Add another way to display without changing the module

Well, just to add another way for people who want to use this (poorly documented but otherwise very nice) module:

Add a CCK-Field "asin" (don't bother using the Amazon-module field, at least in my case its not working 9/10 times, and yes, I will write a bug report). You can get all the information you want by calling:

amazon_item_lookup(_amazon_clean_type($node->asin[0]));

in your node-whatever.tpl.php. (assuming only one is is submitted and the field is named asin). It will return you a very nice array of stuff you always wanted to know ;)

Well, perhaps I should go into more detail:

Content-Type and theme

I just added field 'field_asin' (type: text, textfield) to the content-type xyz. In my "node-xyz.tpl.php" I inserted the following code:

$asin    = _amazon_clean_type($node->field_asin[0]['safe']);
$_amazon = amazon_item_lookup($asin);
$amazon  = $_amazon[$asin];

Now $amazon contains either null (ASIN is invalid) or the corresponding Amazon-information, one example of a random book is attached.
I've printed the array using

print "<pre>" . print_r($amazon,true) . "</pre><br>";

Now to e.g. print the Title from Amazon:

print $amazon['title'];

etc:

Now, an example code to print the content of the node (in your node-xyz.tpl.php) with the cover-image and some basic-information:

$img     = $amazon['imagesets']['mediumimage'];
$height  = $img['height'];
$width   = $img['width'];
$imgh    = "<img id=\"cover\" style='float: right;' title=\"" . $amazon['title'] . " cover\" src=\"" . $img['url'] . "\" width=\"$width\" height=\"$height\">";
print l($imgh,"node/".$node->nid,array('html'=>true)); 
print "<h1>$title</h1>";
print $content;
print implode(',',$amazon['author']) . ": <b>".$amazon['title']."</b><br>";
print $amazon['publisher'] . "; " . t(date("F",$amazon['timestamp'])) . " " . date("Y",$amazon['timestamp'])  . "<br>";
print $amazon['numberofpages'] . " Seiten, " . $amazon['binding'] . ", " . $amazon['listpriceformattedprice'] . "<br>";
$imgurl = base_path() . path_to_theme() . "/logo_amazon_90.gif";
print l("Additional information - <img style=\"vertical-align: middle;\" src=\"$imgurl\" width=\"90\" height=\"45\" title=\"Amazon Logo\">",$amazon['detailpageurl'],array('html'=>true));

Validation

As my content-type is only worth something, if Amazon-Content could be collected, I've added a validator (using http://drupal.org/project/validation_api ) using a PHP-validator:

$asin    = _amazon_clean_type($value);
$_amazon = amazon_item_lookup($asin);
$amazon  = $_amazon[$asin];
if ( ! $amazon && $value != '---' ) { return false; }
return true;

but this is optional. The check fails if a) the ASIN is invalid (no Amazon-content could be retrieved) and b) the ASIN is not '---'. If the
check fails, "preview" or "save" on a node fails with an error-message.

Nodetitle

I'm using http://drupal.org/project/auto_nodetitle to set the node-title to something like "Author - Book", but this is optional too:

  $asin    = _amazon_clean_type($node->field_asin[0]['value']);
  $_amazon = amazon_item_lookup($asin);
  $amazon  = $_amazon[$asin];
  $autor = implode(',',$amazon['author']);
  if ( strlen($amazon) > 40 && count($amazon['author']) > 1 ) {
    $autor = $amazon['author'][0] . "...";
  }
  $ownTitle .= "$autor - ".$amazon['title'];
  print $ownTitle;

System

I'm using Drupal-6.10, Content 6.x-2.1, Amazon API 6.x-1.0-beta5 and Validation API 6.x-1.0 and Automatic Nodetitle 6.x-1.1

I do believe that there are better ways to display this information, but this approach works (for me) and allows me to adjust what information is visible. In fact it allows to integrate with Validation API etc to avoid potential misspellings or problems. I did not check whether this uses the caching mechanism of the Amazon API, but I believe so.

I didn't even know that the Amazon API has a handbook page/area?

That's very nice for you drupal librarian - could you elaborate on your method?