[Docs] [txt|pdf|xml|html] [Tracker] [Email] [Diff1] [Diff2] [Nits]
Versions: (draft-wilde-linkset-link-rel) 00
01 02 03
Network Working Group E. Wilde
Internet-Draft CA Technologies
Intended status: Informational H. Van de Sompel
Expires: February 3, 2018 Los Alamos National Laboratory
August 2, 2017
Linkset: A Link Relation Type and Media Types for Link Sets
draft-wilde-linkset-00
Abstract
This specification defines a link relation type and media types for
working with sets of links. Using this link relation type and/or the
media types is useful when it becomes necessary to represent links
outside the context of a resource they are linking. One typical
example are scenarios in which the number of links to put in an HTTP
Link header field is too big, and thus these links should become a
resource of their own.
Note to Readers
Please discuss this draft on the ART mailing list
(<https://www.ietf.org/mailman/listinfo/art>).
Online access to all versions and files is available on GitHub
(<https://github.com/dret/I-D/tree/master/linkset>).
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 3, 2018.
Wilde & Van de Sompel Expires February 3, 2018 [Page 1]
Internet-Draft Linkset August 2017
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
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. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Origin Resource . . . . . . . . . . . . . . . . . . . . . 3
2.2. Link Set Resource . . . . . . . . . . . . . . . . . . . . 3
3. Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Third-Party Links . . . . . . . . . . . . . . . . . . . . 4
3.2. Challenges Writing to HTTP Header Field . . . . . . . . . 5
3.3. Large Number of Links . . . . . . . . . . . . . . . . . . 5
4. The "linkset" Relation Type for Linking to Link Sets . . . . 5
5. Document Formats for Link Sets . . . . . . . . . . . . . . . 7
5.1. Native Document Format for Link Sets: application/linkset 7
5.2. JSON Document Format for Link Sets:
application/linkset+json . . . . . . . . . . . . . . . . 7
5.2.1. Link Value Objects . . . . . . . . . . . . . . . . . 7
5.2.2. Link Parameters . . . . . . . . . . . . . . . . . . . 8
5.2.3. Internationalized Link Parameters . . . . . . . . . . 8
6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.1. Links Provided in the Header of the Link Set Resource . . 9
6.2. Links Provided in the Body of the Link Set Resource,
Link Set Serialized as application/linkset+json . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
7.1. Link Relation Type: linkset . . . . . . . . . . . . . . . 12
7.2. Media Type: application/linkset . . . . . . . . . . . . . 13
7.2.1. IANA Considerations . . . . . . . . . . . . . . . . . 13
7.3. Media Type: application/linkset+json . . . . . . . . . . 14
8. Security Considerations . . . . . . . . . . . . . . . . . . . 15
9. Normative References . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
Wilde & Van de Sompel Expires February 3, 2018 [Page 2]
Internet-Draft Linkset August 2017
1. Introduction
Resources on the Web often convey typed Web Links
[I-D.nottingham-rfc5988bis] as a part of resource representations,
for example, using the <link> element for HTML representations, or
the "Link" header field in HTTP response headers for representations
of any media type. In some cases, however, providing links by value
is impractical or impossible. In these cases, an approach to provide
links by reference (instead of by value) can solve the problem. This
specification defines the "linkset" relation type that allows to link
resources to sets of links, thereby making it possible to represent
links by reference, and not by value.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
This section introduces two types of resources involved in providing
links by reference, as well as the link relation type used to
interlink them.
2.1. Origin Resource
An "origin resource" is a resource that makes links in which it
participates discoverable by providing a typed link that has a "link
set resource" as the target. From the perspective of the origin
resource, the links in the "link set resource" are therefore provided
by reference.
2.2. Link Set Resource
A "link set resource" is a resource - distinct from the origin
resource, and possibly linked to from the origin resource - that
provides one or more links in which the origin resource participates.
Because the link set resource is distinct from the origin resource,
links provided by the link set resource must represent both the
source and target of each link to allow unambiguous interpretation.
