Lighttpd apparently sets REDIRECT_STATUS=200 for the server.error-handler-404 page. This breaks the 404 plugin which checks this variable for 404 before processing the URI. It also doesn't seem to set REDIRECT_URL.

For what it's worth, the first half is http://redmine.lighttpd.net/issues/1828. One workaround would be to make this script your 404 handler:

#!/bin/sh
REDIRECT_STATUS=404; export REDIRECT_STATUS
REDIRECT_URL="$SERVER_NAME$REQUEST_URI"; export REDIRECT_URL
exec /path/to/your/ikiwiki.cgi "$@"

--smcv

I was able to fix my server to check the REQUEST_URI for ikiwiki.cgi and to continue processing if it was not found, passing $ENV{SEVER_NAME} . $ENV{REQUEST_URI} as the first parameter to cgi_page_from_404. However, my perl is terrible and I just made it work rather than figuring out exactly what to do to get it to work on both lighttpd and apache.

This is with lighttpd 1.4.19 on Debian.

/cgi-bin/ikiwiki.cgi?do=goto also provides redirection in the same way, if that's any help? You might need to set the lighttpd 404 handler to that, then compose REDIRECT_URL from other variables if necessary.

I originally wrote the plugin for Apache; weakish contributed the lighttpd docs and might know more about how to make it work there. --smcv

As I said, I got it working for me, but somebody who knows perl should probably look at it with the aim of making it work for everyone. I considered having lighttpd construct a proper url for the 404 redirect itself, but I don't know if it can do something like that or not. For what it's worth, here's the change I made to the module:

sub cgi ($) {
        my $cgi=shift;
        if ($ENV{REQUEST_URI} !~ /ikiwiki\.cgi/) {
                my $page = cgi_page_from_404(
                        Encode::decode_utf8($ENV{SERVER_NAME} . $ENV{REQUEST_URI}),
                        $config{url}, $config{usedirs});
                IkiWiki::Plugin::goto::cgi_goto($cgi, $page);
        }

#       if (exists $ENV{REDIRECT_STATUS} &&
#           $ENV{REDIRECT_STATUS} eq '404') {
#               my $page = cgi_page_from_404(
#                       Encode::decode_utf8($ENV{REDIRECT_URL}),
#                       $config{url}, $config{usedirs});
#               IkiWiki::Plugin::goto::cgi_goto($cgi, $page);
#       }
}