Amazon Product Advertising APIを使って、キーワードで商品検索して、「アマゾン商品の検索結果」を取得する

<?php

namespace goodsmemo\amazon\withoutsdk;

use goodsmemo\amazon\withoutsdk\SearchItemsRequest;
use goodsmemo\amazon\withoutsdk\AwsV4;
use goodsmemo\exception\HttpRequestException;

require_once GOODS_MEMO_DIR . "amazon/withoutsdk/SearchItemsRequest.php";
require_once GOODS_MEMO_DIR . "amazon/withoutsdk/AwsV4.php";
require_once GOODS_MEMO_DIR . "exception/HttpRequestException.php";

class SearchIndexRequest {

	public static function request(string $partnerTag, string $keyword, string $searchIndex, $resources,
			string $hostname, string $accessKey, string $secretKey, string $regionName) {

		$searchItemRequest = new SearchItemsRequest ();
		$searchItemRequest->PartnerType = "Associates";
		// Put your Partner tag (Store/Tracking id) in place of Partner tag
		$searchItemRequest->PartnerTag = $partnerTag;
		$searchItemRequest->Keywords = $keyword;
		$searchItemRequest->SearchIndex = $searchIndex;
		$searchItemRequest->Resources = $resources;
		$host = $hostname;
		$path = "/paapi5/searchitems";
		$payload = json_encode ( $searchItemRequest );

		// Put your Access Key in place of <ACCESS_KEY> and Secret Key in place of <SECRET_KEY> in double quotes
		$awsv4 = new AwsV4 ( $accessKey, $secretKey );
		$awsv4->setRegionName ( $regionName );
		$awsv4->setServiceName ( "ProductAdvertisingAPI" );
		$awsv4->setPath ( $path );
		$awsv4->setPayload ( $payload );
		$awsv4->setRequestMethod ( "POST" );
		$awsv4->addHeader ( 'content-encoding', 'amz-1.0' );
		$awsv4->addHeader ( 'content-type', 'application/json; charset=utf-8' );
		$awsv4->addHeader ( 'host', $host );
		$awsv4->addHeader ( 'x-amz-target', 'com.amazon.paapi5.v1.ProductAdvertisingAPIv1.SearchItems' );
		$headers = $awsv4->getHeaders ();
		$headerString = "";
		foreach ( $headers as $key => $value ) {
			$headerString .= $key . ': ' . $value . "\r\n";
		}
		$params = array (
				'http' => array (
						'header' => $headerString,
						'method' => 'POST',
						'content' => $payload
				)
		);
		$stream = stream_context_create ( $params );

		$fp = @fopen ( 'https://' . $host . $path, 'rb', false, $stream );

		if (! $fp) {
			$errorMessage = "fopen Exception Occured.";

			$httpStatus;
			if (isset ( $http_response_header )) { // $http_response_header変数は、fopen実行後、PHPが自動的に設定する。
				$httpStatus = $http_response_header [0];
			} else {
				// URLが存在しない場合、変数は未定義らしい。未定義なら、HTTP Status 404 と判断して良さそう。
				$httpStatus = "Variable http_response_header is undefined.";
			}

			$errorMessage .= "http status:" . $httpStatus;
			throw new HttpRequestException ( $errorMessage );
		}

		$responseJSON = @stream_get_contents ( $fp );
		if ($responseJSON === false) {
			throw new HttpRequestException ( "stream_get_contents Exception Occured" );
		}

		$responseObject = json_decode ( $responseJSON );
		if (is_null ( $responseObject )) {
			return NULL;
		}

		if (property_exists ( $responseObject, 'Errors' )) { // $responseObject内にerrorが含まれる場合

			// 検索結果0件の場合、ここに来る。正常処理なので、throw new HttpRequestException()しなくて良い。
			// $errorCodeText: string型。例："NoResults"という文字列が取得された。
			$errorCodeText = $responseObject->{'Errors'} [0]->{'Code'};
			$errorMessage = $responseObject->{'Errors'} [0]->{'Message'};

