Network Working Group A. Newton
Internet-Draft ARIN
Intended status: Standards Track B. Ellacott
Expires: June 8, 2013 APNIC
N. Kong
CNNIC
December 5, 2012
Using the Registration Data Access Protocol (RDAP) with HTTP
draft-ietf-weirds-using-http-01
Abstract
This document describes the usage of the Registration Data Access
Protocol (RDAP) using HTTP.
Status of this Memo
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This Internet-Draft will expire on June 8, 2013.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Design Intents . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Queries . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Accept Header . . . . . . . . . . . . . . . . . . . . . . 6
4.2. Query Parameters . . . . . . . . . . . . . . . . . . . . . 6
5. Types of HTTP Response . . . . . . . . . . . . . . . . . . . . 7
5.1. Positive Answers . . . . . . . . . . . . . . . . . . . . . 7
5.2. Redirects . . . . . . . . . . . . . . . . . . . . . . . . 7
5.3. Negative Answers . . . . . . . . . . . . . . . . . . . . . 7
5.4. Malformed Queries . . . . . . . . . . . . . . . . . . . . 7
6. Extensibility . . . . . . . . . . . . . . . . . . . . . . . . 8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
8. Internationalization Considerations . . . . . . . . . . . . . 10
8.1. URIs and IRIs . . . . . . . . . . . . . . . . . . . . . . 10
8.2. Language Identifiers in Queries and Responses . . . . . . 10
8.3. Language Identifiers in HTTP Headers . . . . . . . . . . . 10
9. Normative References . . . . . . . . . . . . . . . . . . . . . 11
Appendix A. Cache Busting . . . . . . . . . . . . . . . . . . . . 12
Appendix B. Changelog . . . . . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
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1. Introduction
This document describes the usage of HTTP for Registration Data
Directory Services running on RESTful web servers. The goal of this
document is to tie together the usage patterns of HTTP into a common
profile applicable to the various types of Directory Services serving
Registration Data using RESTful styling. By giving the various
Directory Services common behavior, a single client is better able to
retrieve data from Directory Services adhering to this behavior.
In designing these common usage patterns, this draft endeavours to
satisfy requirements for a Registration Data Access Protocol (RDAP)
that is documented in [draft-kucherawy-weirds-requirements]. This
draft also introduces an additional design consideration to define a
simple use of HTTP. Where complexity may reside, it is the goal of
this specification to place it upon the server and to keep the client
as simple as possible. A client implementation should be possible
using common operating system scripting tools.
This is the basic usage pattern for this protocol:
1. A client issues an HTTP query using GET. As an example, a query
for the network registration 192.0.2.0 might be
http://example.com/ip/192.0.2.0.
2. If the receiving server has the information for the query, it
examines the Accept header field of the query and returns a 200
response with a response entity appropriate for the requested
format.
3. If the receiving server does not have the information for the
query but does have knowledge of where the information can be
found, it will return a redirection response (3xx) with the
Location: header containing an HTTP URL pointing to the
information or another server known to have knowledge of the
location of the information. The client is expected to re-query
using that HTTP URL.
4. If the receiving server does not have the information being
requested and does not have knowledge of where the information
can be found, it should return a 404 response.
It is important to note that it is not the intent of this document to
redefine the meaning and semantics of HTTP. The purpose of this
document is to clarify the use of standard HTTP mechanisms for this
application.
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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].
As is noted in SSAC Report on WHOIS Terminology and Structure
[SAC-051], the term "Whois" is overloaded, often referring to a
protocol, a service and data. In accordance with [SAC-051], this
document describes the base behavior for a Registration Data Access
Protocol (RDAP). [SAC-051] describes a protocol profile of RDAP for
Doman Name Registries (DNRs), DNRD-AP. This document and others from
the IETF WEIRDS working group describe a single protocol, RDAP, for
access to the data of both DNRs and Regional Internet Registries
(RIRs). RIRs are also often referred to as number resource
registries and are responsible for the registration of IP address
networks and autonomous system numbers.
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3. Design Intents
There are a few design criteria this document attempts to support.
First, each query is meant to return either zero or one result. With
the maximum upper bound being set to one, the issuance of redirects
is simplified to the known query/respone model used by HTTP
[RFC2616]. Should a result contain more than one result, some of
which are better served by other servers, the redirection model
becomes much more complicated.
