An implementation of the Bayeux (COMET) long-polling protocol with a backend using Rack with Sinatra

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7. Client 1 Server Client 2
Page Load
Poll
Poll
User Event
Request
Resp Async
Poll
User Event
Request
Async Resp
Poll
Timeout
Poll

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<script src="jquery.comet.js"></script>
<script src="json2.js”></script>
<script type="application/javascript">
$.comet.connect(location.origin+"/cometd");
$.comet.subscribe("/chat/demo", function(msg) {...});
$.comet.publish("/chat/demo", {
user: username,
join: true,
chat: username + " has joined"
});
</script>
ALSO:
• startBatch(), endBatch()
• unsubscribe(channel), disconnect()

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require ‘bayeux’
class ChatServer < Bayeux
configure { set :public, File.dirname(__FILE__) }
get '/' { erb :index }
def deliver msg
channel = msg['channel']
publish :data => msg['data'], :channel => channel
{ :successful => true, :channel => channel
:clientId => msg['clientId'],:id => msg['id']
}
end
end
run ChatServer.new

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15. Questions?
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