If you get lost in that maze of OOO, (I did:), you might like to try something like:

#! perl -slw
use strict;
use LWP::Simple;
use XML::Simple;
use Data::Dump qw[ pp ];
use constant ACCESS_ID => 'XXXXXXXX'; ## Your access key here.

my $isbn = $ARGV[ 0 ] or die 'Need an ISBN number';
die "'$isbn' doesn't look like a valid ISBN"
    unless $isbn =~ m[^\d{10}$];

my $uri = sprintf 
    "http://isbndb.com/api/books.xml?access_key=%s&index1=isbn&value1=
+%s",
    ACCESS_ID, $isbn;

my $xml = get $uri or die "Request failed";
my $info = XMLin $xml;

pp $info;
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A sample usage:

C:\test>isbndb 0131101633
{
  BookList => {
    BookData => {
      AuthorsText => "Brian W. Kernighan, Dennis M. Ritchie",
      PublisherText => {
        content => "Englewood Cliffs, N.J. : Prentice-Hall, c1978.",
        publisher_id => "prentice_hall_a01",
      },
      Title => "The C programming language",
      TitleLong => {},
      book_id => "the_c_programming_language",
      isbn => "0131101633",
    },
    page_number => 1,
    page_size => 10,
    shown_results => 1,
    total_results => 1,
  },
  server_time => "2008-04-22T03:13:35Z",
}
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Wrapping that into a module with an api like:

use ISBNDB::Simple ACCESSID => 'XXXXXXXX';

my $isbn = ...;

my $href = Book( $isbn );
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Is left as an exercise :)

BrowserUk,

Thanks for the "hand-rolled" version. I will be back if I can't get the aforementioned module working.

—Brad
"The important work of moving the world forward does not wait to be done by perfect men." George Eliot

I see you got it "working", but here's a thought. Why does that suite of modules have all those setter methods when the isbndb api is read-only?

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

"Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."

Class::Std is used to implement "inside-out objects", which prevents accidental (and to a large extent intentional) mucking with an object's internals. Basically, it's specifically trying to prevent you from writing the bad code you stated you wanted to write (among other things).

Hi Brad :-). The reason you can't see into the objects innards is indeed its inheritance from Class::Std. Take a look at this bit from the introduction of the Class::Std POD:

Most programmers who use Perl's object-oriented features construct their objects by blessing a hash. But, in doing so, they undermine the robustness of the OO approach. Hash-based objects are unencapsulated: their entries are open for the world to access and modify.

So this is a feature of this particular way of doing objects. Not one I personally particularly care for (which is one of the reasons I said the usage of Class::Std-based modules is not necessarily recommended in my email), but in this case seems to be a resounding success if you are in the habit of peeking into the object in order to figure out how best to use it. The innards of an object should never matter to you as a module user, you should always access them via the published interface, i.e. the methods documented in the module POD. "Normal" (hash-based) Perl modules just trust you to do that and don't prevent you from bypassing the interface. Class::Std and its ilk protect you from yourself in that they only allow access via the interface and don't allow you to peek and prod.

So the answer to your question on how to use a CPAN module: read the module documentation and use the module according to that. If something doesn't work, then break out Data::Dumper and maybe try to figure out why, or send a bug report to the module author that they either fix their module or the docs.

I did read what you had quoted from the docs and got some inkling of what was going on, so thanks for expanding the explanation. If you see my reply to perrin below, you will see I ran into a bug (me thinks) that was throwing me off.

—Brad
"The important work of moving the world forward does not wait to be done by perfect men." George Eliot

Just download the tar ball, and take a look at the files in the t/ directory.

They test what the author thinks is important, and you can run the tests easily to see if it's working (that's an advantage over the SYNOPSIS section which often leaves out some details, or contains typos and can't run when copied verbatim).

my $book = WebService::ISBNDB::API->new({ api_key => $key,
                                          isbn => '0596002068' });
my $title = $book->get_title();
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perrin,

I had tried that and was getting zero results (white screen). When I moved the api_key up to the use declaration, I started working. Must be a bug.

#!/usr/bin/perl

use strict;
use CGI::Carp qw(fatalsToBrowser);
use Data::Dumper;
                                 
use WebService::ISBNDB::API (api_key => '12341234');
use WebService::ISBNDB::API::Books;

my $book = WebService::ISBNDB::API::Books->new('0596002068');

my $title = $book->get_title();
my $authors = $book->get_authors_text();

print "Content-type: text/plain\n\n";
print Dumper($title, $authors);

1;
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Returned:

$VAR1 = 'Programming Web services with Perl';
$VAR2 = 'Randy J. Ray and Pavel Kulchenko';
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It really helped to look at the tests. Then the docs made more sense.

—Brad
"The important work of moving the world forward does not wait to be done by perfect men." George Eliot

If it's really broken, don't forget to file a ticket.