Command line app to verify whether an email-id exists or not

[Cupidvogel]

Hi, suppose I want to write a PHP script that checks whether a valid email address exists or not. There are a number of GUI-based tools to verify this, but is there any command line tool to do the same so that I can use PHP to capture the output?

[requinix]

Define "exists". And any particular reason it has to be used via the command line (as opposed to a normal script you'd use in a webpage)?

[Cupidvogel]

By valid I mean that the email address looks like an email address, i.e it is not something like abra..gamil.com, whereas by exists I mean that it actually exists, i.e there is indeed an email address by that name (and of course that means it is valid!). For example, [email protected] is a valid email address (it's my email id!), whereas [email protected] doesn't exist (hopefully!). I need it in order to verify a form credentials, it should check whether the email id the user entered exists or not so that it doesn't send notification emails to a non-existent email address. How to do it in PHP? Of course I don't want to ping the email-address with a dummy email to verify its existence!

[requinix]

Regular expressions are basically the way to go, but unless you want a (theoretically) perfect expression you'll have to settle for some false positives and/or false negatives. Google can help you get one of those.

Next is checking the domain name. getmxrr can look up the mail server for a domain, but if there isn't one you should assume that the hostname also acts as a mail server (IIRC that's part of the standard). You could go another step and try a connection to the server if you wanted.

 

After that you might be able to verify a "username" but it depends on whether the mail server is nice enough to help with that. Generally you don't have to go this far: services that use an address in, for example, a registration process send an email to confirm it. This is what you should do.

[Cupidvogel]

Okay...

[MMDE]

filter_var($email, FILTER_VALIDATE_EMAIL);

filter_var

 

How good this is, I'm not totally sure. I know there are some regex floating around, some take into consideration that some top level domains are more than 2 or 3 letters, but others do not. What FILTER_VALIDATE_EMAIL does exactly to check the email, I don't really know.

 

Oh, and as suggested above, send the user a confirmation e-mail they have to press a link in to really verify it's their e-mail address and it exists.

[Cupidvogel]

There is this page http://verify-email.org/ where you type an email-id, and click the button to check whether the id exists or not. Problem is that the email-id doesn't get appended to the URL for the page, or then I could use a web-scraper such as BeautifulSoup (Python) to capture the response. Any other way to capture the response in PHP?

[MMDE]

There is this page http://verify-email.org/ where you type an email-id, and click the button to check whether the id exists or not. Problem is that the email-id doesn't get appended to the URL for the page, or then I could use a web-scraper such as BeautifulSoup (Python) to capture the response. Any other way to capture the response in PHP?

You could use curl I think.

[requinix]

What FILTER_VALIDATE_EMAIL does exactly to check the email, I don't really know.

It uses a regular expression:

"/^(?!(??:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){255,})(?!(??:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){65,}@)(??:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22))(?:\\.(??:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22)))*@(??:(?!.*[^.]{64,})(??:(?:xn--)?[a-z0-9]+(?:-[a-z0-9]+)*\\.){1,126}){1,}(??:[a-z][a-z0-9]*)|(??:xn--)[a-z0-9]+))(?:-[a-z0-9]+)*)|(?:\\[(??:IPv6:(??:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){7})|(??!(?:.*[a-f0-9][:\\]]){7,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?:?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?)))|(??:IPv6:(??:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){5}|(??!(?:.*[a-f0-9]{5,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3})?:?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3}?)))?(??:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))(?:\\.(??:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))){3}))\\]))$/iD"

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