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Re: Content-Disposition Header

1993-06-25 16:11:41

On Fri, 25 Jun 93 13:39:32 -0700, Gabe Beged-Dov 
<gabe(_at_)hpcvusd(_dot_)cv(_dot_)hp(_dot_)com> said:

  gabe> I would propose keeping hidden but removing the requires/owner
  gabe> stuff.


  gabe> The semantics of "hidden" do not involve the additional
  gabe> functionality described for "owner" and "requires".


  gabe> The question I would pose is not why we should have hidden but
  gabe> why can't we decouple the traceability functionality of
  gabe> "owner" and "requires" from the presentation functionality.

You have perfectly grasped the motivation behind hidden. However,
unless there is some way to tell if a hidden bodypart is displayed
somewhere, we are faced with possibility of the following scenario:

a user recieves a message with three hidden GIF images and a compound
document bodypart to organize their display. The users MUA does not
grok the document format, but could easily display the GIFs.
unfortunately, since they are hidden and there is no way of knowing
that their owner is not being displayed, the user does not get to see

This is the scenario that 'owner' was designed to avoid. I cannot
think of any simpler way to do this, but remain completely open to
suggestions. I think it's an important feature, since one of the
guiding principles of MIME and indeed of Internet software ingeneral
is to be liberal in what you accept.

As to the 'requires' parameter, it is meant as an aid to implementors,
so they can open file descriptors, retrieve from a bodypart server,
or whatever prior to parsing a bodypart that will require other
bodyparts. I think is is a convenience, but by no means necessary.