use socket.io to bridge pooling php rest api - php

Question

i have my php point exposing these endpoints for example
[GET] /api/news --> [return] [ {id:1,title:'news1'},{id:1,title:'news1'} ];
[POST] /api/news?title=<string> --> [return] {id:NEW_ID,title:$title};
and my frontend webapp use angular 1 to get news.
//to get all news
$http.get('http://server.com/api/news').then(function(res){
$scope.news = res.data;
});
//to post a new news
$http.post('http://server.com/api/news',{title:'news3'}).then(function(res){
$scope.news.push(res.data);
});
this would work fine, except that i will have to pool every interval to get any new news, so i thought something like socket.io can help.
I'm tryying to achive.
user connect to io
io send all news once user connects by consuming my php api
when user post new, he send it to io server, and io forward the post request to my rest api and return the result to all connected users.
so my change to front end can be something like
var socket = io('http://localhost:3700');
socket.on('news', function (data) {
$timeout(()=>{$scope.news = data;});
});
socket.on('news_posted', function (data) {
$timeout(()=>{$scope.news.push(data);});
});
$scope.post = function(title){
socket.emit('post_news', { title: title });
}
now what i have no clue is how to make such simple server ?
var express = require("express");
var app = express();
var port = 3700;
var io = require('socket.io').listen(app.listen(port));
//setting CORS
app.all('*', function(req, res, next) {
res.header("Access-Control-Allow-Origin", "http://localhost:8100");
res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE,OPTIONS');
res.header('Access-Control-Allow-Headers', 'Content-type,Accept,X-Access-Token,X-Key,auth-client,auth-uid,auth-token');
if (req.method == 'OPTIONS') {
res.status(200).end();
} else {
next();
}
});
io.sockets.on('connection', function (socket) {
console.log('a user connected');
///BLOCK 1
///GET ALL POSTS FROM API AND EMIT news event BACK TO USER
///
socket.on('new_post', function(msg){
///BLOCK 2
///POST title TO API AND EMIT BACK news_posted WITH THE RESPONSE
});
});