Re: email address syntax checker

[Nilesh Govindarajan <nilesh@xxxxxxxxxx>]

On 01/20/2011 09:44 AM, Donovan Brooke wrote:
> Hi Guys,
>
> I'm waddling my way through database interaction and thought someone on
> the list may already have a simple email checker that they'd like to
> share...
>
> you know, looking for the @ char and dots etc..
>
> I did a quick search of the archives and found a couple elaborate
> things.. but
> I'm looking for something simple. This job will have trusted users and
> the checker is more to help them catch mistakes when registering.
>
> Thanks!,
> Donovan

Well, I had created an email validator long ago, after a neat research 
on Google, reading RFCs, etc.
I don't guarantee that it's without bugs, but it has been correct for me 
in all valid & invalid email addresses I used for test.

Code:

<?php

function checkMail($mail) {

  if(strlen($mail) <= 0) {
    return false;
  }

  $split = explode('@', $mail);

  if(count($split) > 2) {
    return false;
  }

  list($username, $domain) = $split;

  /* 


   * Don't allow
   * Two dots, Two @
   * !, #, $, ^, &, *, (, ), [, ], {, }, ?, /, \, ~, `, <, >, ', "
   */

  $userNameRegex1 = 
'/\.{2,}|@{2,}|[\!#\$\^&\*\(\)\[\]{}\?\/\\\|~`<>\'"]+/';

  /*
   * Username should consist of only
   * A-Z, a-z, 0-9, -, ., _, +, %
   */

  $userNameRegex2 = '/[a-z0-9_.+%-]+/i';

  /*
   * Domain cannot contain two successive dots
   */

  $domainRegex1 = '/\.{2,}/';

  /*
   * Domain can contain only
   * A-Z, a-z, 0-9, ., -,
   */

  $domainRegex2 = '/[a-z0-9.-]+/i';

  if(preg_match($userNameRegex1, $username) or
    !preg_match($userNameRegex2, $username) or
     preg_match($domainRegex1, $domain) or
    !preg_match($domainRegex2, $domain) or
    !checkdnsrr($domain, 'MX')) {
    return false;
  } else {
    return true;
  }

}


--
Regards,
Nilesh Govindarajan
Facebook: http://www.facebook.com/nilesh.gr
Twitter: http://twitter.com/nileshgr
Website: http://www.itech7.com

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