AmazonProductsAPI.php

<?php
/*
 * AmazonProductsAPI
 * ====================
 * This is a lightweight single class for making REST requests to Amazon's
 * Product Advertising API. This program is derived from AmazonProductRequest
 *
 * PHP Version  >= 5.3.0
 * Requires cURL
 *
 * Copyright (C) 2015 Charles Hays
 * Copyright (C) 2014 Yaakov Freedman
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @package AmazonProductsAPI
 * @license http://www.gnu.org/licenses/gpl.txt GPL
 * @author Yaakov Freedman <yaakovfreedman@yahoo.com>
 *
 * This program is derived from AmazonProductRequest by Yaakov Fredman
 * Source: https://github.com/yfree/amazon-product-request-php-class
 * @package AmazonProductRequest
 * @license http://www.gnu.org/licenses/gpl.txt GPL      
 * @author Yaakov Freedman <yaakovfreedman@yahoo.com>
 */
class AmazonProductsAPI
{
    /* Local path of CA Root Certificates file needed for using the
     * SSL option. Available at http://curl.haxx.se/ca/cacert.pem
     * @type string
     * @access private
     */
    private $CERTPATH = 'cacert.pem';
    
    /*Constants for data validation. */
     
    /* List of valid locations.
     * @type array
     * @access private
     */
    private $LOCATIONS = array ('ca','com','cn','co.jp','co.uk','fr','it','cn');

    /* List of locations.
     * @type array
     * @access private
     */
    private $RESPONSEFORMATS = array ('string','simplexml','array','flatarray','serialized','flatserialized');
    
    /* Configuration variables used for the request.
     * @type array
     * @access private
     */
    private $config = array();
    
    /* Amazon query parameters.
     * array keys in $params are used when sending queries to Amazon, and 
     * therefore must be in PascalCase.
     * @type array
     * @access private
     */ 
    private $params = array();
    
    /* Expressions used to construct the power search parameter that can be used
     * for the itemSearch operation. These are only useful when SearchIndex is 
     * set to 'Books'.
     * @type array
     * @access private
     */
    private $powerStrings = array();
    
    /* Message that will be populated and returned as an exception should the
     * execution of a request fail.
     * @type string
     * @access private
     */
    private $errorMsg;
    
	/**
	 * The microtime of when the previous request was made
	 *
	 * @var float
	 */
	protected $previousRequestTime;
    
    /* Constructor
     * @param string $keyId
     * @param string $tag
     * @param string $secretKey
     * @param string $version
     * @param string $location optional
     * @access public
     */
    public function __construct($keyId, $tag, $secretKey, $version, 
                                $location = 'com')
    {                
        try
        {
            $this->setConfigSecretKey($secretKey);
            $this->setConfigLocation($location);   
            $this->setAWSAccessKeyId($keyId);
            $this->setAssociateTag($tag);
            $this->setVersion($version);
        }
        catch (Exception $e)
        {
            throw $e;
        }
        
        $this->config['ssl'] = false;
        $this->config['delay'] = false;
        $this->config['responseFormat'] = 'simplexml';
		$this->setSearchIndex('All'); // set to all by default
    }
    
    /******************
     * config getters * 
     ******************/
    
    /* Delay Configuration getter.
     * @return mixed boolean|null
     * @access public
     */
    public function getConfigDelay()
    {
        return isset($this->config['delay']) ? $this->config['delay'] : null;
    }
    
    /* Location Configuration getter.
     * @return mixed string|null
     * @access public
     */
    public function getConfigLocation()
    {
        return isset($this->config['location'])
        ? $this->config['location'] : null;
    }
    
    /* Response Format Configuration getter.
     * @return mixed string|null
     * @access public
     */
    public function getConfigResponseFormat()
    {
        return isset($this->config['responseFormat']) 
        ? $this->config['responseFormat'] : null;
    }
    
    /* Secret Key Configuration getter.
     * @return mixed string|null
     * @access public
     */
    public function getConfigSecretKey()
    {
        return isset($this->config['secretKey']) 
        ? $this->config['secretKey'] : null;
    }
    
    /* SSL Configuration getter.
     * @return mixed boolean|null
     * @access public
     */ 
    public function getConfigSsl()
    {
        return isset($this->config['ssl']) ? $this->config['ssl'] : null;
    }
    
    /******************
     * params getters * 
     ******************/
    
    /* Associate Tag getter.
     * @return mixed string|null
     * @access public
     */
    public function getAssociateTag()
    {
        return isset($this->params['AssociateTag'])
        ? $this->params['AssociateTag'] : null;
    }
    
    /* Author Parameter getter.
     * @return mixed string|null
     * @access public
     */    
    public function getAuthor()
    {
        return isset($this->params['Author']) ? $this->params['Author'] : null;
    }
    
    /* Availability Parameter getter.
     * @return boolean unset is interpreted as false and is the default
     * @access public
     */
    public function getAvailability()
    {
        return isset($this->params['Availability']) ? true : false;
    }
    
    /* AWS AccessKey ID Parameter getter.
     * @return mixed string|null
     * @access public
     */
    public function getAWSAccessKeyId()
    {
        return isset($this->params['AWSAccessKeyId'])
        ? $this->params['AWSAccessKeyId'] : null;
    }
    
