^(?:"(?:[^"\\]|\\.)+"|[-^!#\$%&'*+\/=?`{|}~.\w]+)@(?=.{3,255}$)(?:[\w][\w-]{0,62}\.){1,128}[\w][\w-]{0,62}$
Not perfect, but the best I can come up with, and most compliant I've found. I'd be interested to see other people's ideas, though. It's still not going to verify you an address fersure, properly, 100% guaranteed legit, though. What else can you do? Well, you could also:
* verify that the address is either a correct dotted-decimal IP, or contains letters.
* remove reserved domains (.localhost, .example, .test, .invalid), reserved IP ranges, and so forth from the address.
* check for banned domains (whitehouse.gov, example.com...)
* check for known TLDs including alt tlds.
* see if the domain has an MX record set up: if so, connect to that host, else connect to the domain.
* see if the given address is accepted by the server as a recipient or sender (this fails for yahoo.*, which blocks after a few attempts, assuming you are a spammer, and for other domains like rediffmail.com, home.com).
But these are moving well out of the realm of generic regex checks and into the realm of application-specific stuff that should be done in code instead - especially the latter two. Hopefully, this is all you needed to point out to your boss "hey, email validation this is a dark pit with no bottom, we really just want to do a basic check, then send them an email with a link in it: it's the industry standard solution."
Of course, if you want to go nuts, here's an idea that you could do. Wouldn't like to do it myself, though: I'd rather just trust them until their mail bounces too many times. But if you want it, this (untested) code checks to see if the mail domain works. It's based on a script by John Coggeshall and Jesse Houwing that also asked the server if the specific email address existed, but I disliked that idea for several reasons. I suspect: it will get you blocked as a spambot address harvester pretty quick; a lot of servers would lie to you; it would take too much time; this way you can cache domains marked as "OK"; and I suspect it would add little to the reliability test.
// Based on work by: John Coggeshall and Jesse Houwing.
// http://www.zend.com/zend/spotlight/ev12apr.php
mailRegex = '^(?:"(?:[^"\\\\]|\\\\.)+"|[-^!#\$%&\'*+\/=?`{|}~.\w]+)';
mailRegex .= '@(?=.{3,255}$)(?:[\w][\w-]{0,62}\.){1,128}[\w][\w-]{0,62}$';
function ValidateMail($address) {
global $mailRegex; // Yes, globals are evil. Put it inline if you want.
if (!preg_match($mailRegex)) {
return false;
}
list ( $localPart, $Domain ) = split ("@",$Email);
// connect to the first available MX record, or to domain if no MX record.
$ConnectAddress = new Array();
if (getmxrr($Domain, $MXHost)) {
$ConnectAddress = $MXHost;
} else {
$ConnectAddress[0] = $Domain;
}
// check all MX records in case main server is down - may take time!
for ($i=0; $i < count($ConnectAddress); $i++ ) {
$Connect = fsockopen ( $ConnectAddress[$i], 25 );
if ($Connect){
break;
}
}
if ($Connect) {
socket_set_blocking($Connect,0);
// Only works if socket_blocking is off.
if (ereg("^220", $Out = fgets($Connect, 1024))) {
fclose($Connect); // Unneeded, but let's help the gc.
return true;
}
fclose($Connect); // Help the gc.
}
return false;
}
yes
Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?
You must be signed in to comment.
commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.
Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.
» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10
Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):
Subscribe to the feed for: