Interesting article: http://coveryourasp.com/ValidateEmail.asp See also: http://search.cpan.org/~cwest/Email-Address-1.80/lib/Email/Address.pm http://www.faqs.org/rfcs/rfc2822.html http://docs.python.org/lib/module-rfc822.html > -----Original Message----- > From: pgsql-general-owner@xxxxxxxxxxxxxx [mailto:pgsql-general- > owner@xxxxxxxxxxxxxx] On Behalf Of Steve Atkins > Sent: Thursday, October 20, 2005 12:35 PM > To: pgsql-general@xxxxxxxxxxxxxx > Subject: Re: Select all invalid e-mail addresses > > On Thu, Oct 20, 2005 at 11:52:40AM -0400, Andrew Sullivan wrote: > > On Thu, Oct 20, 2005 at 06:10:40PM +0300, Andrus wrote: > > > >From this thread I got the regular expression > > > > [snipped] > > > > Note that that regular expression, which appears to be validating > > TLDs as well, is incredibly fragile. John Klensin has actually > > written an RFC about this very problem. Among other problems, what > > do you do when a country code ceases to be? (There's a similar > > problem that the naming bodies struggke with from time to time.) > > > > I suggest that if you want to validate TLDs, you pull them off when > > you write the data in your database, and use a lookup table to make > > sure they're valid (you can keep the table up to date regularly by > > checking the official IANA registry for them). At least that way you > > don't have to change a regex every time ICANN decides to add another > > TLD. > > You need to maintain the data, certainly. To argue that it must > be in a table to be maintained is, well, wrong. My preference would > be to keep it in a table and regenerate the regex periodically, and > in the application layer I do exactly that, but to try and do that > in a check constraint would be painful. A cleaner approach would > be to have a regex that checks for general syntax and extracts the > TLD, which is then compared to a lookup table, perhaps, but that > adds a lot of complexity for no real benefit. > > > (The regex is wrong anyway, I think: it doesn't have .mobi, > > which has been announced although isn't taking registrations yet, and > > it doesn't appear to have arpa, either.) > > While there are valid deliverable email addresses in .arpa, you really > don't want to be accepting them from end users... > > Cheers, > Steve > > ---------------------------(end of broadcast)--------------------------- > TIP 4: Have you searched our list archives? > > http://archives.postgresql.org ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
