fix: add to_bytes() helper for MicroPython

README.md

@@ -59,11 +59,11 @@ and data resolution.
 ## Getting Started
 
 PyCayenneLPP does not have any external dependencies and only uses builtin
-functions and types of Python 3. It is compatible with all the latest and 
-officially supported Python versions 3.6 and above, though even Python 3.4 
+functions and types of Python 3. It is compatible with all the latest and
+officially supported Python versions 3.6 and above, though even Python 3.4
 will do.
 
-Since PyCayenneLPP 1.2.0 MicroPython is officially supported, and published 
+Since PyCayenneLPP 1.2.0 MicroPython is officially supported, and published
 as a separate package under `micropython-pycayennelpp`.
 
 ### Python 3 Prerequisites
@@ -112,6 +112,10 @@ frame.add_humidity(6, 34.5)
 buffer = bytes(frame)
 ```
 
+**Note:** MicroPython does not support `bytes(frame)` utilising the internal
+method `LppFrame.__bytes__(self)` (yet).
+Hence, you need to use `LppFrame.to_bytes(self)` instead.
+
 ***Decoding***
 
 ```Python
@@ -129,7 +133,7 @@ print(frame)
 
 ***JSON Encoding***
 
-The LppUtil class provides helper function for proper JSON encoding of 
+The LppUtil class provides helper function for proper JSON encoding of
 PyCayenneLpp types, i.e. LppFrame, LppData and LppType.
 
 ```python
@@ -146,7 +150,7 @@ frame.add_humidity(6, 34.5)
 print(json.dumps(frame, default=LppUtil.json_encode, indent=2))
 ```
 
-There are two wrapper functions to explicitly encode the LPP type as a 
+There are two wrapper functions to explicitly encode the LPP type as a
 number or string, number being default for `LppUtil.json_encode` (see above):
 
 ```python

cayennelpp/lpp_data.py

@@ -47,6 +47,10 @@ def __str__(self):
         return 'LppData(channel = {}, type = {}, value = {})'.format(
                 self.channel, self.type.name, str(self.value))
 
+    def to_bytes(self):
+        """Explicit wrapper for MicroPython support."""
+        return self.__bytes__()
+
     @classmethod
     def from_bytes(class_object, buf):
         """Parse a given byte string and return a LppData object."""

cayennelpp/lpp_frame.py

@@ -46,7 +46,14 @@ def __bytes__(self):
         """Return this LppFrame object as a byte string."""
         buf = bytearray()
         for d in self._data:
-            buf = buf + bytes(d)
+            buf += bytes(d)
+        return bytes(buf)
+
+    def to_bytes(self):
+        """Return this LppFrame object as a byte string (for MicroPython)."""
+        buf = bytearray()
+        for d in self._data:
+            buf += d.to_bytes()
         return bytes(buf)
 
     @classmethod

cayennelpp/tests/test_lpp_data.py

@@ -21,6 +21,7 @@ def test_generic_from_bytes():
     buff = bytes([0x00, 0x64, 0xff, 0xff, 0xff, 0xfb])
     data = LppData.from_bytes(buff)
     assert buff == bytes(data)
+    assert buff == data.to_bytes()
     assert int(data.type) == 100
     assert data.value == (4294967291,)
 

cayennelpp/tests/test_lpp_frame.py

@@ -82,22 +82,26 @@ def test_frame_from_bytes():
     buf = bytes([0x03, 0x67, 0x01, 0x10, 0x05, 0x67, 0x00, 0xff])
     frame = LppFrame.from_bytes(buf)
     assert buf == bytes(frame)
+    assert buf == frame.to_bytes()
     assert len(frame) == 2
     # 01 67 FF D7
     buf = bytes([0x01, 0x67, 0xFF, 0xD7])
     frame = LppFrame.from_bytes(buf)
     assert buf == bytes(frame)
+    assert buf == frame.to_bytes()
     assert len(frame) == 1
     # 06 71 04 D2 FB 2E 00 00
     buf = bytes([0x06, 0x71, 0x04, 0xD2, 0xFB, 0x2E, 0x00, 0x00])
     frame = LppFrame.from_bytes(buf)
     assert buf == bytes(frame)
+    assert buf == frame.to_bytes()
     assert len(frame) == 1
     # 01 88 06 76 5f f2 96 0a 00 03 e8
     buf = bytes([0x01, 0x88, 0x06, 0x76, 0x5f, 0xf2,
                  0x96, 0x0a, 0x00, 0x03, 0xe8])
     frame = LppFrame.from_bytes(buf)
     assert buf == bytes(frame)
+    assert buf == frame.to_bytes()
     assert len(frame) == 1
 
 

setup.py

@@ -8,7 +8,7 @@ def readme():
 
 setup(
     name='pycayennelpp',
-    version='2.3.0',
+    version='2.4.0',
     python_requires='>=3.6',
     description='Encoder and Decoder for CayenneLLP',
     long_description=readme(),

usetup.py

@@ -9,7 +9,7 @@ def readme():
 
 setup(
     name='micropython-pycayennelpp',
-    version='2.3.0',
+    version='2.4.0',
     description='Encoder and Decoder for CayenneLLP',
     long_description=readme(),
     long_description_content_type='text/markdown',