Merge pull request #485 from basho/fixes/lrb/py273-recv

Add fix for old Python versions

Author: lukebakken

README.md

@@ -21,7 +21,7 @@ Repository Cloning
 Install
 =======
 
-The recommended versions of Python for use with this client are Python `2.7.x`, `3.3.x`, `3.4.x` and `3.5.x`. The latest version from each series should be preferred.
+The recommended versions of Python for use with this client are Python `2.7.8` (or greater, `2.7.11` as of `2016-06-21`), `3.3.x`, `3.4.x` and `3.5.x`. The latest version from each series should be preferred. Older versions of the Python `2.7.X` and `3.X` series should be used with caution as they are not covered by integration tests.
 
 Riak TS (Timeseries)
 ===================

riak/transports/tcp/connection.py

@@ -19,6 +19,9 @@
 
 
 class TcpConnection(object):
+    def __init__(self):
+        self.bytes_required = False
+
     """
     Connection-related methods for TcpTransport.
     """
@@ -163,15 +166,32 @@ def _recv_msg(self):
             # https://github.com/basho/riak-python-client/issues/425
             raise BadResource(e)
         mv = memoryview(msgbuf)
-        msg_code, = struct.unpack("B", mv[0:1])
+        mcb = mv[0:1]
+        if self.bytes_required:
+            mcb = mcb.tobytes()
+        try:
+            msg_code, = struct.unpack("B", mcb)
+        except struct.error:
+            # NB: Python 2.7.3 requires this
+            # http://bugs.python.org/issue10212
+            msg_code, = struct.unpack("B", mv[0:1].tobytes())
+            self.bytes_required = True
         data = mv[1:].tobytes()
         return (msg_code, data)
 
     def _recv_pkt(self):
         # TODO FUTURE re-use buffer
         msglen_buf = self._recv(4)
         # NB: msg length is an unsigned int
-        msglen, = struct.unpack('!I', msglen_buf)
+        if self.bytes_required:
+            msglen_buf = bytes(msglen_buf)
+        try:
+            msglen, = struct.unpack('!I', msglen_buf)
+        except struct.error:
+            # NB: Python 2.7.3 requires this
+            # http://bugs.python.org/issue10212
+            msglen, = struct.unpack('!I', bytes(msglen_buf))
+            self.bytes_required = True
         return self._recv(msglen)
 
     def _recv(self, msglen):