767 Solution Overview if($name=='DETAILS') { $this->_currentProduct = new Product(); } if($name == 'BROWSENODE') { $this->_currentProduct->_currentBrowseName++; } if($name == 'CUSTOMERREVIEW') { $this->_currentProduct->_currentReview++; } } // function to catch callbacks when the XML parser has data from // an element function cdataHandler($parser, $cdata) { $this->_currentName = array_slice($this->_names, -1, 1); $this->_currentName = $this->_currentName[0] ; switch($this->_currentName) { case 'TOTALRESULTS' : $this->_totalResults = $cdata; break; case 'DETAILS' : break; case 'AUTHOR' : $this->_currentProduct->authors[] = $cdata; break; case 'RATING' : case 'SUMMARY' : case 'COMMENT' : @$this->_currentProduct-> customerReviews[$this->_currentProduct->_currentReview] [$this->_currentName] .= $cdata; // fields that may contain returns and &s need to be concatenated // concatenation will give a notice if they are enabled - // hence the @ break; Listing 31.8 Continued 37 525x ch31 1/24/03 3:35 PM Page 767 768 Chapter 31 Connecting to Web Services with XML and SOAP case 'LISTID' : $this->_currentProduct->listIDs[] = $cdata; break; case 'BROWSENAME' : @$this->_currentProduct->browseNames[$this->_currentProduct->_ currentBrowseName] .= $cdata; // fields that may contain returns and &s need to be concatenated // concatenation will give a notice if they are enabled - // hence the @ break; case 'PRODUCT' : $this->_currentProduct->similarProducts[] = $cdata; break; // there are certain keys we are dealing with the // children of separately so can ignore case 'CUSTOMERREVIEW' : case 'AUTHORS' : case 'BROWSELIST' : case 'BROWSENODE' : case 'LISTS' : case 'REVIEWS' : case 'SIMILARPRODUCTS' : //do nothing break; default : @$this->_currentProduct->nodes[$this->_currentName] .= $cdata; break; } } // function to get callbacks when the XML parser reaches an end of element function endElementHandler($parser, $name) { if($name=='DETAILS') { //these are no longer required unset($this->_currentProduct->_currentReview); unset($this->_currentProduct->_currentBrowseName); array_push($this->_products, $this->_currentProduct); Listing 31.8 Continued 37 525x ch31 1/24/03 3:35 PM Page 768 769 Solution Overview } array_pop($this->_names); } } ? > This useful class does exactly the sort of thing classes are good for. It encapsulates the interface to Amazon in a nice black box.Within the class the connection to Amazon can be made either via the XML over HTTP method or the SOAP method.The method it will use is determined by the global METHOD constant we set at the very beginning. Let’s begin by going back to the Category Search example.We use the AmazonResultSet class as follows: $ars = new AmazonResultSet; $ars->browseNodeSearch($parameters['browsenode'], $parameters['page'], $parameters['mode']); This class has no constructor, so we’ll go straight to that browseNodeSearch() method. We are passing it three parameters: the browsenode number we are interested in (corre- sponding to, say, Business & Investing, or Computers & Internet); the page number, rep- resenting the records we would like retrieved; and the mode, representing the type of merchandise we are interested in.The code for this method is shown excerpted in Listing 31.9. Listing 31.9 browseNodeSearch() Method—Performing a Category Search // Perform a query to get a page full of products from a browse node // Switch between XML/HTTP and SOAP in constants.php // Returns an array of Products function browseNodeSearch($browseNode, $page, $mode) { if(METHOD=='SOAP') { // the NuSOAP class generates a lot of notices. Turn them off. error_reporting(error_reporting() & ~E_NOTICE); $soapclient = new soapclient( 'http://soap.amazon.com/schemas2/AmazonWebServices.wsdl', 'wsdl'); $soap_proxy = $soapclient->getProxy(); $parameters['mode']=$mode; $parameters['page']=$page; $parameters['type']='heavy'; $parameters['tag']=$this->_assocID; $parameters['devtag']=$this->_devTag; $parameters['sort']='+salesrank'; Listing 31.8 Continued 37 525x ch31 1/24/03 3:35 PM Page 769 770 Chapter 31 Connecting to Web Services with XML and SOAP $parameters['browse_node'] = $browseNode; // perform actual soap query $result = $soap_proxy->BrowseNodeSearchRequest($parameters) ; if(isSOAPError($result)) return false; $this->_totalResults = $result['TotalResults']; $counter = 0; foreach($result['Details'] as $product) { $this->_products[$counter] = new Product; $this->_products[$counter]->soap = $result['Details'][$counter]; $counter++; } unset($soapclient); unset($soap_proxy); } else { // form URL and call parseXML to download and parse it $this->_type = 'browse'; $this->_browseNode = $browseNode; $this->_page = $page; $this->_mode = $mode; $this->_url = 'http://xml.amazon.com/onca/xml2?t='.ASSOCIATEID .'&dev-t='.DEVTAG.'&BrowseNodeSearch=' .$this->_browseNode.'&mode='.$this->_mode .'&type=heavy&page='.$this->_page.'&sort=+salesrank&f=xml'; $this->parseXML(); } return $this->_products; } Depending on the value of the METHOD constant, this method will either perform the query via XML over HTTP or via SOAP.We will look at each of these separately. Using XML Over HTTP We begin by setting a few important class member variables: n type—The type of search required.We are searching for books within a particular browsenode, so we set the value to browse. n browse —The value of the particular browsenode we have been passed as a parameter. Listing 31.9 Continued 37 525x ch31 1/24/03 3:35 PM Page 770 771 Solution Overview n page —The page number that we have been passed as a parameter. n mode —The type of items we are searching for (for example, books) that we have been passed as a parameter. n url —The URL at Amazon that we need to connect to in order to perform this type of search. The URLs that we make our HTTP connections to for different types of searches and the parameters they expect can be found in the Amazon.com Web Services API and Integration Guide in your developer’s kit. Look closely at the GET parameters we are passing in here: $this->_url = 'http://xml.amazon.com/onca/xml2?t='.ASSOCIATEID .'&dev-t='.DEVTAG.'&BrowseNodeSearch=' .$this->_browseNode.'&mode='.$this->_mode .'&type=heavy&page='.$this->_page .'&sort=+salesrank&f=xml'; The parameters we need to pass to this URL are as follows: n t—Your Associate ID. n dev-t —Your developer token. n BrowseNodeSearch —The browsenode number you want to search. n mode —books, or another valid product type. n type —Heavy or lite (note spelling!). Heavy gives more information. n page —Group of ten results. n sort —The order we would like the results returned in.This is an optional parameter. In this case, we have set it to +salesrank because we would like results in sales rank order. n f —The format.This should always contain the value 'xml'. Valid sort types are as follows: n Featured Items: +pmrank n Bestselling: +salesrank n Average Customer Review: +reviewrank n Price (Low to High): +pricerank n Price (High to Low): +inverse-pricerank n Publication Date: +daterank n Alphabetical (A-Z): +titlerank n Alphabetical (Z-A): -titlerank 37 525x ch31 1/24/03 3:35 PM Page 771 . Connecting to Web Services with XML and SOAP case 'LISTID' : $this->_currentProduct->listIDs[] = $cdata; break; case 'BROWSENAME' : @$this->_currentProduct->browseNames[$this->_currentProduct->_ currentBrowseName]. longer required unset($this->_currentProduct->_currentReview); unset($this->_currentProduct->_currentBrowseName); array_push($this->_products, $this->_currentProduct); Listing. array_slice($this->_names, -1 , 1); $this->_currentName = $this->_currentName[0] ; switch($this->_currentName) { case 'TOTALRESULTS' : $this->_totalResults = $cdata; break; case