WooCommerce: Fixing Fatal error Call to undefined function wc_get_order()
I developed a custom payment gateway plugin for a client, who wanted to add a similar method to “cod” (cash on delivery). FYI, he wanted to add a method called “card on delivery”. I simply duplicated the code, added the PHP to a file, made a plugin and gave him the plugin zip file. And everything was working great… until he did a test checkout.
The error that showed after placing an order
Fatal error: Call to undefined function wc_get_order() in /home/XXXXXXX/public_html/wp-content/plugins/woocommerce-gateway-carddelivery-plugin/woocommerce-gateway-carddelivery-plugin.php on line 201
The fix: wc_get_order() is only valid for WooCommerce 2.2+
It was very simple. The client was still using WooCommerce 2.1, where new orders are called differently. From WooCommerce 2.2, orders are created with wc_get_order() instead.
You can place PHP snippets at the bottom of your child theme functions.php file (delete "?>" if you have it there). CSS, on the other hand, goes in your child theme style.css file. Make sure you know what you are doing when editing such files - if you need more guidance, please take a look at my free video tutorial "Where to Place WooCommerce Customization?"
Does this snippet (still) work?
Please let me know in the comments if everything worked as expected. I would be happy to revise the snippet if you report otherwise (please provide screenshots). I have tested this code with Storefront theme, the WooCommerce version listed above and a WordPress-friendly hosting on PHP 7.3.
Check out these free video tutorials. You can learn how to customize WooCommerce without unnecessary plugins, how to properly configure the WooCommerce plugin settings and even how to master WooCommerce troubleshooting in case of a bug!
Business Bloomer Founder
Author, WooCommerce expert and WordCamp speaker, Rodolfo has worked as an independent WooCommerce freelancer since 2011. His goal is to help entrepreneurs and developers overcome their WooCommerce nightmares. Rodolfo loves travelling, chasing tennis & soccer balls and, of course, wood fired oven pizza.