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Re: [discovery-api] what to put in service name

From: Jean-Claude Dufourd <jean-claude.dufourd@telecom-paristech.fr>
Date: Tue, 27 Nov 2012 18:54:19 +0100
Message-ID: <50B4FE4B.5070104@telecom-paristech.fr>
To: public-device-apis@w3.org
Hi Rich,

Do you not see that your recommandation makes it impossible to 
distinguish between the same service offered by multiple devices ?
As far as I know, there is no obligation to have a different serviceID 
for two services of the same type on two different devices.
Worse: I have started the Intel network light twice on my PC, and both 
instances of the switchPower service are called *.001. This one may be a 
bug, but I am not sure.
If you want to hide the device name, create a hash or something like 
that, but *either the id or the name attribute of your service object 
HAVE to be constructed as different for two or more services of the same 
type running on different devices.* Otherwise, there is no way to 
distinguish them.
Best regards

On 23/11/12 16:10 , Rich Tibbett wrote:
> Hi Jean-Claude,
> Jean-Claude Dufourd wrote:
>> I am working on a platform that will have one same service running on
>> all devices.
>> When discovering that service with the NSD API, the applications gets an
>> array of NetworkService objects and want to discriminate between all of
>> these.
>> Because this is on top of UPnP, and UPnP only has serviceID and
>> serviceType, in my implementation of the NSD API, I wondered what to put
>> in the service "name".
>> Now, I believe that the service "name" should contain the name of the
>> device, so that the application can discriminate between all the
>> services in the array above.
> This is the purpose of the NetworkService.id attribute.
>> Or should I rely on looking into the hostname part of the "url"
>> attribute (I would find this ugly) ?
>> Any hint, Rich ? What is your implementation doing ?
>> Should the spec be more specific about what is the "name" of the
>> NetworkService object ?
> The specification currently says to assign the serviceId from the UPnP 
> Device Descriptor File's service entry as the name attribute [1]. This 
> is the same as we are currently doing in our prototype implementation 
> [2].
> There's a privacy issue here to exposing anything else in the .name 
> attribute. There are a few other areas that we need to tighten up here 
> wrt privacy based on feedback we've received so far. I hope to provide 
> an update on this soon.
> Thanks,
> Rich
> [1] 
> http://www.w3.org/TR/2012/WD-discovery-api-20121004/#dfn-processing-a-upnp-device-description-file
> [2] 
> http://dev.opera.com/articles/view/network-service-discovery-api-support-in-opera/

JC Dufourd
Directeur d'Etudes/Professor
Groupe Multimedia/Multimedia Group
Traitement du Signal et Images/Signal and Image Processing
Telecom ParisTech, 37-39 rue Dareau, 75014 Paris, France
Tel: +33145817733 - Mob: +33677843843 - Fax: +33145817144
Received on Tuesday, 27 November 2012 17:54:53 UTC

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