Category: | Web Stuff |
Author/Contact Info | eg |
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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Re: US Library of Congress perl module
by Anonymous Monk on Nov 10, 2010 at 20:15 UTC |
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