Use socket in nodejs and angularjs - angularjs

Question

I am new in socket.I have problem while using socket in my existing project.I have include socket.io.js file in my project and also create factory for using the socket. socket Request is going successfully from angular side.
I want to do when something is changed in my API response it automatically calls and show result in my page.So here is my code.I dont know how can i achieve this with socket
app.get('/ttms/getAlertsMessage/:customerid/:timstmp', getCookies, ttms.getAlertsMessage);// route
var socket = require('socket.io');
var io = socket.listen(server);
app.set('socketio', io);
io.on('connection', function (socket) {
console.log("==============connected=========")// this shows me connected
socket.on('test',function(data){
console.log(data)
})
});
Here is the node api which will call:
exports.getAlertsMessage = function(req, res, next) {
var customeruuid = req.param('customerid');
var start_time = new Date().getTime(),
request = require('request'),
api_url = global.common.base_url + 'ams/1.0.0/message/customeruuid/'+customeruuid;
var _m = new cLog.mObject('DELETE', 'deleteAllVNFBackup', api_url);
request({
url: api_url,
method: 'GET',
headers: {
'Content-Type': 'application/json',
'Authorization': "Bearer " + req.cookies.apitoken
},
json: req.body
}, function(error, response, body) {
if (response.statusCode == 200 || response.statusCode == 201 || response.statusCode == 202) {
res.end(JSON.stringify(body));
} else {
res.send(response.statusCode, {
"error": JSON.stringify(body)
});
});
}
Here is the angular service:
GetUserSettings.getAlertsMessage($scope.customerId).then(function(data) {
var data1={"test":"test"};
socket.emit('test', data1);
socket.on('result', function (data) {
console.log(data)// gives json {"test":"test"};
});
})
can anyone give me some idea how can i achieve this.