Adding multiple items to WooCommerce cart at once

Thanks to @thatgerhard and dsgnwrks
I found a solution for support variations:

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_action( 'wp_loaded', array( 'WC_Form_Handler', 'add_to_cart_action' ), 20 );

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

      if ( $adding_to_cart->is_type( 'simple' ) ) {

          // quantity applies to all products atm
          $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 );
          }

      } else {

          $variation_id       = empty( $_REQUEST['variation_id'] ) ? '' : absint( wp_unslash( $_REQUEST['variation_id'] ) );
          $quantity           = empty( $_REQUEST['quantity'] ) ? 1 : wc_stock_amount( wp_unslash( $_REQUEST['quantity'] ) ); // WPCS: sanitization ok.
          $missing_attributes = array();
          $variations         = array();
          $adding_to_cart     = wc_get_product( $product_id );

          if ( ! $adding_to_cart ) {
            continue;
          }

          // If the $product_id was in fact a variation ID, update the variables.
          if ( $adding_to_cart->is_type( 'variation' ) ) {
            $variation_id   = $product_id;
            $product_id     = $adding_to_cart->get_parent_id();
            $adding_to_cart = wc_get_product( $product_id );

            if ( ! $adding_to_cart ) {
              continue;
            }
          }

          // Gather posted attributes.
          $posted_attributes = array();

          foreach ( $adding_to_cart->get_attributes() as $attribute ) {
            if ( ! $attribute['is_variation'] ) {
              continue;
            }
            $attribute_key = 'attribute_' . sanitize_title( $attribute['name'] );

            if ( isset( $_REQUEST[ $attribute_key ] ) ) {
              if ( $attribute['is_taxonomy'] ) {
                // Don't use wc_clean as it destroys sanitized characters.
                $value = sanitize_title( wp_unslash( $_REQUEST[ $attribute_key ] ) );
              } else {
                $value = html_entity_decode( wc_clean( wp_unslash( $_REQUEST[ $attribute_key ] ) ), ENT_QUOTES, get_bloginfo( 'charset' ) ); // WPCS: sanitization ok.
              }

              $posted_attributes[ $attribute_key ] = $value;
            }
          }

          // If no variation ID is set, attempt to get a variation ID from posted attributes.
          if ( empty( $variation_id ) ) {
            $data_store   = WC_Data_Store::load( 'product' );
            $variation_id = $data_store->find_matching_product_variation( $adding_to_cart, $posted_attributes );
          }

          // Do we have a variation ID?
          if ( empty( $variation_id ) ) {
            throw new Exception( __( 'Please choose product options…', 'woocommerce' ) );
          }

          // Check the data we have is valid.
          $variation_data = wc_get_product_variation_attributes( $variation_id );

          foreach ( $adding_to_cart->get_attributes() as $attribute ) {
            if ( ! $attribute['is_variation'] ) {
              continue;
            }

            // Get valid value from variation data.
            $attribute_key = 'attribute_' . sanitize_title( $attribute['name'] );
            $valid_value   = isset( $variation_data[ $attribute_key ] ) ? $variation_data[ $attribute_key ]: '';

            /**
             * If the attribute value was posted, check if it's valid.
             *
             * If no attribute was posted, only error if the variation has an 'any' attribute which requires a value.
             */
            if ( isset( $posted_attributes[ $attribute_key ] ) ) {
              $value = $posted_attributes[ $attribute_key ];

              // Allow if valid or show error.
              if ( $valid_value === $value ) {
                $variations[ $attribute_key ] = $value;
              } elseif ( '' === $valid_value && in_array( $value, $attribute->get_slugs() ) ) {
                // If valid values are empty, this is an 'any' variation so get all possible values.
                $variations[ $attribute_key ] = $value;
              } else {
                throw new Exception( sprintf( __( 'Invalid value posted for %s', 'woocommerce' ), wc_attribute_label( $attribute['name'] ) ) );
              }
            } elseif ( '' === $valid_value ) {
              $missing_attributes[] = wc_attribute_label( $attribute['name'] );
            }
          }
          if ( ! empty( $missing_attributes ) ) {
            throw new Exception( sprintf( _n( '%s is a required field', '%s are required fields', count( $missing_attributes ), 'woocommerce' ), wc_format_list_of_items( $missing_attributes ) ) );
          }

        $passed_validation = apply_filters( 'woocommerce_add_to_cart_validation', true, $product_id, $quantity, $variation_id, $variations );

        if ( $passed_validation && false !== WC()->cart->add_to_cart( $product_id, $quantity, $variation_id, $variations ) ) {
          wc_add_to_cart_message( array( $product_id => $quantity ), true );
        }
      }
  }
}
add_action( 'wp_loaded', 'woocommerce_maybe_add_multiple_products_to_cart', 15 );

Here I had forced $_REQUEST[ 'add-to-cart' ] to take the intended product id. Overwriting global variable doesn't sound good approach but it keeps DRY approach and also make all native function available to user.

add_action( 'wp_loaded', 'add_multiple_to_cart_action', 20 );

function add_multiple_to_cart_action() {
    if ( ! isset( $_REQUEST['multiple-item-to-cart'] ) || false === strpos( wp_unslash( $_REQUEST['multiple-item-to-cart'] ), '|' ) ) { // phpcs:ignore WordPress.Security.NonceVerification.NoNonceVerification, WordPress.Security.ValidatedSanitizedInput.InputNotSanitized
            return;
        }

    wc_nocache_headers();

    $product_ids        = apply_filters( 'woocommerce_add_to_cart_product_id', wp_unslash( $_REQUEST['multiple-item-to-cart'] ) ); // phpcs:ignore WordPress.Security.NonceVerification.NoNonceVerification
    $product_ids = explode( '|', $product_ids );
    if( ! is_array( $product_ids ) ) return;

    $product_ids = array_map( 'absint', $product_ids );
    $was_added_to_cart = false;
    $last_product_id = end($product_ids);
    //stop re-direction
    add_filter( 'woocommerce_add_to_cart_redirect', '__return_false' );
    foreach ($product_ids as $index => $product_id ) {
        $product_id = absint(  $product_id  );
        if( empty( $product_id ) ) continue;
        $_REQUEST['add-to-cart'] = $product_id;
        if( $product_id === $last_product_id ) {

            add_filter( 'option_woocommerce_cart_redirect_after_add', function() { 
                return 'yes'; 
            } );
        } else {
            add_filter( 'option_woocommerce_cart_redirect_after_add', function() { 
                return 'no'; 
            } );
        }

        WC_Form_Handler::add_to_cart_action();
    }
}

Example:

https://your-domain/cart?multiple-item-to-cart=68|69 Thanks


I found the answer!

Simply add the following script to your theme's functions.php:

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'] );
$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;
    }

    // For now, quantity applies to all products.. This could be changed easily enough, but I didn't need this feature.
    $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 );

And then you can simply use http://shop.com/shop/cart/?add-to-cart=3001,3282 to add multiple items at once. Put a comma between different IDs.

Thanks to dsgnwrks for the solution.


In case anyone else comes by looking for this function like I did. I updated the top comment's code allowing it to work with woocommerce 3.5.3

    // adds support for multi add to cart for 3rd party cart plugin
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'] );
    $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;
        }

        // only works for simple atm
        if ( $adding_to_cart->is_type( 'simple' ) ) {

            // quantity applies to all products atm
            $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 );
            }

        }
    }
}
add_action( 'wp_loaded', 'woocommerce_maybe_add_multiple_products_to_cart', 15 );