The requested file does not exists

The requested file cannot be served: does not exists, not enough permissions ...

The file is a directory which we should not display

Local file corresponding to a request. The string argument represents the real file or directory to serve, eg. foo/index.html instead of foo

Finds filename in the filesystem, with a possible redirection if it is a directory. Takes into account the fact that filename does not exists, is a symlink or is a directory, and raises Failed_404 or Failed_403 accordingly.

• we return "filename/index.html" if filename corresponds to a directory, "filename/index.html" is valid, and "index.html" is one possible index (trying all possible indexes in order)
• we raise Failed_404 if filename corresponds to a directory, no index exists and list_dir_content is false. Warning: this behaviour is not the same as Apache's but it corresponds to a missing service in Eliom (answers 404). This also allows to have an Eliom service after a "forbidden" directory
• we raise Failed_403 if filename is a symlink that must not be followed
• raises Failed_404 if filename does not exist, or is a special file
• otherwise returns filename

no_check_for is supposed to be a prefix of filename ; directories above no_check_for are not checked for symlinks