Independent Submission E. Wilde
Request for Comments: 6892 EMC Corporation
Category: Informational March 2013
ISSN: 2070-1721
Independent Submission E. Wilde
Request for Comments: 6892 EMC Corporation
Category: Informational March 2013
ISSN: 2070-1721
The 'describes' Link Relation Type
“描述”链接关系类型
Abstract
摘要
This specification defines the 'describes' link relation type that allows resource representations to indicate that they are describing another resource. In contexts where applications want to associate described resources and description resources, and want to build services based on these associations, the 'describes' link relation type provides the opposite direction of the 'describedby' link relation type, which already is a registered link relation type.
此规范定义了“描述”链接关系类型，该类型允许资源表示指示它们正在描述另一个资源。在应用程序希望关联描述的资源和描述资源，并希望基于这些关联构建服务的上下文中，“描述”链接关系类型提供了与“描述对象”链接关系类型相反的方向，该链接关系类型已经是注册的链接关系类型。
Status of This Memo
关于下段备忘
This document is not an Internet Standards Track specification; it is published for informational purposes.
本文件不是互联网标准跟踪规范；它是为了提供信息而发布的。
This is a contribution to the RFC Series, independently of any other RFC stream. The RFC Editor has chosen to publish this document at its discretion and makes no statement about its value for implementation or deployment. Documents approved for publication by the RFC Editor are not a candidate for any level of Internet Standard; see Section 2 of RFC 5741.
这是对RFC系列的贡献，独立于任何其他RFC流。RFC编辑器已选择自行发布此文档，并且未声明其对实现或部署的价值。RFC编辑批准发布的文件不适用于任何级别的互联网标准；见RFC 5741第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6892.
有关本文件当前状态、任何勘误表以及如何提供反馈的信息，请访问http://www.rfc-editor.org/info/rfc6892.
Copyright Notice
版权公告
Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2013 IETF信托基金和确定为文件作者的人员。版权所有。
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document.
本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(http://trustee.ietf.org/license-info)自本文件出版之日起生效。请仔细阅读这些文件，因为它们描述了您对本文件的权利和限制。
Table of Contents
目录
1. Introduction ....................................................2
2. Resource Descriptions ...........................................2
3. Use Case ........................................................3
4. IANA Considerations .............................................4
5. Security Considerations .........................................4
6. Acknowledgements ................................................4
7. References ......................................................5
7.1. Normative References .......................................5
7.2. Informative References .....................................5
1. Introduction ....................................................2
2. Resource Descriptions ...........................................2
3. Use Case ........................................................3
4. IANA Considerations .............................................4
5. Security Considerations .........................................4
6. Acknowledgements ................................................4
7. References ......................................................5
7.1. Normative References .......................................5
7.2. Informative References .....................................5
Resources on the web can be identified by any (registered) URI scheme and can be represented by any (registered) media type. In many cases, applications establish specific (i.e., typed) relations between the resources they are concerned with, which can either be under their control or controlled by another authority. A common usage pattern for associating resources is to have resources that are descriptions of other resources. This specification registers the 'describes' link relation, which allows applications to represent the fact that one resource is a description of another resource.
web上的资源可以由任何（注册的）URI方案标识，并且可以由任何（注册的）媒体类型表示。在许多情况下，应用程序在它们所关注的资源之间建立特定的（即类型化的）关系，这些关系可以在它们的控制下，也可以由另一个权威机构控制。关联资源的一种常见使用模式是使用描述其他资源的资源。该规范注册了“描述”链接关系，允许应用程序表示一个资源是另一个资源的描述这一事实。
RFC 5988 [1] "defines a framework for typed links that isn't specific to a particular serialisation or application. It does so by redefining the link relation registry established by Atom to have a broader domain, and adding to it the relations that are defined by HTML". This registration request intends to augment the link relation registry with a link relation that is the inverse of the already registered 'describedby' relation, so that links between described resources and describing resources can be represented in both directions.
