Cannot retrieve results from amazon mws products api

Question

Using the below code, the only result I can get to echo is the URL. When I copy and paste into browser, I get:

<Message>

The request signature we calculated does not match the signature you provided. Check your AWS Secret Access Key and signing method. Consult the service documentation for details.

Code Being Used;

<?php
date_default_timezone_set('America/New_York');
define('AWS_ACCESS_KEY_ID', '***');
define('AWS_SECRET_ACCESS_KEY', '***');
define('APPLICATION_NAME', 'test');
define('APPLICATION_VERSION', '1.0');
define ('MERCHANT_ID', '***');
define ('MARKETPLACE_ID', '***');

$base_url = "https://mws.amazonservices.com/Products/2011-10-01";
$method = "GET";
$host = "mws.amazonservices.com";
$uri = "/Products/2011-10-01";

function amazon_xml($searchTerm) {

$params = array(
    'AWSAccessKeyId' => AWS_ACCESS_KEY_ID,
    'Action' => "GetCompetitivePricingForASIN",
    'SellerId' => MERCHANT_ID,
    'SignatureMethod' => "HmacSHA256",
    'SignatureVersion' => "2",
    'Timestamp'=> gmdate("Y-m-d\TH:i:s.\\0\\0\\0\\Z", time()),
    'Version'=> "2011-10-01",
    'MarketplaceId' => MARKETPLACE_ID,
    'Query' => $searchTerm,
    'QueryContextId' => "Automotive");

// Sort the URL parameters
$url_parts = array();
foreach(array_keys($params) as $key)
$url_parts[] = $key . "=" . str_replace('%7E', '~', rawurlencode($params[$key]));
sort($url_parts);

// Construct the string to sign
$url_string = implode("&", $url_parts);
$string_to_sign = "GET\nmws.amazonservices.com\n/Products/2011-10-01\n" . $url_string;

// Sign the request
$signature = hash_hmac("sha256", $string_to_sign, AWS_SECRET_ACCESS_KEY, TRUE);

// Base64 encode the signature and make it URL safe
$signature = urlencode(base64_encode($signature));

$url = "https://mws.amazonservices.com/Products/2011-10-01" . '?' . $url_string .           "&Signature=" . $signature;


$ch = curl_init();
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_URL,$url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
$response = curl_exec($ch);

echo $url;
// return $xml if you still want to parse the data elsewhere
$xml = simplexml_load_string($response);

// return this if you just want the raw XML string
return $xml->asXML();
echo $xml->GetMatchingProductResult->Product->Identifiers->MarketplaceASIN->ASIN;
}

$searchTerm = "B00FNNLBK2";

amazon_xml($searchTerm);



//foreach ($xml->GetMatchingProductResult->Product as $product) {
// do something for each <Product>, such as output the ASIN...

//}



echo $xml;
echo $searchTerm;
echo $xml->GetMatchingProductResult->Product->Identifiers->MarketplaceASIN->ASIN;
echo $url;
?>

I did verify multiple times that the sign in credentials are correct, with no absract leading or trailing space.

Josh Brown · Accepted Answer · 2014-06-29T22:37:07.470

Those parameters (e.g. Query and QueryContextId) don't match with the Action you are trying to call (GetCompetitivePricingForASIN). They correspond to the ListMatchingProducts action.

Assuming that you meant ListMatchingProducts try this:

<?php
date_default_timezone_set('America/New_York');
define('AWS_ACCESS_KEY_ID', '***');
define('AWS_SECRET_ACCESS_KEY', '***');
define('APPLICATION_NAME', 'test');
define('APPLICATION_VERSION', '1.0');
define ('MERCHANT_ID', '***');
define ('MARKETPLACE_ID', '***');
function amazon_xml($searchTerm)
{

    $params = array(
        'AWSAccessKeyId' => AWS_ACCESS_KEY_ID,
        'Action' => "ListMatchingProducts",
        'SellerId' => MERCHANT_ID,
        'SignatureMethod' => "HmacSHA256",
        'SignatureVersion' => "2",
        'Timestamp' => gmdate("Y-m-d\TH:i:s.\\0\\0\\0\\Z", time()),
        'Version' => "2011-10-01",
        'MarketplaceId' => MARKETPLACE_ID,
        'Query' => $searchTerm,
        'QueryContextId' => "Automotive"
    );
    $url_parts = array();
    foreach (array_keys($params) as $key)
        $url_parts[] = $key . "=" . str_replace('%7E', '~', rawurlencode($params[$key]));
    sort($url_parts);
    $url_string     = implode("&", $url_parts);
    $string_to_sign = "GET\nmws.amazonservices.com\n/Products/2011-10-01\n" . $url_string;
    $signature = hash_hmac("sha256", $string_to_sign, AWS_SECRET_ACCESS_KEY, TRUE);
    $signature = urlencode(base64_encode($signature));
    $url = "https://mws.amazonservices.com/Products/2011-10-01" . '?' . $url_string . "&Signature=" . $signature;
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
    $response = curl_exec($ch);
    $xml      = simplexml_load_string($response);
    return $xml->asXML();
}
$searchTerm = "B00FNNLBK2";
echo amazon_xml($searchTerm);

You can find the relevant parameters for each Action in the MWS documentation e.g. here: http://docs.developer.amazonservices.com/en_US/products/Products_GetCompetitivePricingForASIN.html

You can also see them using the MWS Scratchpad: https://mws.amazonservices.com/scratchpad/index.html

Works perfect! Thanks. Any idea where I would find the correct parameters for the other Actions? — cardog19973, Jun 27 '14 at 17:42
Easiest place is the Scratchpad: https://mws.amazonservices.com/scratchpad/index.html but it's also in the documentation e.g. here: http://docs.developer.amazonservices.com/en_US/products/Products_GetCompetitivePricingForASIN.html — Josh Brown, Jun 29 '14 at 22:37

Cannot retrieve results from amazon mws products api

1 Answers1