How to Add Product to Cart in WooCommerce Programmatically: A Beginner’s Guide
WooCommerce is a fantastic platform for building online stores. But sometimes, you need to go beyond the standard interface and add products to the cart programmatically. This means using code to add items to the cart, rather than relying on the usual “Add to Cart” button. This can be incredibly useful for creating custom shopping experiences, like bundles, promotions, or even subscription services.
Think of it like this: Instead of a customer manually picking items off a shelf and putting them in their basket, you’re automatically placing specific items into their cart based on certain rules or actions.
This guide will walk you through the process of adding products to the cart in WooCommerce programmatically, even if you’re new to coding. We’ll break down the code, explain the reasoning behind it, and provide real-world examples.
Why Add Products Programmatically?
Before we dive into the code, let’s understand why you might want to do this in the first place. Here are a few compelling reasons:
- Creating Product Bundles: Imagine you sell coffee and a mug as a set. You could automatically add both to the cart when a customer selects the “Coffee & Mug Bundle” option.
- Implementing Special Promotions: Offer a free gift with purchase. When a customer adds a specific item to their cart, your code could automatically add the free gift as well.
- Building Subscription Services: Automatically add a specific product to the cart on a recurring basis, allowing for seamless subscription management.
- Customizing the Customer Journey: Pre-filling the cart with recommended products based on user preferences or browsing history.
- Integrating with External Systems: Adding products to the cart based on data received from another platform, like a CRM or inventory management system.
- Adding Products: This is what we’ll focus on.
- Removing Products: Removing items from the cart.
- Updating Quantities: Changing the number of items in the cart.
- Calculating Totals: Calculating the cart subtotal, taxes, and shipping.
- `$product_id` (required): The ID of the product you want to add.
- `$quantity` (optional, defaults to 1): The number of units of the product to add.
- `$variation_id` (optional, defaults to 0): The ID of a specific product variation (if applicable).
- `$variation` (optional, defaults to null): An array of variation attributes (if applicable).
- `$cart_item_data` (optional, defaults to null): Custom data to associate with the cart item.
Understanding the WooCommerce Cart Object
The core of adding products programmatically lies in understanding the `$woocommerce->cart` object. This object manages everything related to the customer’s cart, including:
The `WC()->cart->add_to_cart()` Function
The magic happens with the `WC()->cart->add_to_cart()` function. This function is responsible for adding products to the cart. It accepts the following arguments:
A Simple Example: Adding a Single Product
Let’s start with a basic example. Suppose you want to add a product with an ID of `123` to the cart. Here’s the code:
<?php // Get the product ID $product_id = 123;
// Add the product to the cart
WC()->cart->add_to_cart( $product_id );
// Optional: Redirect the user to the cart page
wp_redirect( wc_get_cart_url() );
exit;
?>
Explanation:
1. `$product_id = 123;`: We define the product ID. Make sure to replace `123` with the actual ID of your product. You can find the product ID in the WooCommerce product settings within your WordPress dashboard.
2. `WC()->cart->add_to_cart( $product_id );`: This is the core function call. It adds one unit of the product with ID `123` to the cart.
3. `wp_redirect( wc_get_cart_url() );`: This line redirects the user to the cart page after the product is added. This is optional but provides a better user experience.
4. `exit;`: This terminates the script after the redirect.
Where to Put This Code?
This code snippet needs to be placed within a suitable context in your WordPress theme or plugin. Here are a few options:
- Inside a Custom Plugin: This is generally the best practice for maintainability. Create a simple plugin and add your code there.
- In Your Theme’s `functions.php` File: This is a simpler approach but can make your theme harder to update in the future.
- Within a Custom Shortcode: Create a shortcode that executes this code when the shortcode is used on a page.
- Inside a Custom Page Template: If you need to add the product to the cart only on a specific page.
Important: Regardless of where you place the code, make sure it’s triggered by an appropriate action or event. For example, you might trigger it when a user clicks a specific button or visits a particular page.
Adding Multiple Products with Specific Quantities
Now, let’s say you want to add multiple products with different quantities. Here’s how:
123, 'quantity' => 2 ), array( 'product_id' => 456, 'quantity' => 1 ), array( 'product_id' => 789, 'quantity' => 3 ), );
// Loop through the products and add them to the cart
foreach ( $products as $product ) {
WC()->cart->add_to_cart( $product[‘product_id’], $product[‘quantity’] );
}
// Optional: Redirect to the cart page
wp_redirect( wc_get_cart_url() );
exit;
?>
Explanation:
1. `$products = array(…);`: We create an array that holds the product IDs and their corresponding quantities. Replace `123`, `456`, and `789` with your actual product IDs.