			// 検索結果0件以外の場合、Eclipseのデバッグでエラー内容を確認すること。
			$responseObject = NULL; // エラー情報を削除した

			// $errorCode=0;
			// throw new HttpRequestException ( $errorMessage, $errorCode );
		}

		return $responseObject;
	}
}

public static function request(string $partnerTag, string $keyword, string $searchIndex, $resources,
		string $hostname, string $accessKey, string $secretKey, string $regionName) {

	$searchItemRequest = new SearchItemsRequest ();
	$searchItemRequest->PartnerType = "Associates";
	// Put your Partner tag (Store/Tracking id) in place of Partner tag
	$searchItemRequest->PartnerTag = $partnerTag;
	$searchItemRequest->Keywords = $keyword;
	$searchItemRequest->SearchIndex = $searchIndex;
	$searchItemRequest->Resources = $resources;

中略

	$payload = json_encode ( $searchItemRequest );

以下省略

$payload = json_encode ( $searchItemRequest );

$payload = json_encode ( $searchItemRequest );

//SearchItemsRequestクラスの宣言
class SearchItemsRequest {
	public $PartnerType;
	public $PartnerTag;
	public $Keywords;
	public $SearchIndex;
	public $Resources;
}

//$searchItemRequest変数の例

$searchItemRequest->PartnerTypeの値。
Associates

$searchItemRequest->PartnerTagの値。
sample-22
仮の値です。

$searchItemRequest->Keywordsの値。
PHPプログラミング
当プラグインのショートコードのkeyword属性に、設定した文字列です。

$searchItemRequest->SearchIndexの値。
All

$searchItemRequest->Resourcesの値。
Arrayの配列
[
[0] => Images.Primary.Large, 
[1] => Images.Primary.Medium, 
[2] => Images.Primary.Small, 
[3] => ItemInfo.ByLineInfo, 
[4] => ItemInfo.Classifications, 
[5] => ItemInfo.Features, 
[6] => ItemInfo.ProductInfo, 
[7] => ItemInfo.Title, 
[8] => Offers.Listings.MerchantInfo, 
[9] => Offers.Listings.Price, 
[10] => Offers.Summaries.LowestPrice
]

{
"PartnerType":"Associates",
"PartnerTag":"sample-22",
"Keywords":"PHP\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0",
"SearchIndex":"All",
"Resources":[
"Images.Primary.Large",
"Images.Primary.Medium",
"Images.Primary.Small",
"ItemInfo.ByLineInfo",
"ItemInfo.Classifications",
"ItemInfo.Features",
"ItemInfo.ProductInfo",
"ItemInfo.Title",
"Offers.Listings.MerchantInfo",
"Offers.Listings.Price",
"Offers.Summaries.LowestPrice"]
}

$awsv4 = new AwsV4 ( $accessKey, $secretKey );
$awsv4->setRegionName ( $regionName );
$awsv4->setServiceName ( "ProductAdvertisingAPI" );
$awsv4->setPath ( $path );
$awsv4->setPayload ( $payload );
$awsv4->setRequestMethod ( "POST" );
$awsv4->addHeader ( 'content-encoding', 'amz-1.0' );
$awsv4->addHeader ( 'content-type', 'application/json; charset=utf-8' );
$awsv4->addHeader ( 'host', $host );
$awsv4->addHeader ( 'x-amz-target', 'com.amazon.paapi5.v1.ProductAdvertisingAPIv1.SearchItems' );

//AwsV4クラスの宣言
class AwsV4 {
	private $accessKey = null;
	private $secretKey = null;
	private $path = null;
	private $regionName = null;
	private $serviceName = null;
	private $httpMethodName = null;
	private $queryParametes = array ();
	private $awsHeaders = array ();
	private $payload = "";
	private $HMACAlgorithm = "AWS4-HMAC-SHA256";
	private $aws4Request = "aws4_request";
	private $strSignedHeader = null;
	private $xAmzDate = null;
	private $currentDate = null;

	public function __construct($accessKey, $secretKey) {

		$this->accessKey = $accessKey;
		$this->secretKey = $secretKey;
		$this->xAmzDate = $this->getTimeStamp ();
		$this->currentDate = $this->getDate ();
	}

