Add header encoder

hbmqtt/codecs/header.py

@@ -66,29 +66,31 @@ class MQTTHeaderCodec:
 
     @staticmethod
     @asyncio.coroutine
-    def encode(header: MQTTHeader, writer):
-        def encode_remaining_length(length:int):
+    def encode(header: MQTTHeader) -> bytes:
+        def encode_remaining_length(length: int):
             encoded = b''
             while True:
                 length_byte = length % 0x80
-                length /= 0x80
+                length //= 0x80
                 if length > 0:
                     length_byte |= 0x80
-                encoded += int_to_bytes(length_byte, 1)
+                encoded += int_to_bytes(length_byte)
                 if length <= 0:
                     break
             return encoded
 
+        out = b''
         packet_type = 0
         try:
-            packet_type = (header.message_type.value << 4) & header.flags
-            encoded_type = int_to_bytes(packet_type, 1)
-            writer.write(encoded_type)
+            packet_type = (header.message_type.value << 4) | header.flags
+            out += int_to_bytes(packet_type)
         except OverflowError:
             raise CodecException('packet_size encoding exceed 1 byte length: value=%d', packet_type)
 
         try:
             encoded_length = encode_remaining_length(header.remaining_length)
-            writer.write(encoded_length)
+            out += encoded_length
         except OverflowError:
             raise CodecException('message length encoding exceed 1 byte length: value=%d', header.remaining_length)
+
+        return out

hbmqtt/codecs/utils.py

@@ -21,14 +21,13 @@ def bytes_to_int(data):
     """
     return int.from_bytes(data, byteorder='big')
 
-def int_to_bytes(int_value:int, length) -> bytes:
+def int_to_bytes(int_value:int) -> bytes:
     """
     convert an integer to a sequence of bytes using big endian byte ordering
     :param int_value: integer value to convert
-    :param length: byte sequence length
     :return: byte sequence
     """
-    int_value.to_bytes(length, byteorder='big')
+    int_value.to_bytes(int_value.bit_length(), byteorder='big')
 
 
 @asyncio.coroutine

tests/codecs/test_header.py

@@ -4,7 +4,9 @@
 import unittest
 import asyncio
 from hbmqtt.codecs.header import MQTTHeaderCodec, MQTTHeaderException
-from hbmqtt.message import MessageType
+from hbmqtt.message import MessageType, MQTTHeader
+from hbmqtt.codecs.utils import bytes_to_hex_str
+
 
 class TestMQTTHeaderCodec(unittest.TestCase):
     def setUp(self):
@@ -41,3 +43,13 @@ class TestMQTTHeaderCodec(unittest.TestCase):
         stream.feed_data(b'\x10\xff\xff\xff\xff\x7f')
         with self.assertRaises(MQTTHeaderException):
             self.loop.run_until_complete(MQTTHeaderCodec.decode(stream))
+
+    def test_encode(self):
+        header = MQTTHeader(MessageType.CONNECT, 0x00, 0)
+        data = self.loop.run_until_complete(MQTTHeaderCodec.encode(header))
+        self.assertEqual(data, b'\x10\x00')
+
+    def test_encode_2(self):
+        header = MQTTHeader(MessageType.CONNECT, 0x00, 268435455)
+        data = self.loop.run_until_complete(MQTTHeaderCodec.encode(header))
+        self.assertEqual(data, b'\x10\xff\xff\xff\x7f')