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Re: Last-Event-ID in http://dev.w3.org/html5/eventsource/

From: Julian Reschke <julian.reschke@gmx.de>
Date: Tue, 02 Mar 2010 13:07:24 +0100
Message-ID: <4B8CFF7C.9060902@gmx.de>
To: Maciej Stachowiak <mjs@apple.com>
CC: "public-webapps@w3.org" <public-webapps@w3.org>
On 02.03.2010 12:53, Maciej Stachowiak wrote:
> Using If-None-Match this way seems like a bad fit in a couple of ways:
>
> - Event IDs are not ETags at the HTTP level. It seems like a layering
> violation to treat event IDs, or indeed anything in the response body
> rather than in the ETag header, as entity tags.

Event IDs *could* be used as ETags, in which case there wouldn't be a 
layering violation.

> - If-None-Match does a conditional GET. But a 304 response to an
> EventSource request would not make sense under any circumstances. The
> server should wait until it has more events to send, not tell the client
> to consult a cached copy. The client likely won't even have a cached copy.

The server is not strictly required to return a 304 (it's not a MUST). 
As this is a protocol extension in any case, I think that use would be ok.

But I agree, it's a bit of a stretch compared to the Vary:if-none-match 
pattern used for feed retrieval, as in that case, the server really 
returns 304 when there was no change.

Best regards, Julian
Received on Tuesday, 2 March 2010 12:08:01 GMT

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