watch_folder.pl

#TODO Handle Sub Directories
#TODO Check that all the locks are released by the CRUD Handlers. (Delete specifically)

#!/bin/perl

use strict;
use English;
use File::stat;
use LWP::UserAgent;
use XML::XPath;

my $dir = $ARGV[0];
if (!defined $dir) {
	use Cwd;
	$dir = cwd() . "/";
}

our $debug = 0;

our $config = load_config($dir);
our $metadata_files = {};
exit if (!check_config());
exit if (!defined $config);
my $items = get_resource_list();
my $items = undef;
my $update_counter = 0;

while (1) {
	process_directory($dir,0,$items);
	sleep(10);
	$update_counter++;
	if ($update_counter > 5) {
		$items = get_resource_list();
		$update_counter = 0;
	}
}

sub load_config {
	my $dir = shift;

	my $file = $dir . "CONFIG";
	
	if ( -e $file ) {
		
		my $resources = {};
		
		open(HANDLE,$file);
	
		while (<HANDLE>) {
			chomp;
			next if ((substr $_,0,1) eq "#");
			my @parts = split(/:/,$_,2);
			my $key = trim(@parts[0]);
			my $value = trim(@parts[1]);
			$resources->{$key} = $value;
		}

		close(HANDLE);
		
		return $resources;
	} 

	return undef;
}

sub check_config {
	if (!defined $config->{host}) {	
		print "[CRITICAL] No host defined in config, exiting!\n";
		exit;
	} 
	if (!defined $config->{username}) {	
		print "[CRITICAL] No username defined in config, exiting!\n";
		exit;
	} 
	if (!defined $config->{password}) {	
		print "[CRITICAL] No password defined in config, exiting!\n";
		exit;
	} 
	
	my $given_url = $config->{host};

	my $host = $config->{host};

	if ((substr $host,0,7) eq "http://") {
		$host = substr $host, 7;
	}

	if ((index $host,"/") > 0) {
		$host = substr $host,0,index($host,"/");
	}

	if (!((index $host,":") > 0)) {
		$host = $host . ":80";
	}

	$config->{host} = $host;

	$config->{sword_url} = $host;
	
	if (create_container(undef,undef,1)) {
		return 1;
	} 

	use File::Temp;
	my $fh = File::Temp->new();
	my $stuff = get_file_from_uri($fh,$given_url,"text/html");	
	my $uri = get_sword_uri_from_html($fh);
	if (defined $uri) {
		$config->{sword_url} = $uri;
		if (create_container(undef,undef,1)) {
			print "[STARTUP] Deposit Connection Established\n[STARTUP] Completed\n\n";
			return 1;	
		} 
	}

	print "[CRITICAL] Configuration Failed, no connection to the endpoint could be established, please check the Config file for errors.\n";

	return undef;
}

sub get_resources {

	my $content_file = shift;

	if ( -e $content_file ) {

		my $resources = {};
	
		my @lines;
		
		open(HANDLE,$content_file);

		while (<HANDLE>) {
			chomp;
			push @lines, $_;
		}

		close(HANDLE);

		my $URI;
		foreach my $line(@lines) {
			my @parts = split(/:/,$line,2);
			$URI = trim(@parts[1]) if (@parts[0] eq "URI");
		}
		
		foreach my $line(@lines) {
			my @parts = split(/:/,$line,2);
			next if (@parts[0] eq "URI");
			$resources->{$URI}->{trim(@parts[0])} = trim(@parts[1]);
		}
	
		return $resources;
	} 

	return undef;
}

sub process_directory {

	my $dir = shift;
	my $depth = shift;
	my $items = shift;

#print "No items defined in repo\n" if (!defined $items);
	
	my $parent_uri = undef;
	my $resources = {};

	opendir(DIR, $dir);
	
	if ( -e $dir . ".parent_uri" ) {
		$resources = get_resources($dir . ".parent_uri");
	}
	
	foreach my $key (keys %$resources) {
		if ((substr $key,0,4) eq "http") {
			$parent_uri = $key;
		}
	}

