www.mikescher.com/framework/validators/CUrlValidator.php

<?php
/**
 * CUrlValidator class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright 2008-2013 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CUrlValidator validates that the attribute value is a valid http or https URL.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package system.validators
 * @since 1.0
 */
class CUrlValidator extends CValidator
{
	/**
	 * @var string the regular expression used to validate the attribute value.
	 * Since version 1.1.7 the pattern may contain a {schemes} token that will be replaced
	 * by a regular expression which represents the {@see validSchemes}.
	 */
	public $pattern='/^{schemes}:\/\/(([A-Z0-9][A-Z0-9_-]*)(\.[A-Z0-9][A-Z0-9_-]*)+)/i';
	/**
	 * @var array list of URI schemes which should be considered valid. By default, http and https
	 * are considered to be valid schemes.
	 * @since 1.1.7
	 **/
	public $validSchemes=array('http','https');
	/**
	 * @var string the default URI scheme. If the input doesn't contain the scheme part, the default
	 * scheme will be prepended to it (thus changing the input). Defaults to null, meaning a URL must
	 * contain the scheme part.
	 * @since 1.1.7
	 **/
	public $defaultScheme;
	/**
	 * @var boolean whether the attribute value can be null or empty. Defaults to true,
	 * meaning that if the attribute is empty, it is considered valid.
	 */
	public $allowEmpty=true;
	/**
	 * @var boolean whether validation process should care about IDN (internationalized domain names). Default
	 * value is false which means that validation of URLs containing IDN will always fail.
	 * @since 1.1.13
	 */
	public $validateIDN=false;

	/**
	 * Validates the attribute of the object.
	 * If there is any error, the error message is added to the object.
	 * @param CModel $object the object being validated
	 * @param string $attribute the attribute being validated
	 */
	protected function validateAttribute($object,$attribute)
	{
		$value=$object->$attribute;
		if($this->allowEmpty && $this->isEmpty($value))
			return;
		if(($value=$this->validateValue($value))!==false)
			$object->$attribute=$value;
		else
		{
			$message=$this->message!==null?$this->message:Yii::t('yii','{attribute} is not a valid URL.');
			$this->addError($object,$attribute,$message);
		}
	}

	/**
	 * Validates a static value to see if it is a valid URL.
	 * Note that this method does not respect {@link allowEmpty} property.
	 * This method is provided so that you can call it directly without going through the model validation rule mechanism.
	 * @param string $value the value to be validated
	 * @return mixed false if the the value is not a valid URL, otherwise the possibly modified value ({@see defaultScheme})
	 * @since 1.1.1
	 */
	public function validateValue($value)
	{
		if(is_string($value) && strlen($value)<2000)  // make sure the length is limited to avoid DOS attacks
		{
			if($this->defaultScheme!==null && strpos($value,'://')===false)
				$value=$this->defaultScheme.'://'.$value;

			if($this->validateIDN)
				$value=$this->encodeIDN($value);

			if(strpos($this->pattern,'{schemes}')!==false)
				$pattern=str_replace('{schemes}','('.implode('|',$this->validSchemes).')',$this->pattern);
			else
				$pattern=$this->pattern;

			if(preg_match($pattern,$value))
				return $this->validateIDN ? $this->decodeIDN($value) : $value;
		}
		return false;
	}

	/**
	 * Returns the JavaScript needed for performing client-side validation.
	 * @param CModel $object the data object being validated
	 * @param string $attribute the name of the attribute to be validated.
	 * @return string the client-side validation script.
	 * @see CActiveForm::enableClientValidation
	 * @since 1.1.7
	 */
	public function clientValidateAttribute($object,$attribute)
	{
		if($this->validateIDN)
		{
			Yii::app()->getClientScript()->registerCoreScript('punycode');
			// punycode.js works only with the domains - so we have to extract it before punycoding
			$validateIDN='
var info = value.match(/^(.+:\/\/|)([^/]+)/);
if (info)
	value = info[1] + punycode.toASCII(info[2]);
';
		}
		else
			$validateIDN='';

		$message=$this->message!==null ? $this->message : Yii::t('yii','{attribute} is not a valid URL.');
		$message=strtr($message, array(
			'{attribute}'=>$object->getAttributeLabel($attribute),
		));

		if(strpos($this->pattern,'{schemes}')!==false)
			$pattern=str_replace('{schemes}','('.implode('|',$this->validSchemes).')',$this->pattern);
		else
			$pattern=$this->pattern;

		$js="
$validateIDN
if(!value.match($pattern)) {
	messages.push(".CJSON::encode($message).");
}
";
		if($this->defaultScheme!==null)
		{
			$js="
if(!value.match(/:\\/\\//)) {
	value=".CJSON::encode($this->defaultScheme)."+'://'+value;
}
$js
";
		}

		if($this->allowEmpty)
		{
			$js="
if(jQuery.trim(value)!='') {
	$js
}
";
		}

		return $js;
	}

	/**
	 * Converts given IDN to the punycode.
	 * @param string $value IDN to be converted.
	 * @return string resulting punycode.
	 * @since 1.1.13
	 */
	private function encodeIDN($value)
	{
		if(preg_match_all('/^(.*):\/\/([^\/]+)(.*)$/',$value,$matches))
		{
			if(function_exists('idn_to_ascii'))
				$value=$matches[1][0].'://'.idn_to_ascii($matches[2][0]).$matches[3][0];
			else
			{
				require_once(Yii::getPathOfAlias('system.vendors.Net_IDNA2.Net').DIRECTORY_SEPARATOR.'IDNA2.php');
				$idna=new Net_IDNA2();
				$value=$matches[1][0].'://'.@$idna->encode($matches[2][0]).$matches[3][0];
			}
		}
		return $value;
	}

	/**
	 * Converts given punycode to the IDN.
	 * @param string $value punycode to be converted.
	 * @return string resulting IDN.
	 * @since 1.1.13
	 */
	private function decodeIDN($value)
	{
		if(preg_match_all('/^(.*):\/\/([^\/]+)(.*)$/',$value,$matches))
		{
			if(function_exists('idn_to_utf8'))
				$value=$matches[1][0].'://'.idn_to_utf8($matches[2][0]).$matches[3][0];
			else
			{
				require_once(Yii::getPathOfAlias('system.vendors.Net_IDNA2.Net').DIRECTORY_SEPARATOR.'IDNA2.php');
				$idna=new Net_IDNA2();
				$value=$matches[1][0].'://'.@$idna->decode($matches[2][0]).$matches[3][0];
			}
		}
		return $value;
	}
}