source: trunk/gsdl/perllib/plugins/GBBPlug.pm@ 620

###########################################################################
#
# GBBPlug.pm -- plugin for processing gb encoded html books
# A component of the Greenstone digital library software
# from the New Zealand Digital Library Project at the 
# University of Waikato, New Zealand.
#
# Copyright (C) 1999 New Zealand Digital Library Project
#
# 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., 675 Mass Ave, Cambridge, MA 02139, USA.
#
###########################################################################

# creates multi-level document from document containing 
# <<TOC>> level tags. Metadata for each section is taken from any
# other tags on the same line as the <<TOC>>. e.g. <<Title>>xxxx<</Title>>
# sets Title metadata.

# Everything else between TOC tags is expected to be simple html
# and is treated accordingly.

# Imput files are expected to be GB encoded and have .gbb file extension

package GBBPlug;

use BasPlug;
use sorttools;
use util;
use unicode;
use cnseg;
use gb;


sub BEGIN {
    @ISA = ('BasPlug');
}

sub new {
    my ($class) = @_;
    $self = new BasPlug ();

    return bless $self, $class;
}

sub is_recursive {
    my $self = shift (@_);

    return 0; # this is not a recursive plugin
}


# return number of files processed, undef if can't process
# Note that $base_dir might be "" and that $file might 
# include directories
sub read {
    my $self = shift (@_);
    my ($pluginfo, $base_dir, $file, $metadata, $processor) = @_;

    my $filename = &util::filename_cat($base_dir, $file);
    my $absdir = $filename;
    $absdir =~ s/[^\/\\]*$//;

    return undef unless ($filename =~ /\.gbb$/i && (-e $filename));

    print STDERR "GBBPlug: processing $filename\n" if $processor->{'verbosity'};

    # create a new document
    my $doc_obj = new doc ($file, "indexed_doc");
    open (FILE, $filename) || die "GBBPlug::read - ERROR: can't open $filename\n";

    my $cursection = $doc_obj->get_top_section();

    my $text = "";
    my $line = "";
    my $title = "";
    while (defined ($line = <FILE>)) {
    $text .= $line;
    }

    # convert to unicode
    $text = &unicode::unicode2utf8(&gb::gb2unicode($text));
    # segment the Chinese words
    $text = &cnseg::segment($text);

    # we'll use the worthless alarm thingy to temporarily replace 
    # '\n' so we'd better check it doesn't occur naturally
    if ($text =~ /\a/) {
    print STDERR "GBBPlug::read - 'WARNING '\a' character occurs in text!!\n";
    }

    # need to add <classifytype> to each book as we'll be using 'Hierarchy'
    # for HB collections rather than the default ('Book')
    $doc_obj->add_metadata ($cursection, 'classifytype', 'Hierarchy');

    # remove line breaks
    $text =~ s/\n/\a/g;

    # remove any leading rubbish
    $text =~ s/^.*?(<<TOC)/$1/i;
    
    my $curtoclevel = 1;
    my $firstsection = 1;
    while (length ($text) > 0) {
    $text =~ s/^<<TOC(\d+)>>([^\a]*)\a(.*?)(<<TOC|\Z)/$4/i;
    my $toclevel = $1;
    my $metadata = $2;
    my $sectiontext = $3;
    
    # close any sections below the current level and
    # create a new section (special case for the firstsection)
    while (($curtoclevel > $toclevel) ||
           (!$firstsection && $curtoclevel == $toclevel)) {
        $cursection = $doc_obj->get_parent_section ($cursection);
        $curtoclevel--;
    }
    if ($curtoclevel+1 < $toclevel) {
        print STDERR "WARNING - jump in toc levels in $htmlfile " . 
        "from $curtoclevel to $toclevel\n";
    }
    while ($curtoclevel < $toclevel) {
        $curtoclevel++;
        $cursection = 
        $doc_obj->insert_section($doc_obj->get_end_child($cursection));
    }

    # sort out metadata
    while ($metadata =~ s/^.*?<<([^>]*)>>(.*?)<<[^>]*>>//) {
        my $metakey = $1;
        my $metavalue = $2;

        if ($metavalue ne "" && $metakey ne "") {
        # make sure key fits in with gsdl naming scheme 
        $metakey =~ tr/[A-Z]/[a-z]/;
        $metakey = ucfirst ($metakey);
        $doc_obj->add_utf8_metadata ($cursection, $metakey, $metavalue);
        }
    }


    # remove header rubbish
    $sectiontext =~ s/^.*?<body[^>]*>//i;

    # and any other unwanted tags
    $sectiontext =~ s/<(\/p|\/html|\/body)>//g;

    # fix up the image links
    $sectiontext =~ s/(<img[^>]*?src\s*=\s*\"?)([^\">]+)(\"?[^>]*>)/
        &replace_image_links($absdir, $doc_obj, $1, $2, $3)/ige;

    # put line breaks back in
    $sectiontext =~ s/\a/\n/g;

    # add the text
    $doc_obj->add_utf8_text($cursection, $sectiontext);

    $firstsection = 0;
    }

    # add OID
    $doc_obj->set_OID ();

    # process the document
    $processor->process($doc_obj);

    return 1; # processed the file
}

sub replace_image_links {

    my ($dir, $doc_obj, $front, $link, $back) = @_;

    my ($filename, $error);
    my $foundimage = 0;
    
    $link =~ s/\/\///;
    my ($imagetype) = $link =~ /([^\.]*)$/;
    $imagetype =~ tr/[A-Z]/[a-z]/;
    if ($imagetype eq "jpg") {$imagetype = "jpeg";}
    if ($imagetype !~ /^(jpg|gif|png)$/) {
    print STDERR "GBHPlug: Warning - unknown image type ($imagetype)\n";
    }
    my ($imagefile) = $link =~ /([^\/]*)$/;
    my ($imagepath) = $link =~ /^[^\/]*(.*)$/;

    if (defined $imagepath && $imagepath =~ /\w/) {
    # relative link
    $filename = &util::filename_cat ($dir, $imagepath);
    if (-e $filename) {
        $doc_obj->associate_file ($filename, $imagefile, "image/$imagetype");
        $foundimage = 1;
    } else {
        $error = "GBHPlug: Warning - couldn't find image file $imagefile in either $filename or";
    }
    }

    if (!$foundimage) {
    $filename = &util::filename_cat ($dir, $imagefile);
    if (-e $filename) {
        $doc_obj->associate_file ($filename, $imagefile, "image/$imagetype");    
        $foundimage = 1;
    } elsif (defined $error) {
        print STDERR "$error $filename\n";
    } else {
        print STDERR "GBHPlug: Warning - couldn't find image file $imagefile in $filename\n";
    }
    }

    if ($foundimage) {
    return "${front}_httpcollection_/archives/_thisOID_/${imagefile}${back}";
    } else {
    return "";
    }
}

1;