As per Relevance of the word parameter, we have this rfc below:
Network Working Group E.
Request for Comments: 2112 XIson, Inc
Category: Standards Track March 1997
Obsoletes: 1872
The MIME Multipart/Related Content-
Status of this
This document specifies an Internet standards track protocol for
Internet community, and requests discussion and suggestions
improvements. Please refer to the current edition of the "
Official Protocol Standards" (STD 1) for the standardization
and status of this protocol. Distribution of this memo is unlimited
The Multipart/Related content-type provides a common mechanism
representing objects that are aggregates of related MIME body parts
This document defines the Multipart/Related content-type and
examples of its use
1.
Several applications of MIME, including MIME-PEM, and MIME-
and other proposals, require multiple body parts that make sense
in the aggregate. The present approach to these compound objects
been to define specific multipart subtypes for each new object.
keeping with the MIME philosophy of having one mechanism to
the same goal for different purposes, this document describes
single mechanism for such aggregate or compound objects
The Multipart/Related content-type addresses the MIME
of compound objects. The object is categorized by a "type
parameter. Additional parameters are provided to indicate a
starting body part or root and auxiliary information which may
required when unpacking or processing the object
Multipart/Related MIME entities may contain Content-
headers that provide suggestions for the storage and display of
body part. Multipart/Related processing takes precedence
Content-Disposition; the interaction between them is discussed
section 4.
Responsibility for the display or processing of a Multipart/Related'
constituent entities rests with the application that handles
compound object
Levinson Standards Track [Page 1]
RFC 2112 MIME Multipart/Related Content-type March 1997
2. Multipart/Related Registration
The following form is copied from RFC 1590, Appendix A
To: IANA@isi.edu Subject: Registration of new Media Type content
type/
Media Type name:
Media subtype name:
Required parameters: Type, a media type/subtype
Optional parameters:
Start-
Encoding considerations: Multipart content-types cannot
encodings
Security considerations: Depends solely on the referenced type
Published specification: RFC-REL (this document).
Person & email address to contact for further information
Edward
47 Clive
Metuchen, NJ 08840-1060
+1 908 494 1606
XIson@cnj.digex.
3. Intended
The Multipart/Related media type is intended for compound
consisting of several inter-related body parts. For
Multipart/Related object, proper display cannot be achieved
individually displaying the constituent body parts. The content-
of the Multipart/Related object is specified by the type parameter
The "start" parameter, if given, points, via a content-ID, to
body part that contains the object root. The default root is
first body part within the Multipart/Related body
Levinson Standards Track [Page 2]
RFC 2112 MIME Multipart/Related Content-type March 1997
The relationships among the body parts of a compound
distinguishes it from other object types. These relationships
often represented by links internal to the object's components
reference the other components. Within a single
environment the links are often file names, such links may
represented within a MIME message using content-IDs or the value
some other "Content-" headers
3.1. The Type
The type parameter must be specified and its value is the MIME
type of the "root" body part. It permits a MIME user agent
determine the content-type without reference to the enclosed
part. If the value of the type parameter and the root body part'
content-type differ then the User Agent's behavior is undefined
3.2. The Start
The start parameter, if given, is the content-ID of the
object's "root". If not present the "root" is the first body part
the Multipart/Related entity. The "root" is the element
applications processes first
3.3. The Start-Info
Additional information can be provided to an application by
start-info parameter. It contains either a string or points, via
content-ID, to another MIME entity in the message. A typical
might be to provide additional command line parameters or a
entity giving auxiliary information for processing the
object
Applications that use Multipart/Related must specify
interpretation of start-info. User Agents shall provide
parameter's value to the processing application. Processes
distinguish a start-info reference from a token or quoted-string
examining the first non-white-space character, "<" indicates
reference
3.4.
related-param := [ ";" "start" "=" cid ]
[ ";" "start-info" "="
( cid-list / value ) ]
[ ";" "type" "=" type "/" subtype ]
; order
cid-list := cid cid-
Levinson Standards Track [Page 3]
RFC 2112 MIME Multipart/Related Content-type March 1997
cid := msg-id ; c.f. [822]
value := token / quoted-string ; c.f. [MIME
; value cannot begin with "<"
Note that the parameter values will usually require quoting. Msg-
contains the special characters "<", ">", "@", and perhaps
special characters. If msg-id contains quoted-strings, those
marks must be escaped. Similarly, the type parameter contains
special character "/".
