如何在 django-viewflow 中连接两个流

Question

我正在使用 django-viewflow 来跟踪复杂的业务流程。为了避免长流程类和 flows.py 文件，我希望将一个流程馈送到另一个流程。这可能吗？

我试过下面的代码，但是 Python 抛出了一个 NotImplemented Exception。

class SecondFlow(Flow):
    process_class = SecondProcess
    start = (...)

class FirstFlow(Flow):
    process_class = FirstProcess
    start = (
        flow.Start(
            CreateProcessView,
            fields=['foo']
        ).Next(SecondFlow.start)
    )

如果 FirstFlow 路由到 SecondFlow 的开头，那就太好了。

编辑：我尝试使用提供的建议和文档，但出现以下错误：'StartFunction' object has no attribute 'prepare'

下面是我的新代码。

from viewflow import flow, frontend
from viewflow.base import this, Flow
from viewflow.flow.views import CreateProcessView, UpdateProcessView

from .models import FirstProcess, SecondProcess

@frontend.register
class SecondFlow(Flow):
    process_class = SecondProcess
    start = flow.StartFunction(this.create_flow
            ).Next(this.enter_text)

    def create_flow(self, activation, **kwargs):
        activation.prepare()
        activation.done()

    enter_text = (
        flow.View(
            UpdateProcessView,
            fields=['text']
        ).Next(this.end)
    )

    end = flow.End()


@frontend.register
class FirstFlow(Flow):
    process_class = FirstProcess

    start = (
        flow.Start(
            CreateProcessView,
            fields=['text']
        ).Next(this.initiate_second_flow)
    )

    initiate_second_flow = (
        flow.Handler(this.start_second_flow
        ).Next(this.end)
    )

    def start_second_flow(self, activation):
        SecondFlow.start.run()

    end = flow.End()

第二次编辑：在我将装饰器添加到 SecondFlow 的 create_flow 方法后它起作用了。

from django.utils.decorators import method_decorator
...

@frontend.register
class SecondFlow(Flow):
    process_class = SecondProcess
    start = flow.StartFunction(this.create_flow
            ).Next(this.enter_text)

    @method_decorator(flow.flow_start_func)
    def create_flow(self, activation, **kwargs):
        activation.prepare()
        activation.done()

...

Answer 1

flow.Start 是由用户调用并创建流程的开始视图的任务。 View 可以有一些逻辑，通常，该逻辑依赖于 request 数据。因此，您不能在其他地方调用 flow.StartView 和 flow.View，除非通过浏览器访问 URL。

要以编程方式激活某些进程，有 flow.StartFunction - http://docs.viewflow.io/viewflow_core_node.html#viewflow.nodes.StartFunction

要从另一个流程执行它，可以使用 flow.Handler - http://docs.viewflow.io/viewflow_core_node.html#viewflow.nodes.Handler

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