Fix UnicodeDecodeError in serial_comms by adding safe fallback decodi…

gsmmodem/serial_comms.py

@@ -18,7 +18,7 @@ class SerialComms(object):
     # End-of-line read terminator
     RX_EOL_SEQ = b'\r\n'
     # End-of-response terminator
-    RESPONSE_TERM = re.compile('^OK|ERROR|(\+CM[ES] ERROR: \d+)|(COMMAND NOT SUPPORT)$')
+    RESPONSE_TERM = re.compile(r'^OK|ERROR|(\+CM[ES] ERROR: \d+)|(COMMAND NOT SUPPORT)$')
     # Default timeout for serial port reads (in seconds)
     timeout = 1
 
@@ -84,6 +84,15 @@ def _handleLineRead(self, line, checkForResponseTerm=True):
     def _placeholderCallback(self, *args, **kwargs):
         """ Placeholder callback function (does nothing) """
 
+    def safe_decode(data):
+        try:
+            return data.decode('utf-8')
+        except UnicodeDecodeError:
+            try:
+                return data.decode('latin-1')
+            except Exception:
+                return data.decode('utf-8', errors='ignore')
+
     def _readLoop(self):
         """ Read thread main loop
 
@@ -100,7 +109,7 @@ def _readLoop(self):
                     rxBuffer.append(ord(data))
                     if rxBuffer[-readTermLen:] == readTermSeq:
                         # A line (or other logical segment) has been read
-                        line = rxBuffer[:-readTermLen].decode()
+                        line = self.safe_decode(rxBuffer[:-readTermLen])
                         rxBuffer = bytearray()
                         if len(line) > 0:
                             #print 'calling handler'