RFC 5988[1]“定义了一个非特定于特定序列化或应用程序的类型化链接框架。它通过重新定义Atom建立的链接关系注册表以拥有更广泛的域，并向其中添加由HTML定义的关系来实现。”。此注册请求旨在使用与已注册的“describedby”关系相反的链接关系来扩充链接关系注册表，以便可以在两个方向上表示所描述资源和描述资源之间的链接。
Associating resources with descriptions of these resources is a recurring pattern on the web. The IANA "Link Relations" registry established by RFC 5988 [1] currently contains a 'describedby' link relation type, which has been registered by POWDER [2]. The definition given in the reference document for that registration is as follows: "The relationship A 'describedby' B asserts that resource B provides a description of resource A. There are no constraints on the format or representation of either A or B, neither are there any further constraints on either resource".
将资源与这些资源的描述相关联是web上经常出现的模式。RFC 5988[1]建立的IANA“链接关系”注册表当前包含一个“describedby”链接关系类型，该类型已由POWER[2]注册。该注册的参考文件中给出的定义如下：“关系A‘describedby’B声称资源B提供了资源A的描述。对A或B的格式或表示形式没有任何限制，对任何一种资源也没有任何进一步的限制”。
Since many scenarios using resource descriptions need to represent the fact that some resource describes another resource (the opposite of the 'describedby' relation), this document registers a 'describes' link relation type. Establishing a link A 'describes' B asserts that the resource identified by A is a description of the resource identified by B, without constraining in any way the identifiers being used for A and B, and the media types for the representations being provided when those identifiers are dereferenced. Specifically, it is possible that identifiers A and/or B have no associated interaction method (they could be URNs, for example), but it still is valid to establish the A 'describes' B link.
由于许多使用资源描述的场景需要表示某个资源描述另一个资源的事实（与“describedby”关系相反），因此本文档注册了“descriptions”链接关系类型。建立链路a“描述”B断言由a标识的资源是由B标识的资源的描述，而不以任何方式限制用于a和B的标识符，以及在取消引用这些标识符时提供的表示的媒体类型。具体地说，标识符A和/或B可能没有关联的交互方法（例如，它们可以是URN），但建立A“描述”B链接仍然有效。
Another design freedom is to use "chains" of 'describes' (or 'describedby') links, so that one resource is a description of another resource, which in turn is a description of yet another resource. The "levels" of descriptions can go as deep as required by an application and are not constrained by this specification.
另一种设计自由是使用“描述”（或“描述方式”）链接的“链”，以便一个资源是另一个资源的描述，而另一个资源又是另一个资源的描述。描述的“级别”可以按照应用程序的要求进行，并且不受本规范的限制。
Beginning with the POWDER document [2], which specifies the 'describedby' link relation, the use case for the 'describedby' link relation is that a described resource, such as an HTML web page, can specify a link where clients can find a description of this resource. While the 'describedby' link relation is defined to be independent of specific formats and representations, within the context of POWDER, the assumption is that the linked resources most often will provide a description based on the Resource Description Framework (RDF), for example, to provide metadata about a document's author and other provenance information.
从指定“describedby”链接关系的POWDER文档[2]开始，“describedby”链接关系的用例是，所描述的资源（如HTML网页）可以指定一个链接，客户端可以在该链接中找到该资源的描述。虽然“describedby”链接关系定义为独立于特定格式和表示，但在POWER上下文中，假设链接资源通常会提供基于资源描述框架（RDF）的描述，例如，提供有关文档作者和其他出处信息的元数据。
The 'describes' link relation allows servers hosting description resources to associate those description resources with the resources that they are describing. In the RDF-oriented scenario of POWDER, this means that a service managing description resources would use 'describes' links to represent the fact that the description resources it exposes provide some description of the described resource, very likely in some RDF representation. However, since link relations are independent of resource formats or representations, such an association could also be made in other formats such as XML or JavaScript Object Notation (JSON), allowing servers to use a single and consistent link relation to associate description resources with described resources.
“描述”链接关系允许承载描述资源的服务器将这些描述资源与其描述的资源相关联。在面向RDF的POWDER场景中，这意味着管理描述资源的服务将使用“descriptions”链接来表示这样一个事实，即它公开的描述资源提供了对所描述资源的一些描述，很可能是在某些RDF表示中。然而，由于链接关系独立于资源格式或表示，因此这种关联也可以采用其他格式，如XML或JavaScript对象表示法（JSON），从而允许服务器使用单一且一致的链接关系将描述资源与所描述的资源相关联。
Generally speaking, the idea of the 'describes' relation is the same as the idea of the 'describedby' relation; to be independent of specific formats and representations of both described resources and description resources. The 'describes' link relation (together with
一般来说，“描述”关系的概念与“被描述者”关系的概念相同；独立于描述资源和描述资源的特定格式和表示。“描述”链接关系（连同
the already registered 'describedby' link relation) thus serves as a general foundation of how described resources and description resources can be associated.
