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
An https:/salut-a-toi.org URL was used to retrieve external IP, but it's not valid
anymore, resulting in an exception. This feature is currently disabled.
Also moved several methods from legacy inline callbacks to coroutines.
