Implement XEP-0343: Signaling WebRTC Data Channels in Jingle. The current version of the
XEP (0.3.1) has no implementation and contains some flaws. After discussing this on xsf@,
Daniel (from Conversations) mentioned that they had a sprint with Larma (from Dino) to
work on another version and provided me with this link:
https://gist.github.com/iNPUTmice/6c56f3e948cca517c5fb129016d99e74 . I have used it for my
implementation.
This implementation reuses work done on Jingle A/V call (notably XEP-0176 and XEP-0167
plugins), with adaptations. When used, XEP-0234 will not handle the file itself as it
normally does. This is because WebRTC has several implementations (browser for web
interface, GStreamer for others), and file/data must be handled directly by the frontend.
This is particularly important for web frontends, as the file is not sent from the backend
but from the end-user's browser device.
Among the changes, there are:
- XEP-0343 implementation.
- `file_send` bridge method now use serialised dict as output.
- New `BaseTransportHandler.is_usable` method which get content data and returns a boolean
(default to `True`) to tell if this transport can actually be used in this context (when
we are initiator). Used in webRTC case to see if call data are available.
- Support of `application` media type, and everything necessary to handle data channels.
- Better confirmation message, with file name, size and description when available.
- When file is accepted in preflight, it is specified in following `action_new` signal for
actual file transfer. This way, frontend can avoid the display or 2 confirmation
messages.
- XEP-0166: when not specified, default `content` name is now its index number instead of
a UUID. This follows the behaviour of browsers.
- XEP-0353: better handling of events such as call taken by another device.
- various other updates.
rel 441
`init_script_path` option can be used in `[DEFAULTS]` to run a script at the end of
backend initialisation. A new `init_pre_script` method is used to wait for backend to
reach this stage (designed to be used mostly by CLI frontend), then the usual `ready_get`
method is finished once the script is finished.
