gistfile1.PL

package SwitchByLang;
use strict;
use nginx;
sub handler {
    my $r   = shift;
    my $uri = $r->uri;
    if ($uri =~ qr{^/(en|ja)/}) {
        return DECLINED;
    }
    my $lang = "en";
    if ($r->header_in("Accept-Language") =~ qr{(en|ja)}) {
        $lang = $1;
    }
    $uri =~ s{^/(.*)}{/$lang/$1};
    $r->internal_redirect($uri);
    return OK;
}
1;