Hans, Thanks for pointing that out! First, I assumed they were exclusive: a request can have start-updates or stop-updates, but not both. But the draft does not say that. My implementation does not support both in one request, but does not return an error if a request does. (My server just ignores the stop-updates field. My culpa!)
But I just realized there is a use for having both in one request. Suppose a client wants to stop a previous update-stream, and replace it with a new stream. Combining both in the same request is more efficient. On the other hand, is that going to happen often enough to matter? To complicate things, a request with start-updates, stream-id and stop-updates is ambiguous. The stop-updates part is clear. The ambiguity is for the new resources in start-updates. Should the server return updates for those on the new tcp connection? Or should the server add the start-updates resources to the *other* stream - - the one with the stream-id? I see several ways to fix that: 1. Say that start-updates & stop-updates are mutually exclusive. That is, a request has start-updates, or stop-updates and stream-id, but no other combination. And say the server must return an error if the client violates that rule. 2. Allow both in one request. But then we have to decide whether the start-updates resources are to be added to the existing stream, or to be returned in a new stream. 3. Define two separate requests: start-new-update-stream and modify-existing-update-stream. They would have different parameter types, and hence different accepts media-types. That is unambiguous, and is very general, and would allow a client to add resources to an existing update stream. But that approach is more complicated, and I do not know if the extra complication is worth it. What do the rest of you think? My vote is for #1, just to keep it simple. - Wendy Roome From: Hans Seidel <[email protected]> Date: Thu, October 1, 2015 at 10:45 To: "Y. Richard Yang" <[email protected]>, Wendy Roome <[email protected]> Cc: "[email protected]" <[email protected]> Subject: Re: [alto] New Incremental Update draft Wendy, Richard, great work. One question that came up while reading: 1. Is it allowed to use "start-updates" and "stop-updates" in one HTTP request? I found nothing specific that neither supports nor contradicts that. Intuitively, I would say no, it is not allowed to have both in one request but I am not entirely convinced. Hans
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