	my $edit_media_uri;
	my $repo_docs;
	if (defined $parent_uri) {
		my $edit_uri = $resources->{$parent_uri}->{"Edit-URI"};
		$edit_media_uri = $resources->{$parent_uri}->{"Edit-Media-URI"};
		my ($server_file_modified,$server_file_md5,$status_code) = head_uri($edit_uri,"application/atom+xml");
		my $file = $dir . "METADATA.xml";
		if ( -e $file ) {
			my ($local_file_modified, $local_file_md5) = local_info($file);
			my $last_md5 = $metadata_files->{$file};
			if (!($local_file_md5 eq $last_md5) and (defined $last_md5)) {
				put_file_to_uri($file,"METADATA.xml",$edit_uri,"application/atom+xml");
				($local_file_modified, $local_file_md5) = local_info($file);
			} elsif (!($local_file_md5 eq $server_file_md5)) {
				get_file_from_uri($file,$edit_uri,"application/atom+xml");
				($local_file_modified, $local_file_md5) = local_info($file);
			}	
			$metadata_files->{$file} = $local_file_md5;
		} elsif ($status_code == 200) {
			get_file_from_uri($file,$edit_uri,"application/atom+xml");
		}
		$repo_docs = get_resource_contents($edit_media_uri);
	}

	if (!defined $repo_docs) {
		$repo_docs = $items->{$parent_uri}->{"documents"};
	}

	foreach my $file (readdir(DIR)) {

		my $file_name = $file;


		next if ($file_name eq ".parent_uri");
		next if ($file_name eq ".config");
		next if (substr($file_name,0,9) eq "VIEW_ITEM");
		next if (substr($file_name,0,8) eq "METADATA");
		next if ($file_name eq "CONFIG");

		# Delete files on server which have been removed locally
		if ((substr $file_name,0,1) eq ".") {
			my $normal_file = substr $file_name,1;
			next if ( -e $dir . $normal_file );
			my $uri;
			my $resources = get_resources($dir . $file_name);
			foreach my $key(keys %$resources) {
				if ((substr $key,0,4) eq "http") {
					$uri = $key;
				}
			}
			next if (!defined $uri);	
			if (delete_uri($uri)) {
				unlink($dir . $file_name);
				$repo_docs->{$uri} = undef;
			}
		}
		
		next if ((substr $file_name,0,1) eq ".");
	
		$file = $dir . $file;	

#my $path = $dir . "." . $file_name . "\n";
#print "PROCESSING: $path \n";
	
		if ( -d $file ) {
			my $next_depth = $depth + 1;
			process_directory($file.'/',$next_depth,$items);	
		} elsif ( -e ($dir . "." . $file_name) ) {
			my $uri;
			my $resources = get_resources($dir . "." . $file_name);
			foreach my $key(keys %$resources) {
				if ((substr $key,0,4) eq "http") {
					$uri = $key;
				}
			}	
			$repo_docs->{$uri} = undef;
			#See if file exists in eprints and is up to date.
			my ($server_file_modified, $server_file_md5, $status_code) = head_uri($uri);
			if ($status_code == 404 or $status_code == 410) {
				unlink($file);
				unlink($dir . "." . $file_name);
			} else {
				my ($local_file_modified, $local_file_md5) = local_info($file);
				if (defined $server_file_md5) {
					if (!($local_file_md5 eq $server_file_md5) and ($local_file_modified > $server_file_modified)) {
						put_file_to_uri($file,$file_name,$uri,undef);
					} elsif (!($local_file_md5 eq $server_file_md5) and ($local_file_modified < $server_file_modified)) {
						get_file_from_uri($file,$uri,undef);
					}
					
				}
			}
			#If it is out of date or not uploaded, upload it. 
#print "Found the file\n";
		} else {
			if ($depth > 0) {
				if ( -e $dir . ".parent_uri" ) {
					$resources = get_resources($dir . ".parent_uri");
				}
				foreach my $key (keys %$resources) {
					if ((substr $key,0,4) eq "http") {
						$parent_uri = $key;
					}
				}
				$edit_media_uri = $resources->{$parent_uri}->{"Edit-Media-URI"};
				deposit_file($file,$file_name,$edit_media_uri);
			}
		}
	}
#
#	foreach my $remainder(keys %$repo_docs) {
#		if (defined $repo_docs->{$remainder}) {
#			print "[MESSAGE] " . $remainder . " is only in repo, attempting to download\n";
#			my $filename = $repo_docs->{$remainder}->{"filename"};
#			my $file = $dir . $filename;
#			get_file_from_uri($file,$remainder,undef);
#			write_uris_to_file($filename,$file,$remainder,$parent_uri,undef);
#		}
#	}
#
	closedir(DIR);
}


