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 );

with this:

$order = new WC_Order( $order_id );

Where to add this code?

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 delicate files - if you need more guidance, please take a look at my free WooCommerce Customization video tutorial.

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.

If you think this code saved you time & money, please join other Business Bloomer supporters and avail of 365 days of WooCommerce benefits. Thank you in advance :)

Need Help with WooCommerce?

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Rodolfo Melogli

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.

8 thoughts on “WooCommerce: Fixing Fatal error Call to undefined function wc_get_order()

  1. I have same issue, but I the issue when I use the function wc_get_orders()
    Its when I use it inside “my custom function” plugin
    (which I think is just appending to the main functions php file)

    How can I fix that?
    Do I need to include the wc-order-functions.php file before calling wc_get_orders() or how do I fix it ?
    require_once( dirname( __FILE__ ) . ‘/includes/wc-order-functions.php’ );

    Thank You 🙂

    1. Hi Michael, thanks so much for your comment! Yes, this is possible – unfortunately this is custom work and I cannot provide a complementary solution here via the blog comments. Thanks a lot for your understanding! ~R

  2. Thank you! This saved me who-knows-how-much time!
    I was getting a slightly different Fatal Error:
    Uncaught Error: Call to undefined method WC_Order_Refund::get_billing_first_name()

    But this still did the trick!

    1. Awesome!

  3. Hi, could you guide me with this error:

     1=""to"" 2=""undefined"" 3=""function"" 4=""wcs_order_contains_renewal()"" 5=""in"" 6=""/home/xxxxx/domains/xxx.xx/public_html/onlinelearning/wp-content/plugins/ld-group-registration/modules/class-wdm-woocommerce.php"" 7=""on"" 8=""line"" 9=""137"" 10=""
    1. Fred, thanks for your comment! I recommend to talk to the “ld-group-registration” plugin devs 🙂

  4. Minha página principal apresenta o seguinte erro:
    Fatal error: Call to undefined function woocommerce_reset_loop() in /home2/tapetesc/public_html/wp-content/themes/mrtailor/inc/shortcodes/product-categories.php on line 116

    Como posso resolver esse problema?
    Att,
    Camila

    1. Thanks for your message Camila. Did this error appear after you tried using my function?

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