[wp-hackers] is_email

Nikolay Bachiyski nbachiyski at developer.bg
Sat Mar 26 07:36:23 GMT 2005

Dougal Campbell wrote:
> Because it's possible to have those characters in username and hostname 
> portions of email addresses.
I appologize. I shouldn't have posted it before some investigation...

In particular, it's long been a convention
> that many mail servers allow addresses like "user+whatever at example.com", 
> and automagically alias it to "user at example.com". This allows you to 
> generate your own dynamic aliases. It's useful for tracking who's 
> sharing your address. I often use that trick when supplying registration 
> information. For example, if I registered my email address with the New 
> York Times as "dougal+nytimes at gunters.org", then if I get spam to that 
> address later, I know that the Times shared my address (and I can 
> blackhole further email to that address if I want).
Really nice. I didn't know it.

>> Here is a suggestion:
>> $email_regex = '/^[a-z0-9_\-.]+\@([a-z0-9\-]{1,255}\.)+[a-z]{2,6}$/i';
> I'm not sure why '.' was separated out, but I've seen people put '-' 
> outside of a character class due to bugs in some regex implementations. 
> I can't remember if PHP had that bug or not. If not, then I think your 
> suggestion would be a good one.
I haven't experienced any problems with a dash in a character class. 
Though I use it pretty often.


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