WebAPI/WebBluetooth
WebBluetooth
Goals
The aim of WebBluetooth is to establish a DOM API to set up and communicate with Bluetooth devices. This includes setting properties on adapters and devices, scanning for devices, bonding, and socket initialization for audio and communication.
Future versions may include OBEX and profile support.
B2G Needs
Boot2Gecko is the main consumer of WebBluetooth for the moment. Most operating systems already provide a configuration layer for bluetooth, and we do not plan on overriding that. However, B2G will require its own settings and initialization code, so the focus of the API is on that platform for the time being.
Implementation Specifics
For communicating with the bluetooth adapter and devices on B2G, we will be using the DBus message system. This allows us to easily access all parts of the bluetooth system on B2G based platforms, without having to worry about GPL licensing issues.
DOM API
Manager
interface nsIDOMBluetoothManager : nsIDOMEventTarget
{
readonly attribute bool enabled;
nsIDOMDOMRequest setBluetoothEnabled(in boolean enabled);
nsIDOMBluetoothAdapter getDefaultAdapter();
};
Adapter
interface nsIDOMBluetoothAdapter : nsIDOMEventTarget
{
readonly attribute DOMString address;
readonly attribute unsigned long class;
readonly attribute bool discovering;
readonly attribute bool enabled;
attribute bool discoverable;
attribute unsigned long discoverabletimeout;
attribute DOMString name;
nsIDOMDOMRequest setEnabled(bool enabled);
bool startDiscovery();
void stopDiscovery();
nsIDOMBluetoothDevice getDevice(DOMString address);
bool connect(in nsIDOMBluetoothDevice device);
void disconnect(in nsIDOMBluetoothDevice device);
attribute nsIDOMEventListener ondevicefound;
attribute nsIDOMEventListener ondevicedisappeared;
attribute nsIDOMEventListener ondeviceconnected;
attribute nsIDOMEventListener ondevicedisconnected;
};
Device
interface nsIDOMBluetoothDevice : nsISupports
{
readonly attribute DOMString address;
readonly attribute unsigned long class;
readonly attribute bool connected;
readonly attribute DOMString name;
readonly attribute jsval serviceUuids;
};
DBus Usage and Licensing
Bluetooth on Linux and B2G is accessed via the Bluez bluetooth stack. This stack is GPL, and the libraries that come with it to access bluetooth sockets are also GPL. To remove the licensing issues involved with this, the DBus communications layer is used to provide an IPC route for bluetooth related code. The WebBluetooth API (on Linux and B2G) will use DBus to keep the code compatible with the MPL.
DBus on Linux and Android
There are many ways to access DBus from code. On linux, gecko already uses the glib bindings for battery information on linux (UPowerClient.cpp). Android uses the low level DBus bindings, mainly made for writing language binding systems. This tends to create very complicated code, which even the DBus maintainers warn developers off of (See DBus API Documentation).
On B2G, we'd like to avoid tying glib into the gecko build. We'll be using the dbus-c++ library on that platform in order to keep the dbus code simple and clean.
Links
Bugzilla
External
- DBus Intro
- Android Bluetooth Manual
- Android Bluetooth Architecture
- Bluetool C++ Bluez Interaction Code
- Android Bluetooth FAQ
