14 add a class for udp client

examples/udp_echo/python/main.py

@@ -0,0 +1,290 @@
+#!/usr/bin/env python3
+"""
+Simple UDP Echo Server
+
+This server listens for UDP packets and echoes them back to the sender.
+It can be used independently or with the Bridge server for testing.
+
+Usage:
+    python main.py [--port PORT] [--prefix PREFIX]
+
+Examples:
+    python main.py
+    python main.py --port 5000
+    python main.py --port 5000 --prefix "ECHO: "
+"""
+
+import socket
+import sys
+import argparse
+import time
+from datetime import datetime
+
+
+def log(msg):
+    with open("log.log", 'a') as f:
+        f.write(f"{msg}\n")
+
+
+class UDPEchoServer:
+    """Simple UDP echo server"""
+
+    def __init__(self, port=5000, prefix="ECHO: ", buffer_size=4096):
+        self.port = port
+        self.prefix = prefix
+        self.buffer_size = buffer_size
+        self.socket = None
+        self.running = False
+
+        # Statistics
+        self.packets_received = 0
+        self.packets_sent = 0
+        self.bytes_received = 0
+        self.bytes_sent = 0
+        self.start_time = None
+
+    def start(self):
+        """Start the echo server"""
+        try:
+            # Create UDP socket
+            self.socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+            self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+
+            # Bind to all interfaces
+            self.socket.bind(('127.0.0.1', self.port))
+
+            log("=" * 60)
+            log("UDP Echo Server")
+            log("=" * 60)
+            log(f"Listening on: 127.0.0.1:{self.port}")
+            log(f"Echo prefix: \"{self.prefix}\"")
+            log(f"Buffer size: {self.buffer_size} bytes")
+            log("=" * 60)
+            log("Press Ctrl+C to stop\n")
+
+            self.running = True
+            self.start_time = time.time()
+
+            self.run()
+
+        except PermissionError:
+            log(f"ERROR: Permission denied. Port {self.port} may require sudo/admin.")
+            sys.exit(1)
+        except OSError as e:
+            log(f"ERROR: Cannot bind to port {self.port}: {e}")
+            sys.exit(1)
+        except KeyboardInterrupt:
+            log("\n\nShutting down...")
+            self.stop()
+        except Exception as e:
+            log(f"ERROR: {e}")
+            self.stop()
+            sys.exit(1)
+
+    def run(self):
+        """Main server loop"""
+        while self.running:
+            try:
+                # Receive data
+                data, addr = self.socket.recvfrom(self.buffer_size)
+                log(f"Attempt to read incoming messages")
+
+                self.packets_received += 1
+                self.bytes_received += len(data)
+
+                # Print received packet info
+                timestamp = datetime.now().strftime("%H:%M:%S.%f")[:-3]
+                log(f"[{timestamp}] Received {len(data)} bytes from {addr[0]}:{addr[1]}")
+
+                # Decode and print message (if printable)
+                try:
+                    message = data.decode('utf-8', errors='ignore')
+                    if message.isprintable() or message.strip():
+                        log(f"  Message: \"{message}\"")
+                except:
+                    log(f"  Data: {data[:50]}{'...' if len(data) > 50 else ''}")
+
+                # Prepare echo response
+                if self.prefix:
+                    response = self.prefix.encode() + data
+                else:
+                    response = data
+
+                # Send echo back
+                sent = self.socket.sendto(response, addr)
+
+                self.packets_sent += 1
+                self.bytes_sent += sent
+
+                log(f"  Echoed: {sent} bytes\n")
+
+            except socket.timeout:
+                log("UDP socket timeout")
+                continue
+            except KeyboardInterrupt:
+                log("Keyboard interrupt")
+                raise
+            except Exception as e:
+                log(f"Error handling packet: {e}\n")
+
+    def stop(self):
+        """Stop the server"""
+        self.running = False
+
+        if self.socket:
+            self.socket.close()
