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Amazon Advertising API BrowseNodes

sameer — Sun, 01 Jan 2012 16:25:35 +0000

Amazon uses a hierarchy of nodes to organize its various items. Each node represents a collection of items, such as Harry Potter books, not the items themselves. Browse node IDs are positive integers that uniquely identify product collections, for example, Literature & Fiction: (17), Medicine: (13996), Mystery & Thrillers: (18), Nonfiction: (53), Outdoors & Nature: (290060). Amazon uses over 120,000 browse node IDs in the US locale alone.

The BrowseNodes tool automatically gets all the child BrowseNodes and their names. The program recursively traverses the BrowserNode hierarchy and returns all the BrowseNodes and their respective names. You can display the nodes on the console or save it to a CSV file. You can also include the library in your existing projects to process BrowseNodes.

Library Usage

The library is easy to use, and requires PHP and CURL installed on your system. The download includes a sample file with which you can immediately test the code. The sample file is shown below.


 
/* Example usage of the Amazon Product Advertising API */
include("amazon_api_class.php");
 
$public_key     = "YOUR-AMAZON-PUBLIC-KEY";
$private_key    = "YOUR-AMAZON-SECRET-KEY";
$region         = "com"; // or "CA" or "DE" etc.
 
$obj = new AmazonProductAPI($public_key, $private_key, $region);
 
/* Display the BrowseNodes to the console */
$obj->setMedia("display");
 
$obj->getBrowseNodes("1266092011");
 
?>

Before you begin to use the library, you need to enter your Amazon security credentials as shown above. Also in the ‘aws_signed_request.php’ file you will need to enter your Amazon Associate ID, as it is now mandatory. Find the following line in the file and add your Associated ID.

/* aws_signed_request.php */
.
.
$params["AssociateTag"]     = 'YOUR-ASSOCIATES-ID-HERE';
.

That is it. Now you are ready to get the BrowserNodes from Amazon. You can display the BrowserNodes on you console/browser or save it directly to a CSV file. For that you have to use the ‘setMedia’ method. Both example are shown below.

Display the BrowseNodes on the console


 
/* Example usage of the Amazon Product Advertising API */
include("amazon_api_class.php");
 
$public_key     = "YOUR-AMAZON-PUBLIC-KEY";
$private_key    = "YOUR-AMAZON-SECRET-KEY";
$region         = "com"; // or "CA" or "DE" etc.
 
$obj = new AmazonProductAPI($public_key, $private_key, $region);
 
/* Display the BrowseNodes to the console */
$obj->setMedia("display");
 
$obj->getBrowseNodes("1266092011");
 
?>

You enter the parent browsenode in the ‘getBrowseNodes’ method, after which the function recursively retrieves all the children nodes. To get started, you can find all the top browsenode values here, or you can get it from the Amazon link itself.

The output of the above is shown below. The output is indented so that you can visualize the hierarchy of the nodes.

Television & Video : AV Receivers & Amplifiers : 3213035011
Television & Video : Blu-ray Players & Recorders : 3213025011
      Blu-ray Players & Recorders : Blu-ray Recorders : 3213026011
      Blu-ray Players & Recorders : Blu-ray Players : 352697011
Television & Video : DVD Players & Recorders : 3213027011
      DVD Players & Recorders : DVD Players : 1036922
      DVD Players & Recorders : DVD Recorders : 1036920
Television & Video : DVD-VCR Combos : 886258
Television & Video : HD DVD Players : 352696011
Television & Video : Televisions : 172659
Television & Video : Home Theater Systems : 281056
.
.

The format of each line is given below.

Saving the BrowseNodes to a CSV

The following code shows how to save the browsenodes to a CSV file.


 
/* Example usage of the Amazon Product Advertising API */
include("amazon_api_class.php");
 
$public_key     = "YOUR-AMAZON-PUBLIC-KEY";
$private_key    = "YOUR-AMAZON-SECRET-KEY";
$region         = "com"; // or "CA" or "DE" etc.
 
$obj = new AmazonProductAPI($public_key, $private_key, $region);
 
/* Write the BrowseNodes to a CSV file */
$obj->setMedia("csv", "./nodes.csv");
 
$obj->getBrowseNodes("1266092011");
 
?>

The code saves all the browsenodes in a CSV file, after which you can use it with Excel or a simple text editor. A sample CSV ouput is shown below. The format is the same as the one given above.

"PlayStation 3","All Games","14210861"
"PlayStation 3","Action","14210761"
"Action","Fighting","14210981"
"Action","Military & Espionage","14210821"
"Action","Shooter","14210841"
"PlayStation 3","Adventure","14210851"
"PlayStation 3","Arcade","14210911"
"PlayStation 3","Board Games","14210921"

Changing Locales

Amazon being a world-wide venture the Product Advertising API operates in the following locales:
CA
CN
DE
ES
FR
IT
JP
UK
US

You can use different locale code to get the BrowseNodes for different regions. You set the locale parameter using the ‘$region’ variable; for example:

$region = "com"; // or "CA" or "DE" etc.

Getting the parent node details

You can also get information about a nodes parent node using the ‘getParentNode’ method.


 
/* Example usage of the Amazon Product Advertising API */
include("amazon_api_class.php");
 
$public_key     = "YOUR-AMAZON-PUBLIC-KEY";
$private_key    = "YOUR-AMAZON-SECRET-KEY";
$region         = "com"; // or "CA" or "DE" etc.
 
$obj = new AmazonProductAPI($public_key, $private_key, $region);
 
print_r($obj->getParentNode("14210821"));
 
?>

One other useful method you can use it ‘getNodeName’. This allows you to get the name of a given node id. This can be useful if you have a nodeid but need to gets it name.


 
/* Example usage of the Amazon Product Advertising API */
include("amazon_api_class.php");
 
$public_key     = "YOUR-AMAZON-PUBLIC-KEY";
$private_key    = "YOUR-AMAZON-SECRET-KEY";
$region         = "com"; // or "CA" or "DE" etc.
 
$obj = new AmazonProductAPI($public_key, $private_key, $region);
 
echo $obj->getNodeName("14210821");
 
?>

Note: Some categories contain hundreds to thousands of BrowserNodes, retreiving them can take some time and could trigger a PHP timeout error. To avoid this set PHP timeout to a large number as given below.


 
set_time_limit(10000); 
 
/* Example usage of the Amazon Product Advertising API */
include("amazon_api_class.php");
.
.
?>

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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;
    }
}
?>

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