Registration Protocols Extensions (regext) A. Newton Internet-Draft ICANN Intended status: Informational J. Singh Expires: 25 December 2023 ARIN 23 June 2023 RDAP Extensions draft-newton-regext-rdap-extensions-00 Abstract This document describes the usage of extensions in RDAP. 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 https://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 25 December 2023. Copyright Notice Copyright (c) 2023 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 (https://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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Newton & Singh Expires 25 December 2023 [Page 1] Internet-Draft rdap-extensions June 2023 Table of Contents 1. Background . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. The RDAP Extension Identifier . . . . . . . . . . . . . . . . 2 3. Usage in Queries . . . . . . . . . . . . . . . . . . . . . . 3 4. Usage in JSON . . . . . . . . . . . . . . . . . . . . . . . . 3 5. Camel Casing . . . . . . . . . . . . . . . . . . . . . . . . 5 6. Two Classes of Extensions . . . . . . . . . . . . . . . . . . 5 7. Extension Versioning . . . . . . . . . . . . . . . . . . . . 5 8. Extension Definitions . . . . . . . . . . . . . . . . . . . . 5 9. Normative References . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 1. Background The Registration Data Access Protocol (RDAP) defines a uniform means to access data from Internet operations registries, specifically Domain Name Registries (DNRs) and Internet Number Registries (INRs). The queries for DNRs and INRs are defined in [RFC9082] and the responses for DNRs and INRs are defined in [RFC9083]. RDAP contains a means to define extensions for queries not found in [RFC9082] and responses not found in [RFC9083]. 2. The RDAP Extension Identifier Section 6 of [RFC7480] describes the identifier used to signify RDAP extensions and the IANA registry into which RDAP extensions are to be registered. In brief, RDAP extensions identifiers start with an alphabetic character and may contain alphanumeric characters and "_" (underscore) characters. This formulation was explicitly chosen to allow compatibility with variable names in programming languages and transliteration with XML. RDAP extension identifiers have no explicit structure and are opaque in that no inner-meaning can be "seen" in them. When in use in RDAP, extension identifiers are prepended to both URL path segments and JSON attribute names. In both cases, the extension identifier acts as a namespace preventing collisions between extension elements. Newton & Singh Expires 25 December 2023 [Page 2] Internet-Draft rdap-extensions June 2023 3. Usage in Queries Section 5 of [RFC9082] describes the use of extension identifiers in formulating URIs to query RDAP servers. The extension identifiers are to be prepended to the path segments they use. For example, if an extension uses the identifier foobar, then the path segments used in that extension are prepended with foobar_. If the foobar extension defines paths fizz and fazz, the URIs for this extension might take the following form: https://base.example/foobar_fizz https://base.example/foobar_fazz Although [RFC9082] describes the use of URI query strings, it does not define their use with extensions. [RFC7480] instructs servers to ignore unknown query parameters. Therefore, the use of query parameters, prefixed or not with an extension identifier, is undefined. Despite this, there are several extensions that do specify query parameters. 4. Usage in JSON Section 2 of [RFC9083] describes the use of extension identifiers in the JSON returned by RDAP servers. Just as in URIs, the extension identifier is prepended to JSON names to create a namespace so that the JSON name from one extension will not collide with the JSON name of another extension. And just as with URIs, clients are to ignore unknown JSON names. The example given in [RFC9083] is as follows: Newton & Singh Expires 25 December 2023 [Page 3] Internet-Draft rdap-extensions June 2023 { "handle" : "ABC123", "lunarNIC_beforeOneSmallStep" : "TRUE THAT!", "remarks" : [ { "description" : [ "She sells sea shells down by the sea shore.", "Originally written by Terry Sullivan." ] } ], "lunarNIC_harshMistressNotes" : [ "In space,", "nobody can hear you scream." ] } In this example, the extension identified by lunarNIC is prepended to the names of both a JSON string and a JSON array. The following example shows this use with a JSON object. { "handle" : "ABC123", "remarks" : [ { "description" : [ "She sells sea shells down by the sea shore.", "Originally written by Terry Sullivan." ] } ], "lunarNIC_author" : { "firstInitial": "J", "lastName": "Heinlein" } } Here the JSON name "lunarNic_author" will separate the JSON from other extensions that may have an "author" structure. But the JSON contained within "lunarNIC_author" need not be prepended as the extension collision is avoided by "lunarNIC_author". Newton & Singh Expires 25 December 2023 [Page 4] Internet-Draft rdap-extensions June 2023 5. Camel Casing The styling convention used in [RFC9083] for JSON names is often called "camel casing", in reference to the hump of a camel. In this style, the first letter of every word, except the first word, composing a name is capitalized. This convention was adopted to visually separate the namespace from the name, with an underscore between them. Though there is no explicit guidance to use camel case names, extensions would be wise to continue the style. 6. Two Classes of Extensions Though all RDAP extensions are to be registered in the IANA RDAP extensions registry, there is an implicit two-class system of extensions that comes from the inherit ownership of the RDAP specifications by the IETF: extensions created by the IETF and extensions not created by the IETF. In the perspective of how extensions identifiers are used as namespace separators, extensions created by the IETF are not required to be prefixed with an extension identifier as the IETF can coordinate its own activities to avoid name collisions. In practice, extensions owned by the IETF do use extension identifiers. 7. Extension Versioning Because RDAP extensions are opaque, they posses no explicit version despite the fact that some extension identifiers include trailing numbers. That is, RDAP extensions are opaquely versioned. For example, fizzbuzz_1 may be the successor to fizzbuzz_0, but it may also be an extension for a completely separate purpose. Only consultation of the definition of fizzbuzz_1 will determine its relationship with fizzbuzz_0. Additionally, fizzbuzz_99 may be the predecessor of fizzbuzz_0. 8. Extension Definitions Extensions 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. Though RDAP gives each extension its own namespace, the definition of an extension may re-use definitions found in the base RDAP specification or in any other properly registered extension. Newton & Singh Expires 25 December 2023 [Page 5] Internet-Draft rdap-extensions June 2023 [RFC9083] notes that the extension identifiers provide a "hint" to the client as to how to interpret the response. This wording does not intentionally restrict the extension to defining only JSON values within the extensions namespace. Therefore, an extension may define the use of its own JSON values together with the use of JSON values from other extensions or RDAP specifications. As with the ICANN profile or RIR profile extensions, the extension may simply signal policy applied to already defined RDAP structures. 9. Normative References [RFC7480] Newton, A., Ellacott, B., and N. Kong, "HTTP Usage in the Registration Data Access Protocol (RDAP)", STD 95, RFC 7480, DOI 10.17487/RFC7480, March 2015, . [RFC9082] Hollenbeck, S. and A. Newton, "Registration Data Access Protocol (RDAP) Query Format", STD 95, RFC 9082, DOI 10.17487/RFC9082, June 2021, . [RFC9083] Hollenbeck, S. and A. Newton, "JSON Responses for the Registration Data Access Protocol (RDAP)", STD 95, RFC 9083, DOI 10.17487/RFC9083, June 2021, . Authors' Addresses Andy Newton ICANN Email: andy@hxr.us Jasdip Singh ARIN Email: jasdips@arin.net Newton & Singh Expires 25 December 2023 [Page 6]