Add codecs

hbmqtt/messages/connack.py

@@ -1,7 +1,11 @@
 # Copyright (c) 2015 Nicolas JOUANIN
 #
 # See the file license.txt for copying permission.
-from hbmqtt.messages.packet import MQTTPacket, MQTTHeader, PacketType
+import asyncio
+from hbmqtt.messages.packet import MQTTPacket, MQTTFixedHeader, PacketType, MQTTVariableHeader
+from hbmqtt.codecs import int_to_bytes, read_or_raise
+from enum import Enum
+
 
 class ReturnCode(Enum):
     CONNECTION_ACCEPTED = 0x00
@@ -11,14 +15,36 @@ class ReturnCode(Enum):
     BAD_USERNAME_PASSWORD = 0x04
     NOT_AUTHORIZED = 0x05
 
-class ConnackVariableHeader():
+
+class ConnackVariableHeader(MQTTVariableHeader):
     def __init__(self, session_parent=None, return_code=None):
+        super().__init__()
         self.session_parent = session_parent
         self.return_code = return_code
 
+    @classmethod
+    def from_stream(cls, reader: asyncio.StreamReader, fixed_header: MQTTFixedHeader):
+        data = yield from read_or_raise(reader, 2)
+        session_parent = data[0] & 0x01
+        return_code = data[1]
+        return cls(session_parent, return_code)
+
+    def to_bytes(self):
+        out = b''
+        # Connect acknowledge flags
+        if self.session_parent:
+            out += '\x01'
+        else:
+            out += '\x00'
+        # return code
+        out += int_to_bytes(self.return_code)
+
+        return out
+
+
 class ConnackPacket(MQTTPacket):
     def __init__(self, vh: ConnackVariableHeader):
-        header = MQTTHeader(PacketType.CONNACK, 0x00)
+        header = MQTTFixedHeader(PacketType.CONNACK, 0x00)
         super().__init__(header)
         self.variable_header = vh
         self.payload = None