source: main/trunk/greenstone2/perllib/plugins/MetadataCSVPlugin.pm@ 24736

###########################################################################
#
# MetadataCSVPlugin.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 MetadataCSVPlugin;


use BasePlugin;
use MetadataRead;

use strict;
no strict 'refs';
use multiread;


# methods with identical signatures take precedence in the order given in the ISA list.
sub BEGIN {
    @MetadataCSVPlugin::ISA = ('MetadataRead', 'BasePlugin');
}


my $arguments = [
      { 'name' => "process_exp",
    'desc' => "{BasePlugin.process_exp}",
    'type' => "regexp",
    'reqd' => "no",
    'deft' => &get_default_process_exp() }

];


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


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

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

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

    return bless $self, $class;
}


sub get_default_process_exp
{
    return q^(?i)\.csv$^;
}

sub file_block_read {
    my $self = shift (@_);
    my ($pluginfo, $base_dir, $file, $block_hash, $metadata, $gli) = @_;

    my ($filename_full_path, $filename_no_path) = &util::get_full_filenames($base_dir, $file);

    if (!-f $filename_full_path || !$self->can_process_this_file($filename_full_path)) {
    return undef; # can't recognise
    }

    # set this so we know this is a metadata file - needed for incremental 
    # build
    # if this file changes, then we need to reimport everything
    $block_hash->{'metadata_files'}->{$filename_full_path} = 1;

    return 1;
}

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

    # 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='MetadataCSVPlugin'>\n" if ($gli);
    print STDERR "MetadataCSVPlugin: processing $file\n" if ($self->{'verbosity'}) > 1;

    my $outhandle = $self->{'outhandle'};
    my $failhandle = $self->{'failhandle'};

    # add the file to the block list so that it won't be processed in read, as we will do all we can with it here
    &util::block_filename($block_hash,$filename);


    # 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('MetadataCSVPlugin::CSV_FILE');
    $csv_file_reader->read_file(\$csv_file_content);

    # Would be nice if MetadataCSVPlugin was extended to support a minus
    # option to choose the character encoding the CSV file is in 
    # For now we will assume it is always in UTF8
    $csv_file_content = decode("utf8",$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) {
    $self->print_error($outhandle, $failhandle, $gli, $filename, "No Filename field in CSV file");
    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 {
        $self->print_error($outhandle, $failhandle, $gli, $filename, "Badly formatted CSV line: $csv_line");
        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) {
        $self->print_error($outhandle, $failhandle, $gli, $filename, "No Filename metadata in CSV line: $orig_csv_line");
        next;
    }
    my $csv_line_filename = shift(@$csv_line_filename_array);
    delete $csv_line_metadata{"Filename"};


    # Associate the metadata now
    $csv_line_filename = &util::filename_to_regex($csv_line_filename);

    $extrametadata->{$csv_line_filename} = \%csv_line_metadata;
    push(@$extrametakeys, $csv_line_filename);
    # record which file the metadata came from 
    if (!defined $extrametafile->{$csv_line_filename}) {
        $extrametafile->{$csv_line_filename} = {};
    }
    # maps the file to full path
    $extrametafile->{$csv_line_filename}->{$file} = $filename;
    }
}

sub print_error
{

    my $self = shift(@_);
    my ($outhandle, $failhandle, $gli, $file, $error) = @_;

    print $outhandle "MetadataCSVPlugin Error: $file: $error\n";
    print $failhandle "MetadataCSVPlugin Error: $file: $error\n";
    print STDERR "<ProcessingError n='$file' r='$error'/>\n" if ($gli);
}
1;