Internet DRAFT - draft-smith-api-catalog
draft-smith-api-catalog
Internet Engineering Task Force K. Smith, Ed.
Internet-Draft Vodafone
Intended status: Standards Track 24 July 2023
Expires: 25 January 2024
api-catalog: A well-known URI to help discovery of APIs
draft-smith-api-catalog-03
Abstract
This document defines the "api-catalog" well-known URI. It is
intended to facilitate discovery of the APIs published by a Web host.
Status of This Memo
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This Internet-Draft will expire on 25 January 2024.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Goals and non-goals . . . . . . . . . . . . . . . . . . . 2
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Using the 'api-catalog' well-known URI . . . . . . . . . . . 3
3. Link relations . . . . . . . . . . . . . . . . . . . . . . . 3
4. Associated Media type: the api-catalog linkset . . . . . . . 4
5. Conformance to RFC8615 . . . . . . . . . . . . . . . . . . . 5
5.1. Path prefix . . . . . . . . . . . . . . . . . . . . . . . 6
5.2. Supported URI schemes . . . . . . . . . . . . . . . . . . 6
5.3. Registration of the api-catalog well-known URI . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6.1. The api-catalog well-known URI . . . . . . . . . . . . . 6
6.2. The api-catalog link relation . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . 7
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
A Web host may publish Application Programming Interfaces (APIs) to
encourage requests for interaction from external parties. Such APIs
must be discovered before they may be used - i.e., the external party
needs to know what APIs a given Web host exposes, including their
purpose, any policies for usage, and the endpoints to interact with
the APIs. To faciliate discovery of this information, this document
proposes a well-known URI, 'api-catalog', as a location where a Web
host's API endpoints are listed and described.
1.1. Goals and non-goals
The primary goal is to facilitate the discovery of a Web Host's
public API endpoints, along with metadata that describes the purpose
and usage of each API. The api-catalog is primarily machine-readable
to enable automated discovery and usage of APIs. The api-catalog may
also include links to human-readable documentation.
Non-goals: this document does not mandate paths for API endpoints.
i.e., it does not mandate that my_example_api should be available at
example.com/.well-known/api-catalog/my_example_api (although it is
not forbidden to do so).
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1.2. Requirements Language
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] when, and only when, they appear in all capitals, as
shown here.
2. Using the 'api-catalog' well-known URI
The api-catalog well-known URI is intended for HTTP(S) servers that
publish APIs and wish to facilitate their discovery and usage. Since
the purpose of the api-catalog well-known URI is to facilitate API
discovery with minimal prior knowledge, it is recommended that
/.well-known/api-catalog be hosted at a predictable hostname, e.g.
www.example.com . It may also be hosted at other hostnames, e.g.
api.example.com, developer.example.com etc.
A Web host (example.com) supporting this URI:
* SHALL resolve an HTTP(S) GET request to /.well-known/api-catalog
and return an api-catalog linkset as defined in this document
* SHOULD resolve an HTTP(S) HEAD request to /.well-known/api-catalog
with a response including a Link header with the relation(s)
defined in Section 3 (Editor's note: TODO, add a section for
this).
3. Link relations
"api-catalog" . Links to an api-catalog as defined in this document.
"service-desc" . Defined in [RFC8615], used to link to a description
of the API that is primarily intended for machine consumption.
"service-doc" . Defined in [RFC8615], used to link to API
documentation that is primarily intended for human consumption.
"service-meta" . Defined in [RFC8615], used to link to additional
metadata about the API, and is primarily intended for machine
consumption.
"status" . Defined in [RFC8615], used to link to the API status (e.g.
API "health" indication etc.) for machine and/or human consumption.
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4. Associated Media type: the api-catalog linkset
A GET request to the api-catalog well-known URI SHALL return a
linkset [RFC9264] containing an array of linkset context objects.
Each linkset context object MUST include an anchor with a URI
reference for an API endpoint, and a "service-desc" link relation.
The link relations for "status", "service-doc", "service-meta" MAY be
included.
