100 lines
3.2 KiB
Python
100 lines
3.2 KiB
Python
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"""
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A simple adapter to gattlib.
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Handles Connection duties (reconnecting etc.) transparently.
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"""
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import codecs
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import logging
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import threading
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import gattlib
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from . import BackendException
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DEFAULT_TIMEOUT = 1
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_LOGGER = logging.getLogger(__name__)
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class BTLEConnection:
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"""Representation of a BTLE Connection."""
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def __init__(self, mac, iface):
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"""Initialize the connection."""
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self._conn = None
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self._mac = mac
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self._iface = iface
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self._callbacks = {}
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self._notifyevent = None
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def __enter__(self):
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"""
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Context manager __enter__ for connecting the device
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:rtype: BTLEConnection
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:return:
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"""
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_LOGGER.debug("Trying to connect to %s", self._mac)
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if self._iface is None:
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self._conn = gattlib.GATTRequester(self._mac, False)
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else:
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self._conn = gattlib.GATTRequester(self._mac, False, self._iface)
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self._conn.on_notification = self.on_notification
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try:
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self._conn.connect()
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except gattlib.BTBaseException as ex:
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_LOGGER.debug(
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"Unable to connect to the device %s, retrying: %s", self._mac, ex
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)
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try:
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self._conn.connect()
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except Exception as ex2:
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_LOGGER.debug("Second connection try to %s failed: %s", self._mac, ex2)
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raise BackendException(
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"unable to connect to device using gattlib"
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) from ex2
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_LOGGER.debug("Connected to %s", self._mac)
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return self
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def __exit__(self, exc_type, exc_val, exc_tb):
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if self._conn:
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self._conn.disconnect()
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self._conn = None
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def on_notification(self, handle, data):
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"""Handle Callback from a Bluetooth (GATT) request."""
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_LOGGER.debug(
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"Got notification from %s: %s", handle, codecs.encode(data, "hex")
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)
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if handle in self._callbacks:
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self._callbacks[handle](data[3:])
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if self._notifyevent:
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self._notifyevent.set()
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@property
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def mac(self):
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"""Return the MAC address of the connected device."""
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return self._mac
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def set_callback(self, handle, function):
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"""Set the callback for a Notification handle. It will be called with the parameter data, which is binary."""
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self._callbacks[handle] = function
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def make_request(self, handle, value, timeout=DEFAULT_TIMEOUT, with_response=True):
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"""Write a GATT Command without callback - not utf-8."""
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try:
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with self:
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_LOGGER.debug(
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"Writing %s to %s",
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codecs.encode(value, "hex"),
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handle,
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)
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self._notifyevent = threading.Event()
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self._conn.write_by_handle(handle, value)
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if timeout:
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_LOGGER.debug("Waiting for notifications for %s", timeout)
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self._notifyevent.wait(timeout)
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except gattlib.BTBaseException as ex:
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_LOGGER.debug("Got exception from gattlib while making a request: %s", ex)
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raise BackendException("Exception on write using gattlib") from ex
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