PHP preg_match email validation: PHP

by: OdengrPosted on 2009-08-18 at 09:06:37ID: 25124683

You code doesnt check for domains, only for username.

I use this code to validate an email address.

If is valid returns an array with username + hostname.
use implode("@", $array) to merge them.
Else return false.

Hope I helped you!

function ValidateAddress($data, $strict = false) 
{ 
  $regex = $strict? 
      '/^([.0-9a-z_-]+)@(([0-9a-z-]+\.)+[0-9a-z]{2,4})$/i' : 
       '/^([*+!.&#$¦\'\\%\/0-9a-z^_`{}=?~:-]+)@(([0-9a-z-]+\.)+[0-9a-z]{2,4})$/i' 
  ; 
  if (preg_match($regex, trim($data), $matches)) { 
    return array($matches[1], $matches[2]); 
  } else { 
    return false; 
  } 
}

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by: Slick812Posted on 2009-08-18 at 09:12:42ID: 25124759

Hello allanch08, , I have seen many many different attempts on "How To validate Email" web pages for php, with the preg_match or other preg functions, many of these were based on an older standard than the RFC 5322. For me none of them did a great job, but they all worked to some extent. I now use the php filter_var( ) to validate email, this seems to give good results. You can validate with the FILTER_VALIDATE_EMAIL, and also it offers the FILTER_SANITIZE_EMAIL , which can be helpful.
I will include code for a "Test" page in php

<?php
error_reporting(E_ALL);
ini_set("log_errors",0);
ini_set("display_errors",1);
 
// place test emails in the array below
$aryEml= array('Stranded@hodgepodge.com','Set.Back+hop@ymail.com','lont@ornot.cc.co',"moot+doop@hippy.org\r\nkool@log.log",'fizzed@bolo.co.cc&#10&#13cc:has@beem.com');
foreach ($aryEml as &$ref) {
$ref=filter_var($ref, FILTER_SANITIZE_EMAIL);
}
?>
<html><head><title>Email Filter test</title></head>
<BODY BGCOLOR="#bfdf9a"><table width="840" border="1" cellpadding="5"><tr><td><h2>Email Filter test</h2>
<b>First Filter SANITIZE_EMAIL</b><p>
<?php
foreach ($aryEml as &$ref) {echo $ref.'<br>';
	if(!filter_var($ref, FILTER_VALIDATE_EMAIL)) $ref='NOT valid';
	}
?></p><p><b>Second Filter VALIDATE_EMAIL</b></p><p>
<?php
foreach ($aryEml as $ref) echo $ref.'<br>';
?>
</p></td></tr></table></body></html>

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by: allanch08Posted on 2009-08-18 at 09:22:23ID: 25124882

thanks for replies. the code I quoted was for the local part only. i've seen many examples on the web and some better then others, just need expert clarification on this issue. So is FILTER_VALIDATE_EMAIL fairly new? my webserver uses PHP 4.

by: Slick812Posted on 2009-08-18 at 11:18:13ID: 25125990

I beleive that the filter_var( ) function is somewhat new php function, you really shoud do a php manual check for any php functions you are not familiar with, the web addy for the manual is -
http://us.php.net/filter_var

according to it, you will need php ver 5.2 or above, so that leaves you out, I guess. . . The php ver 4 is way old now, you will find alot of code in these experts-ex examples that don't work so well in ver 4

I'll give you my limited opinion, even with the best email validate methods, there's going to be something that's valid, that doesn't pass, and something invalid that does pass. There's so many email addys now that people try all kinds of character substitutes to get something close to what they want. To make it worse, I have read that some Email servers (online emails) do not absolutely follow the RFC standards. (and the RFC standards change from time to time). So you might consider the importance of what you are validating the email for, and then use the least restrictive method for the amount of security you need, I know that what I have just said may not apply for you, or you just want an easy to use way to validate, but as you have seen there are many, and if you are like me, I have no real good way to tell if one is better than another, I am sure that this validate email has been asked here at EE many times before.

by: Slick812Posted on 2009-08-18 at 11:49:56ID: 25126261

Oh well, here a link I have to a web page that give some info about php email validation -
http://www.linuxjournal.com/article/9585

This was posted on June 1st, 2007, so it's kinda old, but it shows some of the steps to take for better validation

by: Ray_PaseurPosted on 2009-08-18 at 14:36:50ID: 25127925

Page 243 of Eli White's excellent book, PHP5 in Practice shows the REGEX this way. I add the test for the routable domain. This is as close as I have been able to get to the "truth" without actually sending a CAPTCHA message and getting a response.

// TEST FOR A VALID EMAIL ADDRESS, RETURN TRUE OR FALSE
function check_valid_email($email)
{
// IS THE PATTERN OF THE EMAIL ADDRESS OK?
    if (!preg_match('/^[A-Z0-9_-][A-Z0-9._-]*@([A-Z0-9][A-Z0-9-]*\.)+[A-Z]{2,6}$/i', $email)) return FALSE;
// IS THE DOMAIN OF THE EMAIL ADDRESS ROUTABLE OVER THE INTERNET FOR MX OR A RECORDS?
    $emaila = explode('@', $email);
    if ( checkdnsrr($emaila[1],"MX") || checkdnsrr($emaila[1],"A") ) return TRUE;
// NOT ROUTABLE
    return FALSE;
}

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by: Ray_PaseurPosted on 2009-08-18 at 14:44:14ID: 25127975

Here is that function wrapped in a form so you can install this script and test it. HTH, ~Ray

<?php // RAY_email_validation.php
error_reporting(E_ALL);
 
 
// A FUNCTION TO TEST FOR A VALID EMAIL ADDRESS, RETURN TRUE OR FALSE
function check_valid_email($email)
{
 
    // IS THE PATTERN OF THE EMAIL ADDRESS OK?
    if (!preg_match('/^[A-Z0-9_-][A-Z0-9._-]*@([A-Z0-9][A-Z0-9-]*\.)+[A-Z]{2,6}$/i', $email)) return FALSE;
    
    // IS THE DOMAIN OF THE EMAIL ADDRESS ROUTABLE OVER THE INTERNET FOR MX OR A RECORDS?
    $emaila = explode('@', $email);
    if ( checkdnsrr($emaila[1],"MX") || checkdnsrr($emaila[1],"A") ) return TRUE;
    
    // NOT ROUTABLE
    return FALSE;
}
 
 
// DEMONSTRATE THE FUNCTION IN ACTION
if (!empty($_GET["e"]))
{
    $e = $_GET["e"];
    if (check_valid_email($e))
    {
        echo "<br/>VALID: $e \n";
    } else
    {
        echo "<br/>BOGUS: $e \n";
    }
}
// END OF PHP - PUT UP THE FORM
?>
<form method="get">
TEST A STRING FOR A VALID EMAIL ADDRESS:
<input name="e" />
<input type="submit" />
</form>

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by: allanch08Posted on 2009-08-18 at 23:02:59ID: 25129933

thanks Slick812, I had a rethink and I don't really need to have a 100% accurate email validation, just my curiosity that lead me to looking for one.

thanks ray for the code, I'll look into it more and try implementing it.

by: allanch08Posted on 2009-08-18 at 23:05:44ID: 31617130

thanks for help

Question

PHP preg_match email validation

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