2. `foreach ( $products as $product ) { … }`: We loop through each product in the `$products` array.
3. `WC()->cart->add_to_cart( $product[‘product_id’], $product[‘quantity’] );`: Inside the loop, we call `add_to_cart()` for each product, passing the product ID and quantity.
Adding Product Variations
If you’re dealing with variable products (products that have different attributes like size or color), you’ll need to specify the variation ID and the variation attributes.
<?php $product_id = 987; // The ID of the variable product $variation_id = 654; // The ID of the specific variation $quantity = 1;
// Define the variation attributes
$variation_attributes = array(
‘attribute_color’ => ‘blue’,
‘attribute_size’ => ‘large’,
);
// Add the product variation to the cart
WC()->cart->add_to_cart( $product_id, $quantity, $variation_id, $variation_attributes );
// Optional: Redirect to the cart page
wp_redirect( wc_get_cart_url() );
exit;
?>
Explanation:
1. `$product_id = 987;`: The ID of the *variable* product.
2. `$variation_id = 654;`: The ID of the *specific variation* you want to add. You can find the variation ID in the product edit screen under the “Variations” tab.
3. `$variation_attributes = array(…);`: An array that defines the attributes for the chosen variation. Replace `’attribute_color’ => ‘blue’` and `’attribute_size’ => ‘large’` with the actual attribute names and values for your variable product. You can find these in the product edit screen under the “Attributes” and “Variations” tabs.
4. `WC()->cart->add_to_cart( $product_id, $quantity, $variation_id, $variation_attributes );`: This time, we pass the `$variation_id` and `$variation_attributes` to the `add_to_cart()` function.
Real-World Example: Free Gift Promotion
Let’s create a real-world example where a free gift (product ID `111`) is added to the cart when a specific product (product ID `222`) is added. We’ll use a WooCommerce action hook to achieve this.
<?php /**
function add_free_gift_on_product_add( $cart_item_key, $product_id, $quantity, $variation_id, $variation, $cart_item_data ) {
// The product ID that triggers the free gift
$trigger_product_id = 222;
// The free gift product ID
$free_gift_product_id = 111;
// Check if the trigger product was added to the cart
if ( $product_id == $trigger_product_id ) {
// Check if the free gift is already in the cart
$found = false;
foreach ( WC()->cart->get_cart() as $cart_item_key => $cart_item ) {
if ( $cart_item[‘product_id’] == $free_gift_product_id ) {
$found = true;
break;
}
}
// Add the free gift to the cart if it’s not already there
if ( ! $found ) {
WC()->cart->add_to_cart( $free_gift_product_id, 1 );
}
}
}
?>
Explanation:
1. `add_action( ‘woocommerce_add_to_cart’, ‘add_free_gift_on_product_add’, 10, 6 );`: This line hooks into the `woocommerce_add_to_cart` action, which is triggered whenever a product is added to the cart.
2. `function add_free_gift_on_product_add(…) { … }`: This is the function that will be executed when the action is triggered.
3. `$trigger_product_id = 222;`: The ID of the product that triggers the free gift. Replace `222` with the actual product ID.
4. `$free_gift_product_id = 111;`: The ID of the free gift product. Replace `111` with the actual product ID.
5. `if ( $product_id == $trigger_product_id ) { … }`: This checks if the product added to the cart is the trigger product.
6. The `foreach` loop checks if the free gift is *already* in the cart to avoid adding it multiple times.
7. `if ( ! $found ) { … }`: If the free gift is not already in the cart, it’s added using `WC()->cart->add_to_cart()`.
Important Considerations:
- Error Handling: Always add error handling to your code. Check if the product ID is valid before attempting to add it to the cart.
- Security: Be careful when accepting product IDs from user input. Sanitize the input to prevent security vulnerabilities.
- Testing: Thoroughly test your code to ensure it works as expected and doesn’t break your WooCommerce store.
- Performance: Be mindful of the performance impact of your code, especially if you’re adding multiple products to the cart.
Conclusion
Adding products to the cart programmatically in WooCommerce opens up a world of possibilities for creating custom shopping experiences. By understanding the `$woocommerce->cart` object and the `WC()->cart->add_to_cart()` function, you can build powerful features that enhance your online store. Remember to test your code thoroughly and prioritize security. With a little practice, you’ll be able to create innovative solutions that delight your customers and boost your sales.
