HTTP 209

W3C TAG F2F April 2014

Jeni Tennison · @JeniT

Problem

Parts of large resources

GET /really-big-map HTTP/1.1

HTTP/1.1 303 See Other
Location: /small.png
Link: </small.png>; rel=preview

Pages of a collection

GET /long-running-blog HTTP/1.1

HTTP/1.1 303 See Other
Location: /first-page
Link: </first-page>; rel=start

Descriptions of non-information resources

GET /tim-berners-lee HTTP/1.1

HTTP/1.1 303 See Other
Location: http://en.wikipedia.org/wiki/Tim_Berners-Lee
Link: <http://en.wikipedia.org/wiki/Tim_Berners-Lee>; rel=describedby

Why not 303?

303s mean two roundtrips
increases latency
(legacy) lack of caching
provides the wrong URL for links

Proposal

209 Contents of Related

http://www.w3.org/2014/02/2xx/draft-prudhommeaux-http-status-209

from discussions of Linked Data Platform Working Group

GET /really-big-map HTTP/1.1

HTTP/1.1 209 Contents of Related
Location: /small.png

Issues

which resource do headers apply to?
how do apps that only recognise 200 react?
how does a server know which clients understand?

Alternatives

link to directly the related resource
use Content-Location
use the content of the response to detail relationship
use HTTP 2.0 Server Push

Process

Via IETF

Internet Draft