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About ResourceTiming API and Page errors

From: Ricardo Oliveira <rvelosoo@gmail.com>
Date: Fri, 1 Jul 2011 16:52:05 -0700
Message-Id: <948EAD7D-77E6-498B-B6BF-AA55D05774DB@gmail.com>
To: public-web-perf@w3.org
Hello All,

I was just glancing at the ResourceTiming API spec here:
http://dvcs.w3.org/hg/webperf/raw-file/f1abd45b5641/specs/ResourceTiming/Overview.html

And i've just noticed that there's not any fields to signal errors in each stage of the component processing. This is also a caveat of HAR v1.2. Basically performance information is mixed with cases where there are errors. In the case of HAR lack of data for a stage (e.g. DNS) is signaled with -1, but that does not necessarily indicate that there was an error in the component, it just indicated there's no data for that stage. I've seen people hacking into HAR and adding extra error fields to encode error conditions.  Also sometimes there's a value in the field but the stage was not completed due to an error so it doesnt make much sense to use that value. This can happen after the Http response is received but e.g. the TCP connection gets broken meanwhile.

I think the main thing is to being able to separate performance from availability, and have explicit fields for errors along with the performance fields. These can be a combination of an error flag and text-free fields due to the entropy between different browsers. Also, there should be a HTTP status field to separate filter 500 cases, etc

Just wanted to toss this at the group and see what you guys think,

Cheers

--Ricardo
Received on Friday, 1 July 2011 23:52:44 UTC

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