### Python 中不同程序之间的通信方法 #### 管道 (Pipe) 管道是一种半双工的通信机制，允许数据在一个方向上流动。匿名管道仅限于父子进程间的通信[^1]： ```python import os, sys read_fd, write_fd = os.pipe() pid = os.fork() if pid > 0: # Parent process closes the read end and writes to pipe os.close(read_fd) with os.fdopen(write_fd, 'w') as f: f.write('Hello from parent') else: # Child process closes the write end and reads from pipe os.close(write_fd) with os.fdopen(read_fd) as f: message = f.read() print(f'Child received: {message}') ``` 对于更广泛的进程间通信需求，可以使用命名管道(FIFO)，它可以被任何具有适当权限的进程访问[^2]: ```bash mkfifo mypipe ``` ```python with open('mypipe', 'r') as fifo: while True: data = fifo.read() if len(data) == 0: break print(f'Received: {data}') ``` #### 套接字 (Socket) 套接字提供了一种更为灵活和强大的通信手段，支持跨机器甚至互联网级别的进程间通信: ```python from socket import * server_socket = socket(AF_INET, SOCK_STREAM) server_socket.bind(('localhost', 8080)) server_socket.listen(5) client_socket, addr = server_socket.accept() while True: data = client_socket.recv(1024).decode() if not data: break print(f"Received '{data}' from {addr}") ``` 客户端代码如下所示: ```python from socket import * client_socket = socket(AF_INET, SOCK_STREAM) client_socket.connect(('localhost', 8080)) msg = "Hello Server" client_socket.sendall(msg.encode()) ``` #### 消息队列 (Message Queue) 消息队列为应用程序提供了异步的消息传递服务，能够有效地解耦生产者与消费者。 创建并打开一个消息队列: ```python import posix_ipc mq_name = "/my_mq" try: mq = posix_ipc.MessageQueue(mq_name, flags=posix_ipc.O_CREAT | posix_ipc.O_EXCL, mode=0o660, max_messages=10, max_message_size=2048) except posix_ipc.ExistentialError: mq = posix_ipc.MessageQueue(mq_name) for i in range(3): msg = str(i * i).encode() mq.send(msg) mq.remove() # Clean up after use. ``` 接收端可以通过相同的名称连接到该队列来获取消息.