4 ms·

Validating Email Addresses with a Regex? Do Yourself a Favor and Don’t

• herbst 10y ago
  Did i miss it or did you forget that domains also can be punycode? My devise this days is, if i need to know the email works. I'll just send them a email.
  • greengobble 10y ago
    > Did i miss it or did you forget that domains also can be punycode? That's an interesting question. DNS doesn't handle non-ASCII characters, so you have to encode them as xn--SOMETING. This will validate. Debatable if it should because it means you have to handle it in the code you are validating for. > My devise this days is, if i need to know the email works. I'll just send them a email. Making validation someone else's problem ;)? Sure, that works, unless your task involves cleaning up a database containing a couple million addresses.
    • herbst 10y ago
      True. thats a different use case. I may would except you (the form or whatever) to translate my inputs to punycode. I live in a german/french country special chars in domains are not exactly unusual, but i avoid them for myself because i've encountered so many sites that simply ignore there existence.
      • greengobble 10y ago
        I guess, that's the whole point of the blogpost: when you try to validate email addresses with a regex, you are screwed with unicode domains. It is not clear if you should let them pass, only let them pass if they are properly encoded or not let them pass at all (as the software behind the validator is clueless about them either way). Building the DFA yourself gives you more control.