因此，已经注册的“描述连接关系”可以作为描述资源和描述资源可以如何关联的一般基础。
The link relation type below has been registered by IANA per Section 6.2.1 of RFC 5988 [1]:
IANA已根据RFC 5988[1]第6.2.1节的规定注册了以下链接关系类型：
Relation Name: describes
关系名称：描述
Description: The relationship A 'describes' B asserts that resource A provides a description of resource B. There are no constraints on the format or representation of either A or B, neither are there any further constraints on either resource.
描述：关系A“描述”B断言资源A提供了资源B的描述。对A或B的格式或表示形式没有任何约束，对任一资源也没有任何进一步的约束。
Reference: [RFC6892]
参考文献：[RFC6892]
Notes: This link relation type is the inverse of the 'describedby' relation type. While 'describedby' establishes a relation from the described resource back to the resource that describes it, 'describes' established a relation from the describing resource to the resource it describes. If B is 'describedby' A, then A 'describes' B.
注意：此链接关系类型与“describedby”关系类型相反。虽然“describedby”建立了从所描述的资源到描述它的资源的关系，“Descriptions”建立了从描述资源到它所描述的资源的关系。如果B由A“描述”，则A“描述”B。
Resource descriptions should never be treated as authoritative or exclusive without relying on additional mechanisms for trust and security. Resources can have many (possibly conflicting) descriptions, and the 'describes' link relation type makes no claim whatsoever about the authority of the party providing the association between the two resources, or about the authority of the party providing the description resource. Before making any assumptions about the authority of the description resource (both the accuracy of the description contained in the description resource, and the authority to provide a description of the described resource), clients need a context that allows them to understand both the authority of the description itself, and the authority to establish the 'describes' relation. Nobody can stop clients from providing misleading unauthorized and/or descriptions, and clients need to have both a security and trust framework to allow them to choose between trusted and untrusted descriptions.
在不依赖其他信任和安全机制的情况下，决不能将资源描述视为权威性或排他性。资源可以有许多（可能相互冲突的）描述，“描述”链接关系类型对提供两个资源之间关联的一方的权限或提供描述资源的一方的权限不作任何声明。在对描述资源的权威性（描述资源中包含的描述的准确性和提供描述资源的权威性）做出任何假设之前，客户需要一个允许他们理解描述本身权威性的上下文，以及建立“描述”关系的权力。没有人能够阻止客户端提供误导性的未经授权和/或描述，客户端需要一个安全和信任框架，以允许他们在可信和不可信描述之间进行选择。
Thanks for comments and suggestions provided by Mark Nottingham.
感谢马克·诺丁汉提供的意见和建议。
[1] Nottingham, M., "Web Linking", RFC 5988, October 2010.
[1] 诺丁汉，M.，“网络链接”，RFC 5988，2010年10月。
[2] Archer, P., Smith, K., and A. Perego, "Protocol for Web Description Resources (POWDER): Description Resources", World Wide Web Consortium Recommendation REC-powder-dr-20090901, September 2009, <http://www.w3.org/TR/2009/REC-powder-dr-20090901/>.
[2] Archer，P.，Smith，K.，和A.Perego，“网络描述资源协议（POED）：描述资源”，万维网联盟建议REC-POND-dr-200909011909年9月<http://www.w3.org/TR/2009/REC-powder-dr-20090901/>.
Author's Address
作者地址
Erik Wilde EMC Corporation 6801 Koll Center Parkway Pleasanton, CA 94566 U.S.A.
Erik Wilde EMC Corporation 6801美国加利福尼亚州普莱森顿科尔中心公园路94566号。
Phone: +1-925-600-6244
EMail: erik.wilde@emc.com
URI: http://dret.net/netdret/
Phone: +1-925-600-6244
EMail: erik.wilde@emc.com
URI: http://dret.net/netdret/