start_server函数只处理几个请求

Question

我正在用 MicroPython 编写。目标是通过调用设备的 IP 地址来控制的伺服电机。 Raspberry Pi Pico 运行一个监听传入请求的服务器：

http://192.168.178.22/servo/on      should start the servo motor
http://192.168.178.22/servo/off     should stop the servo motor

如果调用不是异步的，它可以工作，但我需要随时停止伺服，因此需要异步（应该无限期地运行，直到调用“off”）。这就是我想出 uasyncio 的原因。一切正常，但仅在第二次请求后，服务器不再响应。

main

在循环中运行，仅显示内存（用于以后的实现）：

async def main():
    print("Setting up event loop...")
    showFilesOnPico()
    connectToWifi(secrets.SSID, secrets.PASSWORD, ledInternal)
    servoStartUp()

    # The event loop will keep running while the server is running
    while True:
        print(".")
        # check for low memory
        print("Free Memory:", gc.mem_free(), "bytes" )
        ##
        await uasyncio.sleep(1)  # Yield control to other tasks

服务器逻辑的启动：

async def startServer():
    addr = socket.getaddrinfo('0.0.0.0', 80)[0][-1]
    server = await uasyncio.start_server(handle_request, *addr)

handle_request

（为了测试，我禁用了伺服开/关，因为问题也出现在“测试部门”请求上）：

async def handle_request(reader, writer):
    print('handle_request called')
    try:
        request = await reader.read(1024)
        request = str(request)

        print("Request:", request)

        #led_on = request.find('/servo/on')
        #led_off = request.find('/servo/off')
        testing = request.find('/testingdepartment')

        #if led_on != -1:
        #    ledInternal.value(1)
        #    uasyncio.create_task(demoServo())

        #if led_off != -1:#
        #    ledInternal.value(0)
        #    uasyncio.create_task(deactivateServo())

        if testing != -1:
            print("testing clicked")
            await uasyncio.sleep(1)

        print("before writer.drain")
        response = b'HTTP/1.0 200 OK\r\nContent-type: text/html\r\n\r\n'
        writer.write(response)
        await writer.drain()
        print("after writer.drain")
    except Exception as e:
        print('Error in handle_request:', e)
    finally:
        reader.close()
        writer.close()
    print("end of handle request reached :-D :-D :-D")
    await uasyncio.sleep(1)

异步循环开始：

loop = uasyncio.get_event_loop()
loop.create_task(main())
loop.create_task(startServer())
loop.run_forever()

它仅适用于少数请求。我无法隔离问题。请求是通过调用前面提到的 URL 发出的。伺服电机通过此功能设置有效（测试电机仅重复运动 6 次）。

async def demoServo():
    print('DemoServo is called')

    global isServoRoutineRunning
    global shouldAbortServoRoutine
    if not isServoRoutineRunning:
        # Reset shouldAbortServoRoutine to False
        shouldAbortServoRoutine = False
        isServoRoutineRunning = True
        for x in range(6):
            if shouldAbortServoRoutine:
                break
            print('pos 90')
            pwm.duty_ns(grad090)
            await uasyncio.sleep(2)

            print('pos 0')
            pwm.duty_ns(grad000)
            await uasyncio.sleep(2)

        pwm.deinit()
        print('end')
        isServoRoutineRunning = False

Answer 1

我刚刚遇到了这个问题。对我来说，解决方案是缓冲区。问题是 10-15 次后循环停止并等待，没有错误消息。 wait writer.drain() 会停止它，因为它将数据卸载到缓冲区中，但接收数据的程序在另一端并不活动，只是被堵塞了。客户端读取数据后，就没有问题了。如果您要发送较大的材料，值得从 1024 改为 4096。