multipart/related The MIME Multipart/Related Content-type
This memo defines an Experimental Protocol for the Internet community. This memo does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested. Distribution of this memo is unlimited.
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
* Copyright Notice > Copyright (C) The Internet Society (1998). All Rights Reserved.
The Multipart/Related content-type provides a common mechanism for representing objects that are aggregates of related MIME body parts. This document defines the Multipart/Related content-type and provides examples of its use.
* 1. Introduction > Several applications of MIME, including MIME-PEM, and MIME-Macintosh and other proposals, require multiple body parts that make sense only in the aggregate. The present approach to these compound objects has been to define specific multipart subtypes for each new object. In keeping with the MIME philosophy of having one mechanism to achieve the same goal for different purposes, this document describes a single mechanism for such aggregate or compound objects.
> The Multipart/Related content-type addresses the MIME representation of compound objects. The object is categorized by a "type" parameter. Additional parameters are provided to indicate a specific starting body part or root and auxiliary information which may be required when unpacking or processing the object.
Multipart/Related MIME entities may contain Content-Disposition headers that provide suggestions for the storage and display of a body part. Multipart/Related processing takes precedence over Content-Disposition; the interaction between them is discussed in section 4.
multipart/related 処理は Content-Disposition
より優先します。両者の関係は4章で議論します。
Responsibility for the display or processing of a Multipart/Related's constituent entities rests with the application that handles the compound object.
multipart/related を構成する実体の表示・処理の責任は豪勢物体を扱う応用にあります。
The following form is copied from RFC 1590, Appendix A.
次の書式は
- To: IANA@isi.edu
- Subject: Registration of new Media Type content-type/subtype
- Media Type name: Multipart
- Media subtype name: Related
- Required parameters: Type, a media type/subtype.
- Optional parameters: Start
, a content-id.Start-info, a string or content-id list.> - Encoding considerations: Multipart content-types cannot have encodings. > - Security considerations: Depends solely on the referenced type. > - Published specification:This document.RFC-REL (this document). > - Person & email address to contact for further information:Edward LevinsonAccurate Information Systems, Inc.2 Industrial WayEatontown, NJ 07724+1 908 389 5550+1 908 389 5556 (fax)ELevinson@Accurate.com47 Clive Street Metuchen, NJ 08840-1060 +1 908 494 1606 XIson@cnj.digex.net ]PRE]
The Multipart/Related media type is intended for compound objects consisting of several inter-related body parts. For a Multipart/Related object, proper display cannot be achieved by individually displaying the constituent body parts. The content-type of the Multipart/Related object is specified by the type parameter. The "start" parameter, if given, points, via a content-ID, to the body part that contains the object root. The default root is the first body part within the Multipart/Related body.
multipart/related 物体では構成する本体部分を個々に表示するだけでは適切な表示とは言えません。
multipart/related 物体の内容型は
The relationships among the body parts of a compound object distinguishes it from other object types. These relationships are often represented by links internal to the object's components that reference the other components. Within a single operating environment the links are often file names, such links may be represented within a MIME message using content-IDs or the value of some other "Content-" headers.
合成物体の本体部分間の関係は他の物体型と異なります。
関係はよく物体の部品の内部で他の部品を指す
The type parameter must be specified and its value is the MIME media type of the "root" body part. It permits a MIME user agent to determine the content-type without reference to the enclosed body part. If the value of the type parameter and the root body part's content-type differ then the User Agent's behavior is undefined.
type 引数の値と根本体部分の内容型が異なる時の利用者エージェントの動作は未定義です。
Note: Constraining the "type" parameter's value to an existing media type allows the appropriate processing to be identified without creating yet another hierarchy of registered types. A possible default action would have the MIME mail User Agent (MUA) to display the "start" entity alone when it could process the media type as a basic type but not as Multipart/Related.
注意: type 引数の値を既存の媒体型に制約することで、
新しい登録型階層を作らずに適切な処理を識別できます。
The start parameter, if given, is the content-ID of the compound object's "root". If not present the "root" is the first body part in the Multipart/Related entity. The "root" is the element the applications processes first.
の
は
は最初に
In the case of a Multipart/Alternative body part containing several entities with identical content-IDs the start entity should be selected using the Multipart/Alternative rules.
multipart/alternative
の規則により開始実体を選択するべきです。
Note: The "start" parameter allows for types in which the root element gets generated by the sending application, perhaps on the fly. Such an application can create the "start" content-id when processing begins and then insert the body part when it is complete.
