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Re: [EventSource] Is the field name "event" supported in current browsers?

From: Glenn Maynard <glenn@zewt.org>
Date: Thu, 8 Sep 2011 15:41:45 -0400
Message-ID: <CABirCh-r4d4H=xx5MhX4hGxTtvQG6qnsrdfJLbZuysF2=Y=0aw@mail.gmail.com>
To: Bryan Sullivan <blsaws@gmail.com>
Cc: public-webapps@w3.org
On Thu, Sep 8, 2011 at 3:24 PM, Bryan Sullivan <blsaws@gmail.com> wrote:

> I am trying to develop a test for eventsource, and am finding that when I
> include an "event" field in an eventsource stream, the onmessage events are
> never fired (if I don't send the "event" field, just "data" fields, the
> events *are* fired). This occurs in FF, Safari, and Chrome (latest
> end-user versions).
>

Please see the examples I linked earlier [1].  The default event type is
"message", so if you don't include an "event" field, the "message" event is
fired.  If you set "event: foo", you're changing the event to "foo", so the
"foo" event is fired instead of the "message" event.

(Note that you can't say "source.onfoo" like you can "source.onmessage"; for
custom message types you need to use addEventListener.)

The EventSource spec is not really clear on this (there is no example that
> shows an event field). If anyone is familiar with what should be supported,
> please let me know if the following expectation is correct:
>

The EventSource spec assumes you're familiar with DOM Events via the DOMCORE
and/or DOMEVENTS references.
http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#events


> The event stream below should result in a message event being fired, with
> event.type set to "time" and event.data set to "Thu, 08 Sep 11 13:20:41
> -0600":
>
> event: time
> data: Thu, 08 Sep 11 13:20:41 -0600
> (blank line)
>

This will cause a "time" event to be fired instead of a "message" event.
The default is "message", set in step 3 of the steps you linked to earlier
[2], and changed to "time" in step 4.

Ian: Step 3 of [2] refers to the event type as "the event name", and step 4
refers to it as "the type".  This is confusing, since it looks like it's
referring to two different things.  The DOM specs consistently refer to it
as "type", consistent with the Event interface.  I wish "type" could be
changed to "name" everywhere, but then it'd be inconsistent with the
interface (which obviously can't be changed).

[1] https://zewt.org/~glenn/event-source.html<https://zewt.org/%7Eglenn/event-source2.html>,
https://zewt.org/~glenn/event-source2.html
[2] http://dev.w3.org/html5/eventsource/#dispatchMessage

-- 
Glenn Maynard
Received on Thursday, 8 September 2011 19:42:14 GMT

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