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Ed Morton's questions

Martin Hope
Ed Morton
Asked: 2025-03-04 04:43:30 +0800 CST
  • 6

我正在学习 python 和 asyncio，在成功使用 asyncio 创建 TCP 客户端/服务器后，我第一次尝试使用 pyserial-asyncio 在 Raspberry Pi 5 上使用 Python 3.8（我无法更改版本）在 bash 中运行来创建串行客户端/服务器。

这是服务器：

import asyncio
import serial_asyncio

class UARTProtocol(asyncio.Protocol):
    def __init__(self):
        self.transport = None

    def connection_made(self, transport):
        self.transport = transport
        print('Port opened', transport)

    def data_received(self, data):
        print('Data received:', data.decode())
        # Echo received data back (example)
        self.transport.write(data)
        # Close the connection if 'exit' is received
        if data == b"exit\r":
            self.transport.close()

    def connection_lost(self, exc):
        print('Port closed')
        self.transport = None

    def pause_writing(self):
        print('pause writing')
        print(self.transport.get_write_buffer_size())

    def resume_writing(self):
        print(self.transport.get_write_buffer_size())
        print('resume writing')

async def run_uart_server():
    loop = asyncio.get_running_loop()
    try:
        transport, protocol = await serial_asyncio.create_serial_connection(loop, UARTProtocol, '/dev/ttyAMA2', baudrate=9600)
        print("UART server started.")
        await asyncio.Future()  # Run forever
    except serial.serialutil.SerialException as e:
        print(f"Error: Could not open serial port: {e}")
    finally:
        if transport:
            transport.close()

if __name__ == "__main__":
    asyncio.run(run_uart_server())

和客户：

import asyncio
import serial_asyncio

async def uart_client(port, baudrate):
    try:
        reader, writer = await serial_asyncio.open_serial_connection(url=port, baudrate=baudrate)
        print(f"Connected to {port} at {baudrate} bps")

        async def receive_data():
            while True:
                try:
                    data = await reader.readline()
                    if data:
                        print(f"Received: {data.decode().strip()}")
                except Exception as e:
                    print(f"Error reading data: {e}")
                    break

        async def send_data():
            while True:
                message = input("Enter message to send (or 'exit' to quit): ")
                if message.lower() == 'exit':
                    break
                writer.write((message + '\n').encode())
                # writer.write_eof()
                await writer.drain()
                print(f"Sent: {message}")

        await asyncio.gather(receive_data(), send_data())

    except serial.SerialException as e:
        print(f"Error opening serial port: {e}")
    finally:
      if 'writer' in locals():
        writer.close()
        await writer.wait_closed()
        print("Connection closed.")

if __name__ == "__main__":
    asyncio.run(uart_client('/dev/ttyAMA1', 9600))

我希望客户端提示我输入一些文本，然后立即将其发送到服务器并打印出来。我可以让客户端提示我输入文本，但服务器不会显示任何文本，直到我exit在客户端输入以关闭连接后，服务器才会打印我在客户端循环中输入的所有文本。

除其他事项外，我还尝试添加writer.write_eof()客户端（请参阅下面客户端代码中注释掉的行），并且成功使服务器立即显示来自客户端的前面的文本，但客户端再也没有提示我输入。

如果我运行服务器并且只echo foo > /dev/ttyAMA1从 bash 执行操作，服务器就会foo立即打印，所以我怀疑问题出在客户端。

我做错什么了？

python