path: root/IkiWiki/Plugin/search.pm

#!/usr/bin/perl
# xapian-omega search engine plugin
package IkiWiki::Plugin::search;

use warnings;
use strict;
use IkiWiki 3.00;

sub import {
    hook(type => "getsetup", id => "search", call => \&getsetup);
    hook(type => "checkconfig", id => "search", call => \&checkconfig);
    hook(type => "pagetemplate", id => "search", call => \&pagetemplate);
    hook(type => "postscan", id => "search", call => \&index);
    hook(type => "delete", id => "search", call => \&delete);
    hook(type => "cgi", id => "search", call => \&cgi);
}

sub getsetup () {
    return
        plugin => {
            safe => 1,
            rebuild => 1,
            section => "web",
        },
        omega_cgi => {
            type => "string",
            example => "/usr/lib/cgi-bin/omega/omega",
            description => "path to the omega cgi program",
            safe => 0, # external program
            rebuild => 0,
        },
}

sub checkconfig () {
    foreach my $required (qw(url cgiurl)) {
        if (! length $config{$required}) {
            error(sprintf(gettext("Must specify %s when using the %s plugin"), $required, 'search'));
        }
    }
    
    if (! defined $config{omega_cgi}) {
        $config{omega_cgi}="/usr/lib/cgi-bin/omega/omega";
    }

    # This is a mass dependency, so if the search form template
    # changes, every page is rebuilt.
    add_depends("", "templates/searchform.tmpl");
}

my $form;
sub pagetemplate (@) {
    my %params=@_;
    my $page=$params{page};
    my $template=$params{template};

    # Add search box to page header.
    if ($template->query(name => "searchform")) {
        if (! defined $form) {
            my $searchform = template("searchform.tmpl", blind_cache => 1);
            $searchform->param(searchaction => $config{cgiurl});
            $form=$searchform->output;
        }

        $template->param(searchform => $form);
    }
}

my $scrubber;
my $stemmer;
sub index (@) {
    my %params=@_;

    setupfiles();

    # A unique pageterm is used to identify the document for a page.
    my $pageterm=pageterm($params{page});
    return unless defined $pageterm;
    
    my $db=xapiandb();
    my $doc=Search::Xapian::Document->new();
    my $caption=pagetitle($params{page});
    my $title;
    if (exists $pagestate{$params{page}}{meta} &&
        exists $pagestate{$params{page}}{meta}{title}) {
        $title=$pagestate{$params{page}}{meta}{title};
    }
    else {
        $title=$caption;
    }

    # Remove html from text to be indexed.
    if (! defined $scrubber) {
        eval q{use HTML::Scrubber};
        if (! $@) {
            $scrubber=HTML::Scrubber->new(allow => []);
        }
    }
    my $toindex = defined $scrubber ? $scrubber->scrub($params{content}) : $params{content};
    
    # Take 512 characters for a sample, then extend it out
    # if it stopped in the middle of a word.
    my $size=512;
    my ($sample)=substr($toindex, 0, $size);
    if (length($sample) == $size) {
        my $max=length($toindex);
        my $next;
        while ($size < $max &&
               ($next=substr($toindex, $size++, 1)) !~ /\s/) {
            $sample.=$next;
        }
    }
    $sample=~s/\n/ /g;
    
    # data used by omega
    # Decode html entities in it, since omega re-encodes them.
    eval q{use HTML::Entities};
    error $@ if $@;
    $doc->set_data(
        "url=".urlto($params{page}, "")."\n".
        "sample=".decode_entities($sample)."\n".
        "caption=".decode_entities($caption)."\n".
        "modtime=$IkiWiki::pagemtime{$params{page}}\n".
        "size=".length($params{content})."\n"
    );

    # Index document and add terms for other metadata.
    my $tg = Search::Xapian::TermGenerator->new();
    if (! $stemmer) {
        my $langcode=$ENV{LANG} || "en";
        $langcode=~s/_.*//;

        # This whitelist is here to work around a xapian bug (#486138)
        my @whitelist=qw{da de en es fi fr hu it no pt ru ro sv tr};

        if (grep { $_ eq $langcode } @whitelist) {
            $stemmer=Search::Xapian::Stem->new($langcode);
        }
        else {
            $stemmer=Search::Xapian::Stem->new("english");
        }
    }
    $tg->set_stemmer($stemmer);
    $tg->set_document($doc);
    $tg->index_text($params{page}, 2);
    $tg->index_text($caption, 2);
    $tg->index_text($title, 2) if $title ne $caption;
    $tg->index_text($toindex);
    $tg->index_text(lc($title), 1, "S"); # for title:foo
    foreach my $link (@{$links{$params{page}}}) {
        $tg->index_text(lc($link), 1, "XLINK"); # for link:bar
    }

    $doc->add_term($pageterm);
    $db->replace_document_by_term($pageterm, $doc);
}

sub delete (@) {
    my $db=xapiandb();
    foreach my $page (@_) {
        my $pageterm=pageterm(pagename($page));
        $db->delete_document_by_term($pageterm) if defined $pageterm;
    }
}

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

    if (defined $cgi->param('P')) {
        # only works for GET requests
        chdir("$config{wikistatedir}/xapian") || error("chdir: $!");
        $ENV{OMEGA_CONFIG_FILE}="./omega.conf";
        $ENV{CGIURL}=$config{cgiurl},
        IkiWiki::loadindex();
        $ENV{HELPLINK}=htmllink("", "", "ikiwiki/searching",
            noimageinline => 1, linktext => "Help");
        exec($config{omega_cgi}) || error("$config{omega_cgi} failed: $!");
    }
}

sub pageterm ($) {
    my $page=shift;

    # 240 is the number used by omindex to decide when to hash an
    # overlong term. This does not use a compatible hash method though.
    if (length $page > 240) {
        eval q{use Digest::SHA1};
        if ($@) {
            debug("search: ".sprintf(gettext("need Digest::SHA1 to index %s"), $page)) if $@;
            return undef;
        }

        # Note no colon, therefore it's guaranteed to not overlap
        # with a page with the same name as the hash..
        return "U".lc(Digest::SHA1::sha1_hex($page));
    }
    else {
        return "U:".$page;
    }
}

my $db;
sub xapiandb () {
    if (! defined $db) {
        eval q{
            use Search::Xapian;
            use Search::Xapian::WritableDatabase;
        };
        error($@) if $@;
        $db=Search::Xapian::WritableDatabase->new($config{wikistatedir}."/xapian/default",
            Search::Xapian::DB_CREATE_OR_OPEN());
    }
    return $db;
}

{
my $setup=0;
sub setupfiles () {
    if (! $setup and (! -e $config{wikistatedir}."/xapian" || $config{rebuild})) {
        writefile("omega.conf", $config{wikistatedir}."/xapian",
            "database_dir .\n".
            "template_dir ./templates\n");
        
        # Avoid omega interpreting anything in the misctemplate
        # as an omegascript command.
        my $misctemplate=IkiWiki::misctemplate(gettext("search"), "\0");
        eval q{use HTML::Entities};
        error $@ if $@;
        $misctemplate=encode_entities($misctemplate, '\$');

        my $querytemplate=readfile(IkiWiki::template_file("searchquery.tmpl"));
        $misctemplate=~s/\0/$querytemplate/;

        writefile("query", $config{wikistatedir}."/xapian/templates",
            $misctemplate);
        $setup=1;
    }
}
}

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