มือใหม่รบกวนสอบถามเรื่อง PHP Web Service จากอาจารย์ทุกๆท่านครับ

<?php
           require_once($_SERVER['DOCUMENT_ROOT'] . "/libs/nusoap.php");    
    
           //Create a new soap server
               $server = new soap_server();
    
               //Define our namespace
               $namespace = "http://localhost/service/pos.php";
               $server->wsdl->schemaTargetNamespace = $namespace;
    
               //Configure our WSDL
               $server->configureWSDL("POS");
    
                $varname2 = array(
                          'strItemCode' => "xsd:string"
               );
             
              $server->register('GetItemData',$varname2, array('return' => 'xsd:string'));

               function GetItemData($strItemCode){
                   $itemName = "";
    
                   try {
                       $conn  = mysql_connect('localhost', 'root', 'root1234');
                       if (!$conn){
                           return 'Connection Failed...';
                       }
                       mysql_select_db('mydb');
                       mysql_query('SET NAMES UTF8');
    
                       $queryString = "select * from mitem where itemcode = '" . $strItemCode . "' LIMIT 1";
    
                       $result = mysql_query($queryString);
                       if ($result == FALSE){
                            return "Query Error ".$queryString;
                       }else{
                           if ($result != null && mysql_num_rows($result) != 0 ){
                               $colCount = mysql_num_fields($result);
                               $tempArray = array();
                               while($temp = mysql_fetch_array($result)){
                                   $dd ="";
                                   $arrCol = array();
                                   for($col = 0; $col <= $colCount-1; $col++){
                                        $arrCol[mysql_field_name($result, $col)] = $temp[$col];
                                   }
                                   array_push($tempArray, $arrCol);
                               }
   
                                $itemName = json_encode(array("resultCount"=> mysql_num_rows($result) , "results" => $tempArray));
                                return $itemName;
                           }else{
                               return "Not Found...";
                           }
                       }
                       mysql_close($conn);
                   }
                   catch(Exception $e) {
                      return "Error Catch : " . $e->getMessage();
                   }
    
                   return "Hello " . $itemName;
               }
    
               $POST_DATA = isset($GLOBALS['HTTP_RAW_POST_DATA']) ? $GLOBALS['HTTP_RAW_POST_DATA'] : '';
    
               // pass our posted data (or nothing) to the soap service
               $server->service($POST_DATA);
               exit(); 
?>