Second, multiple response formats are supported by this protocol. At
present the IETF WEIRDS working group is defining only a JSON
[RFC4627] response format, but server operators may use other data
formats when those formats are requested.
Third, HTTP offers a number of transport protocol mechanisms not
described further in this document. Operators are able to make use
of these mechanisms according to their local policy, including cache
control, authorization, compression, and redirection. HTTP also
benefits from widespread investment in scalability, reliability, and
performance, and widespread programmer understanding of client
behaviours for RESTful web services, reducing the cost to deploy
Registration Data Directory Services and clients.
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4. Queries
4.1. Accept Header
Clients SHOULD put the media type of the format they desire in the
Accept header field.
Accept: application/rdap
Servers SHOULD respond with an appropriate media type in the Content-
Type header in accordance with the preference rules for the Accept
header in HTTP [RFC2616].
Content-Type: application/rdap
Clients MAY use a generic media type for the desired data format of
the response (e.g. "application/json"), but servers SHOULD respond
with the most appropriate media type (e.g. "application/rdap"). In
other words, a client may use "application/json" to express that it
desires JSON or "application/rdap" to express that it desires RDAP
specific JSON, but the server would respond with "application/rdap".
4.2. Query Parameters
Servers SHOULD ignore unknown query parameters. Use of unknown query
parameters for cache-busting is described in Appendix A.
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5. Types of HTTP Response
This section describes the various types of responses a server may
send to a client. While no standard HTTP response code is forbidden
in usage, at a minimum clients SHOULD understand the response codes
described in this section. It is expected that usage of response
codes and types for this application not defined here will be
described in subsequent documents.
5.1. Positive Answers
If a server has the information requested by the client and wishes to
respond to the client with the information according to its policies,
it SHOULD encode the answer in the format most appropriate according
to the standard and defined rules for processing the HTTP Accept
header, and return that answer in the body of a 200 response.
5.2. Redirects
If a server wishes to inform a client that the answer to a given
query can be found elsewhere, it SHOULD return either a 301 or a 307
response code and an HTTP URL in the Location: header. The client is
expected to issue a subsequent query using the given URL without any
processing of the URL. In other words, the server is to hand back a
complete URL and the client should not have to transform the URL to
follow it.
A server SHOULD use a 301 response to inform the client of a
permanent move and a 307 response otherwise. For this application,
such an example of a permanent move might be a top level domain (TLD)
operator informing a client the information being sought can be found
with another TLD operator (i.e. a query for the domain bar in
foo.example is found at http://foo.example/domain/bar).
5.3. Negative Answers
If a server wishes to respond that it has no information regarding
the query, it SHOULD return a 404 response code. Optionally, it MAY
include additional information regarding the negative answer in the
HTTP entity body.
5.4. Malformed Queries
If a server receives a query which it cannot understand, it SHOULD
return a 400 response code. Optionally, it MAY include additional
information regarding this negative answer in the HTTP entity body.
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6. Extensibility
For extensibility purposes, this document defines an IANA registry
for prefixes used in JSON [RFC4627] data serialization and URI path
segments (see Section 7).
Prefixes and identifiers SHOULD only consist of the alphabetic ASCII
characters A through Z in both uppercase and lowercase, the numerical
digits 0 through 9, underscore characters, and SHOULD NOT begin with
an underscore character, numerical digit or the characters "xml".
The following describes the production of JSON names in ABNF
[RFC5234].
ABNF for JSON names
name = ALPHA *( ALPHA / DIGIT / "_" )
Figure 1
This restriction is a union of the Ruby programming language
identifier syntax and the XML element name syntax and has two
purposes. First, client implementers using modern programming
languages such as Ruby or Java may use libraries that automatically
promote JSON names to first order object attributes or members.
Second, a clean mapping between JSON and XML is easy to accomplish
using these rules.
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7. IANA Considerations
This specification proposes an IANA registry for RDAP extensions.
The purpose of this registry is to ensure uniqueness of extension
identifiers. The extension identifier is used as prefix in JSON
names and as a prefix of path segments in RDAP URLs.
The production rule for these identifiers is specified in Section 6.
In accordance with RFC5226, the IANA policy for assigning new values
shall be Specification Required: values and their meanings must be
documented in an RFC or in some other permanent and readily available
reference, in sufficient detail that interoperability between
independent implementations is possible.