    /* Brand Parameter getter.
     * @return mixed string|null
     * @access public
     */
    public function getBrand()
    {
        return isset($this->params['Brand']) ? $this->params['Brand'] : null;
    }
    
    /* Browse Node Parameter getter.
     * @return mixed string|null
     * @access public
     */
    public function getBrowseNode()
    {
        return isset($this->params['BrowseNode'])
        ? $this->params['BrowseNode'] : null;
    }
    
    /* Condition Parameter getter.
     * @return mixed string|null
     * @access public
     */
    public function getCondition()
    {
        return isset($this->params['Condition'])
        ? $this->params['Condition'] : null;
    }
    
    /* Id Type Parameter getter.
     * @return mixed string|null
     * @access public
     */
    public function getIdType()
    {
        return isset($this->params['IdType']) ? $this->params['IdType'] : null;
    }
    
    /* Item Page Parameter getter.
     * @return mixed integer|null
     * @access public
     */
    public function getItemPage()
    {
        return isset($this->params['ItemPage']) 
        ? $this->params['ItemPage'] : null;
    }
    
    /* Maximum Price Parameter getter.
     * @return mixed integer|null
     * @access public
     */
    public function getMaxPrice()
    {
        return isset($this->params['MaximumPrice']) 
        ? $this->params['MaximumPrice'] : null;
    }
    
    /* Minimum Price Parameter getter.
     * @return mixed integer|null
     * @access public
     */
    public function getMinPrice()
    {
        return isset($this->params['MinimumPrice']) 
        ? $this->params['MinimumPrice'] : null;
    }
    
    /* Merchant Id Parameter getter.
     * @return mixed string|null
     * @access public
     */    
    public function getMerchantId()
    {
        return isset($this->params['MerchantId']) 
        ? $this->params['MerchantId'] : null;
    }
    
    /* Publisher Parameter getter.
     * @return mixed string|null
     * @access public
     */    
    public function getPublisher()
    {
        return isset($this->params['Publisher']) 
        ? $this->params['Publisher'] : null;
    }
    
    /* Related Item Page Parameter getter.
     * @return mixed integer|null
     * @access public
     */    
    public function getRelatedItemPage()
    {
        return isset($this->params['RelatedItemPage']) 
        ? $this->params['RelatedItemPage'] : null;
    }
    
    /* Relationship Type Parameter getter.
     * @return mixed string|null
     * @access public
     */    
    public function getRelationshipType()
    {
        return isset($this->params['RelationshipType']) 
        ? $this->params['RelationshipType'] : null;
    }
    
    /* Response Group Parameter getter.
     * @return mixed string|null
     * @access public
     */    
    public function getResponseGroup()
    {
        return isset($this->params['ResponseGroup']) 
        ? $this->params['ResponseGroup'] : null;
    }
    
    /* Search Index Parameter getter.
     * @return mixed string|null
     * @access public
     */    
    public function getSearchIndex()
    {
        return isset($this->params['SearchIndex']) 
        ? $this->params['SearchIndex'] : null;
    }

    /* Sort Parameter getter.
     * @return mixed string|null
     * @access public
     */    
    public function getSort()
    {
        return isset($this->params['Sort']) ? $this->params['Sort'] : null;
    }

    /* Title Parameter getter.
     * @return mixed string|null
     * @access public
     */    
    public function getTitle()
    {
        return isset($this->params['Title']) ? $this->params['Title'] : null;
    }
    
    /* Version Parameter getter.
     * @return mixed string|null
     * @access public
     */    
    public function getVersion()
    {
        return isset($this->params['Version']) 
        ? $this->params['Version'] : null;
    }    

    /************************
     * powerStrings getters * 
     ************************/

    /* After Year Power Search String getter.
     * @return mixed integer|null
     */    
    public function getBookAfterYear()
    {
        return isset($this->powerStrings['afterYear']) 
        ? $this->powerStrings['afterYear']['value'] : null;
    }
    
    /* Before Year Power Search String getter.
     * @return mixed integer|null
     * @access public
     */    
    public function getBookBeforeYear()
    {
        return isset($this->powerStrings['beforeYear']) ? 
        $this->powerStrings['beforeYear']['value'] : null;
    }
    
    /* During Year Power Search String getter.
     * @return mixed integer|null
     * @access public
     */    
    public function getBookDuringYear()
    {
        return isset($this->powerStrings['duringYear']) ? 
        $this->powerStrings['duringYear']['value'] : null;
    }
    
    /* Language Power Search String getter.
     * @return mixed string|null
     * @access public
     */    
    public function getBookLanguage()
    {
        return isset($this->powerStrings['language']) ? 
        $this->powerStrings['language']['value'] : null;
    }
    
    /* Subject Power Search String getter.
     * @return mixed string|null
     * @access public
     */    
    public function getBookSubject()
    {
        return isset($this->powerStrings['subject']) ? 
        $this->powerStrings['subject']['value'] : null;
    }

