REST API Media Types
draft-ietf-httpapi-rest-api-mediatypes-05

HTTPAPI                                                         R. Polli
Internet-Draft     Digital Transformation Department, Italian Government
Intended status: Informational                            7 January 2024
Expires: 10 July 2024

                          REST API Media Types
               draft-ietf-httpapi-rest-api-mediatypes-05

Abstract

   This document registers the following media types used in APIs on the
   IANA Media Types registry: application/openapi+json, and application/
   openapi+yaml.

About This Document

   This note is to be removed before publishing as an RFC.

   Status information for this document may be found at
   https://datatracker.ietf.org/doc/draft-ietf-httpapi-rest-api-
   mediatypes/.

   Discussion of this document takes place on the HTTPAPI Working Group
   mailing list (mailto:httpapi@ietf.org), which is archived at
   https://mailarchive.ietf.org/arch/browse/httpapi/.  Subscribe at
   https://www.ietf.org/mailman/listinfo/httpapi/.  Working Group
   information can be found at https://datatracker.ietf.org/wg/httpapi/
   about/.

   Source for this draft and an issue tracker can be found at
   https://github.com/ietf-wg-httpapi/mediatypes/labels/rest-api.

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."

Polli                     Expires 10 July 2024                  [Page 1]
Internet-Draft            REST API Media Types              January 2024

   This Internet-Draft will expire on 10 July 2024.

Copyright Notice

   Copyright (c) 2024 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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Notational Conventions  . . . . . . . . . . . . . . . . .   3
   2.  Media Type registrations  . . . . . . . . . . . . . . . . . .   3
     2.1.  The OpenAPI Media Types . . . . . . . . . . . . . . . . .   3
       2.1.1.  Media Type application/openapi+json . . . . . . . . .   3
       2.1.2.  Media Type application/openapi+yaml . . . . . . . . .   4
   3.  Interoperability Considerations . . . . . . . . . . . . . . .   6
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
     4.1.  General Considerations  . . . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Normative References  . . . . . . . . . . . . . . . . . . . .   6
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   7
   FAQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .   8
   Change Log  . . . . . . . . . . . . . . . . . . . . . . . . . . .   8
     Since -00 . . . . . . . . . . . . . . . . . . . . . . . . . . .   8
     Since -04 . . . . . . . . . . . . . . . . . . . . . . . . . . .   8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   OpenAPI Specification [OAS] version 3 and above is a consolidated
   standard for describing HTTP APIs using the JSON [JSON] and YAML
   [YAML] data format.

   To increase interoperability when processing API description and
   leverage content negotiation mechanisms when exchanging OpenAPI
   description resources this specification register the following media
   types: application/openapi+json and application/openapi+yaml.

Polli                     Expires 10 July 2024                  [Page 2]
Internet-Draft            REST API Media Types              January 2024

1.1.  Notational Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.  These words may also appear in this
   document in lower case as plain English words, absent their normative
   meanings.

   This document uses the Augmented BNF defined in [RFC5234] and updated
   by [RFC7405].

   The terms "content", "content negotiation", "resource", and "user
   agent" in this document are to be interpreted as in [HTTP].

2.  Media Type registrations

   This section describes the information required to register the above
   media types according to [MEDIATYPE].

2.1.  The OpenAPI Media Types

   The OpenAPI Specification Media Types convey OpenAPI document (OAS)
   files as defined in [OAS] for version 3.0 and above.

   Those files can be serialized in [JSON] or [YAML].  Since there are
   multiple OpenAPI Specification versions, those media types support
   the version parameter.

   The following example conveys the desire of a client to receive an
   OpenAPI Specification resource preferably in the following order:

   1.  openapi 3.1 in YAML

   2.  openapi 3.0 in YAML

   3.  any openapi version in JSON

   Accept: application/openapi+yaml;version=3.1,
           application/openapi+yaml;version=3.0;q=0.5,
           application/openapi+json;q=0.3

2.1.1.  Media Type application/openapi+json

   The following information serves as the registration form for the
   application/openapi+json media type.

Polli                     Expires 10 July 2024                  [Page 3]
Internet-Draft            REST API Media Types              January 2024

   Type name:  application

   Subtype name:  openapi+json

   Required parameters:  None

   Optional parameters:  version; unrecognized parameters should be
      ignored

   Encoding considerations:  Same as "application/json"

   Security considerations:  See Section 4 of this document,
      "application/json" and [OAS]

   Interoperability considerations:  See "application/json" and [OAS]

   Published specification:  this document, [OAS]

   Applications that use this media type:  HTTP

   Fragment identifier considerations:  [OAS] or the specific version of
      the OpenAPI document.

   Additional information:

   *  Deprecated alias names for this type: N/A

   *  Magic number(s): N/A

   *  File extension(s): json

   *  Macintosh file type code(s): N/A

   Person and email address to contact for further information:  See Aut
      hors' Addresses section.

   Intended usage:  COMMON

   Restrictions on usage:  None.

   Author:  See Authors' Addresses section.

   Change controller:  IETF

2.1.2.  Media Type application/openapi+yaml

   The following information serves as the registration form for the
   application/openapi+yaml media type.

Polli                     Expires 10 July 2024                  [Page 4]
Internet-Draft            REST API Media Types              January 2024

   Type name:  application

   Subtype name:  openapi+yaml

   Required parameters:  N/A

   Optional parameters:  version; unrecognized parameters should be
      ignored

   Encoding considerations:  Same as "+yaml" Structured Syntax Suffix

   Security considerations:  See Section 4 of this document, "+yaml"
      Structured Syntax Suffix and [OAS]

   Interoperability considerations:  See "+yaml" Structured Syntax
      Suffix and [OAS]

   Published specification:  [OAS]

   Applications that use this media type:  HTTP

   Fragment identifier considerations:  [OAS] or the specific version of
      the OpenAPI document.

