Wednesday, May 28, 2014

Location hackfest 2014 report

So the Location hackfest 2014 took place at the awesome Mozilla offices in London during last weekend. Even though some of the important participants didn't manage to be physically present, enough people did:
  • John Layt (KDE)
  • Hanno Schlichting (Mozilla)
  • Mattias Bengtsson (GNOME)
  • Jonas Danielsson (GNOME)
and some participated remotely:
  • Bastien Nocera (GNOME)
  • Garvan Keeley (Mozilla)
Unfortunately Aaron McCarthy of Jolla couldn't attend remotely either as he lives in a very incompatible timezone (AU) but we had a lot of productive discussion with him through email that still continues.

Some very fruitful discussions we had:

  • Why Mozilla doesn't make wifi data it gathers for its location service, available for everyone to download? Hanno explained in great detail how making this data available would seriously compromise privacy and even safety of people. One good example given was someone getting out of an abusive relationship and not wanting to be traceable by their ex- but if they take their wifi router with them, their significant other has a possible way to easily track them using the wifi database. There is an easy (even though very ugly) way to avoid your AP being scanned by harvesters of such services but most people do not possess enough technical knowledge to know to enable that.

    Hence their reluctance to making it available for download, even though they'd want to. If you are interested in more details, you should read up all about that on Hanno's blog.
  • Had some discussion with Firefox and Firefox OS using Geoclue2. Hopefully we'll at least have Firefox using Geoclue2 soon. I might need to add support for totally unmaintained ofono in Geoclue2 unfortunately for making a very compelling case for Firefox OS to adapt geoclue2.
  • We had a discussion about GPS-A support in Geoclue. There are two possible ways to do that:
    1. Give URL of a SUPL service to the modem and let it do everything for you.
    2. Get the geospacial data that (SUPL service would provide) from a custom service and feed that to the modem.
    Hanno informed us that the only free SUPL implementation out there is that from Google but nobody knows what the ToS really are. He also informed us of how many modem chipsets just don't implement the API to feed it geospatial data and that makes SUPL our only hope to implement GPS-A.
  • There was a discussion about POI and check-in UI in Maps between me and Mattias. We had a bit of disagreement about it but seems now we are coming to come conclusions about how it should look like.
It was a hackfest so we also did some hacking:

  • John spent most of his time getting familiar with Qt's location code and how to port to Geoclue2. He wrote a nice post about it so I wont get into details here.
  • Mattias worked tirelessly to finish off his routing branch to be finally merged. Its not a very easy task so its not surprising that he hasn't managed to finish it yet. I'm pretty hopeful it will be merged in the following few weeks.
  • Hanno added proper support for geoip-only queries in Mozilla location service, made it do better against queries w/ stale wifi data and improved accuracy of results from 300m to 100m among other things.
  • Jonas was doing live reviews of Mattias' patches (in Swedish!) and at the same time working on getting command-line options parsing to work in gjs so we can do so in Maps.
  • Garvan was working on adding Geoclue2 support to Firefox/Gecko.
  • I finished off my patches to port geoclue2 to directly use wpa_supplicant rather than NetworManager, which makes wifi-geolocation work on FreeBSD, Firefox OS and Jolla. The last two don't use Geoclue2 but I'm hoping that this is a step forward towards convincing them to use it. I provided a patch to wpa_supplicant to make its D-Bus policy a bit lenient, while at it.

    I also looked into ofono API but not only is the project unmaintained, it doesn't provide proper introspection on D-Bus and there is no API docs. :( To make things worse, both my modems don't seem to work at least out of the box. I'd really rather I didn't have to deal with it but if I can't convince Firefox OS folks to provide ModemManager API, adding ofono support is essential to get them to use Geoclue.

    I started refactoring of Modem sources in Geoclue so that:
    • all ModemManager code is isolated in its own module so that its easy to add a ofono handling code w/o changing anything in the sources themselves.
    • 3G source can more easily/cleanly share code with Wifi source, use Mozilla Location Service (rather than opencellid that it currently does) and also submit cell tower data to Mozilla.
I can't thank Mozilla and specifically Chris Lord enough for hosting this event for hosting this event.

    1 comment:

    Mattias Bengtsson said...

    Thanks for the report!

    I also took some time to investigate using the timezone Shapefile + Spatialite to do better coordinate → timezone lookup.

    https://bugzilla.gnome.org/show_bug.cgi?id=727698#c25

    Not sure if it counts, since I did that on the airport on the way home though. :)