HTTP Range Header for Entity lists

6
votes

I have resources like this

/entities        # GET, POST
/entities/<id>   # GET, PUT, DELETE

GET /entities gets the list of all entities. Now I want to poll for updates. The case for a single entity is straight forward:

GET /entities/2
If-Modified-Since: <http date>

The list is tricky. I want the response to be a list of entities, updated or created since a given point in time. I'd intuitively use

GET /entities
Range: after <http date>

Which is a valid request by HTTP specification http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35.2 . But the spec also mandates a 206 Partial Content response, which has to include a Content-Range header. A Content-Range header, in turn, mandates a byte range to be specified http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.16 . This is obviously very inconvenient for my use case.

How would you request a semantic range over HTTP?

1
httprestentityrange
are you sure Range can be used with a date? Section 14.35.1 only discusses byte ranges. – Jeff Ogata
I agree with @adrift, I can find no reference anywhere in any RFC to Range: after <http date> being valid in HTTP/1.1 - if it were, the Content-Range: header would be defined to accomodate for it, otherwise the practice would only be half defined. – DaveRandom
The Httpbis spec seems to have a bit more details about non-byte ranges tools.ietf.org/html/draft-ietf-httpbis-p5-range-16 – Darrel Miller
See also w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.12 – Bendlas

1 Answers

2
votes

From reading section 14.35.1, I would say that the Range header is used to request a specific range of bytes from a resource, not to request a group of entities according to when they were modified.

In this case, I believe you should treat your range as a filter and pass the date as a query string parameter:

GET /entities?modified-since=<date>