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Re: [Beacon] spec feedback + few suggestions

From: Ilya Grigorik <igrigorik@google.com>
Date: Thu, 7 Nov 2013 09:57:57 -0800
Message-ID: <CADXXVKoHuoBHpikKchZ10rVmQKwi+pcCOAbFTxZeUTOVY_keKQ@mail.gmail.com>
To: Jonas Sicking <jonas@sicking.cc>
Cc: Jatinder Mann <jmann@microsoft.com>, Chase Douglas <chase@newrelic.com>, "Austin, Daniel" <daaustin@paypal.com>, public-web-perf <public-web-perf@w3.org>
Great stuff, thanks Jatinder! A couple of notes:


> (under 4.2) Throwing the SyntaxError exception for a unsupported method
of transmission may not always be possible, as the User Agent may not yet
have received the Access-Control-Allow-Methods CORS header.

Isn't this redundant? If we limit cross-origin requests to GET/POST
then Access-Control-Allow-Methods should not be required to begin with.


Given that most existing analytics beacons rely on <img> and XHRs GETs,
would it make more sense to default to GET?

navigator.sendBeacon("/log?var=a", "GET", null); // "GET" as default +
analyticsData is optional.
navigator.sendBeacon("/log?var=a"); // equivalent to above?
navigator.sendBeacon("/log", "POST", analyticsData);


I think we should require sendBeacon to automatically append cookies (aka
default to "withCredentials = true" in XHR speak). Most existing <img>
beacons rely on cookies in addition to query params.


Should there be a note that UA will ignore any and all response bodies?
Perhaps recommend returning 204 from server.


Working with GA team to get the beacon size data. They also suggested some
other good feedback.. stay tuned.


On Wed, Nov 6, 2013 at 10:25 PM, Jonas Sicking <jonas@sicking.cc> wrote:

> On Nov 6, 2013 4:11 PM, "Jatinder Mann" <jmann@microsoft.com> wrote:
> >
> > Based on feedback on this thread, Iíve updated the latest editorís draft
> Looks great. The only thing I would add is that if we want to add ability
> to set headers in the future, we might want to make the last argument a
> dictionary instead of a string.
> Also, POST might be a better default given that the request body is not
> optional, and GET requests doesn't have a request body per http 1.1.
> / Jonas
Received on Thursday, 7 November 2013 17:59:05 UTC

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