Adding multiple items to WooCommerce cart at once

/** 
*Adding multiple items to WooCommerce cart at once 
*/
function woocommerce_maybe_add_multiple_products_to_cart() {
// Make sure WC is installed, and add-to-cart qauery arg exists, and contains at least one comma.
if ( ! class_exists( 'WC_Form_Handler' ) || empty( $_REQUEST['add-to-cart'] ) || false === strpos( $_REQUEST['add-to-cart'], ',' ) ) {
    return;
}
// Remove WooCommerce's hook, as it's useless (doesn't handle multiple products).
remove_action( 'wp_loaded', array( 'WC_Form_Handler', 'add_to_cart_action' ), 20 );

$product_ids = explode( ',', $_REQUEST['add-to-cart'] );
$quantities = explode( ',', $_REQUEST['quantities'] );

$count       = count( $product_ids );
$number      = 0;

foreach ( $product_ids as $product_id ) {
    if ( ++$number === $count ) {
        // Ok, final item, let's send it back to woocommerce's add_to_cart_action method for handling.
        $_REQUEST['add-to-cart'] = $product_id;

        return WC_Form_Handler::add_to_cart_action();
    }

    $product_id        = apply_filters( 'woocommerce_add_to_cart_product_id', absint( $product_id ) );
    $was_added_to_cart = false;
    $adding_to_cart    = wc_get_product( $product_id );

    if ( ! $adding_to_cart ) {
        continue;
    }

    $add_to_cart_handler = apply_filters( 'woocommerce_add_to_cart_handler', $adding_to_cart->product_type, $adding_to_cart );

    /*
     * Sorry.. if you want non-simple products, you're on your own.
     *
     * Related: WooCommerce has set the following methods as private:
     * WC_Form_Handler::add_to_cart_handler_variable(),
     * WC_Form_Handler::add_to_cart_handler_grouped(),
     * WC_Form_Handler::add_to_cart_handler_simple()
     *
     * Why you gotta be like that WooCommerce?
     */
    if ( 'simple' !== $add_to_cart_handler ) {
        continue;
    }
//         $_REQUEST['quantity'] = ! empty( $id_and_quantity[1] ) ? absint( $id_and_quantity[1] ) : 1;
$_REQUEST['quantity'] = ! empty( $quantities[$number] ) ? absint( $quantities[$number] ) : 1;
    $quantity          = empty( $quantities[$number - 1] ) ? 1 : wc_stock_amount(  $quantities[$number - 1] );
//     $quantity          = empty( $_REQUEST['quantity'] ) ? 1 : wc_stock_amount( $_REQUEST['quantity'] );
    $passed_validation = apply_filters( 'woocommerce_add_to_cart_validation', true, $product_id, $quantity );

    if ( $passed_validation && false !== WC()->cart->add_to_cart( $product_id, $quantity ) ) {
        wc_add_to_cart_message( array( $product_id => $quantity ), true );
    }
}
}
 // Fire before the WC_Form_Handler::add_to_cart_action callback.
 add_action( 'wp_loaded',        'woocommerce_maybe_add_multiple_products_to_cart', 15 );
// remove "added to cart" notice
add_filter( 'wc_add_to_cart_message_html', '__return_false' );

How to use

Copy and paste the above snippet directly to your child theme’s functions.php. That’s all. Now lets see the front end part. Your single URL for adding multiple products to cart will look like:

https://www.example.com/cart/?add-to-cart=12345,43453

Take a look at the ?add-to-cart=12345,43453 part. Here is where you add your product ids. If you want to add twice the same product, just type twice it’s product id:

https://www.example.com/cart/?add-to-cart=4005,4009,4060

or add the following string: &quantity=3, so the URL will become

https://www.example.com/cart/?add-to-cart=12345&quantity=3

How to add product to cart via url and redirect to checkout

https://www.example.com/checkout/?add-to-cart=12345

Note: for this to work you must tick the “Enable AJAX add to cart buttons on archives” option under WooCommerce –> Settings –> Products -> General and also disable “Redirect to the cart page after successful addition”.

How to add Variable Products to cart via URL

All you need to do is get the variation ID and place it in the ?add-to-cart= url. Remember you can also add &quantity=3 so you add the product several times. Redirecting to Cart or Checkout is also valid here.

How to get Product id in WooCommerce

Go ahead and edit a product. Now take a look at the url, it will look like: 1

https://www.example.com/wp-admin/post.php?post=1493&action=edit