Add to EPRINTS_ROOT/archives/ARCHIVE_ID/cfg/cfg.d/

z_rewrite_url_map.pl

# Map specific URLs to be permanently redirected

use EPrints::Const; # for trigger return values

# define specific URLs that have been moved.
# If all the new URLs are to the same base URL, you could have e.g 1234 => 5678 in the 
#    hash, and prepend a static 'https://new.repo.com/' in the 'Location' line below

$c->{z_url_rewrite_map} = {
	'1234' => 'https://abc.de/1/',
	'2345' => 'https://abc.de/9/',
};

$c->add_trigger( EP_TRIGGER_URL_REWRITE, sub {
	my( %o ) = @_;

	# Available hash keys in %o
	#   request, lang (en), args ("" or "?foo=bar"), urlpath ("" or "/subdir"), cgipath ("/cgi" or "/subdir/cgi")
	#   uri (/foo/bar), secure ( boolean ), return_code (set to trigger a return - stop stack of triggers), repository

	my $redirect_map = $o{repository}->get_conf( "z_url_rewrite_map" );
	return if !defined $redirect_map;

	# Optimisation over the 404 handler regex...
	# If you have a long-standing repository, there may be EPrint URLs out in the wild that refer to repo.com/1234 (without trailing slash).
	# Currently, EPrints will redirect this to repo.com/1234/ - and then m#^/(\d+)/# (from 404 handler) would capture it.
	# This could result in multiple redirects ( /1234 --> /1234/ --> other server ) which isn't best practice for SEO.
	#
	# The first regex below will match /1234 or /1234/.
	# If your repo is _really_ old, you might also want to capture repo.com/archive/1234 or repo.com/archive/00001234...
	# ...I guess looking in the Apache logs will indicate if this is necessary!

	if( defined $o{uri} && ( $o{uri} =~ m#^/(\d+)(?>/|$)#  || $o{uri} =~ m#^/id/eprint/(\d+)/# ) )
	{ 
		# We've got what looks like an EPrintID...
		# Is there a redirect map for it?
		if( defined $redirect_map->{$1} ){
			EPrints::Apache::AnApache::send_status_line( $o{request}, 301, "Moved Permanently" );
			EPrints::Apache::AnApache::header_out( $o{request}, "Location", "$redirect_map->{$1}" );
			EPrints::Apache::AnApache::send_http_header( $o{request} );

			${$o{return_code}} = EPrints::Const::DONE;
			return EP_TRIGGER_DONE;
		}
		# an EPrintID, but not redirected.
	}
	# not an EPrintID URL - just return (could explicitly set a trigger return value, but not necessary)
} );