我的sqlalchemy数据库模型返回为
return f"User('{self.user_a}','{self.email}','{self.level}')
※当我检查网络请求标头时
b: User('aaa','kep@keo.com','ccc')
在我的python代码中
a.py
selected = request.args.get('b')
return render_template('abc.html', selected = selected)
在我的html代码中
abc.html
<input type="text" value={{ selected.user_a.data }}> // I guess here is the problem.
我希望输入值显示在主页窗口中。
但是这里出现错误
jinja2.exceptions.UndefinedError : 'str object' has no attribute 'user'
有人可以帮助我解决此错误吗？
答案 0 :(得分：0)
此异常意味着您正在尝试从字符串而不是对象访问属性。您期望 public async Task InitializeAsync()
{
//TODO: Use a semaphore lock here
if (_IsInitializing)
{
return;
}
_IsInitializing = true;
try
{
//TODO:
//Dispose();
var isPermissionGranted = await RequestPermissionAsync();
if (!isPermissionGranted.HasValue)
{
throw new Exception("User did not respond to permission request");
}
if (!isPermissionGranted.Value)
{
throw new Exception("The user did not give the permission to access the device");
}
var usbInterface = _UsbDevice.GetInterface(0);
//TODO: This selection stuff needs to be moved up higher. The constructor should take these arguments
for (var i = 0; i < usbInterface.EndpointCount; i++)
{
var ep = usbInterface.GetEndpoint(i);
if (_ReadEndpoint == null && ep.Type == UsbAddressing.XferInterrupt && ep.Address == (UsbAddressing)129)
{
_ReadEndpoint = ep;
continue;
}
if (_WriteEndpoint == null && ep.Type == UsbAddressing.XferInterrupt && (ep.Address == (UsbAddressing)1 || ep.Address == (UsbAddressing)2))
{
_WriteEndpoint = ep;
}
}
//TODO: This is a bit of a guess. It only kicks in if the previous code fails. This needs to be reworked for different devices
if (_ReadEndpoint == null)
{
_ReadEndpoint = usbInterface.GetEndpoint(0);
}
if (_WriteEndpoint == null)
{
_WriteEndpoint = usbInterface.GetEndpoint(1);
}
if (_ReadEndpoint.MaxPacketSize != ReadBufferLength)
{
throw new Exception("Wrong packet size for read endpoint");
}
if (_WriteEndpoint.MaxPacketSize != ReadBufferLength)
{
throw new Exception("Wrong packet size for write endpoint");
}
_UsbDeviceConnection = UsbManager.OpenDevice(_UsbDevice);
if (_UsbDeviceConnection == null)
{
throw new Exception("could not open connection");
}
if (!_UsbDeviceConnection.ClaimInterface(usbInterface, true))
{
throw new Exception("could not claim interface");
}
Logger.Log("Hid device initialized. About to tell everyone.", null, LogSection);
IsInitialized = true;
RaiseConnected();
return;
}
catch (Exception ex)
{
Logger.Log("Error initializing Hid Device", ex, LogSection);
}
_IsInitializing = false;
}
public override async Task<byte[]> ReadAsync()
{
try
{
var byteBuffer = ByteBuffer.Allocate(ReadBufferLength);
var request = new UsbRequest();
request.Initialize(_UsbDeviceConnection, _ReadEndpoint);
request.Queue(byteBuffer, ReadBufferLength);
await _UsbDeviceConnection.RequestWaitAsync();
var buffers = new byte[ReadBufferLength];
byteBuffer.Rewind();
for (var i = 0; i < ReadBufferLength; i++)
{
buffers[i] = (byte)byteBuffer.Get();
}
//Marshal.Copy(byteBuffer.GetDirectBufferAddress(), buffers, 0, ReadBufferLength);
Tracer?.Trace(false, buffers);
return buffers;
}
catch (Exception ex)
{
Logger.Log(Helpers.ReadErrorMessage, ex, LogSection);
throw new IOException(Helpers.ReadErrorMessage, ex);
}
}
public override async Task WriteAsync(byte[] data)
{
try
{
var request = new UsbRequest();
request.Initialize(_UsbDeviceConnection, _WriteEndpoint);
var byteBuffer = ByteBuffer.Wrap(data);
Tracer?.Trace(true, data);
request.Queue(byteBuffer, data.Length);
await _UsbDeviceConnection.RequestWaitAsync();
}
catch (Exception ex)
{
Logger.Log(Helpers.WriteErrorMessage, ex, LogSection);
throw new IOException(Helpers.WriteErrorMessage, ex);
}
}
作为对象，但实际上，它是一个字符串。您需要先将其转换为JSON，然后再将其传递到模板中。
selected