examples/ev3/bluetooth: remove 3rd party dependency

Since Python 3.10, RFCOMM sockets are available in Python on Windows
so we no longer need 3rd party code.

Fixes: pybricks/support#902

examples/ev3/bluetooth_pc/pcserver.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python3
+from pybricks.messaging import BluetoothMailboxServer, TextMailbox
+
+# This demo makes your PC talk to an EV3 over Bluetooth.
+#
+# This is identical to the EV3 server example in ../bluetooth_server
+#
+# The only difference is that it runs in Python3 on your computer, thanks to
+# the Python3 implementation of the messaging module that is included here.
+# As far as the EV3 is concerned, it thinks it just talks to an EV3 client.
+#
+# So, the EV3 client example needs no further modifications. The connection
+# procedure is also the same as documented in the messaging module docs:
+# https://docs.pybricks.com/en/latest/messaging.html
+
+server = BluetoothMailboxServer()
+mbox = TextMailbox("greeting", server)
+
+# The server must be started before the client!
+print("waiting for connection...")
+server.wait_for_connection()
+print("connected!")
+
+# In this program, the server waits for the client to send the first message
+# and then sends a reply.
+mbox.wait()
+print(mbox.read())
+mbox.send("hello to you!")

examples/ev3/bluetooth_pc/pybricks/bluetooth.py

@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: MIT
-# Copyright (C) 2020 The Pybricks Authors
+# Copyright (C) 2020,2023 The Pybricks Authors
 
 """
 :class:`RFCOMMServer` can be used to communicate with other Bluetooth RFCOMM
@@ -10,29 +10,13 @@ remain a strict subset of that implementation when it comes to low-level
 implementation details.
 """
 
-from bluetooth import BluetoothSocket, RFCOMM
+from socket import socket, AF_BLUETOOTH, BTPROTO_RFCOMM, SOCK_STREAM
 from socketserver import ThreadingMixIn
 
-BDADDR_ANY = ""
-
-
-def str2ba(string, ba):
-    """Convert string to Bluetooth address"""
-    for i, v in enumerate(string.split(":")):
-        ba.b[5 - i] = int(v, 16)
-
-
-def ba2str(ba):
-    """Convert Bluetooth address to string"""
-    string = []
-    for b in ba.b:
-        string.append("{:02X}".format(b))
-    string.reverse()
-    return ":".join(string).upper()
-
 
 class RFCOMMServer:
-    """Object that simplifies setting up an RFCOMM socket server.
+    """
+    Object that simplifies setting up an RFCOMM socket server.
 
     This is based on the ``socketserver.SocketServer`` class in the Python
     standard library.
@@ -44,10 +28,10 @@ class RFCOMMServer:
         self.server_address = server_address
         self.RequestHandlerClass = RequestHandlerClass
 
-        self.socket = BluetoothSocket(RFCOMM)
+        self.socket = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM)
 
         try:
-            self.socket.bind((server_address[0], server_address[1]))
+            self.socket.bind(server_address)
             # self.server_address = self.socket.getsockname()
             self.socket.listen(self.request_queue_size)
         except Exception:
@@ -83,50 +67,21 @@ class RFCOMMServer:
         self.socket.close()
 
 
-class StreamRequestHandler:
-    """Class that handles incoming requests.
-
-    This is based on ``socketserver.StreamRequestHandler`` from the Python
-    standard library.
-    """
-
-    def __init__(self, request, client_address, server):
-        self.request = request
-        self.client_address = client_address
-        self.server = server
-        self.setup()
-        try:
-            self.handle()
-        finally:
-            self.finish()
-
-    def setup(self):
-        self.wfile = self.request
-        self.rfile = self.request
-
-    def handle(self):
-        pass
-
-    def finish(self):
-        pass
-
-
 class ThreadingRFCOMMServer(ThreadingMixIn, RFCOMMServer):
-    """Version of :class:`RFCOMMServer` that handles connections in a new
-    thread.
     """
-
-    pass
+    Version of :class:`RFCOMMServer` that handles connections in a new thread.
+    """
+    daemon_threads = True
 
 
 class RFCOMMClient:
     def __init__(self, client_address, RequestHandlerClass):
         self.client_address = client_address
         self.RequestHandlerClass = RequestHandlerClass
-        self.socket = BluetoothSocket(RFCOMM)
+        self.socket = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM)
 
     def handle_request(self):
-        self.socket.connect((self.client_address[0], self.client_address[1]))
+        self.socket.connect(self.client_address)
         try:
             self.process_request(self.socket, self.client_address)
         except Exception:
@@ -145,4 +100,7 @@ class RFCOMMClient:
 
 
 class ThreadingRFCOMMClient(ThreadingMixIn, RFCOMMClient):
-    pass
+    """
+    Version of :class:`RFCOMMClient` that handles connections in a new thread.
+    """
+    daemon_threads = True

examples/ev3/bluetooth_pc/pybricks/messaging.py

@@ -1,16 +1,13 @@
 # SPDX-License-Identifier: MIT
-# Copyright (C) 2020 The Pybricks Authors
+# Copyright (C) 2020,2023 The Pybricks Authors
 
-from _thread import allocate_lock
 from errno import ECONNRESET
 from struct import pack, unpack
+from socket import BDADDR_ANY
+from socketserver import StreamRequestHandler
+from threading import Lock
 
-from .bluetooth import (
-    BDADDR_ANY,
-    ThreadingRFCOMMServer,
-    ThreadingRFCOMMClient,
-    StreamRequestHandler,
-)
+from .bluetooth import ThreadingRFCOMMServer, ThreadingRFCOMMClient
 
 
 def resolve(brick):
@@ -151,7 +148,7 @@ class MailboxHandler(StreamRequestHandler):
             self.server._clients[self.client_address[0]] = self.request
         while True:
             try:
-                buf = self.rfile.recv(2)
+                buf = self.rfile.read(2)
                 if len(buf) == 0:
                     break
             except OSError as ex:
@@ -160,7 +157,7 @@ class MailboxHandler(StreamRequestHandler):
                     break
                 raise
             (size,) = unpack("<H", buf)
-            buf = self.rfile.recv(size)
+            buf = self.rfile.read(size)
             msg_count, cmd_type, cmd, name_size = unpack("<HBBB", buf[0:5])
             if cmd_type != SYSTEM_COMMAND_NO_REPLY:
                 raise ValueError("Bad message type")
@@ -180,7 +177,7 @@ class MailboxHandler(StreamRequestHandler):
 class MailboxHandlerMixIn:
     def __init__(self):
         # protects against concurrent access of other attributes
-        self._lock = allocate_lock()
+        self._lock = Lock()
         # map of mailbox name to raw data
         self._mailboxes = {}
         # map of device name/address to object with send() method
@@ -247,7 +244,7 @@ class MailboxHandlerMixIn:
 
     def wait_for_mailbox_update(self, mbox):
         """Waits until ``mbox`` receives a value."""
-        lock = allocate_lock()
+        lock = Lock()
         lock.acquire()
         with self._lock:
             self._updates[mbox] = lock