sub md5sum {
	my $file = shift;
	use Digest::MD5;
	my $digest = "";
	eval{
		open(FILE, $file) or die "[ERROR] md5sum: Can't find file $file\n";
		my $ctx = Digest::MD5->new;
		$ctx->addfile(*FILE);
		$digest = $ctx->hexdigest;
		close(FILE);
	};
	if($@){
		print $@;
		return "";
	}
	return $digest;
}

sub get_sword_uri_from_html {
	my $fh = shift;
	my $p = XML::Parser->new( NoLWP => 1 );
	my $xp = XML::XPath->new(parser => $p, filename=>$fh);
	my $nodeset = $xp->find('/html/head/link'); 
	
	foreach my $node ($nodeset->get_nodelist) {
		my $attr = $node->getAttribute("rel");
		if ($attr eq "SwordDeposit") {
			return $node->getAttribute("href");
		}
	}

}

sub get_uris_from_atom {
	my $content = shift;
	
	my $eprint_uri; 
	my $media_uri;
	my $edit_uri;
		
	my $xp = XML::XPath->new(xml=>$content);
	
	my $nodeset = $xp->find('/entry/id'); 
	foreach my $node ($nodeset->get_nodelist) {
		$eprint_uri = $node->string_value;
	}
	
	$nodeset = $xp->find('/entry/link'); 

	foreach my $node ($nodeset->get_nodelist) {
		my $attr = $node->getAttribute("rel");
		if ($attr eq "edit-media") {
			$media_uri = $node->getAttribute("href");
		}
		if ($attr eq "edit") {
			$edit_uri = $node->getAttribute("href");
		}
	}

	# if $eprint_uri is not defined it's a feed!!!!

	if (!defined $eprint_uri) {
		$nodeset = $xp->find('/feed/entry/id'); 

		foreach my $node ($nodeset->get_nodelist) {
			$media_uri = $node->string_value;
		}
	}
	
	return ($eprint_uri,$media_uri,$edit_uri);
	
}

sub local_info {
	
	my $file = shift;

	my $local_modified = stat($file)->mtime;
	my $local_md5 = md5sum($file);	
	
	return ($local_modified,$local_md5);

}

sub get_user_agent {

	my $ua = LWP::UserAgent->new();

	$ua->credentials(
			$config->{host},
			$config->{realm},
			$config->{username} => $config->{password}
			);

	return $ua;

}

sub head_uri {
	
	my $uri = shift;
	my $content_type = shift;

	my $ua = get_user_agent(undef);

	my $h;
	my $req;

	if (defined $content_type) {
		$h = HTTP::Headers->new(Accept => "application/atom+xml");
		$req = HTTP::Request->new( HEAD => $uri, $h );
	} else {
		$req = HTTP::Request->new( HEAD => $uri );
	}

	my $res = $ua->request($req);
	
	if (!($res->is_success)) {
		my $realm = $res->header("WWW-Authenticate");
	        $realm = substr $realm, index($realm,'"') +1;
        	$realm = substr $realm, 0, index($realm,'"');
		if ($res->code == 401 && (!($config->{realm} eq $realm)) ) {
			$config->{realm} = $realm;
			return head_uri($uri,$content_type);
		} else {
			if ($res->code == 404 or $res->code == 410) {
				return(undef,undef,$res->code);
			} 
			print "[CRITICAL] Head Operation Failed on $uri\n";
			if ($debug) {
				print $res->status_line;
				print "\n";
				print $res->content;
			}
			return undef;
		}
	}
	
	my $last_modified = undef;
	my $content_md5 = undef;
	my $status_code = undef;