4. Handling Content-Disposition
Content-Disposition Headers [DISP] suggest presentation styles
MIME body parts. [DISP] describes two presentation styles,
the disposition type, INLINE and ATTACHMENT. These, used within
multipart entity, allow the sender to suggest
information. [DISP] also provides for an optional storage (file
name. Content-Disposition headers could appear in one or more
parts contained within a Multipart/Related entity
Using Content-Disposition headers in addition to Multipart/
provides presentation information to User Agents that do
recognize Multipart/Related. They will treat the multipart
Multipart/Mixed and they may find the Content-Disposition
useful
With Multipart/Related however, the application processing
compound object determines the presentation style for all
contained parts. In that context the Content-Disposition
information is redundant or even misleading. Hence, User Agents
understand Multipart/Related shall ignore the disposition type
a Multipart/Related body part
It may be possible for a User Agent capable of handling
Multipart/Related and Content-Disposition headers to provide
invoked application the Content-Disposition header's
filename parameter to the Multipart/Related. The use of
information will depend on the specific application and should
specified when describing the handling of the corresponding
object. Such descriptions would be appropriate in an RFC
that object's media type
Levinson Standards Track [Page 4]
RFC 2112 MIME Multipart/Related Content-type March 1997
5.
5.1 Application/X-
The X-FixedRecord content-type consists of one or more octet-
and a list of the lengths of each record. The root, which lists
record lengths of each record within the streams. The record
list, type Application/X-FixedRecord, consists of a set of
in ASCII format, one per line. Each INTEGER gives the number
octets from the octet-stream body part that constitute the
"record".
The example below, uses a single data block
Content-Type: Multipart/Related; boundary=example-1
start="<950120.aaCC@XIson.com>";
type="Application/X-FixedRecord
start-info="-o ps
--example-1
Content-Type: Application/X-
Content-ID: <950120.aaCC@XIson.com
25
10
34
10
25
21
26
10
--example-1
Content-Type: Application/octet-
Content-Description: The fixed length
Content-Transfer-Encoding: base64
Content-ID: <950120.aaCB@XIson.com
T2xkIE1hY0
BFIEkgTwpBbmQgb24gaGlzIGZhcm0
IHNvbWUgZHVja3
BxdWFjayBxdWFjayBoZXJlLAphIHF1YWNrIHF
YWNrIHRoZXJlLApldmVyeSB3aGVyZSBhIHF1
NrIHF1YWNrCkUgSSBFIEkgTwo
--example-1--
Levinson Standards Track [Page 5]
RFC 2112 MIME Multipart/Related Content-type March 1997
5.2 Text/X-
The Text/X-Okie is an invented markup language permitting
inclusion of images with text. A feature of this example is
inclusion of two additional body parts, both picture. They
referred to internally by the encapsulated document via
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="<950118.AEBH@XIson.com>"
type="Text/x-Okie
--example-2
Content-Type: Text/x-Okie; charset=iso-8859-1;
declaration="<950118.AEB0@XIson.com>"
Content-ID: <950118.AEBH@XIson.com
Content-Description:
{doc
This picture was taken by an automatic camera mounted ...
{image file=cid:<950118.AECB@XIson.com>}
{para
Now this is an enlargement of the area ...
{image file=cid:<950118:AFDH@XIson.com>}
{/doc
--example-2
Content-Type: image/
Content-ID: <950118.AFDH@XIson.com
Content-Transfer-Encoding: BASE64
Content-Description: Picture
[encoded jpeg image
--example-2
Content-Type: image/
Content-ID: <950118.AECB@XIson.com
Content-Transfer-Encoding: BASE64
Content-Description: Picture
[encoded jpeg image
--example-2--
Levinson Standards Track [Page 6]
RFC 2112 MIME Multipart/Related Content-type March 1997
5.3 Content-
In the above example each image body part could also have a Content
Disposition header. For example
...
