Accessing Amazon Product Advertising API

sameer — Fri, 21 Aug 2009 05:39:49 +0000

Updated: 19th October 2011

In this post we will see how to access the Amazon Product Advertising API from PHP. Amazon has recently changed (from 15th Aug ’09) the authentication mechanism for accessing their API which must now be signed with your Amazon keys. Unsigned requests will be rejected by Amazon. Also now Amazon Associate Tag is required in the query (effective from 25th Oct. 2011). Note that the code uses the hash_hmac() hash function which is only available for PHP versions 5.1.2 and above, so the code will not work for versions below that.

A small example

Below is an example to access the Amazon Product Advertising API using the provided class.


 
    /* Example usage of the Amazon Product Advertising API */
    include("amazon_api_class.php");
 
    $obj = new AmazonProductAPI();
 
    try
    {
        /* Returns a SimpleXML object */
         $result = $obj->searchProducts("X-Men Origins",
                                       AmazonProductAPI::DVD,
                                       "TITLE");
    }
    catch(Exception $e)
    {
        echo $e->getMessage();
    }
 
    print_r($result);
 
?>

The API access class

Given below is the implementation of the class to access the Amazon Product Advertising API. Comments have been removed for brevity, but are included in the source download. Note that only a few access operations are implemented in the class: ItemLookup, ItemSearch; there are more available in the API, a complete list can be found here. It’s just a simple matter of changing some parameters to implement others.


 
require_once 'aws_signed_request.php';
 
class AmazonProductAPI
{
 
    private $public_key     = "YOUR AMAZON ACCESS KEY ID";
    private $private_key    = "YOUR AMAZON SECRET KEY";
 
    /* 'Associate Tag' now required, effective from 25th Oct. 2011 */
    private $associate_tag  = "YOUR AMAZON ASSOCIATE TAG";
 
    const MUSIC = "Music";
    const DVD   = "DVD";
    const GAMES = "VideoGames";
 
    private function verifyXmlResponse($response)
    {
        if ($response === False)
        {
            throw new Exception("Could not connect to Amazon");
        }
        else
        {
            if (isset($response->Items->Item->ItemAttributes->Title))
            {
                return ($response);
            }
            else
            {
                throw new Exception("Invalid xml response.");
            }
        }
    }
 
    private function queryAmazon($parameters)
    {
        return aws_signed_request("com",
                                  $parameters,
                                  $this->public_key,
                                  $this->private_key,
                                  $this->associate_tag);
    }
 
    public function searchProducts($search,$category,$searchType="UPC")
    {
        $allowedTypes = array("UPC", "TITLE", "ARTIST", "KEYWORD");
        $allowedCategories = array("Music", "DVD", "VideoGames");
 
        switch($searchType) 
        {
            case "UPC" :
                $parameters = array("Operation"     => "ItemLookup",
                                    "ItemId"        => $search,
                                    "SearchIndex"   => $category,
                                    "IdType"        => "UPC",
                                    "ResponseGroup" => "Medium");
                            break;
 
            case "TITLE" :
                $parameters = array("Operation"     => "ItemSearch",
                                    "Title"         => $search,
                                    "SearchIndex"   => $category,
                                    "ResponseGroup" => "Medium");
                            break;
 
        }
 
        $xml_response = $this->queryAmazon($parameters);
 
        return $this->verifyXmlResponse($xml_response);
 
    }
 
    public function getItemByUpc($upc_code, $product_type)
    {
        $parameters = array("Operation"     => "ItemLookup",
                            "ItemId"        => $upc_code,
                            "SearchIndex"   => $product_type,
                            "IdType"        => "UPC",
                            "ResponseGroup" => "Medium");
 
        $xml_response = $this->queryAmazon($parameters);
 
        return $this->verifyXmlResponse($xml_response);
 
    }
 
    public function getItemByAsin($asin_code)
    {
        $parameters = array("Operation"     => "ItemLookup",
                            "ItemId"        => $asin_code,
                            "ResponseGroup" => "Medium");
 
        $xml_response = $this->queryAmazon($parameters);
 
        return $this->verifyXmlResponse($xml_response);
    }
 
    public function getItemByKeyword($keyword, $product_type)
    {
        $parameters = array("Operation"   => "ItemSearch",
                            "Keywords"    => $keyword,
                            "SearchIndex" => $product_type);
 
        $xml_response = $this->queryAmazon($parameters);
 
        return $this->verifyXmlResponse($xml_response);
    }
 
}
 
?>

Amazon signed request

The above class uses the ‘aws_signed_request’ function to generate the new request signature. Original code is by Ulrich Mierendorff, modified here to use cURL.


 
function  aws_signed_request($region,
                             $params,
                             $public_key,
                             $private_key,
                             $associate_tag)
{
 
