changed EmailValidator MX check to be more useful

issue #1246

framework/yii/validators/EmailValidator.php

@@ -38,11 +38,22 @@ class EmailValidator extends Validator
 	 */
 	public $allowName = false;
 	/**
-	 * @var boolean whether to check the MX record for the email address.
-	 * Defaults to false. To enable it, you need to make sure the PHP function 'checkdnsrr'
-	 * exists in your PHP installation.
+	 * @var boolean whether to check whether the emails domain exists and has either an A or MX record.
+	 * Be aware of the fact that this check can fail due to temporary DNS problems even if the email address is
+	 * valid and an email would be deliverable. Defaults to false.
+	 * @see dnsMessage
 	 */
-	public $checkMX = false;
+	public $checkDNS = false;
+	/**
+	 * @var string the error message to display when the domain of the email does not exist.
+	 * It may contain the following placeholders which will be replaced accordingly by the validator:
+	 *
+	 * - `{attribute}`: the label of the attribute being validated
+	 * - `{value}`: the value of the attribute being validated
+	 *
+	 * @see checkDNS
+	 */
+	public $dnsMessage;
 	/**
 	 * @var boolean whether to check port 25 for the email address.
 	 * Defaults to false.
@@ -69,6 +80,9 @@ class EmailValidator extends Validator
 		if ($this->message === null) {
 			$this->message = Yii::t('yii', '{attribute} is not a valid email address.');
 		}
+		if ($this->dnsMessage === null) {
+			$this->dnsMessage = Yii::t('yii', 'The domain of this email address does not seem to exist.');
+		}
 	}
 
 	/**
@@ -105,8 +119,8 @@ class EmailValidator extends Validator
 		}
 		$valid = preg_match($this->pattern, $value) || $this->allowName && preg_match($this->fullPattern, $value);
 		if ($valid) {
-			if ($this->checkMX && function_exists('checkdnsrr')) {
-				$valid = checkdnsrr($domain, 'MX');
+			if ($this->checkDNS) {
+				$valid = checkdnsrr($domain, 'MX') || checkdnsrr($domain, 'A');
 			}
 			if ($valid && $this->checkPort && function_exists('fsockopen')) {
 				$valid = fsockopen($domain, 25) !== false;