Real time page update

Question

I need help, This is what am actually trying to do. I have two files. "index.php" and "realtime.php" the index.php displays news from a particular country base on the url parameter "country_code", and the realtime.php updates the news list every 2 seconds. what I want is for realtime.php to get the current url parameter of index.php so that it can only update news from that particular country base on the url parameter. I really need this help. Thank you again. script for index.php

<script type="text/javascript">
$(document).ready(function () {
    $.arte({'ajax_url': '../realtime.php?lastid='+$('.postitem:first').attr('id'), 'on_success': update_field, 'time': 1000}).start();
    function update_field(data)
    {
        $("#realtimeupdate").html(data);
    }
});

</script>

and script for realtime.php

<?php

include"customDB.php";
$lastid = $_REQUEST['lastid'];
$query = 'SELECT count(*) as newpost FROM wp_posts WHERE country_code = "XXXXX" AND   post_id > "'.$lastid.'"';
$result = mysql_query($query);
$rec = mysql_fetch_object($result);
if($rec->newpost){ ?>
<a href="" id="newpostlink">(<?php echo $rec->newpost; ?>) new posts</a>
<script type="text/javascript">document.title = '(<?php echo $rec->newpost; ?>) new posts'</script>
<?php } ?>

I want the value of country_code ="XXXXXX" in raltime.php to be the url parameter value of index.php Thanks

Why don't you remove realtime.php from the app and instead push the updates to the connected web clients when more news become available? There are a whole host of [realtime web technologies](http://www.leggetter.co.uk/real-time-web-technologies-guide) that make this easy to do as well as removing the potentially very heavy resource load from your servers. — leggetter, Dec 20 '11 at 16:04
It's possible to push updates from a web server to a web client instead of using inefficient polling techniques. If you poll realtime.php every 2 seconds and have a reasonable number of connected clients you will be putting your web server under a lot of load. I suggest reading up on [Push Technologies](http://en.wikipedia.org/wiki/Push_technology) and [WebSockets](http://en.wikipedia.org/wiki/WebSocket). You can see a really [simple demo of push notifications using PHP here](http://j.mp/html5-php-push-frames). — leggetter, Dec 22 '11 at 19:27

score 4 · Accepted Answer · edited May 23 '17 at 10:24

Accessing query string in Javascript

First, you'll need to get the value of "country_code" that has been passed as a query string parameter. You can use Javascript like this to do so:

var urlParams = {};
(function () {
    var e,
        a = /\+/g,  // Regex for replacing addition symbol with a space
        r = /([^&=]+)=?([^&]*)/g,
        d = function (s) { return decodeURIComponent(s.replace(a, " ")); },
        q = window.location.search.substring(1);

    while (e = r.exec(q))
       urlParams[d(e[1])] = d(e[2]);
})();

(taken from this SO question)

Now, urlParams will look something like:

urlParams = {
    country_code: 'US'
}

So, you can change your AJAX call to add this parameter:

$.arte({'ajax_url': '../realtime.php?country_code='+urlParams.country_code+'lastid='+$('.postitem:first').attr('id'), 'on_success': update_field, 'time': 1000}).start();

And now it will be available via PHP under $_GET['country_code'].

Using the variable in PHP

Now you can access the variable and use it in your query.

$country_code = mysql_real_escape_string($_GET['country_code']);
$query = 'SELECT count(*) as newpost FROM wp_posts WHERE country_code = "' . $country_code . '" AND   post_id > "'.$lastid.'"';

Note that I've written this code to conform to your existing coding style. It's not very clean, so you might consider cleaning it up by using helpers like $.param() and MySQLi prepared statements.

thanks, i try your suggestion and i get this error,
Notice: Undefined index: lastid in C:\wamp\www\1afribari\realtime.php on line 5 — David Addoteye, Dec 20 '11 at 23:16
So set $lastid. I copied it right out of your example code :P — Interrobang, Dec 21 '11 at 01:22

Sergio Tulentsev · Answer 2 · 2011-12-20T07:36:46.100

1

At page generation you can echo country code from $_GET['country_code'] to the script that calls realtime.php.

Or, alternatively, on index.php you can get your country parameter from window.location property and then pass it as a parameter to realtime.php.

edited Dec 20 '11 at 07:36

answered Dec 20 '11 at 07:30

Sergio Tulentsev

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Or he could echo $_GET['country_code'] and not have to bother with parsing window.location. – Corbin Dec 20 '11 at 07:33
will be happy if you could show me how to do that. thanks for your responds – David Addoteye Dec 20 '11 at 23:04
In the other example it's pretty well laid out. – Sergio Tulentsev Dec 21 '11 at 03:14
am a novice and don't really know how to customize the examples i have been giving. any help will be greatly depreciated Thanks – David Addoteye Dec 21 '11 at 03:51
your suggestion and the suggestion from "Interrobang" – David Addoteye Dec 21 '11 at 06:22

Real time page update

2 Answers2

Accessing query string in Javascript

Using the variable in PHP