How to check (or avoid) the user field name so that it does not violate my email sending software?

Question

When sending a message, I might have something like this to set the To: field (in Perl)

To: "$name" <$email> 

In Perl, I can check the $ email part with Email :: Valid, but how can I make sure the $ name part accepts Unicode characters, but cannot be tricked by sending to multiple addresses or some other nasty thing? for example This

 $email = ' [e-mail] '; $name = 'Foo" < [e-mail] >, "Bar'; 

seems to create a To field like this:

 To: "Foo" < [e-mail] >, "Bar" < [e-mail] > 

sending email to two addresses.

Answer 1

 use Email::Address qw(); use Encode qw(encode); s{\R}{}g for $email, $name; # newlines be-gone my $to = Email::Address->new($name => $email)->format; print encode 'MIME-Header', $to; 

Answer 2

There cannot be a simple solution. I would recommend a conservative solution manually.

 /\p{L}/ 

matches any unicode letter in any language. Feel free to add dots or dashes, depending on the cultural background of your software.