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Hi Glenn,
> I can't find it. :-(
>
>> Scott Klement wrote an email validater called VALMAIL. A
>> search through the archives should provide a link to it.
This is a somewhat tricky question because there are very few rules
involved in the syntax of an e-mail address. Basically, anything can
precede the '@' symbol, as long as it's properly quoted, and is allowed
by the destination e-mail server. The part after the @ symbol must be a
valid TCP/IP domain name. So that's not a lot of validation!
My first approach to the problem was to check the syntax (Again, that
doesn't provide much help, since the syntax is so broad) and then do a
DNS lookup on the domain name portion. That way, you know that it's a
valid domain name that's available on the Internet.
That code was called VALMAIL (it's the one Matt mentioned) and is
available to System iNetwork members (a free, "Associate" membership is
all you need) at the following link:
http://www.iseriesnetwork.com/article.cfm?id=17633
As I recall, there's an issue with the GetMX routine in that service
program, but it only surfaces with some DNS servers. The solution (to
make it work everywhere) is to add a '.' to the end of the domain
name... it should be as easy as changing this line of code:
c eval count = GetMX(dom: MXSIZE: mx: pty)
to this:
c eval count = GetMX(dom+'.': MXSIZE: mx: pty)
The problem with that method is that it has to do a DNS lookup on every
e-mail address you enter... That can be slow (depending on how fast the
addresses are entered) and it also can produce "false failures" if your
Internet connection happens to be down, or if the company who owns the
e-mail address has their DNS servers down for maintenance or something,
it'll come up as a "bad address".
The other common method is to check the basic syntax using a regular
expression. Here's an article I wrote (also requires a free,
"associate" subscription to SystemiNetwork.com) that demonstrates that
technique from RPG:
http://www.systeminetwork.com/article.cfm?id=52826
The regular expression method only checks the syntax (no DNS lookup) but
is stricter. Theoretically, it can reject a valid e-mail address --
though, most of the invalid ones that would fail the test are so obscure
that it doesn't make much difference.
Good luck
midrange.com
