Multiple Ecommerce Shopping Carts trong Drupal Commerce - Drupal 9

Many people researching Drupal Commerce 2.x for Drupal 8 (or the upcoming Drupal 9) are likely wanting to either remove the extra ecommerce shopping carts or allow checkout for multiple carts. This blog post will explain why we have multiple carts—and why being able to checkout with multiple carts is challenging, but possible.

Why you can have more than one Drupal Commerce cart

First, let’s demonstrate what Commerce 2.x can do out of the box for a single user and is often considered a bug. 

1. Go to Acro Media’s demo store.
2. Start out as anonymous and register as a user.
   1. Register here.
   2. Check your email/spam and click a link.
   3. Set your password because you’ll need to log back in shortly.
      Note: Acro doesn’t use your email address used on the account sign up on this site to contact you for marketing purposes. You can opt into marketing materials by clicking the large red help question mark on the right.
3. Once registered, add something to your cart, and log out.
4. Add something to your cart and log in.
5. Go to /cart.

If you are seeing two carts, then you have discovered, like many others, that Drupal Commerce 2.x shows multiple carts by design. Drupal Commerce 1.x created multiple carts like this as well, but would only show one cart at a time. In 1.x, you could follow the five steps outlined above, then checkout and your original cart would display.

Why? Because the system will not delete carts. We’re using a simple anonymous session to create two carts in a potentially common edge case.

The pros and cons of multiple carts

Turning off multiple carts in Drupal Commerce 2.x

There are two relatively simple Drupal modules you can use to show a single cart to a user:

Commerce Combine Carts—If this module is turned on, the multi-cart demo above would not produce two carts.

Commerce Cart Advanced—This module packs a lot of features into it for the crowd of users who want management tools around their multiple cart experience, but it also includes the feature to display only one cart at a time. It was created and is maintained by Acro Media’s senior developer known as krystalcode (Dimitris Bozelos).

Checking out multiple carts, Etsy/Amazon style

The holy grail of marketplace commerce is multi-store and single-checkout. The idea is that you could have a site that features multiple stores and customers could check out once from more than one store. 

According to the original author and former maintainer of Drupal Commerce 2.x, bojanz, you can do this by coding a form that acts like a checkout flow-form, but changes more than one order simultaneously.

However, you also have to consider a number of other issues: 

• Fulfillment—If the stores are selling physical products, how will these orders appear to the customer and to customer service for each store? Likely, each store would want to only see the products for which they are responsible.
• Order management—Even Amazon does some weird things with orders for its customers. Often, orders are split up for seemingly no reason, changing order totals and making order management challenging for customers and for customer service.
• Payment—If you, as the site owner, plan to pay stores from your own bank account, you’ll want to set up a single, site-wide payment gateway and manage disbursement payments to your store owners. If not, then you’ll require each store to have its own payment gateway credentials or some other even more complex setup.
• Taxes—Assuming you have good solutions for all of the above, taxes will still likely make it very hard to move forward. Tax law is hard in the best of times, and depending on how you take payment, tax rules would need to be created and maintained per store. Solutions like Avalara AvaTax only work per store and can be overly expensive for small retailers.

The bottom line

Basically, you have a few contrib options if you want to manage carts for your customers. But if you want that elusive multi-vendor, single checkout, you’ll have to plan well according to your business needs. Regardless, the flexibility of Drupal’s ecommerce cart functionality is capable of creating the best ecommerce shopping carts out there, you just need to know how to do it.