中略

}

//$awsv4変数の例

$awsv4->accessKeyの値。
SAMPLEUIQALSAKLXXXXX
仮の値

$awsv4->secretKeyの値。
SAMPLEvQnr/XvMjvFxuB4301YuF2WGRXXXXX
仮の値

$awsv4->pathの値。
/paapi5/searchitems

$awsv4->regionNameの値。
us-west-2

$awsv4->serviceNameの値。
ProductAdvertisingAPI

$awsv4->httpMethodNameの値。
POST

$awsv4->queryParametesの値。
[]

$awsv4->awsHeadersの値。
[
[content-encoding] => amz-1.0, 
[content-type] => application/json; charset=utf-8, 
[host] => webservices.amazon.co.jp, 
[x-amz-date] => 20230320T051703Z, 
[x-amz-target] => com.amazon.paapi5.v1.ProductAdvertisingAPIv1.SearchItems, 
[Authorization] => 
AWS4-HMAC-SHA256
Credential=SAMPLEUIQALSAKLXXXXX/20230320/us-west-2/ProductAdvertisingAPI/aws4_request,
SignedHeaders=content-encoding;content-type;host;x-amz-date;x-amz-target,
Signature=SAMPLE8ffbfec91ec8cae4d5da6f5beb58316a9be6ec632f6beefe93f8fXXXXX
]

$awsv4->payloadの値。
{
"PartnerType":"Associates",
"PartnerTag":"sample-22",
"Keywords":"PHP\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0",
"SearchIndex":"All",
"Resources":[
"Images.Primary.Large",
"Images.Primary.Medium",
"Images.Primary.Small",
"ItemInfo.ByLineInfo",
"ItemInfo.Classifications",
"ItemInfo.Features",
"ItemInfo.ProductInfo",
"ItemInfo.Title",
"Offers.Listings.MerchantInfo",
"Offers.Listings.Price",
"Offers.Summaries.LowestPrice"]
}

$awsv4->HMACAlgorithmの値。
AWS4-HMAC-SHA256

$awsv4->aws4Requestの値。
aws4_request

$awsv4->strSignedHeaderの値。
content-encoding;content-type;host;x-amz-date;x-amz-target

$awsv4->xAmzDateの値。
20230320T051703Z
日時の例

$awsv4->currentDateの値。
20230320
日付の例

Credential=SAMPLEUIQALSAKLXXXXX/20230320/us-west-2/ProductAdvertisingAPI/aws4_request

$headers = $awsv4->getHeaders ();
$headerString = "";
foreach ( $headers as $key => $value ) {
	$headerString .= $key . ': ' . $value . "\r\n";
}

[
[content-encoding] => amz-1.0, 
[content-type] => application/json; charset=utf-8, 
[host] => webservices.amazon.co.jp, 
[x-amz-date] => 20230320T051703Z, 
[x-amz-target] => com.amazon.paapi5.v1.ProductAdvertisingAPIv1.SearchItems, 
[Authorization] => 
AWS4-HMAC-SHA256 
Credential=SAMPLEUIQALSAKLXXXXX/20230320/us-west-2/ProductAdvertisingAPI/aws4_request,
SignedHeaders=content-encoding;content-type;host;x-amz-date;x-amz-target,
Signature=SAMPLE8ffbfec91ec8cae4d5da6f5beb58316a9be6ec632f6beefe93f8fXXXXX
]

content-encoding: amz-1.0
content-type: application/json; charset=utf-8
host: webservices.amazon.co.jp
x-amz-date: 20230320T051703Z
x-amz-target: com.amazon.paapi5.v1.ProductAdvertisingAPIv1.SearchItems
Authorization: AWS4-HMAC-SHA256 Credential=SAMPLEUIQALSAKLXXXXX/20230320/us-west-2/ProductAdvertisingAPI/aws4_request,SignedHeaders=content-encoding;content-type;host;x-amz-date;x-amz-target,Signature=SAMPLE8ffbfec91ec8cae4d5da6f5beb58316a9be6ec632f6beefe93f8fXXXXX

