Django ViewFlow:基于验证的导航步骤

Question

我正在使用位于ViewFlow 烹饪书上的ViewFlow示例。整个源代码与helloworld项目相同，唯一的更改是：

flows.py

check_approve = (
    flow.If(lambda activation: activation.process.approved)
    .Then(this.send)
    .Else(this.start)  # Edited (was this.end)
)

因此，基本上，我打算如果用户将Approved复选框保持为未选中的状态并继续进行，那么它将把任务推回开始步骤。

当我运行它时，会得到这个错误：

NotImplementedError at /workflow/helloworld/helloworld/3/approve/11/
No exception message supplied

    Internal Server Error: /workflow/helloworld/helloworld/3/approve/11/
Traceback (most recent call last):
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/django/core/handlers/exception.py", line 41, in inner
    response = get_response(request)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 185, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/django/views/generic/base.py", line 68, in view
    return self.dispatch(request, *args, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/django/utils/decorators.py", line 67, in _wrapper
    return bound_func(*args, **kwargs)
  File "/usr/lib/python3.6/contextlib.py", line 52, in inner
    return func(*args, **kwds)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/decorators.py", line 213, in _wrapper
    return view(request, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/django/utils/decorators.py", line 63, in bound_func
    return func.__get__(self, type(self))(*args2, **kwargs2)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/flow/views/task.py", line 70, in dispatch
    return super(BaseFlowMixin, self).dispatch(request, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/django/views/generic/base.py", line 88, in dispatch
    return handler(request, *args, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/django/views/generic/edit.py", line 240, in post
    return super(BaseUpdateView, self).post(request, *args, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/django/views/generic/edit.py", line 183, in post
    return self.form_valid(form)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/flow/views/task.py", line 86, in form_valid
    self.activation_done(*args, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/flow/views/task.py", line 78, in activation_done
    self.activation.done()
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/fsm.py", line 44, in __call__
    return self.descriptor(self.instance, *args, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/fsm.py", line 112, in __call__
    result = self.func(instance, *args, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/activation.py", line 384, in done
    self.activate_next()
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/fsm.py", line 44, in __call__
    return self.descriptor(self.instance, *args, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/fsm.py", line 112, in __call__
    result = self.func(instance, *args, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/activation.py", line 396, in activate_next
    self.flow_task._next.activate(prev_activation=self, token=self.task.token)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/__init__.py", line 154, in activate
    return self.activation_class.activate(self, prev_activation, token)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/activation.py", line 561, in activate
    activation.perform()
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/fsm.py", line 44, in __call__
    return self.descriptor(self.instance, *args, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/fsm.py", line 112, in __call__
    result = self.func(instance, *args, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/activation.py", line 525, in perform
    self.activate_next()
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/fsm.py", line 44, in __call__
    return self.descriptor(self.instance, *args, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/fsm.py", line 169, in __call__
    result = self.func(instance, *args, **kwargs)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/nodes/ifgate.py", line 24, in activate_next
    self.flow_task._on_false.activate(prev_activation=self, token=self.task.token)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/__init__.py", line 154, in activate
    return self.activation_class.activate(self, prev_activation, token)
  File "/home/admin-12/PycharmProjects/viewflow1/venv/lib/python3.6/site-packages/viewflow/activation.py", line 216, in activate
    raise NotImplementedError
NotImplementedError

Answer 1

问题似乎在于，您试图跳转到The语句中的flow.Start元素。请尝试跳转到例如flow.View元素。