W3C home > Mailing lists > Public > public-web-intents@w3.org > September 2012

Re: CFC: Getting rid of 'extras'

From: Greg Billock <gbillock@google.com>
Date: Tue, 4 Sep 2012 14:18:48 -0700
Message-ID: <CAAxVY9dkWo843qn_Ey6cj=-htSkecFx3h50mE85Y9ty7HhT1xA@mail.gmail.com>
To: Frederick.Hirsch@nokia.com
Cc: jhawkins@google.com, public-web-intents@w3.org
Updates pushed, removing |extras|.

On Tue, Sep 4, 2012 at 12:15 PM,  <Frederick.Hirsch@nokia.com> wrote:
> +1
>
> regards, Frederick
>
> Frederick Hirsch
> Nokia
>
>
>
> On Aug 22, 2012, at 7:14 PM, ext James Hawkins wrote:
>
> Sounds good to me.
>
> Any other folks have opinions on the change?
>
> James
>
> On Wed, Aug 22, 2012 at 4:07 PM, Greg Billock <gbillock@google.com> wrote:
>>
>> Definitely. The big driver for extras was MIME types, so here's a MIME
>> type before:
>>
>> type: image/png
>> data: blob = image contents
>> extras: { "url" : image url,
>>             "filename" : representative filename,
>>           }
>>
>> and a proposal for a format with no extras:
>>
>> type: image/png
>> data: { "blob" : blob image contents,
>>           "url" : url of image contents,
>>           "filename" : representative filename,
>>         }
>>
>> Using a map as a recommended base type for data provides a lot of
>> flexibility. It provides an open namespace into which new optional
>> features can be placed to satisfy new use cases as usage evolves. A
>> goal will be to create a consistent vocabulary across types, so for
>> example "url" means "a url pointing to the content" for all MIME
>> types.
>>
>>
>> On Wed, Aug 22, 2012 at 3:44 PM, James Hawkins <jhawkins@google.com>
>> wrote:
>> > Can you provide an example to show before and after?  A few disparate
>> > cases
>> > would be helpful to see the impact of the change.
>> >
>> > Thanks,
>> > James
>> >
>> >
>> > On Wed, Aug 22, 2012 at 2:09 PM, Greg Billock <gbillock@google.com>
>> > wrote:
>> >>
>> >> In June, we discussed getting rid of getExtra() in favor of an extras
>> >> attribute (i.e. [1]). I'm increasingly persuaded that we should just
>> >> get rid of extras altogether. When this was proposed [2], it was
>> >> because we knew we needed to be able to attach metadata to the payload
>> >> data for pre-existing types (such as MIME types). But a better scheme
>> >> to deal with that is to create extensible payload formats to begin
>> >> with. Such formats have to be documented anyway (see e.g. [3]), and so
>> >> it is better to just use the existing structured-clone payload to
>> >> describe the type. Any extra header information can just be included
>> >> there.
>> >>
>> >> So the proposal is to strike |getExtra()| from the API, and add a best
>> >> practices recommendation that any documented payload type passed
>> >> through |data| be a Javascript Object type so that fields may be added
>> >> to it as necessity arises.
>> >>
>> >> This would mean a revision to documents such as [3], but going forward
>> >> it puts data passing on a firmer footing where types get designed with
>> >> extensibility in mind from the beginning. I don't think we even really
>> >> lose any generality -- web developers need to consult documentation to
>> >> figure out which extras keys mean what, anyway, and as we've learned
>> >> from trying to pass MIME types, there end up being reasons to want to
>> >> pass, say, both URLs and Blobs through the type anyway, not to mention
>> >> even better future constructs, such as Stream [4], so there isn't much
>> >> intuitive power in the type anyway. If you have to consult the
>> >> documentation, it's easier to document the type as one object, rather
>> >> than as the object and then extras data.
>> >>
>> >>
>> >> [1]
>> >>
>> >> http://lists.w3.org/Archives/Public/public-web-intents/2012Jun/0118.html
>> >> [2]
>> >>
>> >> http://lists.w3.org/Archives/Public/public-web-intents/2012Mar/0003.html
>> >> [3] http://www.w3.org/wiki/WebIntents/MIME_Types
>> >> [4]
>> >> http://dvcs.w3.org/hg/streams-api/raw-file/a3858f3ef0ae/Overview.htm
>> >>
>> >
>
>
>
Received on Tuesday, 4 September 2012 21:19:16 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 4 September 2012 21:19:17 GMT