--example-2
Content-Type: image/
Content-ID: <950118.AECB@XIson.com
Content-Transfer-Encoding: BASE64
Content-Description: Picture
Content-Disposition:
[encoded jpeg image
--example-2--
User Agents that recognize Multipart/Related will ignore
Content-Disposition header's disposition type. Other User
will process the Multipart/Related as Multipart/Mixed and may
use of that header's information
6. User Agent
User agents that do not recognize Multipart/Related shall,
accordance with [MIME], treat the entire entity as Multipart/Mixed
MIME User Agents that do recognize Multipart/Related entities but
unable to process the given type should give the user the option
suppressing the entire Multipart/Related body part shall be
Existing MIME-capable mail user agents (MUAs) handle the
media types in a straightforward manner. For discrete media
(e.g. text, image, etc.) the body of the entity can be
passed to a display process. Similarly the existing
subtypes can be reduced to handing one or more discrete types
Handling Multipart/Related differs in that processing cannot
reduced to handling the individual entities
The following sections discuss what information the
application requires
It is possible that an application specific "receiving agent"
manipulate the entities for display prior to invoking
application process. Okie, above, is an example of this; it may
a receiving agent to parse the document and substitute local
names for the originator's file names. Other applications may
require a table showing the correspondence between the local
names and the originator's. The receiving agent takes
for such processing
Levinson Standards Track [Page 7]
RFC 2112 MIME Multipart/Related Content-type March 1997
6.1 Data
MIME-capable mail user agents (MUAs) are required to provide
application
(a) the bodies of the MIME entities and the entity Content-*
headers
(b) the parameters of the Multipart/Related Content-
header,
(c) the correspondence between each body's local file name
that body's header data, and, if present, the body part'
content-ID
6.2 Storing Multipart/Related
The Multipart/Related media type will be used for objects that
internal linkages between the body parts. When the objects
stored the linkages may require processing by the application or
receiving agent
6.3
MIME is a recursive structure. Hence one must expect
Multipart/Related entity to contain other Multipart/Related entities
When a Multipart/Related entity is being processed for display
storage, any enclosed Multipart/Related entities shall be
as though they were being stored
6.4 Configuration
It is suggested that MUAs that use configuration mechanisms,
[CFG] for an example, refer to Multipart/Related
Multipart/Related/, were is the value of the "type
parameter
7. Security
Security considerations relevant to Multipart/Related are
to those of the underlying content-type
Levinson Standards Track [Page 8]
RFC 2112 MIME Multipart/Related Content-type March 1997
8.
This proposal is the result of conversations the author has had
many people. In particular, Harald A. Alvestrand, James Clark
Charles Goldfarb, Gary Houston, Ned Freed, Ray Moody, and
Stinchfield, provided both encouragement and invaluable help.
author, however, take full responsibility for all errors contained
this document
9.
[822] Crocker, D., "Standard for the Format of
Internet Text Messages", August 1982,
of Delaware, RFC 822.
[CID] E. Levinson, J. Clark, "Message/External-
Content-ID Access Type", 12/26/1995, RFC 1873
Levinson, E., "Message/External-Body Content-
Access Type", February 1997, RFC 2111.
[CFG] Borenstein, N., "A User Agent
Mechanism For Multimedia Mail
Information", September 23, 1993, RFC 1524
[DISP] R. Troost, S. Dorner, "Communicating
Information in Internet Messages: The Content
Disposition Header", June 7, 1995, RFC 1806
[MIME] Borenstein, N. and Freed, N., "MIME (
Internet Mail Extensions): Mechanisms
Specifying and Describing the Format of
Message Bodies", June 1992, RFC 1341.
9. Author's
Edward
XIson, Inc
47 Clive
Metuchen, NJ 08840-1060
+1 908 549 3716
Levinson Standards Track [Page 9]
if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.
RFC documents can be found at I.E.T.F.
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