I started with this project for my real time stock price update project.
This project works well when I am working with one or two stocks, but not when I want to update the price of hundreds of stocks at the same time. I'd like to know if I'm doing this the right way. Right now I fetch the data for all stocks in a for loop on the server, but the price update is very very slow. I'd like to know how to improve this.
I'd like to know how to update hundreds of stock prices each second, without affecting server performance.
I don't know if I should be sending the server a list of stocks I need from the client like: var ids = [ '', '', '', ... ], or if I can run those ids from the server itself.
Which is best: Stocks request from client to server, or from server to client?
Note: I will be using a different url to get stock price.
My server side code :
////
// CONFIGURATION SETTINGS
///
var PORT = 4000;
var FETCH_INTERVAL = 5000;
var PRETTY_PRINT_JSON = true;
///
// START OF APPLICATION
///
var express = require('express');
var http = require('http');
var io = require('socket.io');
var app = express();
var server = http.createServer(app);
var io = io.listen(server);
io.set('log level', 1);
server.listen(PORT);
var ticker = "";
app.get('/:ticker', function(req, res) {
ticker = req.params.ticker;
res.sendfile(__dirname + '/index.html');
});
io.sockets.on('connection', function(socket) {
var local_ticker = ticker;
ticker = "";
//Run the first time immediately
get_quote(socket, local_ticker);
//Every N seconds
var timer = setInterval(function() {
var ids = ['AAPL', '' , ..........100 stocks];
var l = ids.length;
for(var i=0; i<l; i++){
get_quote(socket, ids[i])
}
}, FETCH_INTERVAL);
socket.on('disconnect', function () {
clearInterval(timer);
});
});
function get_quote(p_socket, p_ticker) {
http.get({
host: 'www.google.com',
port: 80,
path: '/finance/info?client=ig&q=' + p_ticker
}, function(response) {
response.setEncoding('utf8');
var data = "";
response.on('data', function(chunk) {
data += chunk;
});
response.on('end', function() {
if(data.length > 0) {
try {
var data_object = JSON.parse(data.substring(3));
} catch(e) {
return;
}
var quote = {};
quote.ticker = data_object[0].t;
quote.exchange = data_object[0].e;
quote.price = data_object[0].l_cur;
quote.change = data_object[0].c;
quote.change_percent = data_object[0].cp;
quote.last_trade_time = data_object[0].lt;
quote.dividend = data_object[0].div;
quote.yield = data_object[0].yld;
p_socket.emit('quote', PRETTY_PRINT_JSON ? JSON.stringify(quote, true, '\t') : JSON.stringify(quote));
}
});
});
}
My client side code :
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.js"></script>
<script type="text/javascript" src="http://localhost:4000/socket.io/socket.io.js"></script>
<script type="text/javascript">
$(document).ready(function() {
var socket = io.connect("http://localhost:4000");
socket.on('quote', function(data) {
var data = $("<pre>" + data + "</pre><hr />");
$("#quotes").append(data);
$("html, body").animate({ scrollTop: $(document).height() }, 100);
$(data).show("slide", { direction: "up" }, 250);
$(data).effect("highlight", {}, 1500);
});
});
</script>
<body>
<div id="quotes"></div>
</body>