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Re: [manifest] screen sizes, Re: Review of Web Application Manifest Format and Management APIs

From: Anant Narayanan <anant@mozilla.com>
Date: Sun, 27 May 2012 09:49:44 -0700
Message-ID: <4FC25B28.9030708@mozilla.com>
To: Marcos Caceres <w3c@marcosc.com>
CC: "SULLIVAN, BRYAN L" <bs3131@att.com>, "public-webapps@w3.org" <public-webapps@w3.org>
On 05/27/2012 05:11 AM, Marcos Caceres wrote:
> On 27/05/2012 12:36, SULLIVAN, BRYAN L wrote:
>> Re "At install time or when I am browsing apps, how does a server know
>> my screen resolution? Or is this restriction imposed on by the user
>> agent?": When browsing apps, the server can easily access the screen
>> and window DOM attributes.
> Right, but that requires some communication that is implicit in the
> spec. I'm trying to figure out what data is leaving my device and going
> to the server, and why (i.e., what is the expected life cycle model).
> There is all sorts of things that are implied going on behind the scenes
> that this spec eludes to (e.g., installation management/sync across
> devices), and it's good to get a sense of how it all comes together. If
> it's not clear in the spec, then I have a hard time seeing how multiple
> user agents will be able behave in an interoperable manner.

There is no extra data leaving your device. When you visit a store it 
will probe for your current device capabilities, and the store, at its 
discretion, can decide whether or not to let the user install an app. 
There is no enforcement by the User-Agent at install time.

Synchronization is an interesting problem that we haven't fully tackled 
head-on yet. So we might need to add some UA enforcement at sync time as 
opposed to install time.

>> When installing apps, the installer (browser, app manager, etc) can
>> provide a warning to the user that the app is designed for use on
>> larger screens, and may not work properly on this device.
> Sure, but doesn't that lead to the original complaint that certain
> developers don't want their application to install at all for PR reasons?

In combination with installs_allowed_from, some apps can choose to 
publish only on certain stores with which they have an agreement that 
users won't be allowed to install apps on devices they weren't designed 
for. Sure, it would be easy to bypass this since there is no UA 
enforcement, but this would be limited to a fairly small technical crowd.

-Anant
Received on Sunday, 27 May 2012 16:50:14 GMT

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