+
+        # Print statistics
+        if self.start_time:
+            runtime = time.time() - self.start_time
+
+            log("\n" + "=" * 60)
+            log("Server Statistics")
+            log("=" * 60)
+            log(f"Runtime: {runtime:.1f} seconds")
+            log(f"Packets received: {self.packets_received}")
+            log(f"Packets sent: {self.packets_sent}")
+            log(f"Bytes received: {self.bytes_received}")
+            log(f"Bytes sent: {self.bytes_sent}")
+
+            if runtime > 0:
+                log(f"Packets/sec: {self.packets_received / runtime:.2f}")
+                log(f"Throughput: {self.bytes_received / runtime:.2f} bytes/sec")
+
+            log("=" * 60)
+
+        log("Server stopped")
+
+
+def test_server(host='127.0.0.1', port=5000):
+    """Test the echo server by sending test packets"""
+    log("\n" + "=" * 60)
+    log("Testing Echo Server")
+    log("=" * 60)
+    log(f"Target: {host}:{port}\n")
+
+    test_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    test_sock.settimeout(2.0)
+
+    test_messages = [
+        "Hello, Echo!",
+        "Test message 1",
+        "This is a longer test message with more content",
+        "12345",
+        "Special chars: !@#$%^&*()",
+    ]
+
+    passed = 0
+    failed = 0
+
+    for i, msg in enumerate(test_messages, 1):
+        log(f"[Test {i}/{len(test_messages)}] Sending: \"{msg}\"")
+
+        try:
+            # Send
+            test_sock.sendto(msg.encode(), (host, port))
+
+            # Receive
+            data, addr = test_sock.recvfrom(4096)
+            response = data.decode('utf-8', errors='ignore')
+
+            log(f"  Received: \"{response}\"")
+
+            # Check if echo contains original message
+            if msg in response:
+                log("  ✓ PASS\n")
+                passed += 1
+            else:
+                log("  ✗ FAIL - Response doesn't contain original message\n")
+                failed += 1
+
+        except socket.timeout:
+            log("  ✗ FAIL - Timeout (no response)\n")
+            failed += 1
+        except Exception as e:
+            log(f"  ✗ FAIL - Error: {e}\n")
+            failed += 1
+
+    test_sock.close()
+
+    log("=" * 60)
+    log(f"Test Results: {passed} passed, {failed} failed")
+    log("=" * 60)
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description='Simple UDP Echo Server',
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+        epilog="""
+Examples:
+  %(prog)s                              Start server on default port 5000
+  %(prog)s --port 8888                  Start server on port 8888
+  %(prog)s --prefix "REPLY: "           Use custom echo prefix
+  %(prog)s --no-prefix                  Echo without prefix
+  %(prog)s --test                       Test the server
+        """
+    )
+
+    parser.add_argument(
+        '-p', '--port',
+        type=int,
+        default=5000,
+        help='UDP port to listen on (default: 5000)'
+    )
+
+    parser.add_argument(
+        '--prefix',
+        type=str,
+        default='ECHO: ',
+        help='Prefix to add to echoed messages (default: "ECHO: ")'
+    )
+
+    parser.add_argument(
+        '--no-prefix',
+        action='store_true',
+        help='Echo without any prefix'
+    )
+
+    parser.add_argument(
+        '-b', '--buffer-size',
+        type=int,
+        default=4096,
+        help='Buffer size in bytes (default: 4096)'
+    )
+
+    parser.add_argument(
+        '--test',
+        action='store_true',
+        help='Test the echo server by sending test packets'
+    )
+
+    parser.add_argument(
+        '--test-host',
+        type=str,
+        default='127.0.0.1',
+        help='Host to test (default: 127.0.0.1)'
+    )
+
+    args = parser.parse_args()
+
+    # Handle test mode
+    if args.test:
+        test_server(args.test_host, args.port)
+        return
+
+    # Handle no-prefix option
+    prefix = '' if args.no_prefix else args.prefix
+
+    # Start server
+    server = UDPEchoServer(
+        port=args.port,
+        prefix=prefix,
+        buffer_size=args.buffer_size
+    )
+
+    server.start()
+
+
+if __name__ == "__main__":
+    main()