Saturday, August 27, 2011

How to check domain availability in PHP

How to check domain availability in PHP?

Following example shows you how to check the availability of a domain name using PHP.

Domain Name System (DNS) is a naming system for resources connected to the Internet or any other personal network. It contains details of registered domain names in the world up to date. It is a large database of domain names and the IP address mapped to that domain. A Domain Name Registrar is an organization or commercial entity that manage the reservation of Internet domain names. Domain Name Registar provides the registration service for end-users.

Before you register a domain name, you may need to check the availability of the domain name. This example is based on the Domain Availability API. First you have to create a free account with whoisxmlapi site. They will provide an account with free 500 lookups for checking the availability of domain names. Also they provide hosted whois web service plans. By using this free account you can send up to 500 lookup quires. Also they provide a way to check your remaining lookups and e-mail alert at your threshold limit. They provide an easy way to check the domain availability and whois lookup for a given domain. You can configure this to your web application using following example code.

You can get the output as JSON or XML. To do that you have to set outputFormat to JSON or XML. Note that you will be need to connect to the internet to check this example.

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class CheckDomainNameAvailability{

private $userName;
private $password;
private $domainName;
private $outputFormat;

private $isDomainAvailable=FALSE;
private $accountBalance;

public function __construct() {
$this->outputFormat = 'JSON';//You can set XML also

* Check domain name availability
* @param string $domainName
* @return boolean

public function getDomainNameAvailability($domain){
$this->domainName = str_replace('www.', '', strtolower($domain));
$domain_details = @file_get_contents(self::WHOIS_SERVICE_URL."cmd=GET_DN_AVAILABILITY&domainName=".$this->domainName."&username=".$this->userName."&password=".$this->password."&outputFormat=".$this->outputFormat);
$result = json_decode($domain_details);
$this->isDomainAvailable = ($result->DomainInfo->domainAvailability==='AVAILABLE')?TRUE:FALSE;
return $this->isDomainAvailable;

* Check available lookups
* @return bool

public function getAvailableLookups(){
$accountDetails = @file_get_contents(self::ACCOUNT_SERVICE_URL."servicetype=accountbalance&username=".$this->userName."&password=".$this->password);

$xmlDoc = new DOMDocument();

$balance = $xmlDoc->getElementsByTagName('balance');
$this->accountBalance = $balance->item(0)->nodeValue;
$this->accountBalance = 0;
exit('An unexpected error has occured');
return $this->accountBalance;


$dnc = new CheckDomainNameAvailability();

//To check domain name availability - you can enter domain name witho or without 'www'.

$domainaName = '';
$available = $dnc->getDomainNameAvailability($domainaName);
echo $domainaName." is ".(($available==FALSE)?" not ":" ")."available";

//To check account balance

$balance = $dnc->getAvailableLookups();
echo "You have ".$balance." remaining lookups";
echo "Your account balance is zero";