Amazon Product API with PHP - php

Question

I'm trying to integrate Amazon Product API into my website and came across several posts that helped me construct the URL. Only problem is when I execute the code below I get the following error. Am I doing something wrong?
Internal Server Error The server
encountered an internal error or
misconfiguration and was unable to
complete your request. Please contact
the server administrator,
awsadmin#amazon.com and inform them of
the time the error occurred, and
anything you might have done that may
have caused the error. More
information about this error may be
available in the server error log.
$AWS_ACCESS_KEY_ID = "[myaccesskeyhere]";
$AWS_SECRET_ACCESS_KEY = "[mysecretkeyhere]";
$base_url = "http://ecs.amazonaws.com/onca/xml?";
$url_params = array('Operation'=>"ItemSearch",'Service'=>"AWSECommerceService",
'AWSAccessKeyId'=>$AWS_ACCESS_KEY_ID,'AssociateTag'=>"yourtag-10",
'Version'=>"2006-09-11",'Availability'=>"Available",'Condition'=>"All",
'ItemPage'=>"1",'ResponseGroup'=>"Images,ItemAttributes,EditorialReview",
'Keywords'=>"Amazon");
// Add the Timestamp
$url_params['Timestamp'] = gmdate("Y-m-d\TH:i:s.\\0\\0\\0\\Z", time());
// Sort the URL parameters
$url_parts = array();
foreach(array_keys($url_params) as $key)
$url_parts[] = $key."=".$url_params[$key];
sort($url_parts);
// Construct the string to sign
$string_to_sign = "GET\necs.amazonaws.com\n/onca/xml\n".implode("&",$url_parts);
$string_to_sign = str_replace('+','%20',$string_to_sign);
$string_to_sign = str_replace(':','%3A',$string_to_sign);
$string_to_sign = str_replace(';',urlencode(';'),$string_to_sign);
// Sign the request
$signature = hash_hmac("sha256",$string_to_sign,$AWS_SECRET_ACCESS_KEY,TRUE);
// Base64 encode the signature and make it URL safe
$signature = base64_encode($signature);
$signature = str_replace('+','%2B',$signature);
$signature = str_replace('=','%3D',$signature);
$url_string = implode("&",$url_parts);
$url = $base_url.$url_string."&Signature=".$signature;
print $url;
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_TIMEOUT, 15);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
$xml_response = curl_exec($ch);
echo $xml_response;
EDIT
THE ABOVE CODE NOW WORKS...I WAS MISSING A "?" after the BASE URL

Answer 1

$AWS_ACCESS_KEY_ID = "[myaccesskeyhere]";
$AWS_SECRET_ACCESS_KEY = "[mysecretkeyhere]";
$base_url = "http://ecs.amazonaws.com/onca/xml?";
$url_params = array('Operation'=>"ItemSearch",'Service'=>"AWSECommerceService",
'AWSAccessKeyId'=>$AWS_ACCESS_KEY_ID,'AssociateTag'=>"yourtag-10",
'Version'=>"2006-09-11",'Availability'=>"Available",'Condition'=>"All",
'ItemPage'=>"1",'ResponseGroup'=>"Images,ItemAttributes,EditorialReview",
'Keywords'=>"Amazon");
// Add the Timestamp
$url_params['Timestamp'] = gmdate("Y-m-d\TH:i:s.\\0\\0\\0\\Z", time());
// Sort the URL parameters
$url_parts = array();
foreach(array_keys($url_params) as $key)
$url_parts[] = $key."=".$url_params[$key];
sort($url_parts);
// Construct the string to sign
$string_to_sign = "GET\necs.amazonaws.com\n/onca/xml\n".implode("&",$url_parts);
$string_to_sign = str_replace('+','%20',$string_to_sign);
$string_to_sign = str_replace(':','%3A',$string_to_sign);
$string_to_sign = str_replace(';',urlencode(';'),$string_to_sign);
// Sign the request
$signature = hash_hmac("sha256",$string_to_sign,$AWS_SECRET_ACCESS_KEY,TRUE);
// Base64 encode the signature and make it URL safe
$signature = base64_encode($signature);
$signature = str_replace('+','%2B',$signature);
$signature = str_replace('=','%3D',$signature);
$url_string = implode("&",$url_parts);
$url = $base_url.$url_string."&Signature=".$signature;
print $url;
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_TIMEOUT, 15);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
$xml_response = curl_exec($ch);
echo $xml_response;
For anyone that was wondering. You can then navigate the xml_response using simplexml!
Hope this helps someone out there :)

Answer 2

Use Bellow code for the Amazon Product API:
<?php
//Enter your IDs
define("Access_Key_ID", "[Your Access Key ID]");
define("Associate_tag", "[Your Associate Tag ID]");
//Set up the operation in the request
function ItemSearch($SearchIndex, $Keywords){
//Set the values for some of the parameters
$Operation = "ItemSearch";
$Version = "2013-08-01";
$ResponseGroup = "ItemAttributes,Offers";
//User interface provides values
//for $SearchIndex and $Keywords
//Define the request
$request=
"http://webservices.amazon.com/onca/xml"
. "?Service=AWSECommerceService"
. "&AssociateTag=" . Associate_tag
. "&AWSAccessKeyId=" . Access_Key_ID
. "&Operation=" . $Operation
. "&Version=" . $Version
. "&SearchIndex=" . $SearchIndex
. "&Keywords=" . $Keywords
. "&Signature=" . [Request Signature]
. "&ResponseGroup=" . $ResponseGroup;
//Catch the response in the $response object
$response = file_get_contents($request);
$parsed_xml = simplexml_load_string($response);
printSearchResults($parsed_xml, $SearchIndex);
}
?>