Logging in the 'deadlinesocket' fails if dealing with utf-8 encoded s…

…trings.

The logging of the 'sendheader' and 'recvheader' methods needs unicode,
but the methods itself need to be fed with 'utf-8' encoded data.

See commit e20bd8b for further details.

Since thees methods itself deal with 'utf-8' encoded data, we need to
decode these data to unicode before we send them to the logging instance.

This commit provides and uses a generic function to decode strings to unicode for
python2 and python3, as well.

How to reproduce:

Start python from a PC that has mythtv frontend installed, but it is not currently
running:

When running the MythTV's python binding `BEEventMonitor`
and log events to a file, a traceback occurs:

$ python2 - --nodblog --loglevel debug --verbose all --logfile /tmp/my_logfile
>>> from MythTV import BEEventMonitor
>>> bemon = BEEventMonitor(systemevents=True)
>>> while (True):
....    continue

From another frontend, start playback of a recording that has a description
with German umlauts or French accents:

Enjoy the traceback:

Unhandled exception in thread started by
     <bound method BEEventConnection.eventloop
         of <MythTV.connections.BEEventConnection object at 0x7f6f922c1ad0>>
Traceback (most recent call last):
  File "MythTV/connections.py", line 427, in eventloop
    self.queueEvents()
  File "MythTV/connections.py", line 396, in queueEvents
    event = self.socket.recvheader(deadline=0.0)
  File "MythTV/utility/other.py", line 387, in recvheader
    'read <-- %d' % size, data)
  File "MythTV/logging.py", line 431, in __call__
    self.log(mask, level, message, detail)
  File "MythTV/logging.py", line 376, in log
    self._logwrite(mask, level, message, detail)
  File "MythTV/logging.py", line 408, in _logfile
    self._LOGFILE.write(buff.getvalue())
  File "/usr/lib/python2.7/codecs.py", line 708, in write
    return self.writer.write(data)
  File "/usr/lib/python2.7/codecs.py", line 369, in write
    data, consumed = self.encode(object, self.errors)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 260:
    ordinal not in range(128)

mythtv/bindings/python/MythTV/utility/other.py

@@ -55,7 +55,7 @@ def run(self):
         except AttributeError as e:
             self.log(MythLog.GENERAL, MythLog.CRIT,
                      'failed at %d' % schema, 'no handler method')
-            raise MythDBError('Schema update failed, ' 
+            raise MythDBError('Schema update failed, '
                     "SchemaUpdate has no function 'up%s'" % schema)
 
         except StopIteration:
@@ -383,15 +383,16 @@ def recvheader(self, flags=0, deadline=None):
         """
         size = int(self.dlrecv(8, flags, deadline))
         data = self.dlrecv(size, flags, deadline)
+        # data is utf-8 encoded, convert to unicode for logging and ignore errors
         self.log(MythLog.SOCKET|MythLog.NETWORK, MythLog.DEBUG, \
-                            'read <-- %d' % size, data)
+                            'read <-- %d' % size, py23_str(data, True))
         return data
 
     def sendheader(self, data, flags=0):
         """Send data, prepending the length in the first 8 bytes."""
         try:
             self.log(MythLog.SOCKET|MythLog.NETWORK, MythLog.DEBUG, \
-                                'write --> %d' % len(data), data)
+                            'write --> %d' % len(data), py23_str(data, True))
             data = '%-8d%s' % (len(data), data)
             self.send(data, flags)
         except socket.error as e:
@@ -572,6 +573,17 @@ def check_ipv6(n):
     except socket.error:
         return False
 
+def py23_str(value, ignore_errors=False):
+    error_methods = ('strict', 'ignore')
+    error_method  = error_methods[ignore_errors]
+    try:  # Python 2
+        return unicode(value, errors=error_method, encoding='utf-8')
+    except NameError:  # Python 3
+        try:
+            return str(value,errors=error_method, encoding='utf-8')
+        except TypeError:  # Wasn't a bytes object, no need to decode
+            return str(value)
+
 class QuickProperty( object ):
     def __init__(self, maskedvar, default=None, handler=None):
         self.varname = maskedvar