Content-IDs

[weber@xxxxxxxxxx (Jay C. Weber)]

Here's a problem I have with the definition of Content-IDs.  RFC 1341 says:

  6.1 Optional Content-ID Header Field

  In constructing a high-level user agent, it may be desirable to allow
  one body to make reference to another.  Accordingly, bodies may be
  labeled using the "Content-ID" header field, which is syntactically
  identical to the "Message-ID" header field:

  Content-ID := msg-id

  Like the Message-ID values, Content-ID values must be generated to be
  as unique as possible.

Is it really necessary that Content-IDs be globally unique?  Seems to me
they only need to be unique within the enclosing scope, presumably a
multipart.  Plus, I never saw the need for RFC 822 to be so picky about
msg-ids (angle-brackets, the @-sign, a domain name) except as a *suggested*
way of generating globally-unique strings.  It's unnecessary for MIME to
propagate this, especially for scopes in which unique name generation is
easy.

I'd prefer not to have required special characters in Content-IDs, since
I want them to be identifiers in a language for specifying a multipart layout.
I suppose I could refer to content-id <UniqueName@eitech.com> as just UniqueName
in such a language, but that's a little ugly.  Regardless, I don't want to have
to generate a GloballyUniqueName.

I haven't heard of much implementation experience with Content-IDs; people
are only just starting to use them.  I used them in my servicemail package,
but it turns out I used them inconsistently with the definition.

Jay
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Jay C. Weber					weber@eitech.com
Enterprise Integration Technologies		weber@cis.stanford.edu
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