Web Intents and Web Intents for local services

31 Oct 2012


See also: IRC log


Claes Nilsson (Sony Mobile) / Naoyuki Sato (Sony)


Claes introduces web intents to a crowded room

web intents is a service discovery mechanism for web apps.

greg takes over the introduction. web intents is being standardized by the web intents task force (a joint effort from Device APIs and Web Apps WGs).

An app makes a request for an action on a data type. The browser acts as a broker offering users a means to select a matching intent provider.

An experimental implementation has been shipped as part of the chrome browser.

<nkic> I see 62 people in the room!

Claes: we (Sony) are interested in using web intents to discover services on devices on local networks. We proposed an addendum to the web intent specification to find services via UPnP and mDNS.

The UPnP/mDNS device provides an intent registration page that enables the browser in the requesting device to present a service picker to the user.

Our demo allows you to use a browser on a mobile phone to control a TV on the local network.

He describes the SSDP packet format and the headers used for the intent registration.

Naoyuki presents a few slides on the demo set up.

We plan to show a push action to push movie from a web page so that it can be viewed on the TV instead of the mobile phone. We also plan to show a similar action for images.

The TV provides a control page for play/pause etc. This is retrieved and rendered on the mobile.

Claes then describes an alternative where the service page from the TV is hidden, so that the control is realized as part of the web page itself.

The current web intents spec allows the service page to be displayed inline within the web app's page or in a new window. We are asking for an extension whereby the service page is hidden.

<scribe> scribe: dsr

Kensaku demo's a pick and edit image web intent action.

His app is running on a notebook and accessing the camera on a mobile phone.

We see a preview video feed and he demo's taking a photo.

We think it would be valuable to support existing devices as well as those that have built in support for the web intents local discovery spec addendum.

He shows a web app for a video. The page embeds play/pause/stop controls. These are disabled until the TV has been discovered.

Kensaku shows that you can also control the audio volume of the TV.

The discovery support has been added to the chrome browser via an extension using the socket API.

A RESTful web server is implemented as a BG process (Chrome apps v2). This interfaces to reverse proxy and DLNA.

That enables control of the TV. The web server is invoked by generic XHR2.

The Socket API functionality will be discussed in the new W3C SysApps WG.

Colin Jennings: I hear that some browser vendors like web intents and others don't, what are the concerns and how will they be resolved?

Greg Billock: We have a draft spec right now, and an experimental implementation in chrome. I spoke yesterday about this during the webapps WG meeting.

The dedication to solving the problem is clear. The exact spec details are still in discussion, and we may change the scope of the API for the interaction with the server.

Another challenge is the way the browser presents information to the user in the picker.

It is fine to present a picker in many cases, but it can get in the way in some circumstances.

Cross tab examples present some difficulties that we are still looking at, and we will be talking about them in this week's Device APIs meeting here at TPAC.

It could be that we end up with a navigation approach rather than a service selection approach.

<olivier> hmm, no zakim to manage queue

Colin: the number of people standing around the room demonstrates the level of interest in the opportunities that web intents is addressing.

What about the mozilla proposal, does it support a wider range of use cases?

Can we use the standard DLNA/UPnP functionality without the need for extending SSDP?

Possible security risk with the advertising of services on local networks.

Naoyuki: it is very easy to extend SSDP. If we want to extend DLNA this will take time to standardize.

The use of HTML+JS for the service page is very flexible.

??: DLNA is about profiling UPnP.

Naoyuki: web intents makes it easier to pass information to services in an open way.

??: what about open intents and the registration of web intent actions?

Greg: this will depend on how the client/server ecosystem for web intents emerges.

As uses cases establish the demand for particular web intents, this will stimulate discussion on best practices.

<marcin_hanclik> ?? above about DLNA was Marcin Hanclik / ACCESS

Greg: one of the goals for web intents was to work well with microdata.

Olivier: I was impressed by the demo's but as a representative of a broadcaster (BBC) I note that the demo was made with monitors and not with tuners. Have you looked at more complex use cases with TVs?

Noyuki: using Google TV it may be possible to support control over live TV.

During yesterday's web & tv meeting we looked at use cases. I would like to make people aware that a web & tv business group will meet Thursday and Friday, here at TPAC.

We need to look at a variety of service discovery techniques including Bluetooth and NFC.

Brian: would web intents allow multiple web apps to share a cache resources, e.g. images, and using indexed DB as a storage mechanism.

Greg: I think our implementation should enable the use of indexedDB.
... is a service is intended to be used across web apps, what is the best way to present this to the user?

This is something we could talk about in this week's DAP WG meeting.

Claes wraps up the meeting as it is time for lunch. He thanks everyone for attending.

Summary of Action Items

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