Add support for a TextPacket, as sent using the UART module in the Ad…

adafruit_bluefruit_connect/packet.py

@@ -94,14 +94,24 @@ def from_stream(cls, stream):
             if not start:
                 # Timeout: nothing read.
                 return None
+
             if start == b"!":
                 # Found start of packet.
                 packet_type = stream.read(1)
                 if not packet_type:
                     # Timeout: nothing more read.
                     return None
                 break
-            # Didn't find a packet start. Loop and try again.
+
+            # Didn't find a packet start.
+            raw_text_packet_cls = cls._type_to_class.get(b"RT", None)
+            # Is RawTextPacket registered?
+            # If so, read an entire line and pass that to RawTextPacket.
+            if raw_text_packet_cls:
+                packet = bytes(start + stream.readline())
+                return raw_text_packet_cls(packet)
+
+            # else loop and try again.
 
         header = bytes(start + packet_type)
         packet_class = cls._type_to_class.get(header, None)

adafruit_bluefruit_connect/raw_text_packet.py

@@ -0,0 +1,47 @@
+# SPDX-FileCopyrightText: 2021 Tony Hansen
+#
+# SPDX-License-Identifier: MIT
+
+"""
+`adafruit_bluefruit_connect.raw_text_packet`
+====================================================
+
+Bluefruit Connect App raw text data packet.
+
+Note that the raw text data packet is different from those used by the
+Controller module (e.g. Accelerometer, Control Pad, and Color Picker).
+Those use the bytes "!x" (where x is specific to the type of packet),
+followed by data specific to the packet, followed by a checksum.
+The UART text sender instead sends the bytes followed by a newline.
+There is no length indicator, no checksum, etc. Of course, that also
+precludes the use of an "!" at the beginning of the string.
+
+Consequently, this packet type is MUCH simpler than the other packet types.
+
+* Author(s): Tony Hansen
+
+"""
+
+from .packet import Packet
+
+
+class RawTextPacket(Packet):
+    """A packet containing a text string."""
+
+    _TYPE_HEADER = b"RT"
+
+    def __init__(self, text):
+        """Construct a RawTextPacket from a binary string."""
+        if isinstance(text, bytes):
+            self._text = text.strip()
+        else:
+            raise ValueError("Text must be a bytes string")
+
+    @property
+    def text(self):
+        """Return the text associated with the object."""
+        return self._text
+
+
+# Register this class with the superclass. This allows the user to import only what is needed.
+RawTextPacket.register_packet_type()

docs/examples.rst

@@ -24,3 +24,10 @@ This example demonstrates receiving text from the UART interface.
 .. literalinclude:: ../examples/bluefruitconnect_uart.py
     :caption: examples/bluefruitconnect_uart.py
     :linenos:
+
+This example demonstrates receiving both a color (as in simpletest above)
+and raw text (using RawTextPacket).
+
+.. literalinclude:: ../examples/bluefruitconnect_simpletest.py
+    :caption: examples/bluefruitconnect_simpletest.py
+    :linenos:

examples/bluefruitconnect_simpletest2.py

@@ -0,0 +1,35 @@
+# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+# Print out the color data from ColorPackets and text data from RawTextPackets.
+# To use, start this program, and start the Adafruit Bluefruit LE Connect app.
+# Connect, and then select colors on the Controller->Color Picker screen.
+# Select text by entering the UART screen and sending a string.
+# (Do NOT use a "!" at the start of your string.)
+
+from adafruit_ble import BLERadio
+from adafruit_ble.advertising.standard import ProvideServicesAdvertisement
+from adafruit_ble.services.nordic import UARTService
+from adafruit_bluefruit_connect.packet import Packet
+
+# Only the packet classes that are imported will be known to Packet.
+from adafruit_bluefruit_connect.color_packet import ColorPacket
+from adafruit_bluefruit_connect.raw_text_packet import RawTextPacket
+
+ble = BLERadio()
+uart_server = UARTService()
+advertisement = ProvideServicesAdvertisement(uart_server)
+
+while True:
+    # Advertise when not connected.
+    ble.start_advertising(advertisement)
+    while not ble.connected:
+        pass
+
+    while ble.connected:
+        packet = Packet.from_stream(uart_server)
+        if isinstance(packet, ColorPacket):
+            print(packet.color)
+        elif isinstance(packet, RawTextPacket):
+            print("Received Raw Text Packet:")
+            print(packet.text)