Link set resources can be represented in any way that allows
representation of links in a way that supports both source and target
anchors of links. Section Section 5 defines two possible
representations, both of which are based on the link model defined by
Web Linking [I-D.nottingham-rfc5988bis].
Wilde & Van de Sompel Expires February 3, 2018 [Page 3]
Internet-Draft Linkset August 2017
3. Scenarios
The following sections outline some scenarios in which it is useful
to have the ability to separate resources and links pertaining to
them.
These are all scenarios in which providing (some) links by reference
is advantageous or necessary to accomplish certain goals. It is
important to keep in mind that even when using the pattern of "links
by reference", it is still possible to also provide links by value,
allowing resources to decide and combine which of the two patterns
they would like to use.
3.1. Third-Party Links
In some cases, it is useful that links pertaining to an origin
resource are provided by a server other than the one that hosts the
origin resource. For example, this allows:
o Providing links in which the origin resource is involved not just
as source but also as target.
o Providing links pertaining to the original resource that the
server hosting that resource is not aware of.
o External management of links pertaining to the origin resource in
a special-purpose link management service.
In such cases, a third-party link set resource provides links
pertaining to the origin resource. This link set resource may be
managed by the same custodian as the origin resource, or by a third
party.
In order for the server hosting the origin resource to provide an up-
to-date and complete set of links for it, it would need to obtain the
links from the link set resource, and embed them in the origin
resource's representations prior to responding to a client. Doing so
would increase latency and load, which may be unnecessary if a client
is not intent on consuming these links. Providing links by
reference, instead of by value, removes the server-to-server
communication and resulting overhead required to obtain links.
Instead, the consumer of the origin resource can decide if they need
the additional links as context for the resource.
Wilde & Van de Sompel Expires February 3, 2018 [Page 4]
Internet-Draft Linkset August 2017
3.2. Challenges Writing to HTTP Header Field
In some cases, it is not straightforward to write links to the HTTP
Link header from an application. This can, for example, be the case
because not all required link information is available to the
application or because the application does not have the capability
to directly write HTTP headers. In such cases, providing links by
reference can be a solution because a link to a link set pertaining
to a resource can typcially be added by means of a web server rewrite
rule that leverages the resource's URI.
3.3. Large Number of Links
When conveying links in the HTTP "Link" header, it is possible for
the size of the HTTP response header to become unpredictable. This
can be the case when links are determined dynamically dependent on a
range of contextual factors. It is possible to statically configure
a web server to correctly handle large HTTP response headers by
specifying an upper boundary for their size. But when the number of
links is unpredictable, estimating a reliable upper boundary is
challenging.
HTTP [RFC7231] defines error codes related to excess communication by
the user agent ("413 Request Entity Too Large" and "414 Request-URI
Too Long"), but no specific error codes are defined to indicate that
response header content exceeds the upper boundary that can be
handled by the server, and thus it has been truncated. As a result,
applications take counter measures aimed at controlling the size of
the HTTP "Link" header, for example by limiting the links they
provide to those with select relation types, thereby limiting the
value of the HTTP "Link" header to clients. Providing links by
reference, instead of by value, overcomes challenges related to the
unpredictable nature of the extent of HTTP "Link" headers.
In more extreme scenarios it is conceivable that the number of links
pertaining to the origin resource becomes so large that the response
from the associated link set resource becomes too large. This could
be the case for highly popular origin resources, when the link set
includes incoming links as well. In such cases, the link set
resource could deliver responses incrementally, for example, using a
paged resource model that clients can consume as required, requesting
links incrementally by paging through the provided link set.
4. The "linkset" Relation Type for Linking to Link Sets
A link with the "linkset" link relation type has as Context IRI the
IRI of an origin resource, and as Target IRI the IRI of an associated
link set resource.
Wilde & Van de Sompel Expires February 3, 2018 [Page 5]
Internet-Draft Linkset August 2017
A link with the "linkset" relation type MAY be provided in the header
and/or the body of the origin resource's representation. It may also
be discovered by other means, such as through client-side
information.
More than one link with a "linkset" relation type MAY be provided.
