WooCommerce hooks for customization in Wordpress - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a hook in WooCommerce?

A hook is a way to add or change functionality in WooCommerce without editing core files. It lets you run your own code at specific points.

beginner

What is the difference between an action hook and a filter hook in WooCommerce?

An action hook lets you add code at a point, like showing extra info. A filter hook lets you change data before it is used or shown.

intermediate

How do you add a custom message after the product title using a WooCommerce hook?

Use the action hook 'woocommerce_single_product_summary' with a priority after the title, like this: add_action('woocommerce_single_product_summary', 'your_function', 6);

beginner

What is the purpose of the 'woocommerce_before_cart' hook?

It allows you to add content or run code before the cart page content starts, like showing notices or extra info.

intermediate

How can filters help customize WooCommerce emails?

Filters let you change email content, subject, or headers before sending. For example, 'woocommerce_email_subject_new_order' changes the new order email subject.

Which hook type lets you modify data before it is displayed in WooCommerce?

A Action hook

B Template hook

C Filter hook

D Shortcode hook

Filter hooks let you change data before WooCommerce uses or shows it.

Where would you add code to show extra content after the product price?

A woocommerce_after_shop_loop_item

B woocommerce_single_product_summary

C woocommerce_before_single_product

D woocommerce_before_cart

The 'woocommerce_single_product_summary' hook controls content around the product summary including price.

What function is used to add a callback to a WooCommerce hook?

A add_action()

B add_filter()

C do_action()

D apply_filters()

add_action() attaches your function to an action hook; add_filter() attaches your function to a filter hook.

Which hook would you use to add content before the cart table?

A woocommerce_before_cart_table

B woocommerce_after_cart

C woocommerce_before_cart

D woocommerce_cart_contents

'woocommerce_before_cart_table' runs before the cart table starts.

To change the subject line of the new order email, which filter hook is used?

A woocommerce_email_subject_new_order

B woocommerce_email_header

C woocommerce_email_footer

D woocommerce_email_order_details

'woocommerce_email_subject_new_order' lets you customize the new order email subject.

Explain how WooCommerce hooks help customize a store without changing core files.

Think about how you can add your own code safely.

Describe how you would add a custom message after the product title using WooCommerce hooks.

Focus on the right hook and priority.

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