   Additional information:

   *  Deprecated alias names for this type: N/A

   *  Magic number(s): N/A

   *  File extension(s): Same as "application/yaml"

   *  Macintosh file type code(s): N/A

   Person and email address to contact for further information:  See Aut
      hors' Addresses section

   Intended usage:  COMMON

   Restrictions on usage:  None.

   Author:  See Authors' Addresses section

   Change controller:  IETF

Polli                     Expires 10 July 2024                  [Page 5]
Internet-Draft            REST API Media Types              January 2024

3.  Interoperability Considerations

   Interoperability requirements for media type registrations are
   discussed in Section 4.6 of [MEDIATYPE]. and in the Interoperability
   Considerations of the "+yaml" Structured Syntax Suffix.

4.  Security Considerations

   Security requirements for media type registrations are discussed in
   Section 4.6 of [MEDIATYPE]. and in the Security Considerations of the
   "+yaml" Structured Syntax Suffix.

4.1.  General Considerations

   All REST API Media Types might reference nested or external
   resources, as well as processable information like HTML.

   Implementations that try to dereference or process those resource
   automatically might be subject to various security risks, from
   resource exhaustion (e.g., caused by cyclic references) to retrieval
   and processing of malicious code (e.g., embedded as markup language).

5.  IANA Considerations

   This specification defines the following new Internet media types
   [MEDIATYPE].

   IANA is asked to update the "Media Types" registry at
   https://www.iana.org/assignments/media-types
   (https://www.iana.org/assignments/media-types) with the registration
   information provided in the sections below.

      +==========================+==================================+
      | Media Type               | Registration information section |
      +==========================+==================================+
      | application/openapi+yaml | Section 2.1.2 of this document   |
      +--------------------------+----------------------------------+
      | application/openapi+json | Section 2.1.1 of this document   |
      +--------------------------+----------------------------------+

                                  Table 1

6.  Normative References

   [HTTP]     Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
              Ed., "HTTP Semantics", STD 97, RFC 9110,
              DOI 10.17487/RFC9110, June 2022,
              <https://www.rfc-editor.org/rfc/rfc9110>.

Polli                     Expires 10 July 2024                  [Page 6]
Internet-Draft            REST API Media Types              January 2024

   [JSON]     Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", STD 90, RFC 8259,
              DOI 10.17487/RFC8259, December 2017,
              <https://www.rfc-editor.org/rfc/rfc8259>.

   [jsonschema]
              Wright, A., Andrews, H., Hutton, B., and G. Dennis, "JSON
              Schema Core", 28 January 2020,
              <https://json-schema.org/specification.html>.

   [MEDIATYPE]
              Freed, N., Klensin, J., and T. Hansen, "Media Type
              Specifications and Registration Procedures", BCP 13,
              RFC 6838, DOI 10.17487/RFC6838, January 2013,
              <https://www.rfc-editor.org/rfc/rfc6838>.

   [OAS]      Darrel Miller, Jeremy Whitlock, Marsh Gardiner, Mike
              Ralphson, Ron Ratovsky, and Uri Sarid, "OpenAPI
              Specification 3.1.0", 15 February 2021,
              <https://spec.openapis.org/oas/latest>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/rfc/rfc2119>.

   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234,
              DOI 10.17487/RFC5234, January 2008,
              <https://www.rfc-editor.org/rfc/rfc5234>.

   [RFC7405]  Kyzivat, P., "Case-Sensitive String Support in ABNF",
              RFC 7405, DOI 10.17487/RFC7405, December 2014,
              <https://www.rfc-editor.org/rfc/rfc7405>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.

   [YAML]     Oren Ben-Kiki, Clark Evans, and Ingy dot Net, "YAML Ain't
              Markup Language Version 1.2", 1 October 2021,
              <https://yaml.org/spec/1.2/spec.html>.

Acknowledgements

   Thanks to Erik Wilde and David Biesack for being the initial
   contributors of this specification, and to Darrel Miller and Rich
   Salz for their support during the adoption phase.

Polli                     Expires 10 July 2024                  [Page 7]
Internet-Draft            REST API Media Types              January 2024

   In addition to the people above, this document owes a lot to the
   extensive discussion inside and outside the HTTPAPI workgroup.  The
   following contributors have helped improve this specification by
   opening pull requests, reporting bugs, asking smart questions,
   drafting or reviewing text, and evaluating open issues:

   Austin Wright, Ben Hutton and Jason Desrosiers.

FAQ

   This section is to be removed before publishing as an RFC.

   Q: Why this document?  After all these years, we still lack a proper
      media type for REST related document types.  This has some
      security implications too (eg. wrt on identifying parsers or treat
      downloads)

Change Log

   This section is to be removed before publishing as an RFC.

   RFC EDITOR PLEASE DELETE THIS SECTION.

Since -00

   This section is to be removed before publishing as an RFC.

   *  Split YAML registrations in a separate I-D.

Since -04

   This section is to be removed before publishing as an RFC.

   *  Split JSONSCHEMA registrations in a separate I-D.

Author's Address

   Roberto Polli
   Digital Transformation Department, Italian Government
   Italy
   Email: robipolli@gmail.com

Polli                     Expires 10 July 2024                  [Page 8]