    $method = "GET";
    $host = "ecs.amazonaws.".$region;
    $uri = "/onca/xml";
 
 
    $params["Service"]          = "AWSECommerceService";
    $params["AWSAccessKeyId"]   = $public_key;
    $params["AssociateTag"]     = $associate_tag;
 
    $params["Timestamp"]        = gmdate("Y-m-d\TH:i:s\Z");
    $params["Version"]          = "2009-03-31";
 
    /* The params need to be sorted by the key, as Amazon does this at
      their end and then generates the hash of the same. If the params
      are not in order then the generated hash will be different from
      Amazon thus failing the authentication process.
    */
    ksort($params);
 
    $canonicalized_query = array();
 
    foreach ($params as $param=>$value)
    {
        $param = str_replace("%7E", "~", rawurlencode($param));
        $value = str_replace("%7E", "~", rawurlencode($value));
        $canonicalized_query[] = $param."=".$value;
    }
 
    $canonicalized_query = implode("&", $canonicalized_query);
 
    $string_to_sign = $method."\n".$host."\n".$uri."\n".
                            $canonicalized_query;
 
    /* calculate the signature using HMAC, SHA256 and base64-encoding */
    $signature = base64_encode(hash_hmac("sha256", 
                                  $string_to_sign, $private_key, True));
 
    /* encode the signature for the request */
    $signature = str_replace("%7E", "~", rawurlencode($signature));
 
    /* create request */
    $request = "http://".$host.$uri."?".$canonicalized_query."&Signature=".$signature;
 
    /* I prefer using CURL */
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL,$request);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_TIMEOUT, 15);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
 
    $xml_response = curl_exec($ch);
 
    if ($xml_response === False)
    {
        return False;
    }
    else
    {
        /* parse XML and return a SimpleXML object, if you would
           rather like raw xml then just return the $xml_response.
         */
        $parsed_xml = @simplexml_load_string($xml_response);
        return ($parsed_xml === False) ? False : $parsed_xml;
    }
}
?>

Download Source
Downloads : 4890 / File size : 5 kB

NewYork Times Bestseller API access in PHP

sameer — Fri, 20 Feb 2009 15:20:12 +0000

The New York Times has started offering a set of APIs for their various data services. On January 27th they released the API for their Best-Seller list. According to NYTimes :

Like many organizations, we hope to encourage innovation through collaboration. When you build applications, create mashups and otherwise reveal the potential of our data, we learn more about what our readers want and gain insight into how news and information can be reimagined. We’re hoping you’ll show us what’s next for The Times.

Currently the list offers every weekly list since June 2008 which will eventually go back to the 1930s. According to their blog, the API offers details about specific best sellers, including historical rank information and links to New York Times reviews and excerpts. I created a short class to access the api using CURL. To access the api you need to sign up for an API key here. The api returns data in xml, json or sphp (serialized php).

A sample code using the class is shown below:

$books = new nyTimesBooks("your api key here");
$books = $books->format("xml") // Set return format to xml
                ->listDate("2008-10-01") // publication date (YYYY-MM-DD)
                ->listType("Series-Books"); // List type
 
echo $books->get_bestsellers();

The list type can be any of the following:

* Hardcover-Fiction
* Hardcover-Nonfiction
* Hardcover-Advice
* Paperback-Nonfiction
* Paperback-Advice
* Trade-Fiction-Paperback
* Picture-Books
* Chapter-Books
* Paperback-Books
* Series-Books
* Mass-Market-Paperback

Or you can get the list as follows:

$books = new nyTimesBooks("your api key here");
echo $books->get_list_names();

You can also use the class without any options which will return the current list in xml format with the list type of ‘Mass-Market-Paperback’.

$books = new nyTimesBooks("your api key here");
echo $books->get_bestsellers();

A sample xml output is shown below:

 version="1.0"?>
>
  >OK>
  >Copyright (c) 2009 The New York Times Company.  All Rights Reserved.>
  >20>
  >
    >
      >1>
      >Paperback Nonfiction>
      >2008-09-21>
      >2008-10-05>
      >86>
      >0>
      >0>
      >0>
      >
        >
          >THREE CUPS OF TEA>
          >A former climber builds schools in villages in Pakistan and Afghanistan.>
          >by Greg Mortenson and David Oliver Relin>
          >Greg Mortenson and David Oliver Relin>
          />
          >15>
          />
          >Penguin>
        >
      >
      >
        >
          >9780143038252>
          >0143038257>
        >
        >
          >9780670034826>
          >0670034827>
        >
        >
          >9781597226240>
          >159
.
.
.

The code still needs to implement the following requests:
1. search best-seller lists
2. history of a best seller

Download code

code-diesel » api

Accessing Amazon Product Advertising API

A small example

The API access class

Amazon signed request

NewYork Times Bestseller API access in PHP