注意: start 引数は根要素が送信応用によりおそらくはその場で生成されるような型も認めます。
そのような応用は処理が始まる時に start
内容 ID を作成して、処理が完了してから本体部分を挿入することができます。
Additional information can be provided to an application by the start-info parameter. It contains either a string or points, via a content-ID, to another MIME entity in the message. A typical use might be to provide additional command line parameters or a MIME entity giving auxiliary information for processing the compound object.
応用は追加情報を
Applications that use Multipart/Related must specify the interpretation of start-info. User Agents shall provide the parameter's value to the processing application. Processes can distinguish a start-info reference from a token or quoted-string by examining the first non-white-space character, "<" indicates a
content-idreference.
multipart/related を使う応用は start-info の参照と字句や引用文字列は最初の非空白文字を調べれば区別できます。
最初の文字が < であれば参照です。
related-param := [ ";" "start" "=" cid ]
[ ";" "start-info" "="
( cid-list / value ) ]
[ ";" "type" "=" type "/" subtype ]
; order independent
>
cid-list := cid cid-list
>
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-id contains the special characters "<", ">", "@", and perhaps other special characters. If msg-id contains quoted-strings, those quote marks must be escaped. Similarly, the type parameter contains the special character "/".
注意: 引数値は通常引用が必要です。 <, >, @
を含みますし、おそらく他の特殊文字も含むでしょう。 msg-id
が引用文字列を含む場合、その引用符を逃避しなければなりません。
同様に、 type 引数は特殊文字 /
を含みます。
Content-Disposition Headers [DISP] suggest presentation styles for MIME body parts. [DISP] describes two presentation styles, called the disposition type, INLINE and ATTACHMENT. These, used within a multipart entity, allow the sender to suggest presentation information. [DISP] also provides for an optional storage (file) name. Content-Disposition headers could appear in one or more body parts contained within a Multipart/Related entity.
Using Content-Disposition headers in addition to Multipart/Related provides presentation information to User Agents that do not recognize Multipart/Related. They will treat the multipart as Multipart/Mixed and they may find the Content-Disposition information useful.
multipart/related を認識しない
With Multipart/Related however, the application processing the compound object determines the presentation style for all the contained parts. In that context the Content-Disposition header information is redundant or even misleading. Hence, User Agents that understand Multipart/Related shall ignore the disposition type within a Multipart/Related body part.
しかし、
It may be possible for a User Agent capable of handling both Multipart/Related and Content-Disposition headers to provide the invoked application the Content-Disposition header's optional filename parameter to the Multipart/Related. The use of that information will depend on the specific application and should be specified when describing the handling of the corresponding compound object. Such descriptions would be appropriate in an RFC registering that object's media type.
The X-FixedRecord content-type consists of one or more octet-streams and a list of the lengths of each record. The root, which lists the record lengths of each record within the streams. The record length list, type Application/X-FixedRecord, consists of a set of INTEGERs in ASCII format, one per line. Each INTEGER gives the number of octets from the octet-stream body part that constitute the next "record".
x-fixedrecord 内容型は一つ以上のオクテット列と各application/x-fixedrecord 型の記録長並びは 記録
のオクテット数を表します。
The example below, uses a single data block
which the sender processes on the fly to generate the record length list.Consequently the list appears after the data.
次の例は1つのデータ塊を表します。
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-FixedRecord
Content-ID: <950120.aaCC@XIson.com>
25
10
34
10
25
21
26
10
--example-1
Content-Type: Application/octet-stream
Content-Description: The fixed length records
Content-Transfer-Encoding: base64
Content-ID: <950120.aaCB@XIson.com>
T2xkIE1hY0RvbmFsZCBoYWQgYSBmYXJtCkUgSS
BFIEkgTwpBbmQgb24gaGlzIGZhcm0gaGUgaGFk
IHNvbWUgZHVja3MKRSBJIEUgSSBPCldpdGggYS
BxdWFjayBxdWFjayBoZXJlLAphIHF1YWNrIHF1
YWNrIHRoZXJlLApldmVyeSB3aGVyZSBhIHF1YW
NrIHF1YWNrCkUgSSBFIEkgTwo=
--example-1
Content-Type: Application/X-FixedRecord
Content-ID: <950120.aaCC@XIson.com>
25
10
34
10
25
21
26
10
--example-1--The Text/X-Okie is an invented markup language
, similar to HTML, that permitspermitting 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.
text/x-okie は架空の
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: Document
{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/jpeg
Content-ID: <950118.AFDH@XIson.com>
Content-Transfer-Encoding: BASE64
Content-Description: Picture A
[encoded jpeg image]
--example-2
Content-Type: image/jpeg
Content-ID: <950118.AECB@XIson.com>
Content-Transfer-Encoding: BASE64
Content-Description: Picture B
[encoded jpeg image]
--example-12--In the above example each image body part could also have a Content-Disposition header. For example,
先の例で各画像本体部分に
...--example-2 Content-Type: image/jpeg Content-ID: <950118.AECB@XIson.com> 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.
multipart/related
を認識する
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
shall either suppress the entire Multipart/Related body part or process the root aloneshould give the user the option of suppressing the entire Multipart/Related body part shall be.In either case the user should be notified of the MUA's action.
