Re: Email type

For RFCs support, there might be a dedicated namespace for corresponding 
types. That is what I have recently implemented in my own XQuery engine 
for types such as "ietf:email", "ietf:ipv4", "ietf:mac", "ietf:port",...

Specifically for email addresses, it is, at least, programmatically 
possible to check if the domain part is an effective mail server (a DNS 
request for an MX record). More likely, we want an existing email 
address than a one to be created for a domain to be created too!

It is, of course, a good idea to define our own "xf:email" type for a 
more commonly-used regular expression.

--Alain


Le 24/06/2017 à 00:57, Erik Bruchez a écrit :
> Validation schemes coming from specifications such as RFCs might be 
> correct, but they are not very useful to end users.
>
> It is true that some web sites/web apps reject email address which are 
> definitely valid in practice (I remember the rejection of the "+" 
> character in emails such as `erik+test@example.org 
> <mailto:erik%2Btest@example.org>` by some sites).
>
> But, witness Steven's example: it is technically true that 
> `steven@cwi` is correct, yet there are virtually zero users in 
> practice for whom that kind of email address will not be an actual error.
>
> So there is some tension here which is hard to solve: you don't want 
> to block users, but you also want validation to catch likely errors.
>
> A possible way around this could be to have two kinds of email 
> validations:
>
> 1. per RFC, which would catch a wide net and accept `steven@cwi` and 
> other rare-in-practice addresses
> 2. practical, which would reject `steven@cwi` and other funny cases
>
> This would work better if XForms had a concept of "warning" validation 
> (which our implementation supports): you could have a hard validation 
> catching certainly incorrect addresses and soft/warning validation for 
> the narrower validation. This would allow a determined user to enter a 
> likely incorrect email address if she is sure that it is correct, 
> after accepting the warning. A form author could choose how to deal 
> with the various options of email validation.
>
> -Erik
>
> On Fri, Jun 23, 2017 at 12:51 PM, Liam R. E. Quin <liam@w3.org 
> <mailto:liam@w3.org>> wrote:
>
>     On Fri, 2017-06-23 at 13:28 +0200, Steven Pemberton wrote:
>     > Our definition of email accepts the following as a valid email
>     > address:
>     >
>     >       steven@cwi
>     >
>     > Are we OK with that? I'd expect at least one "." after the @.
>
>     https://tools.ietf.org/html/rfc5321#section-2.3.11
>     <https://tools.ietf.org/html/rfc5321#section-2.3.11>
>     has:
>     [[
>     A domain name (or often just a "domain") consists of one or more
>        components, separated by dots if more than one appears.
>     ]]
>
>     so steven@cwi should be allowed.
>
>     Liam
>
>
>     --
>     Liam R. E. Quin <liam@w3.org <mailto:liam@w3.org>>
>     The World Wide Web Consortium (W3C)
>
>     Web slave for www.fromoldbooks.org <http://www.fromoldbooks.org>
>
>