     /****************** 
      * config setters *
      ******************/
     
    /* Delay Configuration setter.
     * @param boolean $delay
     * @return AmazonProductRequest
     * @access public
     */
    public function setConfigDelay($delay)
    {
        if (is_bool($delay) === false)
        {
            throw new Exception('Delay configuration must be true or false.');
        }
        
        $this->config['delay'] = $delay;
        
        return $this;
    }
    
    /* Location Configuration setter.
     * @param string $location non-case sensitive contained in $this->LOCATIONS
     * @return AmazonProductRequest
     * @access public
     */
    public function setConfigLocation($location)
    {
        $location = strtolower($location);
        
        if (in_array($location, $this->LOCATIONS) === false)
        {
            throw new Exception('Invalid location.');
        }
        
        $this->config['location'] = $location;
        
        return $this;
    }
    
    /* Response Format Configuration setter.
     * @param string $format non-case sensitive contained in 
     *     $this->RESPONSEFORMATS
     * @return AmazonProductRequest
     * @access public
     */
    public function setConfigResponseFormat($format)
    {
        $responseFormat = strtolower($format);
        if (in_array($format, $this->RESPONSEFORMATS) === false)
        {
            throw new Exception('Invalid response format.');
        }
        
        $this->config['responseFormat'] = $format;
        return $this;
    }
    
    /* Secret Key Configuration setter.
     * @param string $secretKey
     * @return AmazonProductRequest
     * @access public
     */
    public function setConfigSecretKey($secretKey)
    {    
        if (is_string($secretKey) === false)
        {
            throw new Exception ('Invalid Secret Key.');
        }
        
        $this->config['secretKey'] = $secretKey;
        
        return $this;
    }
    
    /* SSL Configuration setter.
     * @param boolean $ssl
     * @return AmazonProductRequest
     * @access public
     */
    public function setConfigSsl($ssl)
    {
        if (is_bool($ssl) === false)
        {
            throw new Exception('SSL configuration must be true or false.');
        }
        
        if ($ssl === true && 
            file_exists($this->CERTPATH) === false)
        {
            throw new Exception('SSL Root CA Cert file is not present.');
        }
        
        $this->config['ssl'] = $ssl;
        
        return $this;
    }
    
    /****************** 
     * params setters *
     ******************/
    
    /* Associate Tag Parameter setter.
     * @param boolean $tag
     * @return AmazonProductRequest
     * @access public
     */
    public function setAssociateTag($tag)
    {    
        if (is_string($tag) === false)
        {
            throw new Exception ('Invalid Associate Tag parameter.');
        }
        
        $this->params['AssociateTag'] = $tag;
        
        return $this;
    }
    
    /* Author parameter setter.
     * @param string $author
     * @return AmazonProductRequest
     * @access public
     */    
    public function setAuthor($author)
    {
        if (is_string($author) === false)
        {
            throw new Exception('Invalid Author parameter.');
        }
        
        $this->params['Author'] = $author;
        
        return $this;
    }
    
    /* Availability Parameter setter.
     * When set to true, only available items are returned.
     * When set to false, this filter is disabled.
     * @param boolean $availability
     * @return AmazonProductRequest
     * @access public
     */
    public function setAvailability($availability)
    {
        if ($availability === true)
        {
            $this->params['Availability'] = 'Available';
        }
        elseif ($availability === false)
        {
            if (isset($this->params['Availability']))
            {
                unset($this->params['Availability']);
            }
        }
        else
        {
            throw new Exception('Availability must be true or false.');
        }
        
        return $this;
    }
    
    /* AWS Access Key Id Parameter setter.
     * @param string $keyId
     * @return AmazonProductRequest
     * @access public
     */
    public function setAWSAccessKeyId($keyId)
    {        
        if (is_string($keyId) === false)
        {
            throw new Exception ('Invalid AWS Access Key parameter.');
        }
        $this->params['AWSAccessKeyId'] = $keyId;
        
        return $this;
    }
    
    /* Brand Parameter setter.
     * @param string $brand
     * @return AmazonProductRequest
     * @access public
     */
    public function setBrand($brand)
    {
        if (is_string($brand) === false)
        {
            throw new Exception('Invalid Brand parameter.');
        }
        
        $this->params['Brand'] = $brand;
        
        return $this;
    }
    
    /* Browse Node Parameter setter.
     * @param string $browseNode valid Amazon Browse Node integer string
     * @return AmazonProductRequest
     * @access public
     */
    public function setBrowseNode($browseNode)
    {
        if (is_string($browseNode) === false)
        {
            throw new Exception('Invalid Browse Node parameter.');
        }
        
        $this->params['BrowseNode'] = $browseNode;
        
        return $this;
    }
    
    /* Condition Parameter setter.
     * @param string $condition
     * @return AmazonProductRequest
     * @access public
     */
    public function setCondition($condition)
    {
        if (is_string($condition) === false)
        {
            throw new Exception('Invalid Condition parameter.');
        }
        
        $this->params['Condition'] = $condition;
        
        return $this;
    }
    
    /* Id Type Parameter setter.
     * @param string $idType
     * @return AmazonProductRequest
     * @access public
     */
    public function setIdType($idType)
    {
        if (is_string($idType) === false)
        {
            throw new Exception('Invalid Id Type parameter.');
        }