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
from other media typesin that processing cannot be reduced to handling the individual entities.Existing media types are handled by MIME-capable MUAs handle in a straightforward manner. For basic media types (e.g., text, image, etc.) the body of the entity can be directly passed to a display process. Composite media types can be reduced to handing one or more discrete types.
既存の MIME メイル利用者エージェントは既存の媒体型をそのままの方法で扱います。
分離媒体型 (例えば multipart/related の扱いは処理を個々の実体に分けることができないという点が異なります。
Multipart/Related provides an irreducible composite media type.
The following sections discuss what information the processing application requires.
次の節では処理応用がどんな情報が必要かを議論します。
It is possible that an application specific "receiving agent" will manipulate the entities
, after initial processing by the MIME User Agent,for display prior to invoking actual application process.From the viewpoint of the MUA, the receiving agent is the application.Okie, above,demonstratesis 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.
応用規定の受信エージェント
が実際の応用処理を呼出す前に実体を走査することも可能です。
先の Okie はこの例で、受信エージェントは文書を構文解析し、
局所ファイル名を送信者側のファイル名に書き換えます。
他の応用はただ単に局所ファイル名と受信者のファイル名の対応表が必要かもしれません。
受信エージェントはこのような処理の責任を持ちます。
The receiving agent takes responsibility any for such processing.
MIME-capable
MUAsmail user agents (MUAs) are required to provide the
MIME メイル利用者エージェントは次のものを提供する必要があります。
- (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.
Content-* multipart/related Content-Type 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.
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.
It shall be the responsibility of the application handling the outermost Multipart/Related to insure the appropriate processing of embedded Multipart/Related entities.
MIME は再帰的構造です。ですから multipart/related
実体が別の multipart/related 実体を含んでいることを想定しなければなりません。
multipart/related 実体が表示や蓄積のため処理される時、
囲まれた multipart/related 実体は蓄積されているものであるかのように処理しなければなりません。
It is suggested that MUAs that use configuration mechanisms, see [CFG] for an example, refer to Multipart/Related as Multipart/Related/<type>, were <type> is the value of the "type" parameter.
MUA は設定機構を使う場合 multipart/related
を指すのに Multipart/Related/<type>
(<type> は type 引数の値)
のようにすることを提案します。
Security considerations relevant to Multipart/Related are identical to those of the underlying content-type.
multipart/related に関係する安全上の考慮点は使用する内容型と同じでうs。
This proposal is the result of conversations the author has had with many people. In particular,
similar work was described byHarald A. Alvestrand(early drafts of Multipart/Related), Dave Crocker (Multipart/Families), and Keith Moore (Multipart/References). In addition,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.
[822] Crocker, D., "Standard for the Format of ARPA Internet Text Messages",STD 11, RFC 822, UDEL, August 1982August 1982, University of Delaware, RFC 822STD 11, RFC 822, August 1982.
[CID]
E. LevinsonLevinson, E., and J. Clark, "Message/External-Body Content-ID Access Type",12/26/1995,RFC 1873 December 1995, Levinson, E., "Message/External-Body Content-ID Access Type",February 1997, RFC 2111Work in Progress.
[CFG] Borenstein, N., "A User Agent Configuration Mechanism For Multimedia Mail Format Information",
RFC 1524,RFC 1524,Bellcore,September23,1993, RFC 1524.
[DISP]
R. Troost,Troost, R., and S. Dorner, "Communicating Presentation Information in Internet Messages: The Content-Disposition Header",June 7, 1995, RFC 1806RFC 1806, June 1995.
[MIME] Borenstein, N., and
and N. FreedFreed, N.,"MIME (Multipurpose Internet Mail Extensions)"Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, November 1996.Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies",RFC 1521, Bellcore, Innosoft, September 1993June 1992, RFC 1341
Edward LevinsonAccurate Information Systems, Inc.2 Industrial WayEatontown, NJ 07724-2265XIson, Inc.47 Clive Street Metuchen, NJ 08840-1060 USA
Phone: +1 908 389 5550+1 908 549 3716Phone: +1 908 494 1606EMail: ELevinson@Accurate.com<XIson@cnj.digex.com>EMail: XIson@cnj.digex.com
Corrected cid urls to conform to RFC 2111; the angle brackets were removed.
Copyright (C) The Internet Society (1998). All Rights Reserved.
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