feat: python RPC server w example

Author: eigen-value

extras/examples/serial_server_example.py

@@ -0,0 +1,18 @@
+def add(a, b):
+    return a + b
+
+def greet(name):
+    return f"Hello, {name}!"
+
+server = SerialServer(port='/dev/ttyUSB0', baudrate=115200)
+server.register_callback('add', add)
+server.register_callback('greet', greet)
+server.start()
+
+print("Serial server running... Press Ctrl+C to exit.")
+try:
+    while True:
+        pass  # Keep main thread alive
+except KeyboardInterrupt:
+    server.stop()
+    print("\nSerial server stopped.")

extras/serial_server.py

@@ -0,0 +1,71 @@
+import serial
+import msgpack
+import threading
+
+
+REQUEST = 0
+RESPONSE = 1
+NOTIFY = 2
+
+
+class SerialServer:
+    def __init__(self, port, baudrate=115200):
+        self.ser = serial.Serial(port, baudrate, timeout=0.1)
+        self.callbacks = {}
+        self.running = False
+
+    def register_callback(self, command, func):
+        """Register a callback for a specific command key"""
+        self.callbacks[command] = func
+
+    def on_request(self, msg_id, command, args):
+        """Execute the callback and respond"""
+        try:
+            result = self.callbacks[command](*args)
+            return [RESPONSE, msg_id, None, result]
+        except Exception as e:
+            print("Not handling exceptions yet")
+
+    def handle_message(self, message) -> bytes:
+        """Process incoming messages"""
+        msgsize = len(message)
+        if msgsize != 4 and msgsize != 3:
+            raise Exception("Invalid MessagePack-RPC protocol: message = {0}".format(message))
+
+        msgtype = message[0]
+        if msgtype == REQUEST:
+            response = self.on_request(message[1], message[2], message[3])
+        elif msgtype == RESPONSE:
+            raise Exception("Server receiving RESPONSE not implemented")
+            # response = self.on_response(message[1], message[2], message[3])
+        elif msgtype == NOTIFY:
+            print("Server does nothing on notification")
+            # self.on_notify(message[1], message[2])
+            response = None
+        else:
+            raise Exception("Unknown message type: type = {0}".format(msgtype))
+
+        return msgpack.packb(response)
+
+    def start(self):
+        """Start the serial server loop"""
+        self.running = True
+        threading.Thread(target=self._run, daemon=True).start()
+
+    def _run(self):
+        unpacker = msgpack.Unpacker(raw=False)
+        while self.running:
+            try:
+                data = self.ser.read(1024)
+                if data:
+                    unpacker.feed(data)
+                    for message in unpacker:
+                        response = self.handle_message(message)
+                        if response is not None:
+                            self.ser.write(response)
+            except Exception as e:
+                print(f"Error: {e}")
+
+    def stop(self):
+        self.running = False
+        self.ser.close()