使用 Twisted 更新共享数据

Question

How can I share a blob of data using a Twisted server, while at the time time periodically updating that data in the background?:如何使用 Twisted 服务器共享数据块，同时在后台定期更新该数据？：

from twisted.internet import reactor
from twisted.internet import task
from twisted.web.server import Site
from twisted.web.resource import Resource

data = 1

def update_data():
    data += 1

class DataPage(Resource):
    isLeaf = True
    def render_GET(self, request):
        return "<html><body>%s</body></html>" % (data, )

root = Resource()
root.putChild("data", DataPage())
factory = Site(root)
reactor.listenTCP(8880, factory)

m = task.LoopingCall(update_data)
m.start(10.0)

print "running"
reactor.run()

The above code does not work because of the following exception:由于以下异常，上述代码不起作用：

C:\temp>python discovery.py
Unhandled error in Deferred:
Traceback (most recent call last):
  File "discovery.py", line 23, in <module>
    m.start(10.0)
  File "c:\python25\lib\site-packages\twisted\internet\task.py", line 163, in start
    self()
  File "c:\python25\lib\site-packages\twisted\internet\task.py", line 194, in __call__
    d = defer.maybeDeferred(self.f, *self.a, **self.kw)
--- <exception caught here> ---
  File "c:\python25\lib\site-packages\twisted\internet\defer.py", line 102, in maybeDeferred
    result = f(*args, **kw)
  File "discovery.py", line 10, in update_data
    data += 1
exceptions.UnboundLocalError: local variable 'data' referenced before assignment

I would like HTTP clients to access, in this example, http://127.0.0.1:8880/data and retrieve the current value of data, while at the same time have some other task scheduled to update data every so often.我希望 HTTP 客户端访问，在此示例中， http://127.0.0.1:8880/data并检索数据的当前值，同时安排其他一些任务以每隔一段时间更新数据。

Moreover, I don't really want to use LoopingCall() because I may want to vary the interval depending on whether the update succeeds or not;此外，我真的不想使用 LoopingCall() 因为我可能想根据更新是否成功来改变间隔； the update will be some sort of remote API call.更新将是某种远程 API 调用。 Can I use CallLater() in some fashion instead?我可以以某种方式使用 CallLater() 吗？

I'm sure this is a stupid question.我敢肯定这是一个愚蠢的问题。 Thanks.谢谢。

EDIT: thouis helped with properly making the data variable global.编辑：你帮助正确地使数据变量成为全局变量。 For those that follow, here's how to fit callLater() into the code:对于接下来的那些，这里是如何将callLater()放入代码中：

from twisted.internet import reactor
from twisted.internet import task
from twisted.web.server import Site
from twisted.web.resource import Resource

data = 1

def update_data():
    global data
    data += 1
    reactor.callLater(10, update_data)

class DataPage(Resource):
    isLeaf = True
    def render_GET(self, request):
        return "<html><body>%s</body></html>" % (data, )

root = Resource()
root.putChild("data", DataPage())
factory = Site(root)
reactor.listenTCP(8880, factory)

update_data()

print "running"
reactor.run()

This code still feels a bit hacky.这段代码仍然感觉有点hacky。 I don't like declaring module-level variables, let alone using global variables.我不喜欢声明模块级变量，更不用说使用全局变量了。 I welcome any suggestions that avoid such practises and make the code look cleaner and more re-usable.我欢迎任何避免这种做法并使代码看起来更干净和更可重用的建议。

Answer 1

Add a global def to update_data():将全局 def 添加到 update_data()：

def update_data():
    global data
    data += 1

使用 Twisted 更新共享数据

问题描述

1 个解决方案

解决方案1
2 已采纳

使用 Twisted 更新共享数据

问题描述

1 个解决方案

解决方案1 2 已采纳

解决方案1
2 已采纳