Multiple such links can refer to the same set of links expressed
using different representations, or to different link sets
(potentially provided by different services).
The use of a link with the "linkset" relation type does not preclude
the provision of links with other relation types, i.e. the origin
resource can provide typed links other than a "linkset" link.
Therefore, the effective set of links pertaining to the origin
resource is the union of the links that the resource itself provides,
and of all links in which it participates which are provided by the
link set resources linked from it via "linkset" links.
The link set resource MAY provide the links that pertain to the
origin resource in its HTTP response header and/or body:
o In cases where the link set resource provides these links in its
Link HTTP response header, the payload of that header MUST comply
with the syntax defined in Web Linking
[I-D.nottingham-rfc5988bis]. The media type of the response body
is not constrained.
o In cases where the link set resource provides these links in its
response body, the body SHOULD allow a client to determine the
source and target of each provided link. The media type of the
response body is otherwise not constrained.
There is no constraint on the Target IRI of a link with the "linkset"
relation type; designing and using these links is left to the
discretion of implementers.
If an origin resource provides a "linkset" link pointing at a link
set resource, and that link set resource provides a "linkset" link in
turn, then this latter link points at links pertaining to the link
set resource. This means that in the context of the latter link, the
link set resource is an origin resource. This means that linkset
relations are not transitive, and it is up to a client to decide
whether they follow "nested chains" of linkset links or not.
Wilde & Van de Sompel Expires February 3, 2018 [Page 6]
Internet-Draft Linkset August 2017
5. Document Formats for Link Sets
This section specifies two document formats to convey link sets, one
that is identical to the payload of the HTTP Link header as specified
in RFC 5988bis [I-D.nottingham-rfc5988bis], and the other is a JSON-
based format that does not have the character encoding limitations to
which HTTP headers are subject as per RFC 5987 [RFC5987].
5.1. Native Document Format for Link Sets: application/linkset
This document format is identical to the payload of the HTTP Link
header. It is defined in Section 3 of RFC 5988bis
[I-D.nottingham-rfc5988bis], more specifically by its ABNF production
rule for "Link" and subsequent ones. The assigned media type for
this format is application/linkset.
5.2. JSON Document Format for Link Sets: application/linkset+json
For applications that prefer a JSON serialization of link set
resources, the following definition provides a JSON [RFC7159]
serialization which is intended to faithfully reproduce the abstract
model of RFC 5988bis [I-D.nottingham-rfc5988bis].
In the JSON representation, a link set resource is represented by an
array, where each member of the array is an object, which is the JSON
representation of a link value. Implementations MUST always wrap
link value representations in an array, even if a link set contains
only one link value. Implementations MUST NOT include any members
other than link value objects in the array representing a link set.
5.2.1. Link Value Objects
A link value object represents an individual link of a link set.
Each link value object is represented as a JSON object and MUST have
an "href" member that represents the link target. The value of the
"href" member is a URI-Reference that conveys the target IRI.
[ { "href" : "http://example.com/foo" } ]
This minimal example of a JSON-serialized link set contains just one
link which only uses the link target URI in its representation. In
most cases, links are further qualified by link parameters, which are
serialized as additional members of the link value object.
Wilde & Van de Sompel Expires February 3, 2018 [Page 7]
Internet-Draft Linkset August 2017
5.2.2. Link Parameters
In accordance with RFC 5988bis, link parameters apply to individual
links, and while a number of link parameters are defined by RFC
5988bis, other link parameters MAY occur and implementations MUST
ignore the ones that they do not understand.
Link parameters appear as members of link value objects. Their name
is the name of the link parameter, and their value is the value of
the link parameter.
[ { "href" : "http://example.com/foo",
"rel" : "next" } ]
This example add a link relation type to the link, using the "rel"
link parameter defined by RFC 5988bis.
RFC 5988bis defines the link parameters "rel", "anchor", "rev",
"hreflang", "media", "type", "title", and "title*". For the link
parameters "rel", "anchor", "rev", "hreflang", "media", and "type",
these can appear in the JSON serialization in the same way as shown
in the above example, as members of link value objects that have the
link parameter type as their name, and its value as their value. The
case for "title" and "title*" is different because these have been
specifically introduced to deal with character encoding issues in
HTTP link headers, and can be encoded more effectively in JSON.
