Metacat

 #

 #  '$RCSfile$'

 #  Copyright: 2000 Regents of the University of California

 #

 #   '$Author$'

 #     '$Date$'

 # '$Revision$'

 #

 # 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

 #

package Metacat;

require 5.005_62;

use strict;

use warnings;

require Exporter;

use AutoLoader qw(AUTOLOAD);

use LWP::UserAgent;

use HTTP::Cookies;

our @ISA = qw(Exporter);

# Items to export into callers namespace by default. Note: do not export

# names by default without a very good reason. Use EXPORT_OK instead.

# Do not simply export all your public functions/methods/constants.

# This allows declaration	use Metacat ':all';

# If you do not need this, moving things directly into @EXPORT or @EXPORT_OK

# will save memory.

our %EXPORT_TAGS = ( 'all' => [ qw(

) ] );

our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );

our @EXPORT = qw(

);

our $VERSION = '0.01';

# Preloaded methods go here.

#############################################################

# Constructor creates a new class instance and inits all

# of the instance variables to their proper default values,

# which can later be changed using "set_options"

#############################################################

sub new {

  my $cookie_jar = HTTP::Cookies->new;

  my $type = {

    metacatUrl     => 'http://dev.nceas.ucsb.edu/jones/servlet/metacat',

    message        => '',

    cookies        => \$cookie_jar

  };

  bless $type, shift;

  return $type;

}

#############################################################

# subroutine to set options for the class, including the URL

# for the Metacat database to which we would connect

#############################################################

sub set_options {

  my $self = shift;

  my %newargs = ( @_ );

  my $arg;

  foreach $arg (keys %newargs) {

    $self->{$arg} = $newargs{$arg};

  }

}

#############################################################

# subroutine to send data to metacat and get the response

# return response from metacat

#############################################################

sub sendData {

  my $self = shift;

  my %postData = ( @_ );

  my $userAgent = new LWP::UserAgent;

  $userAgent->agent("MetacatClient/1.0");

  my $request = new HTTP::Request('POST' => "$self->{'metacatUrl'}");

  my $cookie_jar = $self->{'cookies'};

  $$cookie_jar->add_cookie_header($request);

  $request->content_type('application/x-www-form-urlencoded');

  foreach my $key (keys %postData) {

    $request->add_content("$key=$postData{$key}&")

  }

  my $response = $userAgent->request($request);

  if ($response->is_success) {

    # save the cookies

    $$cookie_jar->extract_cookies($response);

    # save the metacat response message

    $self->{'message'} = $response->content;

  } else {

    #print "SendData content is: ", $response->content, "\n";

    return 0;

  }

  return $response;

}

#############################################################

# subroutine to log into Metacat and save the cookie if the

# login is valid.  If valid, return 1, else return 0

#############################################################

sub login {

  my $self = shift;

  my $username = shift;

  my $password = shift;

  my $returnval = 0;

  my %postData = ( action => 'login',

                   qformat => 'xml',

                   username => $username,

                   password => $password

                 );

  my $response = $self->sendData(%postData);

  if (($response) && $response->content =~ /<login>/) {

    $returnval = 1;

  }

  return $returnval;

}

#############################################################

# subroutine to insert an XML document into Metacat

# If success, return 1, else return 0

#############################################################

sub insert {

  my $self = shift;

  my $docid = shift;

  my $xmldocument = shift;

  my $dtd = shift;

  my $returnval = 0;

  my %postData = ( action => 'insert',

                   docid => $docid,

                   doctext => $xmldocument

                 );

  if ($dtd) {

    $postData{'dtdtext'} = $dtd;

  }

  my $response = $self->sendData(%postData);

  if (($response) && $response->content =~ /<success>/) {

    $returnval = 1;

  } elsif (($response)) {

    $returnval = 0;

    #print "Error response from sendData!\n";

    #print $response->content, "\n";

  } else {

    $returnval = 0;

    #print "Invalid response from sendData!\n";

  }

  return $returnval;

}

#############################################################

# subroutine to update an XML document in Metacat

# If success, return 1, else return 0

#############################################################

sub update {

  my $self = shift;

  my $docid = shift;

  my $xmldocument = shift;

  my $dtd = shift;

  my $returnval = 0;

  my %postData = ( action => 'update',

                   docid => $docid,

                   doctext => $xmldocument

                 );

  if ($dtd) {

    $postData{'dtdtext'} = $dtd;

  }

  my $response = $self->sendData(%postData);

  if (($response) && $response->content =~ /<success>/) {

    $returnval = 1;

  }

  return $returnval;

}

#############################################################

# subroutine to delete an XML document in Metacat

# If success, return 1, else return 0

#############################################################

sub delete {

  my $self = shift;

  my $docid = shift;

  my $returnval = 0;

  my %postData = ( action => 'delete',

                   docid => $docid

                 );

  my $response = $self->sendData(%postData);

  if (($response) && $response->content =~ /<success>/) {

    $returnval = 1;

  }

  return $returnval;

}

#############################################################

# subroutine to read an XML document from Metacat

# returns the XML from Metacat, which may be an error response

#############################################################

sub read {

  my $self = shift;

  my $docid = shift;

  my %postData = ( action => 'read',

                   qformat => 'xml',

                   docid => $docid

                 );

  my $response = $self->sendData(%postData);

  my $returnval = 0;

  if ($response) {

    $returnval = $response;

  }

  return $returnval;

}

#############################################################

# subroutine to query metacat using a structured path query

# returns the XML from Metacat, which may be an error response

#############################################################

sub squery {

  my $self = shift;

  my $query = shift;

  my %postData = ( action => 'squery',

                   qformat => 'xml',

                   query => $query

                 );

  my $response = $self->sendData(%postData);

  my $returnval = 0;

  if ($response) {

    $returnval = $response;

  }

  return $returnval;

}

#############################################################

# subroutine to get the message returned from the last executed

# metacat action.  These are generally XML formatted messages.

#############################################################

sub getMessage {

  my $self = shift;

  return $self->{'message'};

}

#############################################################

# subroutine to get the cookies returned from the metacat

# server to establish (and pass on) session info (JSESSIONID).

#############################################################

sub getCookies {

  my $self = shift;

  return $self->{'cookies'};

}

# Autoload methods go after =cut, and are processed by the autosplit program.

1;

__END__

# Below is stub documentation for your module. You better edit it!

=head1 NAME

Metacat - Perl extension for communicating with the Metacat XML database

=head1 SYNOPSIS

  use Metacat;

  my $metacat = Metacat->new();

  my $response = $metacat->login($username, $password);

  print $metacat->getMessage();

  $response = $metacat->insert($docid, $xmldoc);

  print $metacat->getMessage();

  $response = $metacat->insert($docid, $xmldoc, $dtd);

  print $metacat->getMessage();

  $response = $metacat->update($docid, $xmldoc);

  print $metacat->getMessage();

  $htmlResponse = $metacat->read($docid);

  $xmldoc = $htmlResponse->content();

  print $xmldoc;

  $resultset = $metacat->squery($pathquery);

  print $resultset;

  $response = $metacat->delete($docid);

  print $metacat->getMessage();

  $response = $metacat->getCookies();

  print $metacat->getMessage();

=head1 DESCRIPTION

This is a client library for accessing the Metacat XML database.  Metacat

is a Java servlet that accepts commands over HTTP and returns XML and

HTML responses.  See http://knb.ecoinformatics.org for details about

Metacat and its interface.

=head2 EXPORT

None by default.

=head1 AUTHOR

Matthew B. Jones, jones@nceas.ucsb.edu

=head1 SEE ALSO

perl(1).

=cut