Amazon.php

<?php
/**
 * @see       https://github.com/zendframework/ZendService_Amazon for the canonical source repository
 * @copyright Copyright (c) 2005-2017 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   https://github.com/zendframework/ZendService_Amazon/blob/master/LICENSE.md New BSD License
 */

namespace ZendService\Amazon;

use DOMDocument;
use DOMXPath;
use Zend\Crypt\Hmac;
use ZendRest\Client\RestClient;

/**
 * @category   Zend
 * @package    Zend_Service
 * @subpackage Amazon
 */
class Amazon
{
    /**
     * Amazon Web Services Access Key ID
     *
     * @var string
     */
    public $appId;

    /**
     * API Version
     *
     * @var string
     */
    protected static $version = '2011-08-01';

    // TODO: Unsuppress standards checking when underscores removed from property names
    // @codingStandardsIgnoreStart

    /**
     * @var string
     */
    protected $_secretKey = null;

    /**
     * @var string
     */
    protected $_baseUri = null;

    /**
     * List of Amazon Web Service base URLs, indexed by country code
     *
     * @var array
     */
    protected $_baseUriList = [
        'BR' => 'http://webservices.amazon.com.br',
        'CA' => 'http://webservices.amazon.ca',
        'CN' => 'http://webservices.amazon.cn',
        'DE' => 'http://webservices.amazon.de',
        'ES' => 'http://webservices.amazon.es',
        'FR' => 'http://webservices.amazon.fr',
        'IN' => 'http://webservices.amazon.in',
        'IT' => 'http://webservices.amazon.it',
        'JP' => 'http://webservices.amazon.co.jp',
        'MX' => 'http://webservices.amazon.com.mx',
        'UK' => 'http://webservices.amazon.co.uk',
        'US' => 'http://webservices.amazon.com',
    ];

    /**
     * Reference to REST client object
     *
     * @var RestClient
     */
    protected $_rest = null;

    // @codingStandardsIgnoreEnd

    /**
     * Constructs a new Amazon Web Services Client
     *
     * @param  string $appId       Developer's Amazon appid
     * @param  string $countryCode Country code for Amazon service; may be US, UK, DE, JP, FR, CA
     * @param  string $secretKey   API Secret Key
     * @param  string $version     API Version to use
     * @param  bool   $useHttps    Use HTTPS instead of HTTP?
     * @throws Exception\InvalidArgumentException
     * @return Amazon
     */
    public function __construct(
        $appId,
        $countryCode = 'US',
        $secretKey = null,
        $version = null,
        $useHttps = false
    ) {
        $this->appId = (string) $appId;
        $this->_secretKey = $secretKey;

        if (! is_null($version)) {
            self::setVersion($version);
        }

        $countryCode = (string) $countryCode;
        if (! isset($this->_baseUriList[$countryCode])) {
            throw new Exception\InvalidArgumentException("Unknown country code: $countryCode");
        }

        $this->_baseUri = $useHttps
            ? str_replace('http:', 'https:', $this->_baseUriList[$countryCode])
            : $this->_baseUriList[$countryCode];
    }


    /**
     * Search for Items
     *
     * @param  array $options Options to use for the Search Query
     * @throws Exception\RuntimeException
     * @return ResultSet
     * @see http://www.amazon.com/gp/aws/sdk/main.html/102-9041115-9057709?s=AWSEcommerceService&v=2011-08-01&p=ApiReference/ItemSearchOperation
     */
    public function itemSearch(array $options)
    {
        $client = $this->getRestClient();
        $client->setUri($this->_baseUri);

        $defaultOptions = ['ResponseGroup' => 'Small'];
        $options = $this->_prepareOptions('ItemSearch', $options, $defaultOptions);
        $client->getHttpClient()->resetParameters();
        $response = $client->restGet('/onca/xml', $options);

        if ($response->isClientError()) {
            throw new Exception\RuntimeException('An error occurred sending request. Status code: '
                                           . $response->getStatusCode());
        }

        $dom = new DOMDocument();
        $dom->loadXML($response->getBody());
        self::_checkErrors($dom);

        return new ResultSet($dom);
    }


    /**
     * Look up item(s) by ASIN
     *
     * @param  string $asin    Amazon ASIN ID
     * @param  array  $options Query Options
     * @see http://www.amazon.com/gp/aws/sdk/main.html/102-9041115-9057709?s=AWSEcommerceService&v=2011-08-01&p=ApiReference/ItemLookupOperation
     * @throws Exception\RuntimeException
     * @return Item|ResultSet
     */
    public function itemLookup($asin, array $options = [])
    {
        $client = $this->getRestClient();
        $client->setUri($this->_baseUri);
        $client->getHttpClient()->resetParameters();

