path: root/IkiWiki/Plugin/404.pm

#!/usr/bin/perl
# Copyright © 2009 Simon McVittie <http://smcv.pseudorandom.co.uk/>
# Licensed under the GNU GPL, version 2, or any later version published by the
# Free Software Foundation
package IkiWiki::Plugin::404;

use warnings;
use strict;
use IkiWiki 3.00;

sub import {
    hook(type => "cgi", id => '404',  call => \&cgi);
    IkiWiki::loadplugin("goto");
}

sub getsetup () {
    return
        plugin => {
            # not really a matter of safety, but enabling/disabling
            # through a web interface is useless - it needs web
            # server admin action too
            safe => 0,
            rebuild => 0,
        }
}

sub cgi_page_from_404 ($$$) {
    my $path = shift;
    my $baseurl = shift;
    my $usedirs = shift;

    # fail if missing from environment or whatever
    return undef unless defined $path;
    return undef unless defined $baseurl;

    # with usedirs on, path is like /~fred/foo/bar/ or /~fred/foo/bar or
    #    /~fred/foo/bar/index.html
    # with usedirs off, path is like /~fred/foo/bar.html
    # baseurl is like 'http://people.example.com/~fred'

    # convert baseurl to ~fred
    unless ($baseurl =~ s{^https?://[^/]+/?}{}) {
        return undef;
    }

    # convert path to /~fred/foo/bar
    if ($usedirs) {
        $path =~ s/\/*(?:index\.$config{htmlext})?$//;
    }
    else {
        $path =~ s/\.$config{htmlext}$//;
    }

    # remove /~fred/
    unless ($path =~ s{^/*\Q$baseurl\E/*}{}) {
        return undef;
    }

    # special case for the index
    unless ($path) {
        return 'index';
    }

    return $path;
}

sub cgi ($) {
    my $cgi=shift;

    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);
    }
}

1;