5.2.3. Internationalized Link Parameters
While most link parameters can be translated directly from their RFC
5988bis variants, one special case are link parameters following the
model of RFC 5987 [RFC5987]. These link parameters use the pattern
of the "title" and "title*" link parameters defined by RFC 5988bis.
The model defined by RFC 5987 [RFC5987] and used by "title" and
"title*" may be used by additional link parameters as well, which can
be recognized by the naming scheme of using a link parameter name and
its variant with a trailing asterisk. The JSON serialization model
described here applies to all these parameters and MUST be used for
the JSON representation of link sets. In other words,
implementations MUST NOT directly translate RFC 5987 style parameters
into corresponding JSON link value object members. Instead they MUST
map them to the JSON representation defined in this section.
Internationalized link parameters use the link parameter name as
their name, and their value is either a string representing the link
parameter value, or an object representing one or more language
tagged link parameter values. In such an object, the set of members
uses a language tag [RFC5646] as their names, and their values are
Wilde & Van de Sompel Expires February 3, 2018 [Page 8]
Internet-Draft Linkset August 2017
strings representing the link parameter values associated with the
respective language tag.
6. Examples
Sections Section 6.1 and Section 6.2 show examples whereby the link
set resource provides links pertaining to the origin resource, in its
response header and body, respectively.
6.1. Links Provided in the Header of the Link Set Resource
Figure 1 shows a client issuing an HTTP head request against origin
resource http://example.org/resource1.
HEAD /resource1 HTTP/1.1
Host: example.org
Connection: close
Figure 1: Client HTTP HEAD Request
Figure 2 shows the response to the HEAD request of Figure 1. The
response contains a Link header with a link that uses the "linkset"
relation type. It indicates that links pertaining to the origin
resource are provided by link set resource http://example.com/
links?uri=http%3A%2F%2Fexample.org%2Fresource.
HTTP/1.1 200 OK
Date: Mon, 28 Nov 2016 14:37:51 GMT
Server: Apache-Coyote/1.1
Link: <http://example.com/links?uri=http%3A%2F%2Fexample.org%2Fresource>
; rel="linkset"
; type="text/html"
Content-Length: 5214
Content-Type: text/html;charset=utf-8
Connection: close
Figure 2: Response to HTTP HEAD on Origin Resource
While in this example the IRI of the linkset resource uses a pattern
that represents the IRI of the origin resource, this is opaque to the
client, which simply follows the provided linkset IRI when retrieving
the linkset resource.
Figure 3 shows the client issuing an HTTP GET request against the
link set resource provided in Figure 2.
Wilde & Van de Sompel Expires February 3, 2018 [Page 9]
Internet-Draft Linkset August 2017
GET /links?uri=http%3A%2F%2Fexample.org%2Fresource HTTP/1.1
Host: example.com
Connection: close
Figure 3: Client HTTP GET against the Link Set Resource
Figure 4 shows the response headers to the HTTP GET request of
Figure 3. The links pertaining to the origin resource are provided
in the Link response header of the link set resource. As can be
seen, in order to support an unambiguous determination of the Context
IRI of each link, the "anchor" attribute is provided for each link.
Note that most, but not all, links have the origin resource as
Context IRI (anchor).
