On 05/25/2012 07:54 AM, Marcos Caceres wrote:
On Sunday, May 13, 2012 at 5:47 PM, Anant Narayanan wrote:
Interested to see what could be listed here… this is the area of greatest
interop concern, IMO (hopefully it won't be needed at all, as it's only really
useful on extension/proprietary platforms).
Examples include "touch", "webgl", "indexeddb". You're right that it's
possible to use this for proprietary extensions; but there are use cases
for standard web features. The idea is to let the store and runtime have
some control over not allowing the user to purchase/install/launch an
app that is known not to work on their current device.
For instance, if I am browsing for apps on my phone that doesn't support
WebGL, the Mozilla App Marketplace won't let me install any apps that
have that feature listed in required_features. Likewise, the runtime may
prevent launching apps that are known to be incompatible with the
current UA, quire similar to screen_size.
I think this will quickly become unmanageable. It means you need to take the
current web as it is today, freeze it, and then start hiding all future
functionality that can only be enabled through this list (and the list of
things you need to enable grows forever or you end up having to enable
unexpected things, which then may cause security issues that the developer was
not expecting). Hence, features like this should only be used for things that
are sure not to be part of the Web Platform.
This also goes against the trend of responsive design: it means that I can't
make an app that both uses WebGL and falls back to legacy tech because the
store will refuse to install it on my non-webGL-phone. So as a developer, I
would need to release two versions of the same app.
That is not the intent of the field. The "required" prefix indicates
that these are *mandatory* features without which the application will
not function at all. A camera app is no good without camera access,
responsive design does not help.
In your example, if an app is able to fall back to legacy tech, then the
developer is expected /not/ to list WebGL in this field, since it is not
mandatory.
-Anant
