WooCommerce product attributes as selectable options without variations

attributes-as-options.php

<?php


/**
 * List available attributes on product page in a drop-down selection
 */
add_action('woocommerce_before_add_to_cart_button', 'list_attributes_on_product_page');
function list_attributes_on_product_page() {
    global $product;
    $attributes = $product->get_attributes();

    if ( ! $attributes ) {
        return;
    }

    if ($product->is_type( 'variable' )) {
        return;
    }

    echo '<div style="padding-bottom:15px;">';

    foreach ( $attributes as $attribute ) {
        $taxonomy = get_taxonomy($attribute['name']);
        $options = wc_get_product_terms( $product->id, $attribute['name'], array( 'fields' => 'all' ) );
        $label = str_replace('Product ', '', $taxonomy->label);
        ?>
        <div style="padding-bottom:8px;">
            <label for="attribute[<?php echo $attribute['id']; ?>]"><?php echo $label; ?></label>
            <br />
            <select required name="attribute[<?php echo $attribute['id']; ?>]" id="attribute[<?php echo $attribute['id']; ?>]">
                <option value disabled selected>Choose an option</option>
                <?php foreach ( $options as $pa ): ?>
                    <option value="<?php echo $pa->name; ?>"><?php echo $pa->name; ?></option>
                <?php endforeach; ?>
            </select>
        </div>
        <?php
    }

    echo '</div>';
}

/**
 * Add selected attributes to cart items
 */
add_filter('woocommerce_add_cart_item_data', 'add_attributes_to_cart_item', 10, 3 );
function add_attributes_to_cart_item( $cart_item_data, $product_id, $variation_id ) {
    $attributes = $_POST['attribute'];
 
    if (empty( $attributes ) ) {
        return $cart_item_data;
    }
 
    $cart_item_data['attributes'] = serialize($attributes);
 
    return $cart_item_data;
}

/**
 * Display attributes in cart
 */
add_filter( 'woocommerce_get_item_data', 'display_attributes_in_cart', 10, 2 );
function display_attributes_in_cart( $item_data, $cart_item ) {
    if ( empty( $cart_item['attributes'] ) ) {
        return $item_data;
    }

    foreach (unserialize($cart_item['attributes']) as $attributeID => $value) {
        $attribute = wc_get_attribute($attributeID);
        $item_data[] = array(
            'key'     => $attribute->name,
            'value'   => $value,
            'display' => '',
        );
    }

    return $item_data;
}

/**
 * Add attribute data to order items
 */
add_action( 'woocommerce_checkout_create_order_line_item', 'add_attributes_to_order_items', 10, 4 );
function add_attributes_to_order_items( $item, $cart_item_key, $values, $order ) {
    if ( empty( $values['attributes'] ) ) {
        return;
    }

    foreach (unserialize($values['attributes']) as $attributeID => $value) {
        $attribute = wc_get_attribute($attributeID);
        $item->add_meta_data( $attribute->name, $value );
    }
}
 

I tweaked this a bit to work with the current version of WooCommerce, changed the HTML output to more closely match the WooCommerce default for attributes, allowed translation of the "Choose an option" text, prefixed the function names to make collisions less likely.

/**
 * List available attributes on product page in a drop-down selection
 */
add_action('woocommerce_before_add_to_cart_button', 'attr_wo_var_list_attributes_on_product_page');
function attr_wo_var_list_attributes_on_product_page()
{
    global $product;
    $attributes = $product->get_attributes();

    if (! $attributes) {
        return;
    }

    if ($product->is_type('variable')) {
        return;
    }

    echo '<table class="variations" cellspacing="0" role="presentation"><tbody>';

    foreach ($attributes as $attribute) {
        $options = $attribute->get_options();
        ?>
        <tr>
            <th class="label">
                <label for="attribute[<?php echo sanitize_title($attribute->get_name()); ?>]"><?php echo $attribute->get_name(); ?></label>
            </th>
            <td class="value">
                <select required name="attribute[<?php echo $attribute->get_name(); ?>]" id="attribute[<?php echo $attribute->get_name(); ?>]">
                    <option value disabled selected><?php echo __('Choose an option', 'woocommerce') ?></option>
                    <?php foreach ($options as $option) : ?>
                        <option value="<?php echo $option; ?>"><?php echo $option; ?></option>
                    <?php endforeach; ?>
                </select>
            </td>
        </tr>
        <?php
    }

    echo '</tbody></table>';
}

/**
 * Add selected attributes to cart items
 */
add_filter('woocommerce_add_cart_item_data', 'attr_wo_var_add_attributes_to_cart_item', 10, 1);
function attr_wo_var_add_attributes_to_cart_item($cartItemData)
{
    $attributes = $_POST['attribute'];

    if (empty($attributes)) {
        return $cartItemData;
    }

    $validatedAttributes = [];
    foreach ($attributes as $attrKey => $attrValue) {
        $validatedAttributes[sanitize_text_field($attrKey)] = sanitize_text_field($attrValue);
    }

    $cartItemData['attributes'] = serialize($validatedAttributes);

    return $cartItemData;
}

/**
 * Display attributes in cart
 */
add_filter('woocommerce_get_item_data', 'attr_wo_var_display_attributes_in_cart', 10, 2);
function attr_wo_var_display_attributes_in_cart($itemData, $cartItem)
{
    if (empty($cartItem['attributes'])) {
        return $itemData;
    }

    foreach (unserialize($cartItem['attributes']) as $attribute => $value) {
        $itemData[] = array(
            'key'     => $attribute,
            'value'   => $value,
            'display' => '',
        );
    }

    return $itemData;
}

/**
 * Add attribute data to order items
 */
add_action('woocommerce_checkout_create_order_line_item', 'attr_wo_var_add_attributes_to_order_items', 10, 3);
function attr_wo_var_add_attributes_to_order_items($item, $cartItemKey, $values)
{
    if (empty($values['attributes'])) {
        return;
    }

    foreach (unserialize($values['attributes']) as $attribute => $value) {
        $item->add_meta_data($attribute, $value);
    }
}

Thank you! Exactly what I needed.

Something I've noticed is that when customers view an order from their account and click the 'Order again' button, these attributes are not added to the item. I'm trying to work around this now through the woocommerce_order_again_cart_item_data hook.