From: "Julian I. Kamil" <julian.kamil@...>
Date: 2006-03-08T11:33:41+09:00
Subject: Re: Valid email address from CGI input?

How about this for checking the grammar:

def email_valid?(email_address)
    email_address =~
/^([a-zA-Z0-9&_?\/`!|#*$^%=~{}+'-]+|"([\x00-\x0C\x0E-\x21\x23-\x5B\x5D-\x7F]|\\[\x00-\x7F])*")(\.([a-zA-Z0-9&_?\/`!|#*$^%=~{}+'-]+|"([\x00-x0C\x0E-\x21\x23-\x5B\x5D-\x7F]|\\[\x00-\x7F])*"))*@([a-zA-Z0-9&_?\/`!|#*$^%=~{}+'-]+|\[([\x00-\x0C\x0E-\x5A\x5E-\x7F]|\\[\x00-\x7F])*\])(\.([a-zA-Z0-9&_?\/`!|#*$^%=~{}+'-]+|\[([\x00-\x0C\x0E-\x5A\x5E-\x7F]|\\[\x00-\x7F])*\]))*$/
end

To ensure that it is a working email address, I'd do email
verification.  Send an email with an activation code to the address,
and ask the recipient to 'activate' their email registration.  That's
how email registration works in Pandora (http://pandora.rubyveil.com/).

Best regards,

Julian I. Kamil <julian.kamil@gmail.com>
http://pandora.rubyveil.com/ - document publishing and web application
platform
http://books.rubyveil.com/ - The Ruby Bookshelf