rfc2387.txt

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RFC 2387                   Multipart/Related                 August 1998


5.2 Text/X-Okie

   The Text/X-Okie is an invented markup language permitting the
   inclusion of images with text.  A feature of this example is the
   inclusion of two additional body parts, both picture. They are
   referred to internally by the encapsulated document via each
   picture's body part content-ID.  Usage of "cid:", as in this example,
   may be useful for a variety of compound objects.  It is not, however,
   a part of the Multipart/Related specification.

     Content-Type: Multipart/Related; boundary=example-2;
             start="<[e-mail]>"
             type="Text/x-Okie"

     --example-2
     Content-Type: Text/x-Okie; charset=iso-8859-1;
             declaration="<[e-mail]>"
     Content-ID: <[e-mail]>
     Content-Description: Document

     {doc}
     This picture was taken by an automatic camera mounted ...
     {image file=cid:[e-mail]}
     {para}
     Now this is an enlargement of the area ...
     {image file=cid:950118:[e-mail]}
     {/doc}
     --example-2
     Content-Type: image/jpeg
     Content-ID: <[e-mail]>
     Content-Transfer-Encoding: BASE64
     Content-Description: Picture A

     [encoded jpeg image]
     --example-2
     Content-Type: image/jpeg
     Content-ID: <[e-mail]>
     Content-Transfer-Encoding: BASE64
     Content-Description: Picture B

     [encoded jpeg image]
     --example-2--

5.3 Content-Disposition

   In the above example each image body part could also have a Content-
   Disposition header.  For example,




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     --example-2
     Content-Type: image/jpeg
     Content-ID: <[e-mail]>
     Content-Transfer-Encoding: BASE64
     Content-Description: Picture B
     Content-Disposition: INLINE

     [encoded jpeg image]
     --example-2--

   User Agents that recognize Multipart/Related will ignore the
   Content-Disposition header's disposition type.  Other User Agents
   will process the Multipart/Related as Multipart/Mixed and may make
   use of that header's information.

6.  User Agent Requirements

   User agents that do not recognize Multipart/Related shall, in
   accordance with [MIME], treat the entire entity as Multipart/Mixed.
   MIME User Agents that do recognize Multipart/Related entities but are
   unable to process the given type should give the user the option of
   suppressing the entire Multipart/Related body part shall be.

   Existing MIME-capable mail user agents (MUAs) handle the existing
   media types in a straightforward manner.  For discrete media types
   (e.g. text, image, etc.) the body of the entity can be directly
   passed to a display process.  Similarly the existing composite
   subtypes can be reduced to handing one or more discrete types.
   Handling Multipart/Related differs in that processing cannot be
   reduced to handling the individual entities.

   The following sections discuss what information the processing
   application requires.

   It is possible that an application specific "receiving agent" will
   manipulate the entities for display prior to invoking actual
   application process.  Okie, above, is an example of this; it may need
   a receiving agent to parse the document and substitute local file
   names for the originator's file names.  Other applications may just
   require a table showing the correspondence between the local file
   names and the originator's.  The receiving agent takes responsibility
   for such processing.

6.1 Data Requirements

   MIME-capable mail user agents (MUAs) are required to provide the
   application:




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   (a) the bodies of the MIME entities and the entity Content-* headers,

   (b) the parameters of the Multipart/Related Content-type header, and

   (c) the correspondence between each body's local file name, that
       body's header data, and, if present, the body part's content-ID.

6.2 Storing Multipart/Related Entities

   The Multipart/Related media type will be used for objects that have
   internal linkages between the body parts.  When the objects are
   stored the linkages may require processing by the application or its
   receiving agent.

6.3 Recursion

   MIME is a recursive structure.  Hence one must expect a
   Multipart/Related entity to contain other Multipart/Related entities.
   When a Multipart/Related entity is being processed for display or
   storage, any enclosed Multipart/Related entities shall be processed
   as though they were being stored.

6.4 Configuration Considerations

   It is suggested that MUAs that use configuration mechanisms, see
   [CFG] for an example, refer to Multipart/Related as Multi-
   part/Related/<type>, were <type> is the value of the "type"
   parameter.

7.  Security Considerations

   Security considerations relevant to Multipart/Related are identical
   to those of the underlying content-type.

8.  Acknowledgments

   This proposal is the result of conversations the author has had with
   many people.  In particular, Harald A. Alvestrand, James Clark,
   Charles Goldfarb, Gary Houston, Ned Freed, Ray Moody, and Don
   Stinchfield, provided both encouragement and invaluable help.  The
   author, however, take full responsibility for all errors contained in
   this document.









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9.  References

   [822]       Crocker, D., "Standard for the Format of ARPA Internet
               Text Messages", STD 11, RFC 822, August 1982.

   [CID]       Levinson, E., and J. Clark, "Message/External-Body
               Content-ID Access Type",  RFC 1873, December 1995,
               Levinson, E., "Message/External-Body Content-ID Access
               Type", Work in Progress.

   [CFG]       Borenstein, N., "A User Agent Configuration Mechanism For
               Multimedia Mail Format Information", RFC 1524, September
               1993.

   [DISP]      Troost, R., and S. Dorner, "Communicating Presentation
               Information in Internet Messages:  The Content-
               Disposition Header", RFC 1806, June 1995.

   [MIME]      Borenstein, N., and Freed, N., "Multipurpose Internet
               Mail Extensions (MIME) Part One: Format of Internet
               Message Bodies", RFC 2045, November 1996.

9.  Author's Address

   Edward Levinson
   47 Clive Street
   Metuchen, NJ  08840-1060
   USA

   Phone: [phone]
   EMail: [e-mail]

10.  Changes from previous draft (RFC 2112)

   Corrected cid urls to conform to RFC 2111; the angle brackets were
   removed.















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11.  Full Copyright Statement

   Copyright (C) The Internet Society (1998).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
























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