I am working on a rails3 project. Is there a tool to validate the format of email address. It does not have to be fancy regex. Just a few simple validations. However I don't want to reinvent the wheel?
you can use javascript or your own regx. do you need the code?
I'm using this:
:format => { :with => /^([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})$/i }
I use whatever that comes with restful_authentication scaffold generator and for the most part it works fine for me: /^[-a-z0-9_+\.]+\@([-a-z0-9]+\.)+[a-z0-9]{2,4}$/i
If you want to learn more about this or more control over it, I suggest you read How to Find or Validate an Email Address
-sunny http://ezror.com
Using a regex to validate an email format is in most cases a bad idea, the 2 proposed regexes won't for example recognize quoted local parts, which are valid (e.g. "foo@bar"@rails.info is a valid address). There's a validate_email_format_of plugin on github[1] which works fine on rails2, I think there is a branch/fork for rails3 somewhere too. Another method would be to just drop an EmailValidator into your lib so that you can reuse it at other places in your rails app, have a look at [2] (yes, it still is a regex and only matches what the RFC refers to as "addr-spec" as opposed to a "full" address, but a not-so-bad one).
Anyway, I'm a little surprised that rails3 having gone from TMail to Mail hasn't added a validator that would re-use the one already present in Mail…
Regards,
Felix
[1] http://github.com/alexdunae/validates_email_format_of [2] Redirecting…
Felix, I believe it does. In fact I did a quick check of both .info and .me and they worked fine.
-sunny http://ezror.com
Felix Schäfer wrote:
The point being the localpart "foo@bar" (and yes, the quotes are part of the localpart) in "foo@bar"@rails.info, not the TLD.
Oh, and you should use \A and \z (string delimiters) over ^ and $ (line delimiters), as your regex will also validate strings of the form: foo@bar.com\nSome-funky-DB-buster .
Best,
Felix
there is a plugin/gem that tries to find what ever its you have after the @ in the dns servers mx records, i have never use it.
Hi,
I think this is good plugin for email validation...
http://github.com/spectator/validates_email
PB
Nadal wrote:
I am working on a rails3 project. Is there a tool to validate the format of email address. It does not have to be fancy regex. Just a few simple validations. However I don't want to reinvent the wheel?
No reasonable regex will do the trick, since e-mail addresses can take so many formats. Just check for an @ and one . , and trust the user for the rest. If you need to check whether the address works, send the user an activation code.
Do not use regexes to validate e-mail addresses.
Best,
Pffft.
Nah, I'm with Marnen on this. Trying to regex validate an email with
100% surety is a sure-fire way of annoying someone. Same with
postcodes, and even more so with names (can you believe that some
people think they can regex what *name* a person may have - I've seen
it; it's rubbish! 
You can probably regex close to all potential email addresses, but as Marnen says, the best way to validate an email address is to send an email to it.
Michael Pavling wrote:
Do not use regexes to validate e-mail addresses.
Pffft.
Nah, I'm with Marnen on this. Trying to regex validate an email with 100% surety is a sure-fire way of annoying someone.
I have seen regexes that purport to actually be correct for e-mail validation. They are on the order of a page in length when printed in reasonably-sized type.
Same with postcodes,
Really? Shouldn't you at least be able to come up with *country-specific* regexes for those?
> and even more so with names (can you believe that some
people think they can regex what *name* a person may have - I've seen it; it's rubbish!
As the proud bearer of a hyphenated last name, I am intimately familiar with this brand of rubbish.
You can probably regex close to all potential email addresses, but as Marnen says, the best way to validate an email address is to send an email to it.
Best,
You might get away without validating email addresses for a small site, one where you can easily bulk-delete bounced messages. For a large site you're creating a ton of extra work for someone, all because you can't be bothered to write a simple regex.
I couldn't imagine paying a marketing company for new users and not at least doing a simple regex validation on the email address as they arrive. You guys are really in-experienced.
Greg Donald wrote:
Do not use regexes to validate e-mail addresses.
Pffft.
Nah, I'm with Marnen on this.
You might get away without validating email addresses for a small site, one where you can easily bulk-delete bounced messages. For a large site you're creating a ton of extra work for someone, all because you can't be bothered to write a simple regex.
A "simple" regex won't do it. The range of legitimate e-mail address forms is simply too great. Go read RFC 2822 and http://www.linuxjournal.com/article/9585&ved=0CBYQFjAC&usg=AFQjCNHU_zypiBJyMSvi-aD2ueMftTOecg
I couldn't imagine paying a marketing company for new users and not at least doing a simple regex validation on the email address as they arrive. You guys are really in-experienced.
I'm experienced enough to know that e-mail addresses are a lot more complex than inexperienced people think. Go educate yourself with the references above.
-- Greg Donald destiney.com | gregdonald.com
Best,
Marnen Laibow-Koser wrote:
Greg Donald wrote:
Do not use regexes to validate e-mail addresses.
Pffft.
Nah, I'm with Marnen on this.
You might get away without validating email addresses for a small site, one where you can easily bulk-delete bounced messages. For a large site you're creating a ton of extra work for someone, all because you can't be bothered to write a simple regex.
A "simple" regex won't do it. The range of legitimate e-mail address forms is simply too great. Go read RFC 2822 and http://www.linuxjournal.com/article/9585&ved==AFQjCNHU_zypiBJyMSvi-aD2ueMftTOecg
Also RFC 5322 and the (just published, apparently) is_email by dominicsayers .
Best,
You guys are really in-experienced.
Nice tone. I didn't know you'd evaluated my CV (it's not exactly secret materiel though)
I couldn't imagine paying a marketing company for new users and not at least doing a simple regex validation on the email address as they arrive.
The "simple regex" you'd use for such a check is that if a string has some characters followed by an "@" then some more characters with at least one full-stop in them ("period", for the leftpondians), then it's *possibly* an email address, which could be either valid (by being of a format that passes the relevant RFC) and valid (there is actually a mailbox at the other end of it). Marnen has already said that such a cursory check is where you should really stop unless you want a hiding to nothing (and without reverse-engineering them to check for sure, it looks like the example regexes above do just this). However, you can't know *for sure* whether a string passes the former meaning of "valid" without a *really big* regex, and you can't know the latter unless you send a message to it.
You might get away without validating email addresses for a small site, one where you can easily bulk-delete bounced messages. For a large site you're creating a ton of extra work for someone, all because you can't be bothered to write a simple regex.
What work? For who? I'm curious, because I think we must be talking at crossed-purposes if you think we're so far out of line.
If you want to "validate" an email address that someone has typed in to a "please enter your email address for registration" box, the simplest way to validate that address is to send it an email (after performing the "simple" check to see if it even vaguely resembles an email address), with a unique link for the recipient to click to prove the email address works, and that they have access to it.
If you've bought 10,000,000 "email addresses" from a marketing company, then of course a "simple" regex check against each is sensible; what we've said is "bad" is the hope that one can try to guarantee a string could be a valid email address (this, some people do try to do).
I'm being UK-centric here, so YMMV, but I once worked at a company which had a postcode ("WC1E 4HR") that I regularly got "sorry, that postcode is invalid" messages popped-up at me when I tried to buy stuff online. That was mostly due to "simple" regexes not accepting a letter after a number in the district code.
Michael Pavling wrote:
