Server and client development

ressenger_client.py

@@ -0,0 +1,20 @@
+#!/usr/bin/python3
+import socket
+import struct
+import time
+
+HOST = '127.0.0.1'
+PORT = 5273
+
+def send_message(sock, data: bytes):
+    header = struct.pack('!I', len(data))
+    sock.sendall(header + data)
+
+if __name__ == '__main__':
+    with socket.create_connection((HOST, PORT)) as s:
+        send_message(s, b'hello binary \x00\x01')
+        time.sleep(0.2)
+        send_message(s, b'\xff'*1024)   # 发送 1KB 二进制
+        time.sleep(0.5)
+        send_message(s, b'last msg')
+        # 可关闭连接或继续发送更多消息

ressenger_server.py

@@ -0,0 +1,65 @@
+#!/usr/bin/python3
+import socket
+import threading
+import struct
+import time
+import sys
+
+HOST = '0.0.0.0'
+
+def recv_exact(conn, n):
+    """Keep reading until exactly n bytes are received, or return None on EOF"""
+    buf = bytearray()
+    while len(buf) < n:
+        chunk = conn.recv(n - len(buf))
+        if not chunk:
+            return None
+        buf.extend(chunk)
+    return bytes(buf)
+
+def handle_client(conn, addr):
+    print(f'Connected: {addr}')
+    try:
+        while True:
+            header = recv_exact(conn, 4)
+            if header is None:
+                print(f'Client {addr} disconnected')
+                break
+            length = struct.unpack('!I', header)[0]  # Network byte order (big-endian)
+            if length == 0:
+                # Optional: length 0 means heartbeat or empty message
+                print(f'Received an empty message from {addr}')
+                continue
+            data = recv_exact(conn, length)
+            if data is None:
+                print(f'Client {addr} disconnected prematurely while reading data')
+                break
+            # Handle binary data here (may take time)
+            print(f'Received {len(data)} bytes of data from {addr}')
+            print(data)
+            # Simulate time-consuming processing (replace with real logic)
+            # time.sleep(1)  # Even if you have long tasks, other connections are still accepted
+    except Exception as e:
+        print(f'Exception occurred while handling client {addr}: {e}')
+    finally:
+        conn.close()
+        print(f'Closed connection {addr}')
+
+def run_server(PORT):
+    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+    sock.bind((HOST, PORT))
+    sock.listen()
+    print(f'Server listening on {HOST}:{PORT}...')
+    try:
+        while True:
+            conn, addr = sock.accept()
+            t = threading.Thread(target=handle_client, args=(conn, addr), daemon=True)
+            t.start()
+    except KeyboardInterrupt:
+        print('Server shutting down...')
+    finally:
+        sock.close()
+
+if __name__ == '__main__':
+    run_server(int(sys.argv[1]))