[Sugar-devel] Kicking off HTML5 activities work

[Manuel Quiñones]

2013/4/7 Daniel Narvaez <dwnarvaez at gmail.com>:
> Hello,
>
> when Simon is back, it would be good to have an IRC meeting to kickoff the
> work on HTML5 activities. I generally prefer mailing list discussions, but
> in this case I think it would be useful to chat about it to start things
> off...

+1 for a IRC meeting with the interested developers.

> Anyway I've been researching more and I thought I'd post about what I have
> in mind at the moment.
>
> I think if we are able to jump on one of the existing web applications
> trains it's going to be much better than doing our own thing based on Webkit
> embedding. All the major browsers are implementing their web apps stuff at a
> level which is higher than their embedding frameworks. On the long term, I
> don't think it's sustainable with our scarce resources to maintain an
> embedding + web apps framework. Also it would be great to be fully
> compatible with existing apps.

Yes I agree we should go for one or the other framework, and not do a
lower level implementation by ourselves.

> With Agora I've been exploring the Firefox OS framework. There are a lot of
> things I like in it but I don't think it's viable for Sugar on the short
> time because, being fully web based, it would require to rewrite the shell
> and all activities in HTML. It's also not particularly mature, for example
> multiple processes works only on Android at the moment.
>
> In the last couple of days I've been looking at Chromium and I've found
> several good things
>
> * The web apps API seems pretty mature and well documented.
> * Their approach with ChromeOS is to have a native application launcher and
> window manager (aura). It's a cross platform, custom thing, so I don't think
> we could adopt that layer. But still it's more similar to what we need
> compared to Firefox OS.
> * Chrome already has an application mode, activated by command line
> switches, which hides the browser chrome.
> * The extensions and applications API seems to provide everything we need.
> * The multiple process framework is certainly more mature then Firefox and
> perhaps then WebKit too.
>
> So here is more or less what I have in mind
>
> 1. Add support for Chrome web apps to Sugar.

Yes, investigating the Chrome path will be great, specially because of
the adventages you mention.

> We could start by adding a native "App store" activity, which would
> basically be just a (UI less) Chrome browser window, pointing to a website
> hosting web apps. The installation would be all managed by Chrome itself.
> The sugar shell would communicate with Chrome through an extension to get
> the list of installed activities, to request launching and uninstalling
> them. We should be able to do that with these extension APIs:
>
> http://developer.chrome.com/extensions/management.html
>
> http://developer.chrome.com/extensions/runtime.html#method-connect
> http://developer.chrome.com/extensions/examples/extensions/native_messaging.zip
> (There is a connectNative method which is not yet documented. Rather than
> connecting to another extension, it connects to a native process and
> communicates via standard input and output).

Interesting.  Will this make the webapp activity installed so it
appears in the spiral already?  At first glance it looks like a big
task for the first step. But on the other hand, going through all this
process will make us identify any issues.  This could be an
"activities store" + "hello web" activity.

We can start using the term "webact" meaning "web activity" instead of
"webapp" :)

> In the UI web apps would just look like normal activities. We need to figure
> out the window manager bits which might be a bit tricky but I'd think
> possible.
> We need a way to start Chrome without windows to be able to get a list of
> installed applications. I have not investigated it but I suppose at worst we
> would have to add a command line option. Or... we could keep the store
> always running.

We could also look at what Ubuntu is doing regarding this and other
webapp things .  They have integration with both Firefox and Chrome:

https://launchpad.net/webapps
http://developer.ubuntu.com/resources/technologies/webapps/

> 2 Implement html/css/javascript UI controls following the HIG.
>
> I'm pretty happy with the approach I've taken in Agora
>
> https://github.com/ayopa/xi-graphics
> https://github.com/ayopa/xi-artwork
> https://github.com/ayopa/xi-activity

Yes, Agora was useful to test that.

> 3 We could expose datastore access through the html5 filesystem API. The
> application would request persistent storage, save both data and metadata
> there and we would then somehow put that in our datastore.
>
> http://www.html5rocks.com/en/tutorials/file/filesystem/

Hmm looking at that tutorial, seems like each webapp can access it's
own sandboxed filesystem.

> 4 We could expose collaboration using WebRTC.
>
> https://hacks.mozilla.org/2013/03/webrtc-data-channels-for-great-multiplayer/

Excellent.

>
> I have not really explored 3 and 4 much. The point is that if we can use
> existing APIs rather than cooking up our own, it's of course better.
> I think 1 and 2 can be worked on in parallel. Even if we find that we can't
> really do 1, the work on 2 would not be wasted because it will be fine on
> other browsers too.

I totally agree.

>
> Anyway just brainstorming here! It would be useful to have more people
> investigating this stuff. Or starting to write more of the UI bits :)

So thanks for pushing webapps once again!  I hope someone else joins
me with the UI, it will be fun.

--
.. manuq ..