        $this->params['IdType'] = $idType;
        
        return $this;
    }
    
    /* Item Page Parameter setter.
     * @param integer $page between 1 and 10
     * @return AmazonProductRequest
     * @access public
     */
    public function setItemPage($page)
    {
        /* Amazon only returns pages 1 through 10. */
        if (is_int($page) === false || 
            $page < 1 ||
            $page > 10)
        {
           throw new Exception('Invalid Item Page parameter,' . 
                               ' must be a number between 1 and 10.');
        }
        
        $this->params['ItemPage'] = $page;
        
        return $this;
    }
    
    /* Maximum Price Parameter setter.
     * @param integer $maxPrice in lowest denomination, 
     *     for U.S. this means cents, minimum value is 1 
     * @return AmazonProductRequest
     * @access public
     */
    public function setMaxPrice($maxPrice)
    {
        if (is_int($maxPrice) === false || 
            $maxPrice < 1)
        {
            throw new Exception('Invalid Maximum Price parameter.');
        }
        
        $this->params['MaximumPrice'] = $maxPrice;
        
        return $this;
    }
    
    /* Minimum Price Parameter setter.
     * @param integer $minPrice in lowest denomination, 
     *     for U.S. this means cents, minimum value is 1 
     * @return AmazonProductRequest
     * @access public
     */
    public function setMinPrice($minPrice)
    {
        if (is_int($minPrice) === false || 
            $minPrice < 1)
        {
            throw new Exception('Invalid Minimum Price parameter.');
        }
        
        $this->params['MinimumPrice'] = $minPrice;
        
        return $this;
    }
    
    /* Merchant Id Parameter setter.
     * @param string $id
     * @return AmazonProductRequest
     * @access public
     */
    public function setMerchantId($id)
    {    
        if (is_string($id) === false)
        {
            throw new Exception ('Invalid Merchant Id parameter.');
        }
        
        $this->params['MerchantId'] = $id;
        
        return $this;
    }
    
    /* Publisher Parameter setter.
     * @param string $publisher
     * @return AmazonProductRequest
     * @access public
     */
    public function setPublisher($publisher)
    {
        if (is_string($publisher) === false)
        {
            throw new Exception('Invalid Publisher parameter.');
        }
        
        $this->params['Publisher'] = $publisher;
        
        return $this;
    }
    
    /* Related Item Page Parameter setter.
     * @param integer $page minimum value is 1
     * @return AmazonProductRequest
     * @access public
     */
    public function setRelatedItemPage($page)
    {
        if (is_int($page) === false || 
            $page < 1)
        {   
            throw new Exception('Invalid Related Item Page parameter.');
        }
        
        $this->params['RelatedItemPage'] = $page;
        
        return $this;
    }
    
    /* Relationship Type Parameter setter.
     * @param string $relationshipType
     * @return AmazonProductRequest
     * @access public
     */
    public function setRelationshipType($relationshipType)
    {
        if(is_string($relationshipType) === false)
        {
            throw new Exception('Invalid Relationship Type parameter.');
        }
        
        $this->params['RelationshipType'] = $relationshipType;
        
        return $this;
    }
    
    /* Response Group Parameter setter.
     * @param string $responseGroup comma seperated
     * @return AmazonProductRequest
     * @access public
     */
    public function setResponseGroup($responseGroup)
    {
        if (is_string($responseGroup) === false)
        {
            throw new Exception('Invalid Response Group parameter.');
        }
        
        $this->params['ResponseGroup'] = $responseGroup;
        
        return $this;
    }
    
    /* Search Index Parameter setter.
     * @param string $searchIndex
     * @return AmazonProductRequest
     * @access public
     */    
    public function setSearchIndex($searchIndex)
    {
        if (is_string($searchIndex) === false)
        {
            throw new Exception('Invalid Search Index parameter.');
        }
        
        $this->params['SearchIndex'] = $searchIndex;
        
        return $this;
    }
    
    /* Sort Parameter setter.
     * @param string $sort
     * @return AmazonProductRequest
     * @access public
     */
    public function setSort($sort)
    {
        if (is_string($sort) === false)
        {
            throw new Exception ('Invalid Sort parameter.');
        }
        
        $this->params['Sort'] = $sort;
        
        return $this;
    }
    
    /* Title Parameter setter.
     * @param string $title
     * @return AmazonProductRequest
     * @access public
     */    
    public function setTitle($title)
    {
        if (is_string($title) === false)
        {
            throw new Exception('Invalid Title parameter.');
        }
        
        $this->params['Title'] = $title;
        
        return $this;
    }    
    
    /* Version Parameter setter.
     * @param string $version as date in Y-m-d
     * @return AmazonProductRequest
     * @access public
     */    
    public function setVersion($version)
    {
        if ($this->validateDate($version) === false)
        {
            throw new Exception('Invalid Version parameter.');
        }
        
        $this->params['Version'] = $version;
        
        return $this;
    }
    
    /************************ 
     * powerStrings setters *
     ************************/
    
