| Description: |
A perl module to access the library of congress' book database.
Unlike Amazon or Barnes and Noble, you can't just look up a book in the Library of Congress database with an ISBN; you need to first initialize a session with their web server. That's all this module does, it initializes a session for you and returns either a url of a book's web page or a reference to a hash containing that book's data (author, title, etc.) |
package LOC;
use strict;
use CGI;
use IO::Socket;
sub z3950_data {
my $isbn = shift();
local $/ = undef;
my $ua = IO::Socket::INET->new(
Proto => 'tcp',
PeerAddr => 'lcweb.loc.gov',
PeerPort => 'http(80)', );
print $ua "GET " . z3950_url($isbn) . "\x0d\x0a\x0d\x0a";
my ($raw_data) = <$ua> =~ /<pre>(.*?)<\/pre>/is;
return undef unless ( defined($raw_data) );
my %data = ();
my $last = 'UNKNOWN';
foreach my $line ( split(/\n/, $raw_data ) ) {
chomp( $line );
$line =~ s/\s+/ /g;
if ( my ($key, $value) = $line =~ /^([^:]+): (.*)/ ) {
$data{$key} .= $value;
$last = $key;
}
else {
$data{$last} .= $line;
}
}
return \%data;
}
sub z3950_html {
my $isbn = shift();
my $data = z3950_data( $isbn );
if ( !defined($data) ) {
return "<font color='#990000'>z3950_html: Can't get LO
+C data</font>";
}
return "<pre>", join("\n", map { "$_ -> $$data{$_}" } keys( %$
+data )),
"</pre>\n";
}
sub z3950_url {
my $isbn = shift();
my $sid = undef;
local $/ = undef;
my $ua = IO::Socket::INET->new(
Proto => 'tcp',
PeerAddr => 'lcweb.loc.gov',
PeerPort => 'http(80)', );
print $ua "GET /cgi-bin/zgate?ACTION=INIT\&FORM_HOST_PORT=".
"/prod/www/data/z3950/locils.html,z3950.loc.gov,7090".
"\x0d\x0a\x0d\x0a";
($sid) = <$ua> =~ /NAME="SESSION_ID"\s+VALUE="(\d+)"/i;
return undef unless ( defined($sid) );
return
"http://lcweb.loc.gov/cgi-bin/zgate?".
"ESNAME=F&".
"ACTION=SEARCH&".
"DBNAME=VOYAGER&".
# "MAXRECORDS=20&".
# "RECSYNTAX=1.2.840.10003.5.10&".
# "REINIT=" . CGI::escape("/cgi-bin/zgate?ACTION=INIT&
+FORM_HOST_PORT=/prod/www/data/z3950/locils.html,z3950.loc.gov,7090")
+. "&" .
"TERM_1=$isbn&".
"USE_1=7&".
"SESSION_ID=$sid".
"";
}
1;
=pod
=head1 TITLE
LOC.pm - an interface to the Library of Congress' book database
=head1 SYNOPSIS
To redirect from a web page:
use CGI;
use LOC;
my $cgi = new CGI;
my $isbn = $cgi->param('isbn');
print $cgi->redirect( LOC::z3950_url($isbn) );
To get the data for a certain book:
use LOC;
my $data = LOC::z3950_data( $isbn );
foreach my $key ( keys(%$data) ) {
print "$key: $$data{$key}\n";
}
=head1 DESCRIPTION
The Library of Congress' web-interface to their book database is screw
+y.
You just can't find the isbn and plug it into a simple url. No, you
need to initialize a session first, and then plug the isbn into a simp
+le
url. Oh well. So this module initializes a session and redirects you
to the right url. Or, you can just grab the data from the LOC and pre
+sent
it in whatever form you want.
=head1 FUNCTIONS
=over 4
=item \%hash z3950_data( $isbn )
Given an ISBN, return a reference to a hash with the data downloaded f
+rom
the Library of Congress. The keys to the hash are the data field name
+s.
=item $html z3950_html( $isbn )
Dump out the data from z3950_data as HTML. Sort of. It's just plain
text with <pre> tags around it.
=item $url z3950_url( $isbn )
The url that will get the LOC page for this ISBN.
=back
=cut
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