RE: Web Intents for local network services (DAP Action-510)

Hi Claes,

 

Some comments on the proposal.

 

1. I'm afraid you're misusing the ST header in SSDP. The ST header is not
just a simple search string for string matching. It's a means for a client
to narrow the SSDP search to devices that implement a particular UPnP
device/service type. From the device side, by responding to such a search
target, it indicates that it implements the requested UPnP device/service
type. By implementing a UPnP service type
("urn:schemas-webintents-org:service:WebIntents:1" in your proposal), it
means a device has to include this UPnP service in its device description,
and the UPnP service must include some invokable actions, etc. If we create
such a UPnP service type, we'll have to define the actual control protocol
for this service type (i.e. what state variables it has and what they mean,
what actions are available and what they mean). It doesn't occur to me that
that is your intention.

2. You mentioned in another message that you want to add things like Action
and Type in the ST header. That again is not something that a vendor or an
SDO other than UPnP Forum can do. The format and the allowed values of the
ST header are defined in the UPnP Device Architecture [1] and is not
designed to be vendor-extensible. If new search criteria other than those
defined in [1] are desired, such request should be brought to UPnP Forum. In
fact, that idea was discussed in UPnP Forum several years ago but that work
was shelved at the time (that's before my time so I can't say much about
it). Maybe it's a good time to bring it up again (Clarke?).

3. The vendor-defined headers in the SSDP messages (pages 10 and 15) are in
the wrong format. For example, instead of X-WebIntents-action, it should be
action.webintents.org (header name followed by domain). See Section 1.1.3 in
[1]. Also, there should not be a HOST header in the SSDP response.

4. Your proposal talks mostly about SSDP searches, and the
WebIntents-related headers in SSDP responses. But for completeness, it's
necessary to add that such headers are also used in SSDP announcement
messages sent by WebIntents-enabled UPnP devices. This would allow clients
(such as a UA's web intents manager) to keep track of WebIntents-enabled
UPnP devices that enter the network in the background.

5. In alternative 2, shouldn't intent.postResult() occur right after the
user selects the device, and before the client page begins sending
high-level commands (i.e. above the fat arrow on page 18)? My understanding
is that getting the success callback (which is triggered by
intent.postResult() on the service page) is the indication to the client
that the user has selected a target service to use.

 

Regards, Cathy.

 

 

[1] http://upnp.org/specs/arch/UPnP-arch-DeviceArchitecture-v1.1.pdf

 

 

From: ext Nilsson, Claes1 [mailto:Claes1.Nilsson@sonymobile.com] 
Sent: Tuesday, May 15, 2012 11:42 AM
To: public-web-intents@w3.org
Subject: Web Intents for local network services (DAP Action-510)

 

Hi,

 

I have updated the proposal for dynamic registration of Web Intents enabled
services in local UPnP networks. See wiki page:
http://www.w3.org/wiki/WebIntents/SonyMobile_-_Local_Network_Service_Discove
ry. New slides are:
http://www.w3.org/wiki/images/8/8e/V2_W3C_Web_Intents_-_Local_UPnP_Service_D
iscovery.pdf.

 

The main difference compared to the proposal in Shenzhen is that we for
dynamically discovered UPnP Services propose additional SSDP headers stating
the Service registration data (Action, Type, href, Title and Disposition)
instead of having the registration markup in the UPnP Device Description
document.  The main reason for this proposal is that it scales better in
local networks with many Web Intents enabled devices. The UA does not have
to retrieve the Device Description page for each Web Intents enabled device
found in order to check matching Action and Type. Instead this information
is found in the SSDP headers and a more efficient matching can be performed.


 

I have also removed the slides on Web Intents discovery of services on
legacy UPnP devices as I assume this is covered by
http://www.w3.org/2009/dap/track/actions/511.

 

We are also planning to make a proposal for mDNS.

 

Next step is to  make a Web Intents addendum specification according to
http://www.w3.org/2009/dap/track/actions/510.

 

Best regards

  Claes

 

cid:3333625383_1036728

Claes Nilsson M.Sc.E.E
Master Engineer, Research 
Technology Research - Advanced Application Lab

Sony Mobile Communications        
 Phone:  +46 10 80 15178
Mobile: +46 705 56 68 78
Switchboard: +46 10 80 00000
E-Mail:  <mailto:claes1.nilsson@sonyericsson.com>
mailto:claes1.nilsson@sonymobile.com
Visiting Address; Nya Vattentornet 
SE-221 88 LUND,
Sweden 

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