Re: Clarification on Alternative Service Connection Failures

On Fri, Sep 29, 2017 at 12:48 PM, Ryan Hamilton <rch@google.com> wrote:

> On Fri, Sep 29, 2017 at 6:27 AM, Patrick McManus <mcmanus@ducksong.com>
> wrote:
>
>> The text is referring to any failure - the client MAY want to try a
>> different alternative in that case. Its just saying don't feel pinned down
>> by an Alt-Svc announcement just because you started to use it - you can
>> always use a different one (or the default) if you think it would work
>> better. A 500 seems a reasonable input to that choice to me.
>>
>
> ​Wow, really? Hm. While I understand your reasoning here, I don't love it.
> It seems like we might want to have more concrete advice to browsers about
> what kinds of failures should count as a failure. Otherwise we'll end up
> with different behavior in different browsers for no terribly good reason.
> For example, what about 4xx errors? Should all 4xx and all 5xx errors
> count? What behavior should servers be able to count on? Is it "safe" to
> advertise an alternative which is not current reachable (I think so). What
> about one which 404s for all requests, or one which 500s every request?
> Should this be considered "safe" for a server to advertise?
>
> I'm not sure I have a terribly well thought out idea here, but this makes
> me a bit nervous.
>

​One more thought. Should non-idempotent requests be resent in the case
where an alternative 500s?​