plain file and the client acceps gzip encoding, send
the compressed file with Transfer-encoding: gzip.false (default), validate that FileSpec does not
contain references to parent directories. E.g.,
specifications such as www('../../etc/passwd') are
not allowed.
If caching is not disabled, it processes the request headers
If-modified-since and Range.
http_reply(not_modified)http_reply(file(MimeType, Path))