dhelp 0.6.20+nmu1 / usr / lib / cgi-bin / dsearch

#! /usr/bin/perl -T
#
# Copyright 2001,2004 by Stefan Hornburg (Racke) <racke@linuxia.de>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public
# License along with this program; if not, write to the Free
# Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
# MA  02111-1307  USA.

$ENV{'PATH'} = '/bin:/usr/bin';
# Avoid taint problems when any of these environment variables are defined.
# See perlsec(1) manpage 
delete @ENV{qw(IFS CDPATH ENV BASH_ENV)};

use strict;
use warnings;
use CGI qw/:standard/;
use Template;
use DB_File;
use File::Basename;
use HTML::Entities;
use File::Temp qw(tempfile);
use Locale::gettext;
use POSIX;
use Data::Page;
use URI::Escape;
use Encode;

use constant DOCBASEDB            => '/var/lib/dhelp/doc-base_dirs';
use constant RESULTS_PER_PAGE     => 20;
use constant RESULTS_OFFLINE_MODE => 100;

sub word_regex {
    my ($words) = @_;
    return qr/\b/ . join("|", @$words) . qr/\b/;
}

sub highlight_fragment {
    my ($text, $words) = @_;

    my $regex = word_regex($words);
    $text = encode_entities($text);
    $text =~ s/$regex/<span style="background-color: #ff0">$&<\/span>/gi;
    return $text;
}

sub get_highlighted_fragments {
    my ($text, $words) = @_;

    # Only look for results in the first 100K
    $text = substr($text, 0, 100000)."..." if length $text > 100000;

    my $regex = word_regex($words);
    my $max_fragments = 5;
    my @fragment_list = ();
    while ($text =~ /(.{0,31})($regex)(.{0,31})/isg) {
        my ($pre, $word, $post) = ($1, $2, $3);
        if (length $pre > 30) {
            $pre = "...".substr($pre, 1);
        }
        if (length $post > 30) {
            $post = substr($post, 0, 29)."...";
        }
        push @fragment_list, highlight_fragment($pre.$word.$post, $words);
        last if --$max_fragments < 1;
    }
    # Just in case: if we don't match anything, just show the first 60
    # characters
    if (scalar @fragment_list) {
        return @fragment_list;
    }
    else {
        return length $text > 100 ? substr($text, 0, 99)."..." : $text;
    }
}

sub file_to_text {
    my ($cmd, $file_type, $package) = @_;

    $cmd =~ /^(\S+)/;
    my $binary = $1;
    if (-x $binary) {
        return `$cmd`;
    }
    else {
        return "[Cannot show $file_type file preview. Please install package $package]";
    }
}

sub get_text {
    my ($file) = @_;

    # Remove any weird character
    $file =~ s/[^a-z0-9_.\/+-]//gio;
    $file =~ s/\.\.//go;
    $file =~ /(.*)/;
    $file = $1;

    my $basename = basename($file);
    $basename =~ s/\.(\w+)$//go;
    my $ext = $1;

    my $text = undef;
    if ($ext =~ /html?/) {
        # Try to fetch a text version of the HTML
        if (-x '/usr/bin/lynx') {
            $text = `/usr/bin/lynx -dump -nolist "$file"`;
        }
        elsif (-x '/usr/bin/links') {
            $text = `/usr/bin/links -dump -no-references "$file"`;
        }
        elsif (-x '/usr/bin/w3m') {
            $text = `/usr/bin/w3m -dump "$file"`;
        }
        elsif (-x '/usr/bin/html2text') {
            $text = `/usr/bin/html2text -nobs "$file"`;
        }
        else {
            # Fallback to retarded HTML stripper
            open F, $file;
            $text = join("", <F>);
            close F;
            $text =~ s/<.*?>//go;
        }
    }
    elsif ($ext =~ /gz/) {
        my ($fh, $tmp_path) = tempfile("dsearch-XXXXXX",
                                       DIR    => '/tmp',
                                       SUFFIX => "$basename");
        print $fh `gunzip -c "$file"`;
        close $fh;
        $text = get_text($tmp_path);
    }
    elsif ($ext =~ /pdf/) {
        if (-x '/usr/bin/pdftotext') {
            $text = `/usr/bin/pdftotext "$file" -`;
        }
        else {
            # pstotext is a dependency, so this should never fail, but we
            # recommend the user to install xpdf-utils instead, to get
            # pdftotext (better extraction quality and much faster)
            $text = file_to_text("/usr/bin/pstotext '$file'", "PDF", "xpdf-utils");
        }
    }
    elsif ($ext =~ /dvi/) {
        $text = file_to_text("/usr/bin/catdvi '$file'", "DVI", "catdvi");
    }
    elsif ($ext =~ /ps/) {
        $text = file_to_text("/usr/bin/pstotext '$file'", "Postscript", "pstotext");
    }
    else {
        open F, $file;
        $text = join("", <F>);
        close F;
    }

    return $text;
}

sub get_extract {
    my ($file, $search) = @_;

    my $text = get_text($file);
    my @words = split(/\s/, $search);
    return join(" / ", get_highlighted_fragments($text, \@words));
}

sub error {
    my ($msg, $vars) = @_;

    $msg =~ s/\n/<br>\n/go;
    $vars->{error} = $msg;

    my $tt = Template->new({INCLUDE_PATH => '/usr/share/dhelp'});
    $tt->process('search_error.tmpl', $vars);
    exit 0;
}

sub get_doc_base_info {
    my ($info_hash, $file) = @_;

    my $packed_dirname = pack("Z100", dirname($file));
    my $value = $info_hash->{$packed_dirname};
    defined $value || return;
    unpack("Z50 Z1000", $value);
}

