Long Polling using jQuery and PHP

Question

So, I've been trying to do Long-Polling using the jQuery Library and PHP. I'm doing this so I can make some sort of real-time notifications system in the future. The code I have now isn't really working.

index.php

<html>
<head>
    <title>Long Polling</title>
    <script type='text/javascript' src='http://code.jquery.com/jquery-1.6.2.min.js'></script>
    <script type='text/javascript'>
        $(document).ready(function() {
            getData();
        });

        function getData() {
            $.ajax({
                type: "POST",
                url: "ajax.php",
                async: true,
                timeout: 50000,
                data: "get=true",
                success: function(data) {
                    $("#info").append(data);

                    setTimeout("getData()", 1000);
                }
            });
        }
    </script>
</head>
<body>
    <div id='info'></div>
</body>
</html>

Ajax.php

<?php
    if(rand(1, 100) % 2) {
        echo 'even';
    } else {
        sleep(rand(1, 4));
    }   
?>

The requests are being sent, but it's sending a new request even if the if returns false, im trying to make it only recieve data if the if statement returns true. — Joshwaa, Aug 05 '11 at 11:39
Yeah, if `if(rand(1, 100) % 2)` returns true I want the request to be held open waiting for it to return true upon the next try. — Joshwaa, Aug 05 '11 at 11:41
@Joshwaa: sure it's sending new request, even if it returns nothing, you got these lines success: function(data) { $("#info").append(data); setTimeout("getData()", 1000); } — genesis, Aug 05 '11 at 11:53

score 0 · Answer 1 · answered Aug 05 '11 at 11:41

0

Try to use this for ajax.php

<?php
    if(rand(1, 100) % 2) {
        echo 'even<br />';
    } else {
        sleep(rand(8, 12));
    }   
?>

watch this and sometimes you have to wait up to 12 seconds

if you let him to complete in one second it appears to be broken, but it's not

answered Aug 05 '11 at 11:41

genesis

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That's exactly the same as my code just with a longer sleep? What does that do? – Joshwaa Aug 05 '11 at 11:43
@Joshwaa: your problem is that in your case it appears "broken", because you did receive even a lot times. Or what is "broken", what is not working? – genesis Aug 05 '11 at 11:51
@Joshwaa: it is not. When you'll loop over those news for 50 seconds, it's ok. It will output and send new request Only 1. after 50 seconds 2. when there is new new – genesis Aug 05 '11 at 12:06

Long Polling using jQuery and PHP

1 Answers1

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