    /* After Year Power Search String setter.
     * @param int $afterYear
     * @return AmazonProductRequest
     * @access public
     */    
    public function setBookAfterYear($afterYear)
    {
        if (is_int($afterYear) === false || 
            $afterYear < 1)
        {
            throw new Exception('Invalid After Year parameter.');
        }
        
        $this->powerStrings['afterYear']['value'] = $afterYear;
        $this->powerStrings['afterYear']['prefix'] = 'pubdate:after ';

        return $this;
    }
    
    /* Before Year Power Search String setter.
     * @param int $beforeYear
     * @return AmazonProductRequest
     * @access public
     */    
    public function setBookBeforeYear($beforeYear)
    {
        if (is_int($beforeYear) === false || 
            $beforeYear < 1)
        {
            throw new Exception('Invalid Before Year parameter.');
        }
        
        $this->powerStrings['beforeYear']['value'] = $beforeYear;
        $this->powerStrings['beforeYear']['prefix'] = 'pubdate:before ';
        
        return $this;
    }
    
    /* During Year Power Search String setter.
     * @param int $duringYear
     * @return AmazonProductRequest
     * @access public
     */    
    public function setBookDuringYear($duringYear)
    {
        if (is_int($duringYear) === false || 
            $duringYear < 1)
        {
            throw new Exception('Invalid During Year parameter.');
        }
        
        $this->powerStrings['duringYear']['value'] = $duringYear;
        $this->powerStrings['duringYear']['prefix'] = 'pubdate:during ';
        
        return $this;
    }
    
    /* Language Power Search String setter.
     * @param string $language
     * @return AmazonProductRequest
     * @access public
     */    
    public function setBookLanguage($language)
    {
        if (is_string($language) === false)
        {
            throw new Exception('Invalid Language parameter.');
        }
        
        $this->powerStrings['language']['value'] = $language;
        $this->powerStrings['language']['prefix'] = 'language:';
        
        return $this;
    }

    /* Subject Power Search String setter.
     * @param string $subject
     * @return AmazonProductRequest
     * @access public
     */    
    public function setBookSubject($subject)
    {
        if (is_string($subject) === false)
        {
            throw new Exception('Invalid Subject parameter.');
        }
        
        $this->powerStrings['subject']['value'] = $subject;
        $this->powerStrings['subject']['prefix'] = 'subject:';
        
        return $this;
    }
    
    /********************* 
     * operation methods *
     *********************/
    
    /* Performs BrowseNodeLookup Operation.
     * @param string $browseNode
     * @return mixed string|SimpleXMLElement|array
     * @access public
     */    
    public function browseNodeLookup($browseNode)
    {
        $finalParams['Operation'] = 'BrowseNodeLookup';
        $finalParams = array_merge($this->params, $finalParams);
        
        if (is_string($browseNode) === false)
        {
            throw new Exception('Invalid Browse Node Parameter passed' . 
                                ' to browseNodeLookup.');
        }
        
        $finalParams['BrowseNodeId'] = $browseNode;
        
        $response = $this->execRequest($finalParams);
        
        if ($response === false)
        {
            throw new Exception($this->errorMsg);
        }
        
        return $response;
    }
    
    /* Performs ItemLookup Operation.
     * @param string $itemId 1 - 10 comma seperated itemIds
     * @return mixed string|SimpleXMLElement|array
     * @access public
     */
    public function itemLookup($itemId)
    {
        $finalParams['Operation'] = 'ItemLookup';
        $finalParams = array_merge($this->params, $finalParams);
        
        if (is_string($itemId) === false)
        {
            throw new Exception('Invalid itemId Parameter passed' . 
                                ' to itemLookup.');
        }
        
        $finalParams['ItemId'] = $itemId;
        
        $response = $this->execRequest($finalParams);
        
        if ($response === false)
        {
            throw new Exception($this->errorMsg);
        }
        
        return $response;
    }
    
    /* Performs ItemSearch Operation.
     * @param string $keywords optional space seperated keywords
     * @return mixed string|SimpleXMLElement|array
     * @access public
     */
    public function itemSearch($keywords = null)
    {    
		// For All searches
		$original_params = null;
		if($this->params['SearchIndex'] == 'All')
		{
			$original_params = $this->params;

			if(trim($this->params[Keywords]) == '')
			{
				if(trim($keywords) == '')
				{
					$keywords = ''; // build keywords from unusable params
					if($this->params[Actor] != '') $keywords .= $this->params[Actor].' ';
					if($this->params[Artist] != '') $keywords .= $this->params[Artist].' ';
					if($this->params[Author] != '') $keywords .= $this->params[Author].' ';
					if($this->params[Brand] != '') $keywords .= $this->params[Brand].' ';
					if($this->params[Composer] != '') $keywords .= $this->params[Composer].' ';
					if($this->params[Director] != '') $keywords .= $this->params[Director].' ';
					if($this->params[Manufacturer] != '') $keywords .= $this->params[Manufacturer].' ';
					if($this->params[MusicLabel] != '') $keywords .= $this->params[MusicLabel].' ';
					if($this->params[Orchestra] != '') $keywords .= $this->params[Orchestra].' ';
					if($this->params[Publisher] != '') $keywords .= $this->params[Publisher].' ';
					if($this->params[Title] != '') $keywords .= $this->params[Title].' ';
					$keywords = trim($keywords);
					if($keywords == '') $keywords = 'new'; // ?? if still no keywords
				}
			}

