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Re: Email::Address::XS

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From:
Ricardo Signes
Date:
August 1, 2016 23:00
Subject:
Re: Email::Address::XS
Message ID:
20160801230002.GA19612@debian
* pali@cpan.org [2016-07-12T11:43:02]
> On Monday 04 July 2016 01:52:41 Ricardo Signes wrote:
> > 
> > I'd stick to header_str, I think, but I'm not sure.  At any rate:
> > yes.
> 
> And this is what I do not like... to pass objects to function with name 
> header_str. That name sounds like it takes string, not object (or more 
> objects)...

Either we can add a new name, so people end up having to give "header_str" and
"header_obj" or we can say "in general everything uses header_str, which
follows these simple rules."  I would rather do that.

> > > Still do not know how to handle non-MIME headers correctly in
> > > Email::MIME module. We can either create blacklist of non-MIME
> > > headers and extend it every time when somebody report problem or
> > > create whitelist of MIME headers... Or let caller to decide if his
> > > header must be MIME-encoded or not.
> > 
> > I'm sorry, I don't understand.  Could you elaborate?
> 
> If passed pair (header-name, header-value) needs to be MIME encoded or 
> not. Currently there is blacklist in Email::MIME for header names which 
> are never MIME encoded (like Message-Id, Date, ...) when passing as 
> header_str.

So, I'd assume we'd go forward with:

* if you know exactly octets you, the user, want in the header field, use
  "header", but this is likely rare
* if you want to provide a string for a field that's pretty much just a string,
  use header_str and if it requires special handling, we do our best, which
  should get better over time
* but if things are complicated, use an object that represents the structured
  data

I don't like the idea that this will be broken further by adding the object
behavior, though.

  $email->header_str_set($field => $email->header($field));

...should not break things.

> > "header_str" is "text string" which means it will get encoded.
> 
> Not exactly, there are exceptions (Message-Id, Date, ...) plus special 
> behaviour for addresses headers.

Those /mostly/ still get encoded, but we know that the strings are meant to be
structured, so we try to deconstruct them and encode them correctly.
I think those fields that get passed through unchanged are probably in error at
least insofar as they let you put non-7-bit-clean data in your headers.  This
should probably be fatal:

  header_str => [ Date => "\N{SMILING FACE WITH HORNS}" ]

> Addresses and groups are really something different as previous types 
> (strings). And if we threat them as objects, I would rather see e.g. 
> header_obj (or other different name) instead mixing it again with 
> header_str (which already have exceptions :-(). This is my initial 
> reason for header_addr/grps to distinguish it.

My feeling is that Perl programmers are used to polymorphic interfaces, and
that multiplying the number of ways to specify headers is a needless confusion.
What is the benefit to the end user of splitting things up?

-- 
rjbs

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