[jdev] XMPP on Android, Round #2

[René Treffer]

Hi,

It's been some time since my last posting. But I didn't stop thinking 
about XMPP on Android devices. I've always been unhappy with asmack, 
because it's sort of a hack. It does solve a problem, mainly to reduce 
the amount of code to be written. But it doesn't solve the problem of 
nice phone integration. We've ended up with many jabber apps on Android, 
but none that's as native as e.g. a GTalk service.

So what has happened in the meantime? I've spend the past months with 
prototyping and developing an android-only xmpp connection service. From 
scratch, but with a good system integration. And I've now reached the 
point where everything starts to work.
Have a look: http://measite.de/xmppservice.avi (music is "sad robot" by 
pornophonique [1]).

The basic concept is a bit different from classic xmpp apps: Every 
Stanzas will be isolated by the transport service and broadcasted to all 
interrested apps. The demo chat app is just a few hundred lines of code, 
because acting on XMPP events is plain simple (4 lines of XML plus 
implementing the BroadcastReceiver). Apps and Service are thus 100% 
isolated. Even app crashed won't cause the service to quit.

The source was just pushed to github:
http://github.com/rtreffer/AsmackService
http://github.com/rtreffer/AsmackChat
I thought LGPL 2.1 and Apache 2.0 would give every project a chance to 
use it. There are still some Apache 2 only parts, but they are on my 
to-be-replaced list.

Feature/Integration wise:
- Ping is done every minute, based on android time ticks
- Compression is done with the hidden Java7 API and reflection (this 
can't break as the API should be frozen anyway)
- The roster is stored in the contacts db
- Roster fetch is done on global sync
- All XMPP accounts are managed by the android accounts system
- Broadcast Intents are used to push received messages to multiple

Bad:
- Still SASL/DNS libs, need to be replaced
- Presence updates can stall/kill the service
- Working with the android contacs api feels bad

TODO (short term):
- Rework presence
- Build more app APIs
- Get rid of all dependencies (sasl code is bad, the dns lib looks 
wired, too)
- Better certificate handling (read: check it!)
- Add/Remove contacts
- Build a fancy demo app :-)

TODO (long term):
- AOSP: no idea if there is a chance for such a code drop, but I think 
system wide XMPP should be part of every android phone.
- Build a smack compatible parser: Smack has the biggest OOP parsing 
system I've seen.

Anyway, the code is now open, give it a try.

Regards,
     René Treffer

PS: I'm a fan of releasing software as software that respects your 
freedom. I'd have usually picked WTFPL or UNLICENSE, but I'm intending 
to contribute to the AOSP in the long run (read: this can easily take 12 
months). That's why I ended up choosing Apache as well. But it's 
incompatible with GPL, one of the most popular licenses. So we've now 
this wired dual licensing, which noone really wants....

[1] http://www.pornophonique.de/music.php / 
http://www.jamendo.com/en/artist/pornophonique