			$this->resetParams();
			$this->params['SearchIndex'] = 'All';
			if(isset($original_params[ResponseGroup]))
			{
				$this->params[ResponseGroup] = $original_params[ResponseGroup];
			}
			if(isset($original_params[Keywords]))
			{
				$this->params[Keywords] = $original_params[Keywords];
			}
			if(isset($original_params[ItemPage]))
			{
				$this->params[ItemPage] = $original_params[ItemPage];
			}
		}

        $finalParams['Operation'] = 'ItemSearch';
        $finalParams = array_merge($this->params, $finalParams);

        if ($keywords !== null)
        {
            if (is_string($keywords) === false)
            {
                throw new Exception('Invalid Keywords Parameter passed' . 
                                    ' to itemSearch.');
            }

            $finalParams['Keywords'] = $keywords;
        }

        if (empty($this->powerStrings) === false)
        {
            $finalParams['Power'] = $this->buildPowerSearch($this->powerStrings);
        }

        $response = $this->execRequest($finalParams);

        if ($response === false)
        {
            throw new Exception($this->errorMsg);
        }
        
        if(is_array($original_params))
        {
			$this->params = $original_params;
		}

        return $response;
    }

    /* Performs ItemSearch Operation But for All available pages
     * @param string $keywords optional space seperated keywords
     * @return an ARRAY OF EACH PAGE of mixed string|SimpleXMLElement|array
     * @access public
     */
	public function itemSearchAllPages($keywords = null)
	{
		$pages = $this->getTotalPages($keywords);
		
		if($this->params['SearchIndex'] == 'All')
			{
			if($pages > 5) $pages = 5; // max returned pages is 5 for All
			}
		else
			{
			if($pages > 10) $pages = 10; // max returned pages is 10
			}

		$return = array();
		if($pages > 1)
		{
			for($i = 1; $i <= $pages; $i++)
			{
				$this->setItemPage($i);
				$return[] = $this->itemSearch($keywords);
			}
		}
		else
		{
			$return[] = $this->itemSearch($keywords);
		}
		return $return;
	}

    /* Performs a check on how many pages are available
     * @param string $keywords optional space seperated keywords
     * @return a string/int of total pages
     * @access public
     */
	public function getTotalPages($keywords = null)
	{
		$wanted_format = $this->config['responseFormat'];
		$this->config['responseFormat'] = 'array'; // need it in a normalized method

		// get first response to determine number of pages
		$response = $this->itemSearch($keywords);

		$this->config['responseFormat'] = $wanted_format; // restore forat

		if(trim($response[Items][TotalPages]) > 0)
			{
			return trim($response[Items][TotalPages]);
			}

		return 0;
	}

    /* Performs a check on how many items are available
     * @param string $keywords optional space seperated keywords
     * @return a string/int of total items
     * @access public
     */
	public function getTotalItems($keywords = null)
	{
		$wanted_format = $this->config['responseFormat'];
		$this->config['responseFormat'] = 'array'; // need it in a normalized method

		// get first response to determine number of pages
		$response = $this->itemSearch($keywords);

		$this->config['responseFormat'] = $wanted_format; // restore forat

		if(trim($response[Items][TotalResults]) > 0)
			{
			return trim($response[Items][TotalResults]);
			}

		return 0;
	}

    /* Resets member arrays $this->params and $this->powerStrings,
     * does not reset $this->config.
     * @return AmazonProductRequest
     * @access public
     */
    public function resetParams()
    {
        /* Reset PowerStrings. */
        $this->powerStrings = array();
        
        /* Reset Params. */
        $newParams = array();
        $newParams['AWSAccessKeyId'] = $this->params['AWSAccessKeyId'];
        $newParams['AssociateTag'] = $this->params['AssociateTag'];
        $newParams['Version'] = $this->params['Version'];
         
        $this->params = $newParams;
        
        return $this;
    }

     /*******************
      * private methods *
      *******************/
    
    /* Builds the value for Power parameter for use with the itemSearch 
     * operation. 
     * @param array $powerStrings each element must contain the
     * elements 'prefix' and 'value' for concatenation.
     * @return string|boolean - false upon failure
     * @access private
     */     
    private function buildPowerSearch($powerStrings)
    {        
        $powerSearchParam = array();
        
        foreach ($powerStrings as $powerString)
        {
            if (isset($powerString['prefix']) === false || 
                isset($powerString['value']) === false)
                {
                    return false;
                }
                
            $powerSearchParam[] = $powerString['prefix'] . 
                                  $powerString['value'];
        }
    
        return implode(' and ', $powerSearchParam);
    }
    
    /* Builds the http request url using the request parameters that have been
     * set. Does not add the protocol prefix to the url. 
     * @param array $requestParams.
     * @return string
     * @access private
     */ 
    private function buildRequest($requestParams)    
    {      
        $requestParams['Service'] = 'AWSECommerceService';
        $requestParams['Timestamp'] = gmdate('Y-m-d\TH:i:s\Z');
    
