Add To Cart abnormal behaviour

[yaseent]

Hi,

I am suddenly having some weird behaviour.

I haven't installed any new plugins, or changed anything for that matter in the files.

When I add to cart, the default setting is to add the product to the cart, and redirect back to the product info page that you were on.

After this, the add to cart sidebox is populated as well.

Now all of a sudden, the sidebox remains as if the cart is empty. If I was to visit another link on the site, then suddenly, the add to cart sidebox is populated.

I go back to the product page, add to cart again, and the quantity stays on 1. I visit another page, the quantity then shows 2 as it should.

Any ideas I'm lost. I don't see any errors in my logs or any such thing.

[yaseent]

Okay, so upon further inspection, I've noticed this:

The shopping cart sidebox, and the shopping cart page, do not update the contents of the cart, or the quantities of the cart.

If the About Us page was loaded with 1x ProductA inside the cart, it will always show that. Even if you add another 1x ProductA, or add 1x ProductB - it will only show 1x ProductA.

If however I visit the..Contact Us page, it will then show the additional 1x ProductA and 1x ProductB that was added.

I don't get this issue. At first I thought browser cache and so on, but a few customers have complained already.

This is really weird.

[lat9]

A link to your site (which really, really needs to be upgraded) would help us help you.

[yaseent]

Lol i'm so sorry - that's the reason I didn't want to post a link.

I've already got my 1.5.4 rebuild and just waiting for a few things to me rectified.

But I think I've figured out the issue lat9!

Here is a brand new install of 1.5.4 on my host:
http://fatcats.co.za/July2015/

Right, now go to the only product there is, and add to cart.

Once done, you will be redirected to the shopping cart page.

Easiest way to replicate the problem is, while you're on the shopping cart page, adjust the quantity. So change it from 1, to 2, and then click the little blue arrows.

Watch what happens to the quantity after you click the blue arrows. It reverts back to 1.

This is a server issue no?

[lat9]

How is that product defined? What is the product's quantity? What are its min/max/units settings?

What are your settings for Configuration->Stock?

[yaseent]

Hi lat9,

1000 quantity.

Max: 0, Min 1, Qty Units 1.

This is a basic straightforward install of Zen-Cart 1.5.4.

All I did was add one normal product, and put the quantity of that product to 1000. Nothing else was changed or done.

The same issue occurring on this new install, and happening on my actual site, doesn't this suggest that the problem has nothing to do with my configuration, and nothing to do with how my products are set up, but instead, this seems to be some sort of issue with my host.

[lat9]

Make a backup copy of /includes/classes/shopping_cart.php and then edit that file. Locate this section (towards the top):

  /**
   * set to TRUE to see debug messages for developer use when troubleshooting add/update cart
   * Then, Logout/Login to reset cart for change
   * @var string
   */
  var $display_debug_messages = FALSE;
  var $flag_duplicate_msgs_set = FALSE;

and change that to:

  /**
   * set to TRUE to see debug messages for developer use when troubleshooting add/update cart
   * Then, Logout/Login to reset cart for change
   * @var string
   */
  var $display_debug_messages = true;
  var $flag_duplicate_msgs_set = FALSE;

That will cause shopping-cart debug messages to be displayed in the "messageStack".

[yaseent]

Make a backup copy of /includes/classes/shopping_cart.php and then edit that file. Locate this section (towards the top):

  /**
   * set to TRUE to see debug messages for developer use when troubleshooting add/update cart
   * Then, Logout/Login to reset cart for change
   * @var string
   */
  var $display_debug_messages = FALSE;
  var $flag_duplicate_msgs_set = FALSE;

and change that to:

  /**
   * set to TRUE to see debug messages for developer use when troubleshooting add/update cart
   * Then, Logout/Login to reset cart for change
   * @var string
   */
  var $display_debug_messages = true;
  var $flag_duplicate_msgs_set = FALSE;

That will cause shopping-cart debug messages to be displayed in the "messageStack".

Tried this out, doesn't show any errors in the message stack.

The thing is, it is adding the additional products (or updated quantities) to the cart, but this isn't reflecting on pages that have already been visited.

So if you update the quantity, in the shopping cart page, it will show as 1. But if you were to visit another page, other than the shopping cart page, or the product info page of the product you updated the quantity for, and scroll down to look at the sidebox shopping cart, then you will see the actual quantities you updated to. Also, if for example, you updated quantity to 2, and visit the Conditions of Use page, you will see 2 in the shopping cart sidebox.

But if you go back to shopping cart page, and update quantity to 3 for example, and go back to conditions of use, you will see the 2 only. Then you have to visit a completely different page, to see the actual 3. If that makes sense.

I noticed something else quite funny as well.

If I continue to the checkout process, and put the following in the special instructions box: "hello" and 'hello' and `hello` <---exactly like this with those exact punctuation marks and all of the "and"'s in their place - it throws a 403 forbidden error when you try to continue checkout.

This is very odd stuff - but it's most definitely my hosting. I've already informed them and asked them to check what's going on.

Also, they did reply, saying they think its a mod_security issue related to AJAX. But i've told them there's no ajax being used in the problems that are occurring.

[DrByte]

Your host is caching the output generated by PHP, so things are not showing up in real-time.

Get your host to disable whatever caching service is interrupting normal operation.

Specs: www.eli teho st.co.za/hosting#2

[yaseent]

Thanks DrByte!

I was googling my entire life away before you replied.

I read something about hosts setting up something called Varnish Cache incorrectly - which could cause this issue.

I will inform my host of your solution.