VbzCart

Technology: VbzCart

Having evaluated osCommerce and found that, although it had many features I would like to have on vbz.net, it also lacked some crucial features currently needed (many of which are provided by the existing shopping cart system, and some of which would be needed in order to effectively manage porting the data from the existing system).

So I'm writing a new system, in PHP, based on the data design of the existing VBZ cart system and adding new pieces as needed.

I will be taking notes on this page and gradually refining them into something resembling documentation, with the ultimate goal of producing a system which could be released under an open source license.

Documents

• VbzCart Tables

Notes

Identifying Sessions

I've been debating about the idea of allowing carts to work using IP address/domain plus browser ID (user_agent) because cookies don't always seem to work (and some people have them turned off), and I think I've come up with a reasonable compromise.

The problem is that one user might connect through a dial-up (dynamic IP), place orders in a cart and disconnect, and then another user with the same browser and OS might happen to connect through the same dial-up -- which would cause that user to be assigned the previous user's shopping cart. This isn't a serious problem, because no personal information will be conveyed, but it can be off-putting to go to a store and find that your cart already has items in it. I would be inclined to immediately go somewhere else.

What I've come up with is the following:

• sessions IDed via IP/browser have a much shorter expiration than cookie sessions
• sessions IDed via IP/browser will show a warning to indicate the shorter expiration time (should show the time when the session will expire -- and the current time, to prevent timezone confusion)
• cookies have never been used for checkout; we have always used POST data (?session=xxxxx), so that's not an issue

Sequence of Events

• On receiving one or more items to add to the cart:
  • Try to match with existing session:
    • Check for session cookie; if found, use that
    • If no session cookie, look for unexpired IP/browser match
  • If no usable existing session found, create a new one (empty cart)
  • Add items to the session cart
  • Display cart & session info