        $host = 'webservices.amazon.' . $this->config['location'];
        $path = '/onca/xml';
        $method = 'GET';
        
        /* Sort keys in byte order, similiar to Alphabetical except
         * lowercases are a higher value than uppercases as per byte value. */
        ksort($requestParams);
     
        /* Arrange and encode parameters into a parameter string. */
        $paramsString = str_replace(array('+', '%7E'),array('%20', '~'),http_build_query($requestParams, null, '&')); // PHP 5.3 capable
		//$paramsString = http_build_query($requestParams, null, '&', PHP_QUERY_RFC3986);

        /* Create the string to sign. */
        $stringToSign = implode("\n", array($method, $host, $path, 
                                $paramsString));

        /* Hash the signing string using the private key and encode it. */
        $signature = hash_hmac('sha256', $stringToSign, 
                               $this->config['secretKey'], true);
        $signature = rawurlencode(base64_encode($signature));
        
        /* Build the request and append the signature. */
        $request = $host . $path . '?'. $paramsString . '&Signature=' . 
                   $signature;    
        
        return $request;
    }

    /* Checks the response from Amazon for curl request failure,
     * invalid xml response, or errors returned by Amazon.
     * If an error is encountered, $this->errorMsg will be populated and 
     * the method will return false. If the above checks pass, 
     * it will return true.
     * @param string $response xml or malformed xml response
     * @param $ch curl handle
     * @return bool
     * @access private
     */ 
    private function checkResponse($response, $ch)
    {    
        /* Populate errorMsg with last curl error message if curl GET fails. */
        if ($response === false)
        {
            $this->errorMsg = curl_error($ch);
            return false;
        }
        
        /* Temporarily suppress libxml errors so that we can handle them. */
        @$xml = simplexml_load_string($response);
        
        /* Populate errorMsg with appropriate message if invalid xml response. */  
        if ($xml === false)
        {
            $this->errorMsg = implode("\n", libxml_get_errors());
            return false;
        }    
        
        /* Extract error message(s) from xml. */    
        $namespaces = $xml->getNamespaces();
        $xml->registerXPathNamespace('ns', array_shift($namespaces));
        $error = $xml->xpath('//ns:Error/ns:Message');
        
        /* Set errorMsg to a string of the error mesage(s) if they exist. */
        if (isset($error[0]))
        {
            $this->errorMsg = implode("\n", $error);
            return false;
        }
        
        return true;
    }
    
    /* Executes request using cURL.
     * For SSL, a CA Root Certificates file is required. The path is
     * defined by CERTPATH.
     * @param array $requestParams appended with operation specific
     *     fields
     * @return mixed string|SimpleXMLElement|array|boolean - false if
     *     invalid response
     * @access private
     */ 
    private $_request_bucket = array(); // mem cached requests
    private function execRequest($requestParams)
    {
		if($requestParams['ItemPage'] < 2) unset($requestParams['ItemPage']);
		ksort($requestParams);
		if(isset($this->_request_bucket[md5(serialize($requestParams))]))
		{
			return $this->_request_bucket[md5(serialize($requestParams))];
		}
		else
		{
        	if ($this->config['delay'] === true)
        	{
				// If it's been under one second since the last request, then sleep for the remaining time.
				$timeSinceLastRequest = microtime(true) - $this->previousRequestTime;
				if ($timeSinceLastRequest < 1)
				{
					usleep((1 - $timeSinceLastRequest) * 1000000);
				}
        	}

        	$ch = curl_init();

        	if ($this->config['ssl'] === true)
        	{
        	    $protocol = 'https';
        	    curl_setopt ($ch, CURLOPT_CAINFO, $this->CERTPATH);
        	    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
        	}
        	else
        	{
        	    $protocol = 'http';
        	}

        	$request = $protocol . '://' . $this->buildRequest($requestParams);

    	    /* Use GET request. */
    	    curl_setopt($ch, CURLOPT_URL,$request);
    	    /* Return response as a string value. */
    	    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

			$this->previousRequestTime = microtime(true);

    	    $response = curl_exec($ch);
    	    $check = $this->checkResponse($response, $ch);

    	    $this->_request_bucket[md5(serialize($requestParams))] = $check ? $this->formatResponse($response) : false;;
		}

        return $check ? $this->formatResponse($response) : false;
    }
    
    /* Formats the response according to the setting in $this->responseFormat.
     * @param string $response validated xml response
     * @return mixed string|SimpleXMLElement|array
     * @access private
     */  
    private function formatResponse($response)
    {    
        switch($this->config['responseFormat'])
        {
            case 'simplexml':
                return simplexml_load_string($response);
            break;
            
            case 'array':
                return $this->xmlToArray($response);
            break;

			case 'flatarray':
				return $this->flattenArray($this->xmlToArray($response));
			break;

			case 'serialized':
				return serialize($this->xmlToArray($response));
			break;

			case 'flatserialized':
				return serialize($this->flattenArray($this->xmlToArray($response)));
			break;

            default:
                return $response;
        }
    }
    
    /* Validates a Date string. original function submitted to 
     * www.php.net/manual/en/function.checkdate.php
     * by glavic at gmail dot com.
     * @param string $dateToTest
     * @param string $format optional
     * @return boolean
     * @access private
     */  
    private function validateDate($dateToTest, $format = 'Y-m-d')
    {
        /* Suppress warnings requiring a timezone, 
         * timezone is irrelevant to date format checking and UTC is specified 
         * by default anyway. */
        @$date = DateTime::createFromFormat($format, $dateToTest);