$params = array (
		'http' => array (
				'header' => $headerString,
				'method' => 'POST',
				'content' => $payload
		)
);
$stream = stream_context_create ( $params );

$fp = @fopen ( 'https://' . $host . $path, 'rb', false, $stream );

//$hostの値
//webservices.amazon.co.jp

//$pathの値
// /paapi5/searchitems

[
[http] => 
  [
    [header] => content-encoding: amz-1.0
    content-type: application/json; charset=utf-8
    host: webservices.amazon.co.jp
    x-amz-date: 20230320T051703Z
    x-amz-target: com.amazon.paapi5.v1.ProductAdvertisingAPIv1.SearchItems
    Authorization: AWS4-HMAC-SHA256 Credential=SAMPLEUIQALSAKLXXXXX/20230320/us-west-2/ProductAdvertisingAPI/aws4_request,
    SignedHeaders=content-encoding;content-type;host;x-amz-date;x-amz-target,
    Signature=SAMPLE8ffbfec91ec8cae4d5da6f5beb58316a9be6ec632f6beefe93f8fXXXXX, 
    [method] => POST, 
    [content] => 
      {
      "PartnerType":"Associates",
      "PartnerTag":"sample-22",
      "Keywords":"PHP\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0",
      "SearchIndex":"All",
      "Resources":
        [
        "Images.Primary.Large",
        "Images.Primary.Medium",
        "Images.Primary.Small",
        "ItemInfo.ByLineInfo",
        "ItemInfo.Classifications",
        "ItemInfo.Features",
        "ItemInfo.ProductInfo",
        "ItemInfo.Title",
        "Offers.Listings.MerchantInfo",
        "Offers.Listings.Price",
        "Offers.Summaries.LowestPrice"
        ]
      }
  ]
]

resource id='598' type='stream-context'

$fp = @fopen ( 'https://' . $host . $path, 'rb', false, $stream );

//$hostの値
//webservices.amazon.co.jp

//$pathの値
// /paapi5/searchitems

$fp = @fopen ( 'https://' . $host . $path, 'rb', false, $stream );

//$hostの値
//webservices.amazon.co.jp

//$pathの値
// /paapi5/searchitems

$responseJSON = @stream_get_contents ( $fp );
if ($responseJSON === false) {
	throw new HttpRequestException ( "stream_get_contents Exception Occured" );
}

$responseObject = json_decode ( $responseJSON );
if (is_null ( $responseObject )) {
	return NULL;
}

