I'm trying to find how can I use Redis and Tornado asynchronously. I found the tornado-redis but I need more than just add a yield
in the code.
I have the following code:
import redis
import tornado.web
class WaiterHandler(tornado.web.RequestHandler):
@tornado.web.asynchronous
def get(self):
client = redis.StrictRedis(port=6279)
pubsub = client.pubsub()
pubsub.subscribe('test_channel')
for item in pubsub.listen():
if item['type'] == 'message':
print item['channel']
print item['data']
self.write(item['data'])
self.finish()
class GetHandler(tornado.web.RequestHandler):
def get(self):
self.write("Hello world")
application = tornado.web.Application([
(r"/", GetHandler),
(r"/wait", WaiterHandler),
])
if __name__ == '__main__':
application.listen(8888)
print 'running'
tornado.ioloop.IOLoop.instance().start()
I need getting access the /
url and get the "Hello World" while there's a request pending in the /wait
.
How can I do it?
You should not use Redis pub/sub in the main Tornado thread, as it will block the IO loop. You can handle the long polling from web clients in the main thread, but you should create a separate thread for listening to Redis. You can then use ioloop.add_callback()
and/or a threading.Queue
to communicate with the main thread when you receive messages.