WooCommerce hooks for customization in Wordpress

Introduction

WooCommerce hooks let you change or add features without changing the main code. This keeps your store safe and easy to update.

Add a custom message on the product page.

Change the order confirmation email content.

Add extra fields to the checkout page.

Modify the price display on product listings.

Run code after a customer completes an order.

Syntax

Wordpress

add_action('hook_name', 'your_function_name', priority, accepted_args);

function your_function_name() {
    // Your custom code here
}

// Or for filters:
add_filter('hook_name', 'your_function_name', priority, accepted_args);

function your_function_name($content) {
    // Modify and return $content
    return $content;
}

add_action is used to add new behavior at a specific point.

add_filter is used to change data before it shows up.

Examples

This adds a message before the product details on the product page.

Wordpress

add_action('woocommerce_before_single_product', 'show_custom_message');

function show_custom_message() {
    echo '<p>Free shipping on orders over $50!</p>';
}

This changes how the price is shown by adding extra text.

Wordpress

add_filter('woocommerce_get_price_html', 'change_price_display');

function change_price_display($price) {
    return $price . ' <small>including tax</small>';
}

This saves a custom field value when the customer finishes checkout.

Wordpress

add_action('woocommerce_checkout_update_order_meta', 'save_custom_checkout_field');

function save_custom_checkout_field($order_id) {
    if (!empty($_POST['custom_field'])) {
        update_post_meta($order_id, '_custom_field', sanitize_text_field($_POST['custom_field']));
    }
}

Sample Program

This code adds a note below the product title on the product page. It uses the woocommerce_single_product_summary hook with priority 20 to place the message in the right spot.

Wordpress

<?php
// Add a custom note on the product page
add_action('woocommerce_single_product_summary', 'add_custom_note', 20);

function add_custom_note() {
    echo '<p><strong>Note:</strong> This product ships within 24 hours.</p>';
}
?>

Important Notes

Hooks let you add or change features without touching WooCommerce core files.

Always use child themes or custom plugins to add hooks so updates don't erase your changes.

Use the right hook name and priority to control where your code runs.

Summary

WooCommerce hooks let you customize your store safely and easily.

Use add_action to add new things and add_filter to change existing data.

Hooks help keep your custom code organized and update-proof.

Practice

1. What is the main purpose of WooCommerce hooks in customizing a store?

easy

A. To disable WooCommerce features permanently

B. To directly modify WooCommerce core plugin files

C. To safely add or change features without editing core files

D. To create new WooCommerce plugins from scratch

Solution

1. Step 1: Understand what hooks do

   Hooks let you add or change features without touching core plugin files, keeping updates safe.

2. Step 2: Compare options

   Directly modifying core files or disabling features permanently is unsafe or unrelated to hooks.

3. Final Answer:

   To safely add or change features without editing core files -> Option C

4. Quick Check:

   Hooks = safe customization [OK]

Hint: Hooks let you add or change without touching core files [OK]

Common Mistakes:

• Thinking hooks edit core plugin files directly
• Confusing hooks with plugin creation
• Believing hooks disable features permanently

2. Which of the following is the correct syntax to add a custom function to a WooCommerce action hook?

easy

A. add_action('woocommerce_before_checkout_form', 'my_custom_function');

B. add_filter('woocommerce_before_checkout_form', 'my_custom_function');

C. add_hook('woocommerce_before_checkout_form', 'my_custom_function');

D. hook_action('woocommerce_before_checkout_form', 'my_custom_function');

Solution

1. Step 1: Identify correct function for actions

   WooCommerce uses add_action to add functions to action hooks.

2. Step 2: Check syntax correctness

   add_action('woocommerce_before_checkout_form', 'my_custom_function'); uses add_action with correct parameters; others use wrong functions or names.

3. Final Answer:

   add_action('woocommerce_before_checkout_form', 'my_custom_function'); -> Option A

4. Quick Check:

   Use add_action for actions [OK]

Hint: Use add_action for actions, add_filter for filters [OK]

Common Mistakes:

• Using add_filter instead of add_action for actions
• Using non-existent functions like add_hook or hook_action
• Mixing up action and filter hook functions

3. What will be the output of this code snippet added to a WooCommerce store?

add_filter('woocommerce_product_get_price', function($price) { return $price * 0.9; });

medium

A. All product prices will be reduced by 10%

B. All product prices will increase by 10%

C. No change to product prices

D. Syntax error, code will not run

Solution

1. Step 1: Understand the filter hook used

   The filter woocommerce_product_get_price modifies the product price before display.

2. Step 2: Analyze the callback function

   The function multiplies the price by 0.9, reducing it by 10%.

3. Final Answer:

   All product prices will be reduced by 10% -> Option A

4. Quick Check:

   Filter changes price = 10% off [OK]

Hint: Filter modifies data; multiplying by 0.9 reduces price [OK]

Common Mistakes:

• Thinking it increases price instead of reducing
• Assuming no effect without priority argument
• Confusing add_filter with add_action

4. Identify the error in this WooCommerce hook usage:

add_action('woocommerce_before_cart', 'display_message');
function display_message() {
  echo 'Welcome to your cart!';
}

medium

A. Hook name 'woocommerce_before_cart' does not exist

B. No error, code works correctly

C. Echo cannot be used inside hooked functions

D. Function display_message is defined after add_action call

Solution

1. Step 1: Check function definition timing

   In PHP, functions can be defined after usage if in the same file, so no error here.

2. Step 2: Verify hook name and usage

   'woocommerce_before_cart' is a valid WooCommerce action hook; echo is allowed in hooked functions.

3. Final Answer:

   No error, code works correctly -> Option B

4. Quick Check:

   Valid hook and function = works [OK]

Hint: Functions can be defined after add_action in same file [OK]

Common Mistakes:

• Assuming function must be defined before add_action
• Thinking echo is disallowed in hooks
• Believing hook name is invalid without checking docs

5. You want to add a custom message only on the WooCommerce checkout page before the form starts. Which hook and method combination is best to achieve this without modifying core files?

hard

A. Use add_filter('woocommerce_checkout_message', 'custom_message_function');

B. Use add_action('woocommerce_after_checkout_form', 'custom_message_function');

C. Directly edit checkout template file to add message

D. Use add_action('woocommerce_before_checkout_form', 'custom_message_function');

Solution

1. Step 1: Identify correct hook location

   'woocommerce_before_checkout_form' runs before the checkout form, perfect for adding a message before it.

2. Step 2: Choose correct method

   Use add_action to add new content; filters modify existing data, so add_filter is not suitable here.

3. Step 3: Avoid direct template edits

   Editing core template files is unsafe and breaks updates; hooks keep customization safe.

4. Final Answer:

   Use add_action('woocommerce_before_checkout_form', 'custom_message_function'); -> Option D

5. Quick Check:

   Action hook before form + add_action = correct [OK]

Hint: Add message before form with add_action on before_checkout_form [OK]

Common Mistakes:

• Using add_filter instead of add_action for adding content
• Editing core template files directly
• Using after_checkout_form hook which shows message too late