{
"SearchResult":
{
"Items":
[
{
"ASIN":"XXXX000001",
"DetailPageURL":"https://www.amazon.co.jp/dp/4873116686?tag=sample-22&linkCode=osi&th=1&psc=1",
"Images":
{
"Primary":
{
"Large":
{
"Height":500,
"URL":"https://m.media-amazon.com/images/I/XXXXSSmCnjL._SL500_.jpg",
"Width":391
},
"Medium":
{
"Height":160,
"URL":"https://m.media-amazon.com/images/I/XXXXSSmCnjL._SL160_.jpg",
"Width":125
},
"Small":
{
"Height":75,
"URL":"https://m.media-amazon.com/images/I/XXXXSSmCnjL._SL75_.jpg",
"Width":58
}
}
},
"ItemInfo":
{
"ByLineInfo":
{
"Contributors":
[
{
"Locale":"ja_JP",
"Name":"Kevin XXXX",
"Role":"著",
"RoleType":"author"
},
{
"Locale":"ja_JP",
"Name":"Peter XXXX",
"Role":"著",
"RoleType":"author"
},
{
"Locale":"ja_JP",
"Name":"Rasmus XXXX",
"Role":"著",
"RoleType":"author"
},
{
"Locale":"ja_JP",
"Name":"高木 XXXX",
"Role":"翻訳",
"RoleType":"translator"
}
],
"Manufacturer":
{
"DisplayValue":"XXXXジャパン",
"Label":"Manufacturer",
"Locale":"ja_JP"
}
},
"Classifications":
{
"Binding":
{
"DisplayValue":"大型本",
"Label":"Binding",
"Locale":"ja_JP"
},
"ProductGroup":
{
"DisplayValue":"本",
"Label":"ProductGroup",
"Locale":"ja_JP"
}
},
"ProductInfo":
{
"IsAdultProduct":
{
"DisplayValue":false,
"Label":"IsAdultProduct",
"Locale":"en_US"
},
"ItemDimensions":
{
"Height":
{
"DisplayValue":9.448818888,
"Label":"Height",
"Locale":"ja_JP",
"Unit":"インチ"
},
"Length":
{
"DisplayValue":1.574803148,
"Label":"Length",
"Locale":"ja_JP",
"Unit":"インチ"
},
"Weight":
{
"DisplayValue":1.322773572,
"Label":"Weight",
"Locale":"ja_JP",
"Unit":"ポンド"
},
"Width":
{
"DisplayValue":7.480314953,
"Label":"Width",
"Locale":"ja_JP",
"Unit":"インチ"
}
},
"UnitCount":
{
"DisplayValue":1,
"Label":"NumberOfItems",
"Locale":"en_US"
}
},
"Title":
{
"DisplayValue":"プログラミングPHP",
"Label":"Title",
"Locale":"ja_JP"
}
},
"Offers":
{
"Listings":
[
{
"Id":"XXXXuqZV9p%2F9pThe3wpI3Fjh2M8oyA4O1gf5jmywp2AigraEoBosy%2B9UXq31F6Xjpgb2EgfNU9zKiaF%2Bw6VX2ctWetmRXxRdVs8hTELGa8iJBqm%2FTizDYbJueUUaGTkmWesG%2BH%2FF72w%3D",
"MerchantInfo":
{
"FeedbackCount":0,
"FeedbackRating":0.0,
"Id":"AN1VRQENFRJN5",
"Name":"Amazon.co.jp"
},
"Price":
{
"Amount":4180.0,
"Currency":"JPY",
"DisplayAmount":"￥4,180"
},
"ViolatesMAP":false
}
],
"Summaries":
[
{
"Condition":
{
"Value":"Collectible"
},
"LowestPrice":
{
"Amount":8350.0,
"Currency":"JPY",
"DisplayAmount":"￥8,350"
}
},
{
"Condition":
{
"Value":"New"
},
"LowestPrice":
{
"Amount":4180.0,
"Currency":"JPY",
"DisplayAmount":"￥4,180"
}
},
{
"Condition":
{
"Value":"Used"
},
"LowestPrice":
{
"Amount":1066.0,
"Currency":"JPY",
"DisplayAmount":"￥1,066"
}
}
]
}
},

{
"ASIN":"XXXX000002",

中略

},

中略

],
"SearchURL":"https://www.amazon.co.jp/s?k=PHP%E3%83%97%E3%83%AD%E3%82%B0%E3%83%A9%E3%83%9F%E3%83%B3%E3%82%B0&rh=p_n_availability%3A-1&tag=sample-22&linkCode=osi",
"TotalResultCount":462
}
}