	$status_code = $res->code;
	if ($res->is_success) {
		$last_modified = $res->header("Last-Modified");
		$content_md5 = $res->header("ETag");
	}
	
	if (defined $last_modified && $last_modified ne "") {
		$last_modified = utc_to_epoch($last_modified);
	}
	
	chomp $content_md5;	
	
	return($last_modified,$content_md5,$status_code);
}

sub utc_to_epoch {
	
	my $timestring = shift;
	use Time::Local;
	my @elements = split / /,$timestring;
	my @timebits = split /:/,@elements[4];
	my $sec = @timebits[2];
	my $min = @timebits[1];
	my $hour = @timebits[0];
	my $day = @elements[1];
	my $month;
	$month = 0 if (@elements[2] eq "Jan"); 
	$month = 1 if (@elements[2] eq "Feb"); 
	$month = 2 if (@elements[2] eq "Mar"); 
	$month = 3 if (@elements[2] eq "Apr"); 
	$month = 4 if (@elements[2] eq "May"); 
	$month = 5 if (@elements[2] eq "Jun"); 
	$month = 6 if (@elements[2] eq "Jul"); 
	$month = 7 if (@elements[2] eq "Aug"); 
	$month = 8 if (@elements[2] eq "Sep"); 
	$month = 9 if (@elements[2] eq "Oct"); 
	$month = 10 if (@elements[2] eq "Nov"); 
	$month = 11 if (@elements[2] eq "Dec"); 
	my $year = @elements[3];
	
	my $date = timelocal($sec,$min,$hour,$day,$month,$year);
	
	return $date;	
}


sub delete_uri {
	
	my $uri = shift;

	print "[MESSAGE] Attempting to delete $uri\n";

	my $ua = get_user_agent();

	my $req = HTTP::Request->new( DELETE => $uri );

	my $res = $ua->request($req);
	
	if (!($res->is_success)) {
		my $realm = $res->header("WWW-Authenticate");
	        $realm = substr $realm, index($realm,'"') +1;
        	$realm = substr $realm, 0, index($realm,'"');
		if ($res->code == 401 && (!($config->{realm} eq $realm)) ) {
			$config->{realm} = $realm;
			return delete_uri($uri);
		} else {
			print "[CRITICAL] Operation Failed\n";
			if ($debug) {
				print $res->status_line;
				print "\n";
				print $res->content;
			}
			return undef;
		}
	}

	return 1; 
	
}

sub get_file_from_uri {
	
	my $file = shift;
	my $uri = shift;
	my $accept_type = shift;

	print "[MESSAGE] Attempting to get $file from $uri\n";

	my $ua = get_user_agent(undef);

	open(FILE, ">", "$file" ) or die('cant open input file');
	binmode FILE;

	my $h;
	my $req;

	if (defined $accept_type) {
		$h = HTTP::Headers->new(Accept => $accept_type);
		$req = HTTP::Request->new( GET => $uri, $h );
	} else {
		$req = HTTP::Request->new( GET => $uri );
	}

	my $file_handle = "";

	# Et Zzzzooo!
	my $res = $ua->request($req);	

	my $content_string = substr $res->content,0,17;
	if ($res->code == 500 and ($content_string eq "500 Can't connect")) {
		print "[CRITICAL] Could not connect to server, please check your config or connection to the server.\n";
		print "[CRITICAL] Exiting\n\n";
		exit;
	}

	if (!($res->is_success)) {
		my $realm = $res->header("WWW-Authenticate");
	        $realm = substr $realm, index($realm,'"') +1;
        	$realm = substr $realm, 0, index($realm,'"');
		if ($res->code == 401 && (!($config->{realm} eq $realm)) ) {
			$config->{realm} = $realm;
			return get_file_from_uri($file,$uri,$accept_type);
		} else {
			print "[CRITICAL] Operation Failed\n";
			if ($debug) {
				print $res->status_line;
				print "\n";
				print $res->content;
			}
			return undef;
		}
	}
	
	open(FILE,">$file");
	print FILE $res->content;
	close(FILE);
	return 1;
	
}

sub put_file_to_uri {
	
	my $file = shift;
	my $filename = shift;
	my $uri = shift;
	my $mime_type = shift;

	print "[MESSAGE] Attempting to put $file to $uri\n";

	open(FILE, "$file" ) or die('cant open input file');
	binmode FILE;

	my $ua = get_user_agent();

	my $req = HTTP::Request->new( PUT => $uri );

	# Tell SWORD to process the XML file as EPrints XML
	#$req->header( 'X-Packaging' => 'http://eprints.org/ep2/data/2.0' );
	$req->header( 'Content-Disposition' => 'form-data; name="'.$filename.'"; filename="'.$filename.'"');
	$req->header( 'X-Extract-Media' => 'true' );
	$req->header( 'In-Progress' => 'true' );
	$req->header( 'X-Override-Metadata' => 'true' );
	$req->header( 'X-Extract-Archive' => 'true' );

	use MIME::Types qw(by_suffix by_mediatype);

	my $encoding;
	if (!defined $mime_type) {
		($mime_type,$encoding) = by_suffix($file);
	}

