On 02:17 am, lokare.am...@gmail.com wrote:
Hi everyone,
I'm writing a client library that makes (potentially long running) HTTP
requests. Since the library will be used within non-Twisted code, I was
thinking of running the reactor in a separate thread. The library code
looks roughly like this:
def start():
Thread(target=reactor.run, args=(False,)).start()
def shutdown():
reactor.callFromThread(lambda x: reactor.stop(), None)
def make_request(url):
agent = Agent(reactor)
d = agent.request(
'GET',
url,
Headers({
'User-Agent': ['Twisted SSE Client'],
'Cache-Control': ['no-cache'],
}),
None)
d.addCallback(self.cbRequest)
Then I make requests from the application like so:
start()
make_request("http://localhost:12000";)
....
make_request("http://localhost:12000";)
...
shutdown()
However, it looks like the 'd' deferred never gets fired. From a little
playing around, it looks like this is because the reactor is started
before
the call(s) to agent.request are made. All examples in the twisted docs
create the request before running the reactor. I'm sure I'm missing
something very obvious here. Also, is there a better way to design such
a
library?
It sounds like you want to use Crochet (which Hynek already linked you
to).
The reason your code doesn't work, though, is that Twisted APIs are not
thread safe. You may *only* call them in the thread the reactor is
running in.
Your `start` function runs the reactor in a new thread. Then the code
proceeds to try to use `Agent` from the original thread. This is
unsupported.
Jean-Paul
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