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Re: Email::Address::XS

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From:
Ricardo Signes
Date:
July 1, 2016 00:51
Subject:
Re: Email::Address::XS
Message ID:
20160701005131.GA27257@debian

My coworkers have returned to the other side of the world!  I attended YAPC!  i
had a vacation!  I am back.

* pali@cpan.org [2016-06-01T12:44:01]
> On Tuesday 31 May 2016 02:42:48 Ricardo Signes wrote:
> > * pali@cpan.org [2016-05-28T16:48:40]
> > 
> > > Basically yes. From caller perspective I want to pass email address
> > > object and let Email::MIME to do MIME encoding correctly. Something
> > > like this:
> > > 
> > > my $email = Email::MIME->create(
> > > 
> > > 	header_addr => [ ... ],
> > > 
> > > );
> > 
> > I think that requiring people to break headers up even further into
> > to add a "header_addr" argument is a bit much.  And why header_grps?

So, you had some responses to this which were quite helpful.

My suggestion was meant to be something like "why not make Email::MIME
understand some kind of object as the value in a header?"  I think this is
still right.

Your main responses were (please correct me if I am misunderstanding them):

1.  it should be possible and easy to supply a list of address objects
2.  it should be possible to have a named group, but not required
3.  we don't want ambiguity in how objects passed to (header_str => [...])
    are interpreted

What if we defined a role (here, just a well-known name) called
Email::MIME::Header::Value, which is used to signal that a particular method,
say "as_mime_header", should be used to stringify?

When building the header, the code will do something like:

  $string = $name . ": "
          . ($value->DOES('Email::MIME::Header::Value')
              ? $value->as_mime_header
              : "$value");

No existing object will become confused by this change, only objects which do
the new role.

Then Email::Address::XS could provide some helper routines, so you could write
and of:

    From => 'rjbs@cpan.org'

    From => Email::Address::XS->new(...)

    From => address('rjbs@cpan.org', 'Ricardo SIGNES')

    From => addrlist( address('rjbs@cpan.org', 'Ricardo SIGNES'), ... )

    From => addrgroup( Humans => address('rjbs@cpan.org', 'Rik'), ... )

It might be best to make the first code sample actually do:

  $string = $name . ": "
          . ($value->DOES('Email::MIME::Header::Value')
              ? $value->as_mime_header($name, $mycrlf)  # <-- changed
              : "$value");

...to let the object do folding.  I'm not sure about that one.  I'd want to
double-check whether there's a reason to not always do the folding of the
post-stringified form in Email::MIME.

Anyway, this avoids adding multiple more places to set headers and makes the
API extensible for other header types like Message-ID, etc, in the future.

What do you think of this all?

-- 
rjbs

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