Re:SQL Keys in Depth
by Dylan16807 on Wednesday January 03, 2018 @04:47AM
(#16059719)
That's an interesting choice of rules. When cutting down the complexity so drastically, do you really need to double the length of your regex just to enforce the rule that dashes only appear in the middle of a domain segment? This version is so much more legible:
/^[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9-]{1,63}(?:\.[a-zA-Z0-9-]{1,63})*$/
> This requirement is a willful violation of RFC 5322, which defines a syntax for e-mail addresses that is simultaneously too strict (before the "@" character), too vague (after the "@" character), and too lax (allowing comments, whitespace characters, and quoted strings in manners unfamiliar to most users) to be of practical use here.
> The following JavaScript- and Perl-compatible regular expression is an implementation of the above definition.
> /^[a-zA-Z0-9.!#$%&'+\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)$/
To quote the DBA Stack Exchange post, "if it's good enough for HTML5, it's probably good enough for you". And if you're using inputs with `type="email"` in HTML5, you already are constraining your emails to that format.
(That said, it sounds like the regular expression you were asked to use was not a good one)
[2] https://html.spec.whatwg.org/multipage/input.html#valid-e-ma...