Re: [server-timing] first run at spec draft

On Fri, Feb 13, 2015 at 6:38 AM, Yoav Weiss <yoav@yoav.ws> wrote:

> On top of what we discussed during the call, do you know of any browser
> that intends to implement trailer support. Currently it seems like there is no
> support for it <http://www.browserscope.org/?category=network>.
>

I believe most browsers "support it", in the sense that you can send a
trailer and it won't break anything, but we just don't do anything
meaningful with it - e.g. if you show a trailer we won't show it in
developer tools, etc. For Server-Timing I can see trailers being an
important and popular feature, so we'd have to get the right processing
logic in place.


> Also - regarding syntax, if I'm reading it correctly, why are metric and
> description optional?
>

- sometimes the name of the metric is sufficient - e.g. "edgehit" /
"cachehit", you could report 1/0 value but there is no reason to.
- sometimes there is no meaningful numeric value to report - e.g. "dc;atl"
indicates that Atlanta DC was used.

Since these are communicated via HTTP headers we want to keep things terse,
I don't think we should force everyone to have a mandatory value and
description. The only required field is the name.

And what's the use case to enable multiple descriptions on a single metric?
>

Hmm? That's not allowed. The format is: name=value;description, where value
and description are optional. That said, you *can* have multiple metrics
with the same name.

ig