stdClass Object 
( 
[SearchResult] => stdClass Object 
( 
[Items] => Array 
( 
[0] => stdClass Object 
(
[ASIN] => XXXX000001
[DetailPageURL] => https://www.amazon.co.jp/dp/4873116686?tag=sample-22&linkCode=osi&th=1&psc=1
[Images] => stdClass Object 
( 
[Primary] => stdClass Object 
( 
[Large] => stdClass Object 
( 
[Height] => 500 
[URL] => https://m.media-amazon.com/images/I/XXXXSSmCnjL._SL500_.jpg 
[Width] => 391 
) 
[Medium] => stdClass Object 
( 
[Height] => 160 
[URL] => https://m.media-amazon.com/images/I/XXXXSSmCnjL._SL160_.jpg 
[Width] => 125 
) 
[Small] => stdClass Object 
( 
[Height] => 75 
[URL] => https://m.media-amazon.com/images/I/XXXXSSmCnjL._SL75_.jpg 
[Width] => 58
)
)
)
[ItemInfo] => stdClass Object 
( 
[ByLineInfo] => stdClass Object 
( 
[Contributors] => Array 
( 
[0] => stdClass Object 
( 
[Locale] => ja_JP 
[Name] => Kevin XXXX 
[Role] => 著 
[RoleType] => author 
) 
[1] => stdClass Object 
( 
[Locale] => ja_JP 
[Name] => Peter XXXX 
[Role] => 著 
[RoleType] => author 
) 
[2] => stdClass Object 
( 
[Locale] => ja_JP 
[Name] => Rasmus XXXX 
[Role] => 著 
[RoleType] => author 
) 
[3] => stdClass Object 
( 
[Locale] => ja_JP 
[Name] => 高木 XXXX 
[Role] => 翻訳 
[RoleType] => translator 
) 
) 
[Manufacturer] => stdClass Object 
( 
[DisplayValue] => XXXXジャパン 
[Label] => Manufacturer 
[Locale] => ja_JP 
) 
) 
[Classifications] => stdClass Object 
( 
[Binding] => stdClass Object 
( 
[DisplayValue] => 大型本 
[Label] => Binding 
[Locale] => ja_JP 
) 
[ProductGroup] => stdClass Object 
( 
[DisplayValue] => 本 
[Label] => ProductGroup 
[Locale] => ja_JP 
) 
) 
[ProductInfo] => stdClass Object 
( 
[IsAdultProduct] => stdClass Object 
( 
[DisplayValue] => false
[Label] => IsAdultProduct 
[Locale] => en_US 
) 
[ItemDimensions] => stdClass Object 
( 
[Height] => stdClass Object 
( 
[DisplayValue] => 9.448818888 
[Label] => Height 
[Locale] => ja_JP 
[Unit] => インチ 
) 
[Length] => stdClass Object 
( 
[DisplayValue] => 1.574803148 
[Label] => Length 
[Locale] => ja_JP 
[Unit] => インチ 
) 
[Weight] => stdClass Object 
( 
[DisplayValue] => 1.322773572 
[Label] => Weight 
[Locale] => ja_JP 
[Unit] => ポンド 
) 
[Width] => stdClass Object 
( 
[DisplayValue] => 7.480314953 
[Label] => Width 
[Locale] => ja_JP 
[Unit] => インチ 
) 
) 
[UnitCount] => stdClass Object 
( 
[DisplayValue] => 1 
[Label] => NumberOfItems 
[Locale] => en_US 
) 
) 
[Title] => stdClass Object 
( 
[DisplayValue] => プログラミングPHP 
[Label] => Title 
[Locale] => ja_JP 
) 
) 
[Offers] => stdClass Object 
( 
[Listings] => Array 
( 
[0] => stdClass Object 
( 
[Id] => XXXXuqZV9p%2F9pThe3wpI3Fjh2M8oyA4O1gf5jmywp2AigraEoBosy%2B9UXq31F6Xjpgb2EgfNU9zKiaF%2Bw6VX2ctWetmRXxRdVs8hTELGa8iJBqm%2FTizDYbJueUUaGTkmWesG%2BH%2FF72w%3D 
[MerchantInfo] => stdClass Object 
( 
[FeedbackCount] => 0 
[FeedbackRating] => 0 
[Id] => AN1VRQENFRJN5 
[Name] => Amazon.co.jp 
) 
[Price] => stdClass Object 
( 
[Amount] => 4180 
[Currency] => JPY 
[DisplayAmount] => ￥4,180 
) 
[ViolatesMAP] => 
) 
) 

