implementing socket.io on existing application - angularjs

Question

My current application poll using MEAN stack and in controller I have a function vote() and API route defined as follow:
"/api/polls/pollID/pollChoiceID"
(ex. http://localhost:3001/api/polls/5587ad060a9e110816f9f1a8/5587ad060a9e110816f9f1a9)
I have the app working fine as it's but now I'm looking to implement socket.io on this app so that when client #2 connected and vote the voting result graph of client #1 will update in real time. I did some research about socket.io but I'm still stuck on implementing it.
For instance, in controller.js and inside the vote() I need to add:
socket.emit('send:vote', poll);
and over the routes/index.js I'll need to handle the socket.emit from controller so I wrap existing router.post codes with socket.on :
socket.on('send:vote', function(data){
router.post('/api/polls/:poll_id2/:poll_choice2', function(req, res)
{
//existing code here
}
}
However, Ii'm not sure if I'm taking the right steps so that they will work with my existing API route. Any inputs would be great! Thanks
/*
controller.js
*/
var voteObj = { poll_id1: pollSelected, choice1: pollChoiceSelected };
$scope.votedPollID = voteObj.poll_id1;
$scope.votedPollChoiceID = voteObj.choice1;
$scope.vote = function()
{
$http.post('/api/polls/' + $scope.votedPollID + '/' + $scope.votedPollChoiceID)
.success(function (data)
{
console.log(data);
$scope.poll = data;
})
.error(function(data) {
console.log('Error: ' + data);
})
/*
routes/index.js
*/
router.post('/api/polls/:poll_id2/:poll_choice2', function(req, res)
{
var testpollid = req.params.poll_id2;
var testpollchoiceid = req.params.poll_choice2;
var ipCounter = 0;
PollModel.findById({_id: req.params.poll_id2}, function(err, poll)
{
if(poll)
{
var choice = poll.choices.id(testpollchoiceid);
choice.votes.push({ ip: ip });
var ipCounter = ipCounter++;
poll.save(function(err, doc)
{
if(err)
{
return (err);
}
else
{
var theDoc = {
question: doc.question, id: doc._id, choices: doc.choices,
userVoted: false, totalVotes: 0
};
for(var i = 0, ln = doc.choices.length; i< ln; i++)
{
var choice = doc.choices[i];
for(var j= 0, jLn = choice.votes.length; j< jLn; j++)
{
var vote = choice.votes[j];
theDoc.totalVotes++;
theDoc.ip = ip;
if(vote.ip === ip)
{
theDoc.userVoted = true;
theDoc.userChoice = { _id: choice._id, text: choice.text };
}
}
}
poll.userVoted = theDoc.userVoted;
}
});
return res.json(poll);
}
else
{
return res.json({error:true});
}
});
});
});
});