Update stock price using ajax - php

Question

I am doing a small personal web portfolio in order to learn web development. I have a list of all the stocks that I have "bought" and I would like to update the price in real-time from yahoo finance. I can already do the price update but I override the table that I display the stocks with a new one that is called using javascript.
I know there must be a cleaner way. I am trying to update the price using javascript but I don't think I am doing everything right.
Here is what I have so far.
Portfolio.php displays all the stocks I have
<?php foreach ($shares as $row): ?>
<tr >
<td><?php echo $row["symbol"];?></td>
<td><?php echo $row["name"];?></td>
<td style="text-align: right;"><?php echo $row["shares"];?></td>
<td id="price" style="text-align: right;">$ <?php echo number_format($row["price"],2);?></td>
<td style="text-align: right;"><?php
$change = number_format($row["change"],2);
echo sprintf( "%+1.2f", $change );
echo " ( ";
echo $row["pct"];
echo " )";
?></td>
<td style="text-align: right;">$ <?php echo $row["dayGain"];?></td>
<td style="text-align: right;">$ <?php echo number_format($row["total"],2);?></td>
</tr>
<?php endforeach; ?>
</table>
<script type="text/javascript" src="../html/js/update.js" ></script>
Then I have update.php which returns all the stock information from yahoo finance as a json
<?php
// configuration
require("../includes/config.php");
//query user's portfolio
$rows = query("SELECT * FROM shares WHERE id = ?", $_SESSION["id"]);
$cash = query("SELECT cash FROM users WHERE id = ?", $_SESSION["id"]);
//create array to store the shares
$shares = array();
//for each of the user info
foreach($rows as $row){
$yql_base_url = "http://query.yahooapis.com/v1/public/yql";
$yql_query = "select%20*%20from%20yahoo.finance.quotes%20where%20symbol%20in%20(%22".$row['symbol']."%22)%0A%09%09";
$env = "env=http%3A%2F%2Fdatatables.org%2Falltables.env";
$yql_full_query = $yql_base_url . "?q=" . $yql_query . "&format=json&" . $env;
$session = curl_init($yql_full_query);
curl_setopt($session, CURLOPT_RETURNTRANSFER, true);
$json = curl_exec($session);
$stock = json_decode($json);
if($stock->query->results !== false){
$shares [] = array(
"symbol" => $stock->query->results->quote->symbol,
"price" => $stock->query->results->quote->LastTradePriceOnly
);
}
}
$return = array("price" => $shares );
echo json_encode($return);
?>
And the third file is update.js in which I am trying to have javascript
$(document).ready(function(){
function stock() {
$(function() {
$.getJSON('../update.php',function(result){
$("div#price2").html(result.price);
});
});
stock();
setInterval(stock(), 10000);
});
});
If I go directly to update.php I can view the prices as json. I think the problem lies with the update.js file but I cannot figure out what the problem is. I cannot even print Hello from update.js in the price field.
What I am trying to do is display the stocks that I have stored in the database and then update the price using ajax and javascript. Any help would be appreciated. Thanks in advance.

Answer 1

Use php's json functions coupled with a .getJSON to update it... Here's some example code:
// pull_stock_price.php
<?php
$return = array("content" => "New Stock Price: $2000");
json_encode($return);
?>
// Jquery to pull stock price once every 10 seconds:
function stock() {
$(function() {$.getJSON("pull_stock_price.php",function(result){
$("#StockPrice").html(result.content);
});
});
stock();
setInterval(stock, 10000);
// HTML!
<td><div id="StockPrice"></div></td>
What this does: Every 10 seconds the user's browser will pull pull_stock_price.php and will take the content provided from the json and update . You can have pull_stock_price.php pull from the database, curl or really anywhere and format the data how you want it.