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.
I simply substituted this:
$order = wc_get_order( $order_id );
$order = new WC_Order( $order_id );
Where to add this snippet?
You can place PHP snippets at the bottom of your child theme functions.php file (before "?>" if you have it). 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+.
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Author, WooCommerce expert and WordCamp speaker, Rodolfo has worked as a 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.