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Perfect email regex finally found

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Re: Perfect email regex finally found

#61

Post by huherto »

snprbob86 wrote: post #38

So many web services do this wrong, that it isn't even worth doing it right: no one is going to complain that your service doesn't accept their "wacky! quoted"@email.address Sometimes, you aren't validating a whole string, you are searching for email addresses in a sea of text, or an arbitrarily delimited, user-entered list of contacts. Support usernames with alphanumerics, dashes, underscores, periods, and plus sign…

I see your point. If somebody is using something weird, they probably have problems everywhere.

Re: Perfect email regex finally found

#62

Post by ElbertF »

pornel wrote: post #37
percept wrote: post #14

I've accepted that it's best to treat people like grown-ups and if there's '@' and '.' and it's retyped then it passes. Someone can easily submit a fake name or phone number or street address, and e-mail's no different. If they get it wrong, intentionally or not, then they don't get their receipt, confirmation, validation link, etc. and I believe in most cases the incentive is there for them to get it right. In the r…

Retyped!? Grown-ups can read what they write. Retyping only makes sense for password field, which is obfuscated and doesn't allow copy&paste.

My routine for dealing with a second e-mail field is shift+tab, ctrl+a, ctrl+c, tab, ctrl-v. Usually auto-fill takes care of the first fields anyway, never of the second one. It doesn't help me in any way.

Re: Perfect email regex finally found

#63

Post by mhartl »

jeff18 wrote: post #42
pornel wrote: post #37

Earlier quoted context omitted.

Retyped!? Grown-ups can read what they write. Retyping only makes sense for password field, which is obfuscated and doesn't allow copy&paste.

I would estimate about 0.25% of people will make a typo like "@homail.com" or "@gmial.com" Multiply that by say, 130,000 people, and you are dealing with 325 people who don't receive their download, etc. and are not happy! I think what would be really awesome is a regex that catches these common typos and warns the user immediately.

True, but you have to balance that against the small but nonzero number of people put off by an extra text field. Plus, I would find email repetition more annoying if I didn't always do Cmd-A/Cmd-C/Tab/Cmd-V, and in this case the repeated field won't catch any errors.

Re: Perfect email regex finally found

#64

Post by gojomo »

sigzero wrote: post #57
gojomo wrote: post #11

Nothing is finished, nothing is permanent, and nothing is perfect. In particular, one of the evaluation tests used here is wrong: it requires failure-to-match on a TLD with a digit in it: numbersInTLD@domain.c0m In fact, IDN TLDs will have digits in them. An internet-draft is in the works to replace RFC1123's IDN-unfriendly implication that digits in TLDs are illegal: http://tools.ietf.org/html/draft-liman-tld-names-…

If you say "will have" and "in the works" means it isn't the standard and the current test is valid.

A nice try at pedantry, which I would usually respect, but in the domain of internet standards with which I familiar, you are wrong.

The existing specs are in conflict, with the more recent ones (such as IDN) allowing digits. Internet authorities, including ICANN, have enabled domains with digits in TLDs; software which is far more foundational than any web-app's email validation regex has been updated.

Registration of names in some of these digited-TLDs has begun; you can visit these TLDs with your browser; your users can have functioning email addresses on these TLDs.

If your app rejects such email addresses because of slavish compliance with imprecise language in a 31-year-old RFC, you'd be the one violating prevailing standards, which are a function of more than just formal IETF RFCs.

That the Internet-Draft I referenced may soon become an RFC is just cleaning up loose ends on a change that's already happened. This final step isn't even strictly necessary for the de facto standard to have changed by consensus among practitioners. Plenty of vibrant well-understood standards never reach RFC status, nor pass through any formal standards body. The standard is ultimately what people do, not what someone once-upon-a-time decreed.

Re: Perfect email regex finally found

#65

Post by lazyant »

AFAIK a naked IP address as domain like IPInsteadOfDomain@127.0.0.1 doesn't work (at least in some mail servers like Postfix they are bounced with a "bad address syntax error). The address has to be like IPInsteadOfDomain@[127.0.0.1] and I don't see this case covered.

Re: Perfect email regex finally found

#66

Post by mike-cardwell »

jbr wrote: post #28
percept wrote: post #14

I've accepted that it's best to treat people like grown-ups and if there's '@' and '.' and it's retyped then it passes. Someone can easily submit a fake name or phone number or street address, and e-mail's no different. If they get it wrong, intentionally or not, then they don't get their receipt, confirmation, validation link, etc. and I believe in most cases the incentive is there for them to get it right. In the r…

Along those lines, I've settled on the following overly permissive regex: /^[^\s@]+@[^\s@]+\.[^\s@]{2,}$/ -- it makes sure it looks something like an email address (a@b.cd)

What if my email address is:

"@"@example.com

?

Re: Perfect email regex finally found

#68

Post by th »

gojomo wrote: post #11

Nothing is finished, nothing is permanent, and nothing is perfect. In particular, one of the evaluation tests used here is wrong: it requires failure-to-match on a TLD with a digit in it: numbersInTLD@domain.c0m In fact, IDN TLDs will have digits in them. An internet-draft is in the works to replace RFC1123's IDN-unfriendly implication that digits in TLDs are illegal: http://tools.ietf.org/html/draft-liman-tld-names-…

Those hard-coded top-level domains in the "improved" regex may also be also an issue: http://en.wikipedia.org/wiki/Top-level_domain#Proposed_domai...

Re: Perfect email regex finally found

#69

Post by tgandrews »

Zak wrote: post #43
jeff18 wrote: post #42

Earlier quoted context omitted.

I would estimate about 0.25% of people will make a typo like "@homail.com" or "@gmial.com" Multiply that by say, 130,000 people, and you are dealing with 325 people who don't receive their download, etc. and are not happy! I think what would be really awesome is a regex that catches these common typos and warns the user immediately.

You'd need something more along the lines of a spell checking algorithm to do that sanely. Don't abuse regular expressions for things they're not good at.

Yeah, that python script (from StackOverflow London - http://norvig.com/spell-correct.html) that learned what was correct from a large number of words would work. Analyse your DB of users' email address url (after @) that have registered fully and provide a "Did you mean.." type response if a new users email url was not found and something close (within 2 alterations) to it was.

Re: Perfect email regex finally found

#70

Post by Zev »

percept wrote: post #14

I've accepted that it's best to treat people like grown-ups and if there's '@' and '.' and it's retyped then it passes. Someone can easily submit a fake name or phone number or street address, and e-mail's no different. If they get it wrong, intentionally or not, then they don't get their receipt, confirmation, validation link, etc. and I believe in most cases the incentive is there for them to get it right. In the r…

There are more reasons to check for an email than simply validation. Perhaps you want to detect emails in a field and let people click/tap on them to send that person an email? Don't want to let people send email off to foo@bar.baz now, do we?
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