a virtual server here can speed up Web performance.
path: URL path, relative to the server, to find files. Defaults to
main path + '/file/'.
+ssl: whether to use HTTPS for file URLs. Defaults to null, meaning to
+ guess based on other SSL settings.
filecommand: command to use for determining the type of a file. May be
skipped if fileinfo extension is installed. Defaults to
'/usr/bin/file'.