source: gsdl/trunk/perllib/plugins/MetadataCSVPlugin.pm@ 15865

###########################################################################
#
# MetadataCSVPlug.pm -- A plugin for metadata in comma-separated value format
#
# A component of the Greenstone digital library software
# from the New Zealand Digital Library Project at the 
# University of Waikato, New Zealand.
#
# Copyright 2006 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.
#
###########################################################################

package MetadataCSVPlug;


use BasPlug;
use strict;


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


my $arguments =
    [ { 'name' => "block_exp",
    'desc' => "{BasPlug.block_exp}",
    'type' => "regexp",
    'reqd' => "no",
    'deft' => &get_default_block_exp() } ];


my $options = { 'name'     => "MetadataCSVPlug",
        'desc'     => "{MetadataCSVPlug.desc}",
        'abstract' => "no",
        'inherits' => "yes",
        'args'     => $arguments };


sub new
{
    my ($class) = shift (@_);
    my ($pluginlist,$inputargs,$hashArgOptLists) = @_;
    push(@$pluginlist, $class);

    if(defined $arguments){ push(@{$hashArgOptLists->{"ArgList"}},@{$arguments});}
    if(defined $options) { push(@{$hashArgOptLists->{"OptList"}},$options)};

    my $self = new BasPlug($pluginlist, $inputargs, $hashArgOptLists);

    return bless $self, $class;
}


# Not used, just here to prevent a warning
sub get_default_process_exp
{
    return q^(?i)\.csv$^;
}


# We don't want any other plugins to see .csv files
sub get_default_block_exp
{
    return q^(?i)\.csv$^;
}


sub metadata_read
{
    my $self = shift (@_);
    my ($pluginfo, $base_dir, $file, $metadata, $extrametakeys, $extrametadata, $processor, $maxdocs, $gli) = @_;

    # Read metadata from CSV files
    my $filename = &util::filename_cat($base_dir, $file);
    if ($filename !~ /\.csv$/ || !-f $filename) {
    return undef;
    }
    print STDERR "\n<Processing n='$file' p='MetadataCSVPlug'>\n" if ($gli);
    print STDERR "MetadataCSVPlug: processing $file\n" if ($self->{'verbosity'}) > 1;

    # Read the CSV file to get the metadata
    my $csv_file_content;
    open(CSV_FILE, "$filename");
    my $csv_file_reader = new multiread();
    $csv_file_reader->set_handle('MetadataCSVPlug::CSV_FILE');
    $csv_file_reader->read_file(\$csv_file_content);
    close(CSV_FILE);

    # Split the file into lines and read the first line (contains the metadata names)
    $csv_file_content =~ s/\r/\n/g;  # Handle non-Unix line endings
    $csv_file_content =~ s/\n+/\n/g;
    my @csv_file_lines = split(/\n/, $csv_file_content);
    my $csv_file_field_line = shift(@csv_file_lines);
    my @csv_file_fields = split(/\,/, $csv_file_field_line);
    my $found_filename_field = 0;
    for (my $i = 0; $i < scalar(@csv_file_fields); $i++) {
    # Remove any spaces from the field names
    $csv_file_fields[$i] =~ s/ //g;
    if ($csv_file_fields[$i] eq "Filename") {
        $found_filename_field = 1;
    }
    }

    if (!$found_filename_field) {
    print STDERR "MetadataCSVPlug Error: No Filename field in CSV file: $filename\n";
    return -1; # error
    }
    # Read each line of the file and assign the metadata appropriately
    foreach my $csv_line (@csv_file_lines) {
    # Ignore lines containing only whitespace
    next if ($csv_line =~ /^\s*$/);
    my $orig_csv_line = $csv_line;
    # Build a hash of metadata name to metadata value for this line
    my %csv_line_metadata;
    my $i = 0;
    $csv_line .= ",";  # To make the regular expressions simpler
    while ($csv_line ne "") {
        # Metadata values containing commas are quoted
        if ($csv_line =~ s/^\"(.*?)\"\,//) {
        # Only bother with non-empty values
        if ($1 ne "" && defined($csv_file_fields[$i])) {
            if (!defined $csv_line_metadata{$csv_file_fields[$i]}) {
            $csv_line_metadata{$csv_file_fields[$i]} = [];
            }
            push (@{$csv_line_metadata{$csv_file_fields[$i]}}, $1);
        }
        }
        # Normal comma-separated case
        elsif ($csv_line =~ s/^(.*?)\,//) {
        # Only bother with non-empty values
        if ($1 ne "" && defined($csv_file_fields[$i])) {
            if (!defined $csv_line_metadata{$csv_file_fields[$i]}) {
            $csv_line_metadata{$csv_file_fields[$i]} = [];
            }
            push (@{$csv_line_metadata{$csv_file_fields[$i]}}, $1);
        }
        }
        # The line must be formatted incorrectly
        else {
        print STDERR "MetadataCSVPlug Error: Badly formatted CSV line: $csv_line.\n";
        last;
        }

        $i++;
    }

    # We can't associate any metadata without knowing the file to associate it with
    my $csv_line_filename_array = $csv_line_metadata{"Filename"};
    if (!defined $csv_line_filename_array) {
        print STDERR "MetadataCSVPlug Error: No Filename metadata in CSV line: $orig_csv_line\n";
        next;
    }
    my $csv_line_filename = shift(@$csv_line_filename_array);
    delete $csv_line_metadata{"Filename"};

    # Associate the metadata now
    $extrametadata->{$csv_line_filename} = \%csv_line_metadata;
    push(@$extrametakeys, $csv_line_filename);
    }
}


1;