A simple “comet” server in C, streaming data to web clients
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You need to fetch the http-parser submodule, by typing:

git submodule init
git submodule update

Run demo

1 - run make clean all
2 - run ./river

3 - In a terminal, run:

curl -N -d "name=public-channel" ""

The call to /subscribe is blocking.

4 - And then, in another terminal:

curl -d "name=public-channel&data=hello-world-of-comet" ""

5 - The call to /subscribe returns, with the data published in the channel.

Embed in an HTML page

The following example considers the page to be at example.com, and the comet server at river.example.com.

1 - Add a reference to the lib.js script in your page:

	<script type="text/javascript" src="http://river.example.com/lib.js?domain=example.com"></script>

2 - Initialize the server:

	document.domain = "example.com";

	function onMsg(msg) {
		alert("received message: ", msg);

	Comet.init(function() {
		var c = new Comet.Client();
		c.connect("public-channel", onMsg); // call onMsg upon reception of a message.

3 - The onMsg function will now receive all messages published on public-channel.


  • Parameters can be sent in GET or POST.
  • /subscribe takes 3 more (optional) parameters:
    • keep: Use HTTP streaming or close connection after every push (value=0 or 1, defaults to 1)
    • seq: Stream messages from a the sequence number up. Example: If 1000 messages have been sent, seq=990 will push 10 messages.
    • callback: function name for a JSONP callback.
  • The tests directory contains two benchmarking programs, websocket and bench. They can simulate large numbers of concurrent clients reading and writing messages. A single core can process more than 450,000 messages per second.

Chat Demo

A chat demo is available in the chat-demo directory. In order to use it, follow these steps:

  • Add the line www.chat-demo.com river.chat-demo.com to your /etc/hosts file.
  • Configure your web server to server the index.html file for www.chat-demo.com. On Apache2:
<VirtualHost *:80>
	ServerName www.chat-demo.com
	DocumentRoot /var/www/chat-demo.com
  • Restart Apache.
  • Start river.
  • Open www.chat-demo.com in your web browser.


  • Test support for Flash’s <policy-file-request>\0 in the WebSocket implementation.
  • More efficient channel deletion.
  • Remove dependency on dict.c in channels, use own HT.