(Edit: The first line went missing, just the greetings) Hello guys! I'm both new to Stack Exchange and relatively new to Magento.

What I want to do:

Use a self-written JQuery Script to get the ID of a currently selected Simple Product (which is the child of a Configurable Product), call a PHP-File to load the stock-quantity of this product and read it into JQuery again.

However, when trying to call the PHP-File, I get a Internal server error - when trying to open the file directly, I get the HTTP Error 500 (both should be the same as far as I know).

What I have

My current JQuery (the part using Ajax) (update.js):

function getQuantity(productId){
    if (productId === null)
        Qty = 0;    
        var simpleIdJSON = '[{"simpleIdJSON":"' + productId + '"}]';
            url: '/js/stock/qty.php',
            type: "POST",
            dataType: 'json',
            data: simpleIdJSON,
            success: function(data){
            failure: function(msg){
            error: function(xhr, status, error) {

My current PHP (qty.php):

    //load and build up Mage
    require_once 'app/Mage.php';

    //get the data of the chosen product
    $model = Mage::getModel('catalog/product'); 
    $productId = $_POST['simpleIdJSON'];
    $_product = $model->load($productId);

    //get the quantity of the chosen product and return it 
    $qty = (int)Mage::getModel('cataloginventory/stock_item')->loadByProduct($_product)->getQty();
    echo json_encode($qty);

I don't receive any Error when I delete every content from qty.php, while the errors are already comming up when using both require_once 'app/Mage.php' or require 'app/Mage.php' and also tried altering the path using /app.., ../app.., /../app.. and ../../app... The path to the JQuery and PHP files is: ROOT/js/stock/. I do not think it has anything to do with the Path itself, but rather the way I try to get the Classes. If anyone could tell me what (possibly stupid) mistake I'm making, I would be very happy. Criticism, especially about this post (which I would then edit), are welcomed.


1 Answer 1


Looking at your qty.php you require function is wrong and should be

//load and build up Mage

Require reference: http://php.net/manual/en/function.require-once.php

  • 1
    Goodness gracious, I even used require / include on another website (non-CMS), so as I said, "tupid mistake" - altering the path a bit using the brackets made the page not throw the stated error (doing the rest now). Thanks alot, guess I would have searched years for the answer as I didn't expect THIS to be the problem ;) (Also surprised by how fast the answer came. Accepting the answer :) )
    – jekkst
    Aug 19, 2016 at 10:54
  • 1
    Glad i could help, always helps to have a fresh pair of eyes :)
    – DanCarlyon
    Aug 19, 2016 at 10:58
  • 2
    Weird, because require 'file.php' is valid syntax and actually the correct way, the brackets do nothing. require and require_once are not functions! I bet the problem really was the path itself Aug 19, 2016 at 11:31
  • 1
    true, i've always done it with brackets myself, maybe a quirk in this specific version of php ¯_(ツ)_/¯
    – DanCarlyon
    Aug 19, 2016 at 12:02
  • 2
    Weird, trying it with works, while not using them gives the error. Just checked, and the website I mentioned actually DOESN'T have brackets, and works. Well, I for myself don't need to know the specific reason for that, as long as I know I should try both versions :P
    – jekkst
    Aug 19, 2016 at 12:54

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