Snippet to add handling charge to WooCommerce Shipping Methods based on Shipping Class. PluginHive WooCommerce Shipping Plugins - https://www.pluginhive.com/product/multiple-carrier-shipping-plugin-woocommerce/, https://www.pluginhive.com/product/woocommerce-ups-shipping-plugin-with-print-label/, https://www.pluginhive.com/product/woocommerce-fe…

functions.php

/**
 * Snippet to add handling charge to WooCommerce Shipping Methods based on Shipping Class.
 * Created at : 06 Aug 2018
 * Updated at : 06 Aug 2018
 * PluginHive Plugins : https://www.pluginhive.com/plugins/
 * Gist Link : https://gist.github.com/xadapter/288aff384db2a04fb3b96ec53239dbc0
 */

add_filter( 'woocommerce_package_rates', 'ph_add_extra_cost_based_on_shipping_class', 10, 2);
if( ! function_exists('ph_add_extra_cost_based_on_shipping_class') ) {
	function ph_add_extra_cost_based_on_shipping_class( $shipping_rates, $package ){

		$handling_fee_based_on_shipping_class = array(
			array(
				'shipping_classes'	=>	array( 'smart_phone', 'test'),			// Shipping Class slug array
				'adjustment'		=> 70,									// Adjustment
			),
			array(
				'shipping_classes'	=>	array( 'shoe', 'electronic' ),
				'adjustment'		=>	50,
			),
		);

		$shipping_method_ids = array( 'wf_fedex_woocommerce_shipping' );		// Shipping methods on which adjustment has to be applied

		$adjustment = null;
		foreach( $package['contents'] as  $line_item ) {
			$line_item_shipping_class = $line_item['data']->get_shipping_class();
			if( ! empty($line_item_shipping_class) ) {
				foreach( $handling_fee_based_on_shipping_class as $adjustment_data ) {
					if( in_array( $line_item_shipping_class, $adjustment_data['shipping_classes']) ) {
						$adjustment = ( $adjustment_data['adjustment'] > $adjustment ) ? $adjustment_data['adjustment'] : $adjustment;
					}
				}
			}
		}

		if( ! empty($adjustment) ) {
			foreach( $shipping_rates as $shipping_rate ) {
				$shipping_method_id = $shipping_rate->get_method_id();
				if( in_array($shipping_method_id, $shipping_method_ids) ) {
					$shipping_rate->set_cost( (float) $shipping_rate->get_cost() + $adjustment );
				}
			}
		}
		
		return $shipping_rates;
	}
}