title: Protocol buffers python - unicode decode error
body: <p>I need to receive a protocol buffers message on my python - tornado server and get the stuff out of the binary message. </p>
  
  <pre><code>postContent = self.request.body
  message = prototemp.ReqMessage()
  message.ParseFromString(postContent)
  </code></pre>
  
  <p>It works perfectly using a test tool. When i run it in sandbox environment and simulate 1000 requests from my client, it works in certain cases, but in most of the requests, it throws an exception - </p>
  
  <pre><code>  File "server1.py", line 21, in post
      message.ParseFromString(postContent)
    File "/usr/lib/python2.6/site-packages/protobuf-2.4.1-py2.6.egg/google/protobuf/message.py", line 179, in ParseFromString
      self.MergeFromString(serialized)
    File "/usr/lib/python2.6/site-packages/protobuf-2.4.1-py2.6.egg/google/protobuf/internal/python_message.py", line 755, in MergeFromString
      if self._InternalParse(serialized, 0, length) != length:
    File "/usr/lib/python2.6/site-packages/protobuf-2.4.1-py2.6.egg/google/protobuf/internal/python_message.py", line 782, in InternalParse
      pos = field_decoder(buffer, new_pos, end, self, field_dict)
    File "/usr/lib/python2.6/site-packages/protobuf-2.4.1-py2.6.egg/google/protobuf/internal/decoder.py", line 544, in DecodeField
      if value._InternalParse(buffer, pos, new_pos) != new_pos:
    File "/usr/lib/python2.6/site-packages/protobuf-2.4.1-py2.6.egg/google/protobuf/internal/python_message.py", line 782, in InternalParse
      pos = field_decoder(buffer, new_pos, end, self, field_dict)
    File "/usr/lib/python2.6/site-packages/protobuf-2.4.1-py2.6.egg/google/protobuf/internal/decoder.py", line 410, in DecodeField
      field_dict[key] = local_unicode(buffer[pos:new_pos], 'utf-8')
  UnicodeDecodeError: 'utf8' codec can't decode byte 0xce in position 1: invalid continuation byte
  </code></pre>
  
  <p>In some other cases it gives these errors -</p>
  
  <pre><code>UnicodeDecodeError: 'utf8' codec can't decode byte 0xbf in position 3: invalid start byte
  
  UnicodeDecodeError: 'utf8' codec can't decode byte 0xe7 in position 3: unexpected end of data
  </code></pre>
  
  <p>What could be the reason ?</p>