	$req->content_type( $mime_type );

	my $file_handle = "";
	while(<FILE>) { $file_handle .= $_; }

	$req->content( $file_handle );

	# Et Zzzzooo!
	my $res = $ua->request($req);	
	
	close(FILE);
	
	if (!($res->is_success)) {
		my $realm = $res->header("WWW-Authenticate");
	        $realm = substr $realm, index($realm,'"') +1;
        	$realm = substr $realm, 0, index($realm,'"');
		if ($res->code == 401 && (!($config->{realm} eq $realm)) ) {
			$config->{realm} = $realm;
			return put_file_to_uri($file,$filename,$uri,$mime_type);
		} else {
			print "[CRITICAL] Operation Failed\n";
			if ($debug) {
				print $res->status_line;
				print "\n";
				print $res->content;
			}
			return undef;
		}
	}
	
	return 1;
	
}

sub create_container {

	my $filename = shift;
	my $filepath = shift; 
	my $no_op = shift;

	my $title = substr $filepath, 0, length($filepath) - length($filename);
	$title = substr $title, 0, length($title)-1;
	$title = substr $title, rindex($title, "/")+1, length($title);

	my $content = '<?xml version="1.0" encoding="utf-8" ?>
<entry xmlns="http://www.w3.org/2005/Atom">
<title>' . $title . '</title>
</entry>
';
		
	my $url = $config->{sword_url};

	if ($no_op) {
		print "[STARTUP] Attempting to establish deposit connection to server at $url\n";
	} else {
		print "[MESSAGE] Attempting to create resource container at $url\n";
	}
	
	my $ua = get_user_agent();

	my $req = HTTP::Request->new( POST => $url );
	
	$req->content_type( "application/atom+xml" );
	if ($no_op) 
	{
		$req->header( 'X-No-Op' => 'true' );
	}
	$req->header( 'In-Progress' => 'true' );
	
	$req->content( $content );
	
	my $res = $ua->request($req);	

	if (!($res->is_success)) {
		my $realm = $res->header("WWW-Authenticate");
	        $realm = substr $realm, index($realm,'"') +1;
        	$realm = substr $realm, 0, index($realm,'"');
		if ($res->code == 401 && (!($config->{realm} eq $realm)) ) {
			$config->{realm} = $realm;
			return create_container($filename,$filepath,$no_op);
		} else {
			if ($no_op) {
				print "[STARTUP] Failed to create the container, trying alternatives...\n";
			} else {
				print "[CRITICAL] Failed to create the contatiner\n";
			}
			if ($debug) {
				print $res->status_line;
				print "\n";
				print $res->content;
			}
			return undef;
		}
	}
	
	if ($res->is_success && $no_op) {
		return 1;
	}

	my $location_url = $res->header("Location");
	my $content = $res->content;
	my ($location_uri,$media_uri,$edit_uri) = get_uris_from_atom($content);
	
	if (defined $location_url) {
		$location_uri = $location_url;
	}
	
	write_parent_uris($filename,$filepath,$media_uri,$location_uri,$edit_uri);
	return $media_uri;
	
}

sub deposit_file {
	
	my $filepath = shift;
	my $filename = shift;
	my $url = shift;
	
	print "[MESSAGE] Attempting to post $filepath to $url\n";

	# Need to create a container to deposit into
	if (!defined $url) {
		print "[MESSAGE] Creating the conatiner\n";
		$url = create_container($filename,$filepath);
		print "[MESSAGE] Got url of $url\n"
	}
	
	print "[MESSAGE] Attempting to post $filepath to $url\n";

	return undef if (!defined $url);

	# credentials:
	open(FILE, "$filepath" ) or die('cant open input file');
	binmode FILE;

	my $ua = get_user_agent();

	my $req = HTTP::Request->new( POST => $url );

