Improved error handling in open

alarmdecoder/decoder.py

@@ -152,7 +152,7 @@ class AlarmDecoder(object):
         self._panic_status = False
         self._relay_status = {}
         self._internal_address_mask = 0xFFFFFFFF
-        
+
         self.last_fault_expansion = 0
         self.fault_expansion_time_limit = 30  # Seconds
 
@@ -251,17 +251,26 @@ class AlarmDecoder(object):
         self._internal_address_mask = value
 
     def open(self, baudrate=None, no_reader_thread=False):
-        """
-        Opens the device.
+        """Opens the device.
+
+        If the device cannot be opened, an except is thrown.  In that
+        case, open() can be called repeatedly to try and open the
+        connection.
 
         :param baudrate: baudrate used for the device.  Defaults to the lower-level device default.
         :type baudrate: int
         :param no_reader_thread: Specifies whether or not the automatic reader
                                  thread should be started.
         :type no_reader_thread: bool
+
         """
         self._wire_events()
-        self._device.open(baudrate=baudrate, no_reader_thread=no_reader_thread)
+        try:
+            self._device.open(baudrate=baudrate,
+                              no_reader_thread=no_reader_thread)
+        except:
+            self._unwire_events
+            raise
 
         return self
 
@@ -269,11 +278,8 @@ class AlarmDecoder(object):
         """
         Closes the device.
         """
-        if self._device:
-            self._device.close()
-
-        del self._device
-        self._device = None
+        self._device.close()
+        self._unwire_events()
 
     def send(self, data):
         """
@@ -387,6 +393,17 @@ class AlarmDecoder(object):
         self._zonetracker.on_fault += self._on_zone_fault
         self._zonetracker.on_restore += self._on_zone_restore
 
+    def _unwire_events(self):
+        """
+        Wires up the internal device events.
+        """
+        self._device.on_open -= self._on_open
+        self._device.on_close -= self._on_close
+        self._device.on_read -= self._on_read
+        self._device.on_write -= self._on_write
+        self._zonetracker.on_fault -= self._on_zone_fault
+        self._zonetracker.on_restore -= self._on_zone_restore
+
     def _handle_message(self, data):
         """
         Parses keypad messages from the panel.
@@ -792,7 +809,7 @@ class AlarmDecoder(object):
                 # Handle bouncing status changes and timeout in order to revert back to NONE.
                 if last_status != fire_status or fire_status == True:
                     self._fire_status = (fire_status, time.time())
-                
+
                 if fire_status == False and time.time() > last_update + self._fire_timeout:
                     self._fire_state = FireState.NONE
                     self.on_fire(status=FireState.NONE)

test/test_devices.py

@@ -1,11 +1,6 @@
 from unittest import TestCase
 from mock import Mock, MagicMock, patch
 from serial import Serial, SerialException
-try:
-    from pyftdi.pyftdi.ftdi import Ftdi, FtdiError
-except:
-    from pyftdi.ftdi import Ftdi, FtdiError
-from usb.core import USBError, Device as USBCoreDevice
 import sys
 import socket
 import time