Python: Receive n bytes example

#!/usr/bin/python

data = self.request.recv(4)
            if len(data) == 0:
                print "Length is 0. Aborting."
                break
            length = struct.unpack("I", data)[0]
            offset = 0
            all_data = []
            while offset < length:
                tmp_data = self.request.recv(length-offset)
                if len(tmp_data) == 0:
                    print "Length is 0. Aborting."
                    break
                offset += len(tmp_data)
                all_data.append(tmp_data)
            data_str = ''.join(tmp_data)
            message = cPickle.loads(data_str)
            print message, message.number, message.rate, message.samples