Nginx module to turn it into a long-polling message queuing HTTP push server.

http://github.com/slact/nginx_http_push_module

by labria • 17 years ago

80 25 17 years ago

github.com

_ck_• 17 years ago

Does Google do something like this for their servers for the chat service inside gmail?

I've noticed it can keep http connections open for extremely long times.

axod3• 17 years ago

http://en.wikipedia.org/wiki/Comet_(programming) is a good ref. Gmail chat does this.

gcb• 17 years ago

This wiki page covers mostly the frontend part.

The link covers a server side message passing interface.

I just glanced over it (do not use nginx) think it's just a more efficient way for your idle process to know if they need to send anything over the wire or if they can keep idleing.

mrshoe• 17 years ago

If I'm reading the docs correctly, you'd have to make a server-side HTTP request from your synchronous app to nginx for each message you want to push to each client. I'm pretty sure that will be prohibitively slow.

It would be much nicer if you could make one server-side request for each event, and have nginx track which clients are interested in that type of event and even queue that event for a while for clients that are yet to connect.

labria3• 17 years ago

No. You just set the "push_listener_concurrency" setting to "broadcast", and have as many listeners on one channel as you like.

danielrhodes• 17 years ago

HTTP prohibitively slow? You don't say! :-)

If this does become an issue, it is a tradeoff between speed and memory usage and ease of implementation.

elliottkember• 17 years ago

Personally, I prefer Juggernaut (http://juggernaut.rubyforge.org/) for this. Sure, it's Flash, but it just seems like a bit less of a hack than long-polling.

Jasber• 17 years ago

Have you had any problems using this in production? My understanding with using Flash/Java is that all traffic has to be tunneled through port 80 to not interfere with proxy servers. Even then sometimes traffic that doesn't look like HTTP can be blocked. Has this been a problem for you?

http://cometdaily.com/2008/09/30/why-flash-must-adopt-comet/

http://orbited.org/blog/2007/08/juggernaut-is-a-bad-idea/

defied• 17 years ago

I'm using it in production since last week, about 50,000 connections / day. For some reason it seems to stop/crash after 24-36hrs without leaving anything in the logs.

I am using it on port 443 (https).

axod3• 17 years ago

>> "Sure, it's Flash"

.... and there goes half your potential users.

dugmartin• 17 years ago

Maybe half of open source linux developers but more like 0.000002% of normal users

wizard_24• 17 years ago

Nobody asked; Why do you prefer Juggernaut?

WALoeIII• 17 years ago

This is fantastic. EZ-Mode push using a very simple to deploy piece of software.

simonw• 17 years ago

Quick question for any nginx experts: the following config setting:

set $push_channel_id $arg_id; #/?id=239aff3 or somesuch

Means that the ?id= querystring paramater is used as the push channel ID. Any idea if it would be possible to set it up so /channel/12345/ would result in 12345 being set as the push channel ID?

wizard_24• 17 years ago

Quite possible - You'd need to use the rewrite module to pass it as an argument. http://wiki.nginx.org/NginxHttpRewriteModule

Maybe something like this...

  location / {
    rewrite  ^/channel/(.+)$ /channel/?id=$1 last;
  }
  
  location /channel/{
    #stuff
    set $push_channel_id $arg_id; #/?id=239aff3 or somesuch
  }

karanbhangui• 17 years ago

I'm curious how this compares to twisted.web/tornado in terms of use case (friendfeed type sites). Can anyone quickly explain this to me? Thanks!

labria3• 17 years ago

Tornado is a web framework on its own, it handles the polling and the replies internally. This nginx module is just a helper to the framework behind it. It keeps the connections to the listeners, waiting for the framework to signal it, and then sends the message back to the listeners.

sh1mmer• 17 years ago

This just creepy. We had a session at the Real-time web summit yesterday where we described needing something like this.

One of the guys from Google named it the "Comet Tornado Reverse HTTP Proxy" because we were talking about adapting Tornado, this look like exactly that.

jbyers• 17 years ago

Nice. I hacked something like this into nginx a while back via kestrel but a native module is better by far. Assuming it's up to the high expectations of nginx stability, it's going to further cement nginx as the proxy / lightweight webserver of choice.

bham• 17 years ago

Do you work at Twitter? I wasn't aware that anyone was using Kestrel outside of Twitter - Zing!

slact• 17 years ago

hey guys, I'm responsible for this frankenstein of a creation. I am 2 bugs away from a release with quite a few essential improvements.

(of course, the bugs in question seem to be concurrency related, so it might take a day or two or more to fix)

Clever suggestions and constructive forks are welcome.

Nginx module to turn it into a long-polling message queuing HTTP push server.

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