# Selects the best matching language between two lists (the available languages
# list, in normal locale format, and the acceptable languages list, in
# HTTP_ACCEPT_LANGUAGE format).
sub select_matching_language {
    my ($available_list, $accept_list) = @_;

    foreach my $accept (@$accept_list) {
        return $accept if grep { $accept eq $_ } @$available_list;
        my $stripped_accept = $accept;
        $stripped_accept =~ s/-.*//go;
        $stripped_accept =~ s/;.*//go;
        foreach my $available (@$available_list) {
            my $stripped_available = $available;
            $stripped_available =~ s/_.*//go;
            $stripped_available =~ s/\..*//go;
            return $available if $stripped_accept eq $stripped_available;
        }
    }
}



my $online = !param('file');
print header(-charset=>'utf-8') if $online;

my $gettext = Locale::gettext->domain_raw("dhelp");
$gettext->codeset('UTF-8'); # Always UTF-8, specified in the HTML templates
my @available_languages = map { chomp; $_ } split(/\n/, `/usr/bin/locale -a`);
my @accept_languages = split(",", $ENV{HTTP_ACCEPT_LANGUAGE} || "");
setlocale(LC_MESSAGES, select_matching_language(\@available_languages,
                                                \@accept_languages));
my $vars = {
    online   => $online,
    base_url => $online ? '' : 'file:/usr/share',
    results  => [],
    gettext  => $gettext,
};

sub _ {
    $gettext->get($_[0]);
}

unless (-f '/var/lib/dhelp/documents.index') {
    error(_("No search database found.\nPlease run /etc/cron.weekly/dhelp as superuser to create it."), $vars);
}

# Fetch, decode, untaint and check search parameter
my $search = param('search');
# This script may be called from command-line too, so the string might be just
# a bunch of octets. Assume UTF-8 in that case.
unless (Encode::is_utf8($search)) {
    $search = decode('utf-8', $search);
}
$search =~ m/(.+)/;                 # Is there anything we shouldn't allow?
$search = $1;
$vars->{search_terms} = encode('utf8', $search);

if ($search !~ /\S/) {
    error(_("Please specify a search term."), $vars);
}


# Pass parameters to Swish++ search program
(param('page') || "") =~ /(\d+)/;
my $current_page = defined($1) ? $1 : 1;
my $skipped_results = ($current_page - 1) * RESULTS_PER_PAGE;
# search++ seems to support only Latin-1. Everything else makes it die with
# "malformed query"
my $encoded_search = encode('latin1', $search);
open (SEARCH, '-|')
    or exec '/usr/bin/search++', '-i', '/var/lib/dhelp/documents.index',
                                 '-r', $skipped_results,
                                 '-m', RESULTS_PER_PAGE,
                                       $encoded_search;

# Open the doc-base info database, and tie to %docs_info
my %docs_info;
tie %docs_info, 'DB_File', DOCBASEDB, O_RDONLY or die "Cannot tie ".DOCBASEDB.": $!";

##
# Read the search results back and store somewhere, so we can calculate the
# pages.
##
my ($n_results, $ignored);
my @results;
while ( <SEARCH> ) {
    if ( /^\# ignored: / ) {
        ##
        # Get the ignored words so we can report them to the user.
        ##
        $ignored = $';
        $ignored =~ s/\s+$//;
        next;
    }
    if ( /^\# results: (\d+)/) {
        $n_results = $1;
        if ($n_results == 0) {
            if ($ignored) {
                $vars->{msg} = sprintf(_("No results (ignored words: %s). Search terms must be at least 4 characters long, and must not be \"stop words\". The command \"<tt>index++ -S</tt>\" gives the stop word list."), $ignored);
            } else {
                $vars->{msg} = _("No results.");
            }
            last;
        }
    }
    ##
    # Future releases of SWISH++ may emit other comments: ignore ones we
    # don't know about.
    ##
    next if /^\#/;

    my( $rank, $file, $size, $title ) = split(/ /, $_, 4);
    my $extract = get_extract($file, $search);

    $size = int( $size / 1024 );
    if ( $size ) {
        $size .= 'K';
    } else {
        $size = '&lt;1K';
    }
    my $file_url = $file;
    if ($online) {
        my $file_url_encoded = uri_escape($file_url);
        $file_url = "/cgi-bin/dhelp_fetcher?file=$file_url_encoded";
    } else {
        $file_url = "file:$file";
    }
    # Calculate the real title
    my ($doc_id, $doc_base_title) = get_doc_base_info(\%docs_info, $file);
    $title .= " ($doc_base_title)" if $doc_base_title;
    push @{$vars->{results}}, {rank    => $rank,
                               file    => $file_url,
                               title   => $title,
                               size    => $size,
                               extract => $extract};
}

if (!$online && $n_results > RESULTS_OFFLINE_MODE) {
    $vars->{msg} .= " ".sprintf(_("Showing only %s out of %s results in offline mode."), RESULTS_OFFLINE_MODE, $n_results);
}

close (SEARCH);

# We are already fetching just the data page we want, but Data::Page is
# useful to calculate information about _other_ pages of data
my $pager = Data::Page->new($n_results,
                            RESULTS_PER_PAGE,
                            $current_page);

# Include paging information
$vars->{current_page}  = $pager->current_page;
$vars->{previous_page} = $pager->previous_page;
$vars->{next_page}     = $pager->next_page;
$vars->{last_page}     = $pager->last_page;

my $tt = Template->new({INCLUDE_PATH => '/usr/share/dhelp'});
$tt->process('search_results.tmpl', $vars) or die $tt->error;

__END__