Re: [EME] Exposing key status to applications

On Thu, Oct 2, 2014 at 12:58 PM, David Dorwin <ddorwin@google.com> wrote:

>
> On Fri, Sep 26, 2014 at 8:54 AM, Boris Zbarsky <bzbarsky@mit.edu> wrote:
>
>> I assume myKeyId is some kinda arbitrary string, right?
>>
>
> myKeyId is probably an ArrayBuffer[View]. (However, see question #4.) I
> don't know whether that affects this discussion.
>
>>
>> The best way to do that, as of today's thinking on API design, is to
>> create an interface that mimics the ES Map API but doesn't provide any of
>> the mutation methods.
>>
>> That would give you things like:
>>
>>   var mykeystatus = session.keys.get(myKeyId)
>>
>
> The ability to get the status for a known key ID like this seems useful.
>
>>
>> and
>>
>>   for (keyId of session.keys.keys())  // loops over key ids
>>
>> and
>>
>>   for (keyStatus of session.keys.values()) // loops over key statuses
>>
>
> For any type of iteration (or indexes), applications must not assume the
> containers are consistent outside the current synchronous execution.
>
>>
>> The fact that two very different things are being called "keys" here is a
>> bit annoying, I agree.  :(
>>
>> You can certainly do this all with Web IDL, though it's a pretty manual
>> process to define things like keys() and values().  There are some
>> proposals to doing it somewhat automagically via dedicated "make this look
>> like a Map" IDL syntax, but nothing concrete there yet.
>>
>
> I was referred to this bug:
> https://www.w3.org/Bugs/Public/show_bug.cgi?id=26183
>
> Given that there is a general effort to do things like this, this may be
> the best direction for us.
>

See the newly-added maplike declaration feature of WebIDL:
http://heycam.github.io/webidl/#idl-maplike

>
>> The reason to do it that way instead of using direct JS property access
>> as you proposed is that this will prevent issues like name collisions with
>> various builtin stuff (like methods on the object itself).
>>
>> Whether this sort of API is best for solving your initial problem, I
>> can't tell you, but if it is it's quite possible to create.
>>
>> -Boris
>>
>
>