Example request:
GET .well-know/api-catalog HTTP/1.1
Host: example.com
Accept: application/linkset+json
HTTP/1.1 200 OK
Date: Mon, 01 Jun 2023 00:00:01 GMT
Server: Apache-Coyote/1.1
Content-Type: application/linkset+json
{
"linkset": [
{
"anchor": "https://developer.example.com/apis/foo_api",
"service-desc": [
{
"href": "https://developer.example.com/apis/foo_api/spec",
"type": "text/n3"
}
],
"status": [
{
"href": "https://developer.example.com/apis/foo_api/status",
"type": "application/json"
}
],
"service-doc": [
{
"href": "https://developer.example.com/apis/foo_api/doc",
"type": "text/html"
}
],
"service-meta": [
{
"href": "https://developer.example.com/apis/foo_api/policies",
"type": "text/xml"
}
]
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},
{
"anchor": "https://developer.example.com/apis/bar_api",
"service-desc": [
{
"href": "https://developer.example.com/apis/bar_api/spec",
"type": "application/json"
}
],
"status": [
{
"href": "https://developer.example.com/apis/bar_api/status",
"type": "application/json"
}
],
"service-doc": [
{
"href": "https://developer.example.com/apis/bar_api/doc",
"type": "text/plain"
}
]
},
{
"anchor": "https://developer.example.com/apis/cantona_api",
"service-desc": [
{
"href": "https://developer.example.com/apis/cantona_api/spec",
"type": "text/n3"
}
],
"service-doc": [
{
"href": "https://developer.example.com/apis/cantona_api/doc",
"type": "text/html"
}
]
}
]
}
Figure 1: api-catalog linkset example
5. Conformance to RFC8615
The requirements in section 3 of [RFC8615] for defining Well-Known
Uniform Resource Identifiers are met as follows:
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5.1. Path prefix
The api-catalog URI SHALL be appended to the /.well-known/ path-
prefix for "well-known locations".
5.2. Supported URI schemes
The api-catalog well-known URI may be used with the HTTP and HTTPS
URI schemes.
5.3. Registration of the api-catalog well-known URI
See Section 6 considerations below.
6. IANA Considerations
6.1. The api-catalog well-known URI
This specification registers the "api-catalog" well-known URI in the
Well-Known URI Registry as defined by [RFC6415] .
URI suffix: api-catalog
Specification document(s): draft-smith-api-catalog-03
Related information: The "api-catalog" documents obtained from the
same host using the HTTP and HTTPS protocols (using default ports)
MUST be identical.
6.2. The api-catalog link relation
This specification registers the "api-catalog" link relation by
following the procedures per section 4.2.2 of [RFC8288] (Editor's
note: IANA registrations are TODO).
Relation Name: api-catalog
Description: Identifies a catalog of APIs published by the context
Web host.
Reference: draft-smith-api-catalog-03
7. Security Considerations
TBD
8. References
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8.1. Normative References
[RFC6415] Hammer-Lahav, E., Ed. and B. Cook, "Web Host Metadata",
RFC 6415, DOI 10.17487/RFC6415, October 2011,
<https://www.rfc-editor.org/info/rfc6415>.
[RFC8288] Nottingham, M., "Web Linking", RFC 8288,
DOI 10.17487/RFC8288, October 2017,
<https://www.rfc-editor.org/info/rfc8288>.
[RFC8615] Nottingham, M., "Well-Known Uniform Resource Identifiers
(URIs)", RFC 8615, DOI 10.17487/RFC8615, May 2019,
<https://www.rfc-editor.org/info/rfc8615>.
[RFC9264] Wilde, E. and H. Van de Sompel, "Linkset: Media Types and
a Link Relation Type for Link Sets", RFC 9264,
DOI 10.17487/RFC9264, July 2022,
<https://www.rfc-editor.org/info/rfc9264>.
[RFC8631] Wilde, E., "Link Relation Types for Web Services",
RFC 8631, DOI 10.17487/RFC8631, July 2019,
<https://www.rfc-editor.org/info/rfc8631>.
8.2. Informative References
[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/info/rfc2119>.
Acknowledgements
TODO
Author's Address
Kevin Smith (editor)
Vodafone
One Kingdom Street
London
W2 6BY
United Kingdom
Email: kevin.smith@vodafone.com
URI: www.vodafone.com
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