PHP, Singleton and $.ajax

Question

It seems like $.ajax (jQuery) doesn't work well with PHP Singleton.

I have a simple Class defined like this:

class MySingleton
{
    protected static $instance = null;
    private $array;
    protected function __construct()
    {
       ...
       $this->array = array();
       //get something from database, 
       $this->array[] = object from database;
       $this->array[] = object from database;
       ...
    }
    protected function __clone()
    {
    }

    public static function getInstance()
    {
        if (!isset(static::$instance)) {
            static::$instance = new static;
        }
        return static::$instance;
    }

    public function someFunction() {
         $this->array[0]->someField = "set something without saving it to database";
         ...
    }
}

I also have a helper.php file that get the singleton object then do something. ie:

<?php
require "MySingleton.php";
$singleton = MySingleton::getInstance();
$singleton->someFunction();
$singleton->someOtherFunction();
?>

In my index.php, I tried to use the $.ajax to do something for me:

$.each(data, function(key, value) {

            $.ajax({
                url: 'helper.php',
                type: 'POST',
                data: someData,
                dataType: 'JSON'
            }).always(function(result) {

                ...

            });

});//each

as you can see in my jQuery code, I have called $.ajax a few times.

I traced the MySingleton, and instead of returning the same instance, it created a few times (depending on the $.each loop size).

I have read an article: http://www.daniweb.com/web-development/php/threads/393405/php-singletone-pattern-in-php-files-where-ajaxs-requests-are-sent

and this happens because of the singleton pattern will only work during the same request. In my case I have a few ajax requests (again, based on the $.each loop) and that's why it never worked.

The reason I am using a singleton object is because I don't want to make multiple database connections, also MySingleton will have an array (which will be used to store some objects) and in the MySingleton class I will use the array to temporary store some information without saving it back to the database)

So is there anyway to solve my problem? I really want to use the $.ajax and PHP Singleton.

Right, every time you run a PHP script, you're starting from scratch. One run doesn't have access to the context of the previous run unless you save it somewhere. You could do that, or maybe consider using `.each()` to build up a single POST that does all the DB queries in a single pass? — SaganRitual, Aug 07 '13 at 16:54
It looks like your singleton is slightly off: http://stackoverflow.com/a/203359/16959 but to be honest I don't know enough to understand what part is causing your issue. possibly the `new static`? — Jason Sperske, Aug 07 '13 at 16:58
The reason why I'm using multiple $.ajax instead of one big POST is I would like to get the result back from the server side and display them immediately. each $.ajax may take up to a few seconds, so if I use one big POST, it may take quite some time (more than 10 seconds) to display all outputs to the index main screen. — Josh, Aug 07 '13 at 17:00

score 1 · Accepted Answer · answered Aug 07 '13 at 17:07

1

The only way to save data between requests is storing it somewhere. Which basically means either the session or a file or in the database.

I don't think that loading all data at once is slower than loading only one record, because 90% if this loading time is creating the request, creating database connection etc. So how about you try to load all the data at once and if its too slow you can add a cache or something else on top of it, but I am pretty sure it will be fast enought.

answered Aug 07 '13 at 17:07

m0c

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actually in my __construct I have loaded everything from database and save it in the array. So I'll only make one quick db connection. It's just some functions in MySingleton will take some time to execute. That's why I'm using a few $.ajax requests instead of combining into a big one, as @GreatBigBore suggested – Josh Aug 07 '13 at 17:11

PHP, Singleton and $.ajax

1 Answers1