email validation for localparts that contain dot - email

Question

What I'm doing:
Trying to reduce spammers who wants to register in my site.
And I know that:
Dot is ignored in gmail and you can put dots in everywhere of the localpart of the email address but the first position and last before #.
Problem:
When a user register in the site with ex.ample#gmail.com, everthing is ok, but problem arise when he can register again with ex.am.pl.e#gmail.com etc in the site.
what I did was:
removing any dot in the local part of the email, but I realized that the user can't submit with his email address that he just entered.
What I want is that:
Is there a way to overcome this problem? 'cause with this situation a person can register so many times by changing the dot position in the email address.

Answer 1

I'm sure you found the solution by now, but for the sake of completeness...
Basically you'd need to store the local part as is, without stripping the dots out, and later strip the dots out from both application and registry upon comparison. Like:
$registered_emails[0]="e.xample#gmail.com"; //This is just to show how it was registered first time
$application_email="exam.ple#gmail.com"; //New application email
$discard=0; //flag for discarding application
if (preg_match("/#gmail.com$/i", $application_email)===1) {
$app_em=str_replace(".", "", $application_email);
foreach ($registered_emails as $reg_em)
if ($app_em==str_replace(".", "", $reg_em)) {
// "example#gmailcom"=="example#gmailcom"
$discard=1; // discard application
break;
}
//can't use an "else" clause here to break, as you need to loop through all registries
}
if ($discard==1)
echo "discard application";
else
array_push($registered_emails, $application_email); //register $application_email as is (exam.ple#gmail.com)
Probably it could be worth to filter out all gmail emails from the list before, or even storing all gmail emails aside; certainly not the most elegant solution, but probably the fastest one