Re: [Server Timing] Proposal how a user-agent can request that a server adds the server-timing header response field

Without waiting for browsers to implement the spec, you might also be able
to do something in service workers where you add the headers you want to
specific requests and parse the response headers.

On Thu, Jun 16, 2016 at 11:04 AM, Kenneth Hunt <kenneth.hunt@bayer.com>
wrote:

> Exactly what I was looking for, thanks for the reference Patrick!
>
>
>
> I would prefer that this fail gracefully, the client would specify that
> they would like this information, and it is optional if the server returns
> the data.
>
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>
>
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> Best regards,
>
>
>
> Kenneth Hunt
>
> Application Analysis Engineer
>
> ITPI4BHC (IT Performance Improvement for BHC)
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> *From:* Patrick Meenan [mailto:pmeenan@webpagetest.org]
> *Sent:* Thursday, June 16, 2016 10:00 AM
> *To:* Zurmuehl, Martin
> *Cc:* public-web-perf@w3.org
> *Subject:* Re: [Server Timing] Proposal how a user-agent can request that
> a server adds the server-timing header response field
>
>
>
> Have you looked over the server timing draft
> <https://www.w3.org/TR/server-timing/> to see how closely it matches your
> needs?
>
>
>
> On Thu, Jun 16, 2016 at 9:48 AM, Zurmuehl, Martin <martin.zurmuehl@sap.com>
> wrote:
>
> On the one hand side Server-Timing information would  very beneficial for
> some user agents, but on the other hand side many user-agents are not
> interested in server-timing data.
> Have you thought about providing the server timing data via the header
> field only when they are requested by the client/user-agent?
> One mechanism to request server timing data would be to use a prefer
> header as specified in rfc 7240 (https://tools.ietf.org/html/rfc7240);
> Preference: Server-Timing
> Description: Indicates that the client/user-agent prefers that the server
> adds the header field Server-Timing to the response.
>
> Example:
> > GET /resource HTTP/1.1
> > Host: example.com
> > Prefer: Server-Timing
>
> < HTTP/1.1 200 OK
> < Server-Timing: miss, db=53, app=47.2;
> < Server-Timing: customView, dc;atl
>
> The prefer header could be automatically set, if an "observer" exists on
> the client side - e.g. an observer defined in the Java-Script layer or a
> developer tool in the browser displaying timing data.
>
> Since this is only  a *preference* of the client, the server still have
> all the freedom - e.g. the server may only provide metrics to authenticated
> users or provide metrics to all users independent from the preference
> header, because the server is in a "performance testing" mode.
>
> -- Martin
>
>
>
>
>
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