	# Tell SWORD to process the XML file as EPrints XML
	#$req->header( 'X-Packaging' => 'http://eprints.org/ep2/data/2.0' );
	$req->header( 'Content-Disposition' => 'form-data; name="'.$filename.'"; filename="'.$filename.'"');
	$req->header( 'In-Progress' => 'true' );
	$req->header( 'X-Extract-Media' => 'true' );
	$req->header( 'X-Override-Metadata' => 'true' );
	#$req->header( 'X-Extract-Archive' => 'true' );

	use MIME::Types qw(by_suffix by_mediatype);

	my ($mime_type,$encoding) = by_suffix($filepath);
	$req->content_type( $mime_type );

	my $file = "";
	while(<FILE>) { $file .= $_; }

	$req->content( $file );

	# Et Zzzzooo!
	my $res = $ua->request($req);	
	
	close(FILE);
	
	if (!($res->is_success)) {
		my $realm = $res->header("WWW-Authenticate");
	        $realm = substr $realm, index($realm,'"') +1;
        	$realm = substr $realm, 0, index($realm,'"');
		if ($res->code == 401 && (!($config->{realm} eq $realm)) ) {
			$config->{realm} = $realm;
			return deposit_file($filepath,$filename,$url); 
		} else {
			print "[CRITICAL] Failed to POST the FILE\n";
			if ($debug) {
				print $res->status_line;
				print "\n";
				print $res->content;
			}
			return undef;
			
		}
	}
		
	my $location_url = $res->header("Location");
	print "[MESSAGE] GOT File location of $location_url\n\n";
	my $content = $res->content;
	my ($location_uri,$media_uri,$edit_uri) = get_uris_from_atom($content);
	if (defined $location_url) {
		$location_uri = $location_url;
	}
	write_uris_to_file($filename,$filepath,$media_uri,$location_uri);
	
}

sub write_parent_uris {
	my $filename = shift;
	my $full_path = shift;
	my $media_uri = shift;
	my $parent_uri = shift;
	my $edit_uri = shift;

	my $file_last_modified = stat($full_path)->mtime;
	my $path = substr($full_path,0, 0 - length($filename));
	my $parent_file = $path . ".parent_uri";
	my $parent_mtime = stat($path)->mtime;
	
	if ( -e $parent_file ) {
		my $resources = get_resources($parent_file);
		if (!defined $edit_uri) {
			$edit_uri = $resources->{$parent_uri}->{"Edit-URI"};
		}
	}

	open(FILE,">$parent_file");
	print FILE "URI: $parent_uri\nLast-Modified: $parent_mtime\nEdit-URI: $edit_uri\nEdit-Media-URI: $media_uri\n";
	close(FILE);

	if ($OSNAME eq "MSWin32") {
		eval "use Win32::File";
		Win32::File::SetAttributes($parent_file,Win32::File::HIDDEN());
	}

	my $html_file = $path . "VIEW_ITEM.HTML";
	open(FILE,">$html_file");
	print FILE '
<html><head>
<meta http-equiv="REFRESH" content="0;url='.$parent_uri.'"/>
</head>
<body style="margin: 7em;">
<div align="center">
<a href="'.$parent_uri.'">Click here if you are not automatically redirected</a>
</div>
</body>
</html>
';
	close(FILE);
}

sub write_uris_to_file {

	my $filename = shift;
	my $full_path = shift;
	my $media_uri = shift;
	my $location_uri = shift;

#	print $filename . " : " . $full_path . " : " . $media_uri . " : " . $parent_uri . "\n\n"; 

	my $file_last_modified = stat($full_path)->mtime;
	my $path = substr($full_path,0, 0 - length($filename));
	my $file_index = $path . "." . $filename;
	
	open (FILE,">$file_index");
	print FILE "URI: $location_uri\nLast-Modified: $file_last_modified\n";
	close (FILE);
	
	if ($OSNAME eq "MSWin32") {
		eval "use Win32::File";
		Win32::File::SetAttributes($file_index,Win32::File::HIDDEN());
	}
	
}

sub trim($)
{
	my $string = shift;
	$string =~ s/^\s+//;
	$string =~ s/\s+$//;
	return $string;
}

sub get_resource_list {
	
	my $uri = "http://" . $config->{host} . "/id/contents";

	print "[MESSAGE] Starting sync of resources\n";

	my $ua = get_user_agent(undef);

	my $h = HTTP::Headers->new(Accept => "application/atom+xml");
	my $req = HTTP::Request->new( GET => $uri, $h );

	my $items;

