Even without wrapper functions, retrieving data directly from Amazon with XML/HTTP is straightforward. You just need the ability to grab a file from the Web and parse the results.

The Code

This code accepts a command-line argument and builds an Amazon URL with the argument as the keyword. Create the file amazon_http.pl with the following code:

#!/usr/bin/perl
# amazon_http.pl
# A typical Amazon Web API Perl script using the XML/HTTP interface
# Usage: amazon_http.pl <keyword> 

#Your Amazon developer's token
my $dev_key='insert developer token';

#Your Amazon affiliate code
my $af_tag='insert associate tag';

#Take the keyword from the command-line
my $keyword =shift @ARGV or die "Usage:perl amazon_http.pl <keyword>\n";

#Assemble the URL
my $url = "http://xml.amazon.com/onca/xml3?t=" . $af_tag . 
    "&dev-t=" . $dev_key .
    "&type=lite&f=xml&mode=books&" .
    "KeywordSearch=" . $keyword;

use strict;

#Use the XML::Parser  and LWP::Simple Perl modules
use XML::Simple;
use LWP::Simple;

my $content = get($url);
die "Could not retrieve $url" unless $content;

my $xmlsimple = XML::Simple->new(  );
my $response = $xmlsimple->XMLin($content);

foreach my $result (@{$response->{Details}}){
    #Print out the main bits of each result
    print
    join "\n",
    $result->{ProductName}||"no title",
    "ASIN: " . $result->{Asin} . ", " .
    $result->{OurPrice} . "\n\n";
}

The foreach at the end of the code loops through the results from Amazon and prints them out. By changing the variable names, you can change the information that is displayed. For example, changing OurPrice on the last line to ListPrice would display that price instead of Amazon's price.