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app.get('/class/:classID',function(req,res){
className = req.params.classID;
nsp = io.of('/' + className)
res.sendFile(__dirname + '/index.html');
nsp.on('connection', function(socket) {
nsp.emit('welcome', { message: 'Welcome!', id: socket.id });
nsp.on('i am client', console.log);
});
});