[Summaries] => Array 
( 
[0] => stdClass Object 
( 
[Condition] => stdClass Object 
( 
[Value] => Collectible 
) 
[LowestPrice] => stdClass Object 
( 
[Amount] => 8350 
[Currency] => JPY 
[DisplayAmount] => ￥8,350 
) 
) 
[1] => stdClass Object 
( 
[Condition] => stdClass Object 
( 
[Value] => New 
) 
[LowestPrice] => stdClass Object 
( 
[Amount] => 4180 
[Currency] => JPY 
[DisplayAmount] => ￥4,180 
) 
) 
[2] => stdClass Object 
( 
[Condition] => stdClass Object 
( 
[Value] => Used 
) 
[LowestPrice] => stdClass Object 
( 
[Amount] => 1066 
[Currency] => JPY 
[DisplayAmount] => ￥1,066 
) 
) 
) 
) 
) 

[1] => stdClass Object 
(
[ASIN] => XXXX000002

中略

)

中略

[SearchURL] => https://www.amazon.co.jp/s?k=PHP%E3%83%97%E3%83%AD%E3%82%B0%E3%83%A9%E3%83%9F%E3%83%B3%E3%82%B0&rh=p_n_availability%3A-1&tag=sample-22&linkCode=osi 
[TotalResultCount] => 462 
) 
)

$fp = @fopen ( 'https://' . $host . $path, 'rb', false, $stream );

if (! $fp) {
	$errorMessage = "fopen Exception Occured.";

	$httpStatus;
	if (isset ( $http_response_header )) { // $http_response_header変数は、fopen実行後、PHPが自動的に設定する。
		$httpStatus = $http_response_header [0];
	} else {
		// URLが存在しない場合、変数は未定義らしい。未定義なら、HTTP Status 404 と判断して良さそう。
		$httpStatus = "Variable http_response_header is undefined.";
	}

	$errorMessage .= "http status:" . $httpStatus;
	throw new HttpRequestException ( $errorMessage );
}

if (isset ( $http_response_header ))

[
[0] => HTTP/1.1 401 Unauthorized, 
[1] => Server: Server, 
[2] => Date: Wed, 22 Mar 2023 08:19:52 GMT, 
[3] => Content-Type: application/json, 
[4] => Content-Length: 183, 
[5] => Connection: close, 
[6] => x-amz-rid: HS7X0X57W359CFGHNBJ4, 
[7] => x-amzn-RequestId: 7a61c4d7-abc8-470f-b055-8b91b9c17d30, 
[8] => Vary: Content-Type,Accept-Encoding,User-Agent, 
[9] => Strict-Transport-Security: max-age=47474747; includeSubDomains; preload
]

$httpStatus = $http_response_header [0];

$httpStatus = "Variable http_response_header is undefined.";

$errorMessage .= "http status:" . $httpStatus;
throw new HttpRequestException ( $errorMessage );

if (property_exists ( $responseObject, 'Errors' )) { // $jsonResponse内にerrorが含まれる場合

	// 検索結果0件の場合、ここに来る。正常処理なので、throw new HttpRequestException()しなくて良い。
	// $errorCodeText: string型。例："NoResults"という文字列が取得された。
	$errorCodeText = $responseObject->{'Errors'} [0]->{'Code'};
	$errorMessage = $responseObject->{'Errors'} [0]->{'Message'};

	// 検索結果0件以外の場合、Eclipseのデバッグでエラー内容を確認すること。
	$responseObject = NULL; // エラー情報を削除した

	// $errorCode=0;
	// throw new HttpRequestException ( $errorMessage, $errorCode );
}

return $responseObject;

stdClass Object (
[Errors] => Array (
[0] => stdClass Object 
  (
  [__type] => com.amazon.paapi5#ErrorData 
  [Code] => NoResults 
  [Message] => No results found for your request. 
  ) 
) 
)

$responseObject = NULL;

return $responseObject;