我有一台ESC打印机。我制作了一个简单的脚本来向设备发送数据，但在更改了脚本的内容后-1x会打印上一版本的字幕，然后，当再次调用时，会打印当前版本。就好像USB的数据被缓存在某个地方一样。我该怎么冲？
test.py
usb_= Connector(showUsbDevices=False)
usb_.send(b'I LOVE YOU')
连接器：
class Connector:
def __init__(self, idVendor=0x0123, idProduct=0x1234, showUsbDevices=False):
self.idVendor = idVendor
self.idProduct = idProduct
if showUsbDevices:
pass
self.device = self.FindAndConnect()
if self.device is not None:
#if self.device.is_kernel_driver_active(0):
#self.device.detach_kernel_driver(0)
#self.device.detach_kernel_driver(1)
self.device.reset()
self.device.set_configuration()
self.cfg = self.device.get_active_configuration()
data_itfs = list(usb.util.find_descriptor(self.cfg, find_all=True,custom_match=lambda e: (e.bInterfaceClass == 0xA)))
intf = data_itfs[0]
self.device.set_interface_altsetting(intf)
itf_num = intf.bInterfaceNumber
print ("inf descriptor:===============", intf)
print("numer:===============",itf_num)
self.messageOut = usb.util.find_descriptor(intf, custom_match=lambda e: not (e.bEndpointAddress & 0x80))
self.messageIn = usb.util.find_descriptor(intf, custom_match=lambda e: (e.bEndpointAddress & 0x80))
#print(">>>>>>>>>>>>>>>>>>>Message Out",self.messageOut)
#print(">>>>>>>>>>>>>>>>>>>Message In",self.messageIn)
#print(repr(self.cfg))
def __del__(self):
if self.device is not None:
usb.util.dispose_resources(self.device)
def send(self, data):
#print ("endpoint_out",self.messageOut)
if self.device is not None:
print(data.decode("IBM852"))
self.messageOut.write(data)
#self.device.write(1,data,100)
#dane = self.messageIn.read(300)
#print("IN|->",dane)
def FindAndConnect(self):
device=usb.core.find(idVendor=self.idVendor, idProduct=self.idProduct)
if device is None:
raise ValueError('Not found idVendor 0x%04x i idProduct 0x%04x' % (self.idVendor,self.idProduct))
print('Printer found idVendor 0x%04x i idProduct 0x%04x.... ' %(self.idVendor,self.idProduct))
return device
所以当我运行一个测试脚本我爱你
我明白我爱你
当我把铭文改为我恨你并运行脚本又印了一份《我爱你》只有下一家初创公司会说：我恨你
它是什么？虫子在哪里？
我找到了！它：终结器处的self.device.reset()：
def __del__(self):
if self.device is not None:
self.device.reset() ############### <<<< THIS IS THE KEY>>>> (added to all code)
usb.util.dispose_resources(self.device)