HTTP/1.1 200 OK
Date: Mon, 28 Nov 2016 14:40:02 GMT
Server: Apache-Coyote/1.1
Link: <http://authors.example.net/johndoe>
; rel="author"
; type="application/rdf+xml"
; anchor="http://example.org/resource1",
<http://authors.example.net/janedoe>
; rel="author"
; type="application/rdf+xml"
; anchor="http://example.org/resource1",
<http://example.org/resource1/items/AF48EF.pdf>
; rel="item"
; type="application/pdf"
; anchor="http://example.org/resource1",
<http://example.org/resource1/items/CB63DA.html>
; rel="item"
; type="text/html"
; anchor="http://example.org/resource1",
<http://example.net/resource41/>
; rel="related"
; type="application/pdf"
; anchor="http://example.org/resource1/items/AF48EF.pdf"
Content-Type: text/html
Content-Length: 3018
Figure 4: Response to HTTP GET against the Link Set Resource
Wilde & Van de Sompel Expires February 3, 2018 [Page 10]
Internet-Draft Linkset August 2017
6.2. Links Provided in the Body of the Link Set Resource, Link Set
Serialized as application/linkset+json
Figure 5 is an example of a client issuing an HTTP head request
against origin resource http://example.org/article?id=10.1371/
journal.pone.0167475
HEAD article?id=10.1371/journal.pone.0167475 HTTP/1.1
Host: example.org
Connection: close
Figure 5: Client HTTP HEAD Request
Figure 6 shows the response to the HEAD request of Figure 5. The
response contains a Link header with a link that has the "linkset"
relation type. It indicates that links pertaining to the origin
resource are provided by link set resource
http://example.com/links/10.1371/journal.pone.0167475, which provides
a representation with vendor media type application/
vnd.example.org.linkset+json.
HTTP/1.1 200 OK
Date: Mon, 28 Nov 2016 14:37:51 GMT
Server: Apache-Coyote/1.1
Link: <http://example.com/links/10.1371/journal.pone.0167475>
; rel="linkset"
; type="application/linkset+json"
Content-Length: 236
Content-Type: text/html;charset=utf-8
Connection: close
Figure 6: Response to HTTP HEAD on Origin Resource
In this example, the IRI of the linkset resource does not directly
represent the IRI of the origin resource anymore. There still is an
association possible through a IRI pattern that is including DOI
information, but as in the example above, the linkset IRI is opaque
to the client which simply accesses the IRI to retrieve the linkset
resource.
Figure 7 shows the client issuing an HTTP GET request against the
link set resource provided in Figure 6.
Wilde & Van de Sompel Expires February 3, 2018 [Page 11]
Internet-Draft Linkset August 2017
GET /links/10.1371/journal.pone.0167475 HTTP/1.1
Host: example.com
Accept: application/linkset+json
Connection: close
Figure 7: Client HTTP GET against the Link Set Resource
Figure 8 shows the response headers to the HTTP GET request of
Figure 7. The links pertaining to the origin resource are provided
in the response body of the link set resource and are serialized
according to the vendor media type application/
vnd.example.org.linkset+json.
HTTP/1.1 200 OK
Date: Mon, 28 Nov 2016 14:40:02 GMT
Server: Apache-Coyote/1.1
Content-Type: application/linkset+json
Content-Length: 794
[{"href":"http://authors.example.net/johndoe","anchor":"http://example.org/article?id=10.1371/journal.pone.0167475","rel":"author","type":"application/rdf+xml"},
{"href":"http://authors.example.net/janedoe","anchor":"http://example.org/article?id=10.1371/journal.pone.0167475","rel":"author","type":"application/rdf+xml"},
{"href":"http://example.org/resource1/items/AF48EF.pdf","anchor":"http://example.org/article?id=10.1371/journal.pone.0167475","rel":"item","type":"text/html"},
{"href":"http://example.org/resource1/items/CB63DA.html","anchor":"http://example.org/article?id=10.1371/journal.pone.0167475","rel":"item","type":"application/pdf"},
{"href":"http://example.net/resource41/","anchor":"http://example.org/resource1/items/AF48EF.pdf","rel":"related","type":"application/pdf"}]
Figure 8: Response to HTTP GET against the Link Set Resource
If Figure 6 would have provided a link to a link set with media type
application/linkset, and if the client would have requested that link
set, then the body of the response would have been similar to
Figure 8. But it would have had application/linkset as Content-Type,
the payload of the HTTP Link header of Figure 4 as body, and an
accordingly adjusted value for Content-Length.
7. IANA Considerations
7.1. Link Relation Type: linkset
The link relation type below has been registered by IANA per
Section 6.2.1 of Web Linking [I-D.nottingham-rfc5988bis]:
Relation Name: linkset
Description: The Target IRI of a link with the "linkset" relation
type provides a set of links that pertain to the Context IRI of
the link.
