Python Flask WTForms-创建动态无线电元素，工作不一致

Question

我有以下代码来生成从Spotify API返回的播放设备列表：

class SpotifyForm(FlaskForm):
    pass

json_response = response.json()
devicelist = json_response['devices']

devices = {}
for i in range(0, len(devicelist)):
    devices[devicelist[i]['id']] = devicelist[i]['name']

for device in devices:
    choices.append((device, devices[device]))

setattr(SpotifyForm, 'device', RadioField("device", choices=choices))
setattr(SpotifyForm, 'submit', SubmitField('Submit'))

form = SpotifyForm()
if form.validate_on_submit():
    session['spotify_device'] = form.device.data
    return redirect(url_for('index'))

该列表已正确生成，并且在我的生产烧瓶环境中非常有效。但是，一旦移到生产服务器（Gunicorn），就会得到以下错误回溯：

Exception on /spotify [POST]
Traceback (most recent call last):
  File "/home/composerexplorer/composer-explorer/venv/lib/python3.6/site-packages/flask/app.py", line 2446, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/composerexplorer/composer-explorer/venv/lib/python3.6/site-packages/flask/app.py", line 1951, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/composerexplorer/composer-explorer/venv/lib/python3.6/site-packages/flask/app.py", line 1820, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/composerexplorer/composer-explorer/venv/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/home/composerexplorer/composer-explorer/venv/lib/python3.6/site-packages/flask/app.py", line 1949, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/composerexplorer/composer-explorer/venv/lib/python3.6/site-packages/flask/app.py", line 1935, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/composerexplorer/composer-explorer/app/routes.py", line 373, in spotify
    session['spotify_device'] = form.device.data
AttributeError: 'SpotifyForm' object has no attribute 'device'

由于某种原因，我一次或两次出现此错误，但是如果我坚持下去，该错误就会消失，并且表单可以正确提交。有什么想法吗？

Answer 1

我认为您在声明表单类时应该做这样的事情：

class SpotifyForm(FlaskForm):
    device = SelectField(choices=my_choices)
    submit = SubmitField('Submit')

而且，我认为您应该通过form.data访问数据