        $defaultOptions = ['ResponseGroup' => 'Small'];
        $options['ItemId'] = (string) $asin;
        $options = $this->_prepareOptions('ItemLookup', $options, $defaultOptions);
        $response = $client->restGet('/onca/xml', $options);

        if ($response->isClientError()) {
            throw new Exception\RuntimeException(
                'An error occurred sending request. Status code: ' . $response->getStatusCode()
            );
        }

        $dom = new DOMDocument();
        $dom->loadXML($response->getBody());
        self::_checkErrors($dom);
        $xpath = new DOMXPath($dom);
        $xpath->registerNamespace('az', 'http://webservices.amazon.com/AWSECommerceService/' . self::getVersion());
        $items = $xpath->query('//az:Items/az:Item');

        if ($items->length == 1) {
            return new Item($items->item(0));
        }

        return new ResultSet($dom);
    }


    /**
     * Returns a reference to the REST client
     *
     * @return RestClient
     */
    public function getRestClient()
    {
        if ($this->_rest === null) {
            $this->_rest = new RestClient();
        }
        return $this->_rest;
    }

    /**
     * Set REST client
     *
     * @param RestClient $client
     * @return Amazon
     */
    public function setRestClient(RestClient $client)
    {
        $this->_rest = $client;
        return $this;
    }

    // TODO: Unsuppress standards checking when underscores removed from method name
    // @codingStandardsIgnoreStart

    /**
     * Prepare options for request
     *
     * @param  string $query          Action to perform
     * @param  array  $options        User supplied options
     * @param  array  $defaultOptions Default options
     * @return array
     * @deprecated Underscore should be removed from method name
     */
    protected function _prepareOptions($query, array $options, array $defaultOptions)
    {
        $options['AWSAccessKeyId'] = $this->appId;
        $options['Service']        = 'AWSECommerceService';
        $options['Operation']      = (string) $query;
        $options['Version']        = self::getVersion();

        // de-canonicalize out sort key
        if (isset($options['ResponseGroup'])) {
            $responseGroup = explode(',', $options['ResponseGroup']);

            if (! in_array('Request', $responseGroup)) {
                $responseGroup[] = 'Request';
                $options['ResponseGroup'] = implode(',', $responseGroup);
            }
        }

        $options = array_merge($defaultOptions, $options);

        if ($this->_secretKey !== null) {
            $options['Timestamp'] = gmdate("Y-m-d\TH:i:s\Z");
            ksort($options);
            $options['Signature'] = self::computeSignature($this->_baseUri, $this->_secretKey, $options);
        }

        return $options;
    }

    // @codingStandardsIgnoreEnd

    /**
     * Compute Signature for Authentication with Amazon Product Advertising Webservices
     *
     * @param  string $baseUri
     * @param  string $secretKey
     * @param  array $options
     * @return string
     */
    public static function computeSignature($baseUri, $secretKey, array $options)
    {
        $signature = self::buildRawSignature($baseUri, $options);
        return base64_encode(
            Hmac::compute($secretKey, 'sha256', $signature, Hmac::OUTPUT_BINARY)
        );
    }

    /**
     * Build the Raw Signature Text
     *
     * @param  string $baseUri
     * @param  array $options
     * @return string
     */
    public static function buildRawSignature($baseUri, $options)
    {
        ksort($options);
        $params = [];
        foreach ($options as $k => $v) {
            $params[] = $k."=".rawurlencode($v);
        }

        return sprintf(
            "GET\n%s\n/onca/xml\n%s",
            str_replace('http://', '', $baseUri),
            implode("&", $params)
        );
    }

    // TODO: Unsuppress standards checking when underscores removed from method name
    // @codingStandardsIgnoreStart

    /**
     * Check result for errors
     *
     * @param  DOMDocument $dom
     * @throws Exception\RuntimeException
     * @return void
     * @deprecated Underscore should be removed from method name
     */
    protected static function _checkErrors(DOMDocument $dom)
    {
        $xpath = new DOMXPath($dom);
        $xpath->registerNamespace('az', 'http://webservices.amazon.com/AWSECommerceService/' . self::getVersion());

        if ($xpath->query('//az:Error')->length >= 1) {
            $code = $xpath->query('//az:Error/az:Code/text()')->item(0)->data;
            $message = $xpath->query('//az:Error/az:Message/text()')->item(0)->data;

            switch ($code) {
                case 'AWS.ECommerceService.NoExactMatches':
                    break;
                default:
                    throw new Exception\RuntimeException("$message ($code)");
            }
        }
    }

    // @codingStandardsIgnoreEnd

    /**
     * Set the Amazon API version
     *
     * @static
     * @param string $version API Version
     */
    public static function setVersion($version)
    {
        if (! preg_match('/\d{4}-\d{2}-\d{2}/', $version)) {
            throw new Exception\InvalidArgumentException("$version is an invalid API Version");
        }
        self::$version = $version;
    }

    /**
     * Return the Amazon API version
     *
     * @static
     * @return string
     */
    public static function getVersion()
    {
        return self::$version;
    }
}