	# Et Zzzzooo!
	my $res = $ua->request($req);	

	if (!($res->is_success)) {
		my $realm = $res->header("WWW-Authenticate");
	        $realm = substr $realm, index($realm,'"') +1;
        	$realm = substr $realm, 0, index($realm,'"');
		if ($res->code == 401 && (!($config->{realm} eq $realm)) ) {
			$config->{realm} = $realm;
			return get_resource_list();
		} else {
			print "[CRITICAL] Operation Failed\n";
			if ($debug) {
				print $res->status_line;
				print "\n";
				print $res->content;
			}
			return undef;
		}
	}
	
	my $content = $res->content;

	my $xp = XML::XPath->new(xml=>$content);

	my $nodeset = $xp->find('/feed/entry'); 
	foreach my $node ($nodeset->get_nodelist) {
		my $eprint_id;	
		my $sub_nodeset = $xp->find('id',$node);
		foreach my $sub_node ($sub_nodeset->get_nodelist) {
			$eprint_id = $sub_node->string_value;
#print "FOUND: " . $sub_node->string_value . "\n";
		}
		my $sub_nodeset = $xp->find('title',$node);
		foreach my $sub_node ($sub_nodeset->get_nodelist) {
			$items->{$eprint_id}->{"title"} = $sub_node->string_value;
#print "TITLE: " . $sub_node->string_value . "\n";
		}
		my $sub_nodeset = $xp->find('link',$node);
		foreach my $sub_node ($sub_nodeset->get_nodelist) {
			my $attr = $sub_node->getAttribute("rel");
			if ($attr eq "edit-media") {
				$items->{$eprint_id}->{"edit-media"} = $sub_node->getAttribute("href");
#print $sub_node->getAttribute("href") . "\n";
			}
		}
	}
	
	if (!defined $items) {
		print "[WARNING] No items found on server\n";
		if ($debug) {
			print $res->status_line;
			print "\n";
			print $res->content;
		}
		return undef;
	}

	foreach my $eprint_id(keys %$items) {
		my $uri = $items->{$eprint_id}->{"edit-media"};
		$items->{$eprint_id}->{"documents"} = get_resource_contents($uri);
	}
		
	print "[MESSAGE] Sync Complete\n";
	return $items;
	
}

sub get_resource_contents 
{
	my $uri = shift;

	my $ua = get_user_agent(undef);

	my $h = HTTP::Headers->new(Accept => "application/atom+xml");
	my $req = HTTP::Request->new( GET => $uri, $h );

	# Et Zzzzooo!
	my $res = $ua->request($req);	

	if (!($res->is_success)) {
		my $realm = $res->header("WWW-Authenticate");
	        $realm = substr $realm, index($realm,'"') +1;
        	$realm = substr $realm, 0, index($realm,'"');
		if ($res->code == 401 && (!($config->{realm} eq $realm)) ) {
			$config->{realm} = $realm;
			return get_resource_contents($uri);
		} else {
			print "[CRITICAL] Contents Retrieve Operation Failed for $uri\n";
			if ($debug) {
				print $res->status_line;
				print "\n";
				print $res->content;
			}
			return undef;
		}
	}
	
	my $documents;

	my $content = $res->content;

	my $xp = XML::XPath->new(xml=>$content);

	my $nodeset = $xp->find('/feed/entry'); 
	foreach my $node ($nodeset->get_nodelist) {
		my $doc_id;	
		my $sub_nodeset = $xp->find('id',$node);
		foreach my $sub_node ($sub_nodeset->get_nodelist) {
			$doc_id = $sub_node->string_value;
		}
		my $sub_nodeset = $xp->find('title',$node);
		foreach my $sub_node ($sub_nodeset->get_nodelist) {
			$documents->{$doc_id}->{"title"} = $sub_node->string_value;
		}
		my $sub_nodeset = $xp->find('link',$node);
		foreach my $sub_node ($sub_nodeset->get_nodelist) {
			my $attr = $sub_node->getAttribute("rel");
			if ($attr eq "alternate") {
				my $filename = $sub_node->getAttribute("href");
				$filename = substr $filename, rindex($filename,"/")+1,length($filename);
				$documents->{$doc_id}->{"filename"} = $filename;
			}
		}
	}

	return $documents;

}