plugin XEP-0353, XEP-0234, jingle: WebRTC data channel signaling implementation: 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

#!/usr/bin/env python3


# SAT communication bridge
# Copyright (C) 2009-2021 Jérôme Poisson (goffi@goffi.org)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


class BridgeException(Exception):
    """An exception which has been raised from the backend and arrived to the frontend."""

    def __init__(self, name, message="", condition=""):
        """

        @param name (str): full exception class name (with module)
        @param message (str): error message
        @param condition (str) : error condition
        """
        super().__init__()
        self.fullname = str(name)
        self.message = str(message)
        self.condition = str(condition) if condition else ""
        self.module, __, self.classname = str(self.fullname).rpartition(".")

    def __str__(self):
        return self.classname + (f": {self.message}" if self.message else "")

    def __eq__(self, other):
        return self.classname == other