As I promised before, here is the entire code for the "QueryProcessor" class, after including the additional methods that you saw before:

class QueryProcessor{
    private $host;
    private $services=array('http','https','ftp','telnet','imap','smtp','nicname',
'gopher','finger','pop3','www');
    private $ports=array(21,23,25,43,70,79,80,110,143,443);
    public function __construct($host='myhost.com'){
        $this->host=$host;
    }
    // get IP address
    public function getIp(){
        if(!$ip=gethostbyname($this->host)){
            throw new Exception('Error resolving host IP
address.');
        }
        return $ip;
    }
    // get list of IP addresses
    public function getIpList(){
        if(!$ips=implode(' - ',gethostbynamel($this->host))){
            throw new Exception('Error getting list of IP
addresses for the provided hostname.');
        }
        return $ips;
    }
    // get host name
    public function getHost(){
        if(!$host=gethostbyaddr($this->getIp())){
            throw new Exception('Error resolving host name.');
        }
        return $host;
    }
    // get TCP ports of Internet services
    public function getServicePorts(){
        $output='Retrieving services ports...Please wait.<br />';
        foreach($this->services as $service){
            if(!$port=getservbyname($service,'tcp')){
                $output.='Error retrieving port of service
'.$service.'<br />';
            }
            else{
                $output.='Service '.$service. ' runs on TCP
port :'. $port.'<br />';
            }
        }
        return $output;
    }
    // get Services by TCP ports
    public function getServiceNames(){
        $output='Retrieving services names...Please wait.<br />';
        foreach($this->ports as $port){
            if(!$service=getservbyport($port,'tcp')){
                $output.='Error retrieving service name on port
'.$port.'<br />';
            }
            else{
                $output.='TCP Port '.$port. ' is used by
service :'. $service.'<br />';
            }
        }
        return $output;
    }
}  

Now that you know how the whole "QueryProcessor" class looks, here is an example that shows how to use its methods:

try{
    // instantiate 'QueryProcessor' object
    $queryProc=new QueryProcessor('hotmail.com');
    // display host IP address
    //echo $queryProc->getIp(); // displays 64.4.32.7
    // display host name
    //echo $queryProc->getHost(); // displays 'hotmail.com.br'
    // display IP list
    //echo $queryProc->getIpList(); // displays 64.4.32.7 -
64.4.33.7
    // display services ports
    echo $queryProc->getServicePorts();
    /* displays the following list
    Retrieving services ports...Please wait.
    Service http runs on TCP port :80
    Service https runs on TCP port :443
    Service ftp runs on TCP port :21
    Service telnet runs on TCP port :23
    Service imap runs on TCP port :143
    Service smtp runs on TCP port :25
    Service nicname runs on TCP port :43
    Service gopher runs on TCP port :70
    Service finger runs on TCP port :79
    Service pop3 runs on TCP port :110
    Service www runs on TCP port :80
    */
    // display service names
    echo $queryProc->getServiceNames();
    /* displays the following list
    Retrieving services names...Please wait.
    TCP Port 21 is used by service :ftp
    TCP Port 23 is used by service :telnet
    TCP Port 25 is used by service :smtp
    TCP Port 43 is used by service :nicname
    TCP Port 70 is used by service :gopher
    TCP Port 79 is used by service :finger
    TCP Port 80 is used by service :http
    TCP Port 110 is used by service :pop3
    TCP Port 143 is used by service :imap
    TCP Port 443 is used by service :https
    */
}
catch(Exception $e){
    echo $e->getMessage();
    exit();
}

Final thoughts

In this first tutorial of the series, you learned how to use some useful PHP networking functions, which were encapsulated within a PHP 5 class, in order to perform some common networking tasks, such as converting host names to the corresponding IP addresses and vice versa, listing Internet service names and TCP port numbers.

Nevertheless, I'm just scratching the surface of the PHP networking library. That's why in the next article I'll continue adding more methods to the "QueryProcessor" class, which will surely be quite interesting to you.  Meet you in the next article!