Init message streaming for message encoding/decoding

hbmqtt/message.py

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+# Copyright (c) 2015 Nicolas JOUANIN
+#
+# See the file license.txt for copying permission.
+from enum import Enum
+
+class MessageType(Enum):
+    RESERVED_0 = 0
+    CONNECT = 1
+    CONNACK = 2
+    PUBLISH = 3
+    PUBACK = 4
+    PUBREC = 5
+    PUBREL = 6
+    PUBCOMP = 7
+    SUBSCRIBE = 8
+    SUBACK = 9
+    UNSUBSCRIBE = 10
+    UNSUBACK = 11
+    PINGREQ = 12
+    PINGRESP = 13
+    DISCONNECT = 14
+    RESERVED_15 = 15
+
+
+def get_message_type(byte):
+    return MessageType(byte)
+
+class Message:
+    def __init__(self, msg_type, length, dup_flag=False, qos=0, retain_flag=False):
+        if isinstance(msg_type, int):
+            enum_type = msg_type
+        else:
+            enum_type = get_message_type(msg_type)
+        self.message_type = enum_type
+        self.remainingLength = length
+        self.dupFlag = dup_flag
+        self.qos = qos
+        self.retain = retain_flag

hbmqtt/streams/__init__.py

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+# Copyright (c) 2015 Nicolas JOUANIN
+#
+# See the file license.txt for copying permission.

hbmqtt/streams/base.py

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+# Copyright (c) 2015 Nicolas JOUANIN
+#
+# See the file license.txt for copying permission.
+import asyncio
+from hbmqtt.utils import (
+    bytes_to_hex_str,
+    hex_to_int,
+)
+from hbmqtt.message import Message
+from hbmqtt.streams.errors import FixedHeaderException
+
+class BaseStream:
+    def __init__(self):
+        pass
+
+    def decode(self, reader):
+        b1 = yield from reader.read(1)
+        msg_type = BaseStream.get_message_type(b1)
+        (dup_flag, qos, retain_flag) = BaseStream.get_flags(b1)
+        remain_length = yield from self.decode_remaining_length(b1, reader)
+        return Message(msg_type, remain_length, dup_flag, qos, retain_flag)
+
+    @staticmethod
+    def get_message_type(byte):
+        return (hex_to_int(byte) & 0xf0) >> 4
+
+    @staticmethod
+    def get_flags(data):
+        byte = hex_to_int(data)
+        b3 = True if (byte & 0x08) >> 3 else False
+        b21 = (byte & 0x06) >> 1
+        b0 = True if (byte & 0x01) else False
+        return b3, b21, b0
+
+    @asyncio.coroutine
+    def decode_remaining_length(self, reader):
+        multiplier = 1
+        value = 0
+        length_bytes = b''
+        while True:
+            encoded_byte = yield from reader.read(1)
+            length_bytes += encoded_byte
+            int_byte = hex_to_int(encoded_byte)
+            value += (int_byte & 0x7f) * multiplier
+            if (int_byte & 0x80) == 0:
+                break
+            else:
+                multiplier *= 128
+                if multiplier > 128*128*128:
+                    raise FixedHeaderException("Invalid remaining length bytes:%s" % bytes_to_hex_str(length_bytes))
+        return value

hbmqtt/streams/errors.py

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+# Copyright (c) 2015 Nicolas JOUANIN
+#
+# See the file license.txt for copying permission.
+
+class StreamException(BaseException):
+    pass
+
+
+class FixedHeaderException(StreamException):
+    pass

tests/errors/test_base_stream.py

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+# Copyright (c) 2015 Nicolas JOUANIN
+#
+# See the file license.txt for copying permission.
+import unittest
+import asyncio
+from hbmqtt.streams.base import BaseStream
+from hbmqtt.streams.errors import FixedHeaderException
+
+class TestBaseStream(unittest.TestCase):
+    def setUp(self):
+        self.loop = asyncio.new_event_loop()
+
+    def test_get_message_type(self):
+        m_type = BaseStream.get_message_type(b'\x10')
+        self.assertEqual(m_type, 1)
+
+    def test_get_flags(self):
+        (dup_flag, qos, retain_flag) = BaseStream.get_flags(b'\x1f')
+        self.assertTrue(dup_flag)
+        self.assertEqual(qos, 3)
+        self.assertTrue(retain_flag)
+
+    def test_decode_remaining_length1(self):
+        stream = asyncio.StreamReader(loop=self.loop)
+        stream.feed_data(b'\x7f')
+        s = BaseStream()
+        length = self.loop.run_until_complete(s.decode_remaining_length(stream))
+        self.assertEqual(length, 127)
+
+    def test_decode_remaining_length2(self):
+        stream = asyncio.StreamReader(loop=self.loop)
+        stream.feed_data(b'\xff\x7f')
+        s = BaseStream()
+        length = self.loop.run_until_complete(s.decode_remaining_length(stream))
+        self.assertEqual(length, 16383)
+
+    def test_decode_remaining_length3(self):
+        stream = asyncio.StreamReader(loop=self.loop)
+        stream.feed_data(b'\xff\xff\x7f')
+        s = BaseStream()
+        length = self.loop.run_until_complete(s.decode_remaining_length(stream))
+        self.assertEqual(length, 2097151)
+
+    def test_decode_remaining_length4(self):
+        stream = asyncio.StreamReader(loop=self.loop)
+        stream.feed_data(b'\xff\xff\xff\x7f')
+        s = BaseStream()
+        length = self.loop.run_until_complete(s.decode_remaining_length(stream))
+        self.assertEqual(length, 268435455)
+
+    def test_decode_remaining_length5(self):
+        stream = asyncio.StreamReader(loop=self.loop)
+        stream.feed_data(b'\xff\xff\xff\xff\x7f')
+        s = BaseStream()
+        with self.assertRaises(FixedHeaderException):
+            self.loop.run_until_complete(s.decode_remaining_length(stream))