        /* If $date was not created properly, it would be impossible to 
         * date->format(). */
        return $date && $date->format($format) == $dateToTest;
    }
    
    /* Converts an xml string to an associative array.
     * @param string $xml validated xml
     * @return array
     * @access private
     */
    private function xmlToArray($xml)
    {
        $xml = simplexml_load_string($xml);
        /* Xml has to be encoded in json before it can be decoded 
           as an associative array. */
        $json = json_encode($xml);
        $array = json_decode($json, true);
        
        return $array;
    }

    /* Flattens a multidimesnional array into a simple array and merges keys
     * @param array, prefix, merging deliminator
     * @return simple flattened array
     * @access public
     */
	public function flattenArray($array, $prefix = '', $delim = '_')
	{
		$arr = array();
		foreach($array as $k => $v)
		{
			if(is_array($v))
			{
				$arr = array_merge($arr, $this->flattenArray($v, $prefix . $k . $delim, $delim));
			}
			else
			{
				$arr[$prefix . $k] = $v;
			}
		}
	return $arr;
	}

	//
	// Nodes
	//

	private $root_nodes_loaded = false;
	public $root_nodes = array();
	public $nodes = array();

    /* Loads the Root Nodes list amazon_root_nodes.csv only once
     * @param [optional: bool $force, if set to true it forces a reload of roots]
     * @return none
     * @access private
     */
	private function loadRootNodes($force = false)
	{
		if($force == true)
			{
			$this->node_list = array();
			}
		else if ($this->root_nodes_loaded)
			return;
		
		$list_nodes = file('amazon_root_nodes.csv', FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
		
		foreach ($list_nodes as $k => $v)
		{
			$n                       = explode(',', trim($v));
			$this->root_nodes[$n[2]] = array(
				'name' => $n[0],
				'category' => $n[1],
				'parent' => ''
			);
			$this->node_list[0]      = $this->root_nodes;
		}
		
		$this->root_nodes_loaded = true;
	}


	public $node_list = array();

    /* Creates an array $node_list which is a heirarchy from the root to the current supplied node.
     * @param node id #
     * @return array of nodes where index 0 is root up to the level the node is found
     * @access public
     */
	public function nodeInfoArray($node)
	{
		$this->loadRootNodes();

		if(($node == '') || ($node < 1)) return;

		$response = $this->setResponseGroup('BrowseNodeInfo')->browseNodeLookup(trim($node));

		if (is_array($response[BrowseNodes][BrowseNode][Children][BrowseNode][0]))
		{
			if ($response[BrowseNodes][BrowseNode][IsCategoryRoot] != 1)
			{
				$this->nodeInfoArray($response[BrowseNodes][BrowseNode][Ancestors][BrowseNode][BrowseNodeId]);
			}

			//$last = end($this->node_list);
			foreach ($response[BrowseNodes][BrowseNode][Children][BrowseNode] as $k => $v)
			{
				$node_array[$v[BrowseNodeId]] = array('name' => $v[Name],'parent' => $node);
			}
			asort($node_array);

			$this->node_list[] = $node_array;
		}

		return $this->node_list;
	}

	private $_node_category_bucket = array(); // stop unneeded calls

    /* Gets the nodes base useful when you don't know what the actual root category or searchIndex is of a node.
     * @param node id #
     * @return string of the root searchIndex
     * @access public
     */
	public function getNodeCategory($node)
	{
		$node = trim($node);

		if($this->_node_category_bucket[$node] != '')
			{
			return $this->_node_category_bucket[$node];
			}

		$this->loadRootNodes();

		if(($root == '') || ($root < 1)) 'All';

		$response = $this->setResponseGroup('BrowseNodeInfo')->browseNodeLookup(trim($node));

		if($response[BrowseNodes][BrowseNode][IsCategoryRoot] == 1) // this is the root
			{
			$id = $node;
			}
		else
			{
			$found = false;
			$n = $response[BrowseNodes][BrowseNode][Ancestors][BrowseNode];
			while($found == false)
				{
				if($n[IsCategoryRoot] == 1) // this is root
					{
					$id = $n[BrowseNodeId];
					$found = true;
					}
				else
					{
					if(is_array($n[Ancestors][BrowseNode]))
						{
						$n = $n[Ancestors][BrowseNode];
						}

					}
				}
			}

		if($this->root_nodes[$id]['category'] != '')
			{
			$this->_node_category_bucket[$node] = $this->root_nodes[$id]['category'];
			return $this->root_nodes[$id]['category'];
			}

		$this->_node_category_bucket[$node] = 'All';
		return 'All'; // fallback to All
	}



}