The following is a preliminary template for an RDAP extension
registration:
Extension identifier: the identifier of the extension
Registry operator: the name of the registry operator
Published specification: RFC number, bibliographical reference or
URL to a permanent and readily available specification
Person & email address to contact for further information: The
names and email addresses of individuals for contact regarding
this registry entry
Intended usage: brief reasons for this registry entry
The following is an example of a registration in the RDAP extension
registry:
Extension identifier: lunarNic
Registry operator: The Registry of the Moon, LLC
Published specification: http://www.example/moon_apis/rdap
Person & email address to contact for further information:
Professor Bernardo de la Paz <berny@moon.example>
Intended usage: COMMON
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8. Internationalization Considerations
8.1. URIs and IRIs
Clients MAY use IRIs as they see fit, but MUST transform them to URIs
[RFC3986] for interaction with RDAP servers. RDAP servers MUST use
URIs in all responses, and clients MAY transform these URIs to IRIs.
8.2. Language Identifiers in Queries and Responses
Depending on the data format of the response, servers MAY include
data in character sets other than ASCII and languages other than
English (the data format will most likely be in Unicode and almost
certainly languages other than English will be encountered). Under
most scenarios, clients requesting data will not signal that the data
be returned in a particular language or script. On the other hand,
when servers return data and have knowledge that the data is in a
language or script, the data should be annotated with language
identifiers thus allowing clients to process and display the data
accordingly.
A language identifier in the response is specified in section 5.3 of
[draft-ietf-weirds-json-response]. It is used to indicate the
language/script of the response data. It is possible that
registration data is stored in several different languages and
returned in a single response. Data portion of different language
types SHOULD be tagged with its corresponding identifier if known.
8.3. Language Identifiers in HTTP Headers
Given the description of the use of language identifiers in
Section 8.2, unless otherwise specified servers SHOULD ignore the
HTTP [RFC2616] Accept-Language header when formulating responses.
However, servers MAY return language identifiers in the Content-
Language header so as to inform clients of the intended language of
HTTP layer messages.
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9. Normative References
[draft-kucherawy-weirds-requirements]
Kucherawy, M., "Requirements For Internet Registry
Services", Work in progress: Internet
Drafts draft-kucherawy-weirds-requirements-04.txt,
April 2011.
[draft-ietf-weirds-json-response]
Newton, A. and S. Hollenbeck, "JSON Responses for the
Registration Data Access Protocol (RDAP)", Work in
progress: Internet
Drafts draft-ietf-weirds-json-response-01.txt,
December 2012.
[SAC-051] Piscitello, D., Ed., "SSAC Report on Domain Name WHOIS
Terminology and Structure", September 2011.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4627] Crockford, D., "The application/json Media Type for
JavaScript Object Notation (JSON)", RFC 4627, July 2006.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008.
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Appendix A. Cache Busting
To overcome issues with misbehaving HTTP [RFC2616] cache
infrastructure, clients MAY use an adhoc and improbably used query
parameter with a random value of their choosing. As Section 4.2
instructs servers to ignore unknown parameters, this is unlikely to
have any known side effects.
An example of using an unknown query parameter to bust caches:
http://example.com/ip/192.0.2.0?__fuhgetaboutit=xyz123
Use of an unknown parameter to overcome misbehaving caches is not
part of any specification and is offered here for informational
purposes.
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Appendix B. Changelog
Initial WG -00: Updated to working group document 2012-September-20
-01
* Updated for the sections moved to the JSON responses draft.
* Simplified media type, removed "level" parameter.
* Updated 2119 language and added boilerplate.
* In section 1, noted that redirects can go to redirect servers
as well.
* Added Section 8.2 and Section 8.3.
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Authors' Addresses
Andrew Lee Newton
American Registry for Internet Numbers
3635 Concorde Parkway
Chantilly, VA 20151
US
Email: andy@arin.net
URI: http://www.arin.net
Byron J. Ellacott
Asia Pacific Network Information Center
6 Cordelia Street
South Brisbane QLD 4101
Australia
Email: bje@apnic.net
URI: http://www.apnic.net
Ning Kong
China Internet Network Information Center
4 South 4th Street, Zhongguancun, Haidian District
Beijing 100190
China
Phone: +86 10 5881 3147
Email: nkong@cnnic.cn
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