Reference: [[ This document ]]
Wilde & Van de Sompel Expires February 3, 2018 [Page 12]
Internet-Draft Linkset August 2017
7.2. Media Type: application/linkset
7.2.1. IANA Considerations
The Internet media type [RFC6838] for a natively encoded link set is
application/linkset.
Type name: application
Subtype name: linkset
Required parameters: none
Optional parameters: none
Encoding considerations: ...
Security considerations: ...
Interoperability considerations: ...
Published specification: [[ This document ]]
Applications that use this media type: ...
Additional information:
Magic number(s): N/A
File extension(s): This media type does not propose a specific
extension.
Macintosh file type code(s): TEXT
Person & email address to contact for further information: Herbert
Van de Sompel <herbertv@lanl.gov>
Intended usage: COMMON
Restrictions on usage: none
Author: Herbert Van de Sompel <herbertv@lanl.gov>
Change controller: IETF
Wilde & Van de Sompel Expires February 3, 2018 [Page 13]
Internet-Draft Linkset August 2017
7.3. Media Type: application/linkset+json
The Internet media type [RFC6838] for a JSON-encoded link set is
application/linkset+json.
Type name: application
Subtype name: linkset+json
Required parameters: none
Optional parameters: none
Encoding considerations: ...
Security considerations: ...
Interoperability considerations: ...
Published specification: [[ This document ]]
Applications that use this media type: ...
Additional information:
Magic number(s): N/A
File extension(s): JSON documents often use ".json" as the file
extension, and this media type does not propose a specific
extension other than this generic one.
Macintosh file type code(s): TEXT
Person & email address to contact for further information: Herbert
Van de Sompel <herbertv@lanl.gov>
Intended usage: COMMON
Restrictions on usage: none
Author: Herbert Van de Sompel <herbertv@lanl.gov>
Change controller: IETF
Wilde & Van de Sompel Expires February 3, 2018 [Page 14]
Internet-Draft Linkset August 2017
8. Security Considerations
...
9. Normative References
[I-D.nottingham-rfc5988bis]
Nottingham, M., "Web Linking", draft-nottingham-
rfc5988bis-06 (work in progress), June 2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<http://www.rfc-editor.org/info/rfc3986>.
[RFC5646] Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
September 2009, <http://www.rfc-editor.org/info/rfc5646>.
[RFC5987] Reschke, J., "Character Set and Language Encoding for
Hypertext Transfer Protocol (HTTP) Header Field
Parameters", RFC 5987, DOI 10.17487/RFC5987, August 2010,
<http://www.rfc-editor.org/info/rfc5987>.
[RFC6690] Shelby, Z., "Constrained RESTful Environments (CoRE) Link
Format", RFC 6690, DOI 10.17487/RFC6690, August 2012,
<http://www.rfc-editor.org/info/rfc6690>.
[RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type
Specifications and Registration Procedures", BCP 13,
RFC 6838, DOI 10.17487/RFC6838, January 2013,
<http://www.rfc-editor.org/info/rfc6838>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <http://www.rfc-editor.org/info/rfc7159>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014,
<http://www.rfc-editor.org/info/rfc7231>.
Wilde & Van de Sompel Expires February 3, 2018 [Page 15]
Internet-Draft Linkset August 2017
[W3C.REC-html401-19991224]
Rivoal, F., "Media Queries", World Wide Web
Consortium Recommendation REC-css3-mediaqueries-20120619,
June 2012.
Authors' Addresses
Erik Wilde
CA Technologies
Email: erik.wilde@dret.net
URI: http://dret.net/netdret/
Herbert Van de Sompel
Los Alamos National Laboratory
Email: herbertv@lanl.gov
URI: http://public.lanl.gov/herbertv/
Wilde & Van de Sompel Expires February 3, 2018 [Page 16]
Html markup produced by rfcmarkup 1.129b, available from
https://tools.ietf.org/tools/rfcmarkup/