Empty content type?

[John Haug]

Looking at this again, the allowance here may be due to the distinction between the conceptual package model and the physical package model.  Clause 8 (in WD 1; clause 9 in the published doc) is Package Model and deals with concepts.  The next clause (9 / 10) is Physical Package and deals with mapping those concepts to a particular physical package format.

The statement about permitting an empty string is in the concept clause.  9.2.3.2 in WD 1 (10.1.2.1 in 29500-2:2012) states that physical package formats with a native way to represent content types (the concept) must use that mechanism while physical package formats without a native way to represent them use the OPC-specific Content Types stream.  It is the Content Types stream schema that introduces the regexp restriction in ST_ContentType.  I think that the “empty string” statement could apply to physical package formats with a native way to represent content types.

John

From: eb2mmrt at gmail.com [mailto:eb2mmrt at gmail.com] On Behalf Of MURATA Makoto
Sent: Monday, April 6, 2015 3:50 PM
To: SC34
Subject: Re: Empty content type?

But the value of @ContentType is constrained by a
regexp in opc-contentTypes.xsd.  It does not allow the
empty string.

What happens when the Media Types stream has neither
an Override element nor a Default element for a part?  In
that case, "the implementation shall not map this part
name to a part" (10.1.2.4  Getting the Content Type of a Part).

I thus believe that


  "The value of the content type is permitted to be the empty string."

should be dropped.  If we do not drop it, we have to modify
the schema and allow the empty string.

Regards,
Makoto



2015-04-07 6:24 GMT+09:00 Arms, Caroline <caar at loc.gov<mailto:caar at loc.gov>>:
This was my interpretation too.  Caroline

Caroline Arms
Library of Congress Contractor
Co-compiler of Sustainability of Digital Formats resource    http://www.digitalpreservation.gov/formats/

** Views expressed are personal and not necessarily those of the institution **

From: John Haug [mailto:johnhaug at exchange.microsoft.com<mailto:johnhaug at exchange.microsoft.com>]
Sent: Monday, April 06, 2015 2:27 PM
To: SC34
Subject: RE: Empty content type?

I interpret it as meaning that the value of an attribute that specifies a content type can be “”?

John

From: eb2mmrt at gmail.com<mailto:eb2mmrt at gmail.com> [mailto:eb2mmrt at gmail.com] On Behalf Of MURATA Makoto
Sent: Friday, April 3, 2015 5:51 PM
To: SC34
Subject: Empty content type?

Folks,

I have started to rewrite the spec (by rewriting John's latest
text for XAdES) for using media types wherever possible.

But

  "The value of the content type is permitted to be the empty string."

in 8.2.3 is beyond me..  What does it mean?

Regards,
Makoto



--

Praying for the victims of the Japan Tohoku earthquake

Makoto
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