How to create a custom plugin for imports in WooCommerce

1. Create a new plugin directory and PHP file in your WordPress plugins directory, for example `/wp-content/plugins/my-woocommerce-import-plugin/my-woocommerce-import-plugin.php`[1]

2. In the plugin PHP file, register an admin page for the import functionality:

php
add_action('admin_menu', 'my_woocommerce_import_menu');
function my_woocommerce_import_menu() {
    add_submenu_page('edit.php?post_type=product', 'Import Products', 'Import Products', 'manage_woocommerce', 'my-woocommerce-import', 'my_woocommerce_import_page');
}

This will add an "Import Products" submenu under the Products admin page[1]

3. Create the admin page callback function `my_woocommerce_import_page()` to display the import form and handle file uploads[1]

4. Use the `WP_Filesystem` API to read the uploaded CSV file[1]

5. Parse the CSV data into a PHP array using a library like PHPExcel[4]

6. Loop through the parsed product data array and use WooCommerce functions to create new products or update existing ones:

php
$product = new WC_Product_Simple();
$product->set_name($name);
$product->set_description($description);
$product->set_price($price);
$product->save();

7. For custom fields, use the `add_post_meta()` function to add the data to the product post[4]

8. Handle other product data like categories, tags, attributes, variations, etc. as needed[3]

9. Display import status and any errors/warnings to the user[1]

10. Optionally, add a settings page to configure the import process[1]

Some additional tips:

- Use the `woocommerce_product_import_inserted_product_object` action hook to modify the product object before it is saved[3]

- Validate the CSV data and handle errors gracefully[1]

- Provide options to update existing products, skip duplicates, delete missing products, etc.[5]

- Implement security checks and nonces to prevent unauthorized access[1]

- Provide documentation and support for your plugin[3]

By following these steps and leveraging the WooCommerce API, you can create a powerful custom import plugin tailored to your specific requirements. The key is to break down the process into manageable steps and handle each aspect carefully.