Php 在 WooCommerce 中何时何地执行 woocommerce_order_status_completed_notification 挂钩

挂钩woocommerce_order_status_completed_notification是multi composite hook，其允许在订单状态被改变为"完成"时触发发送给客户的邮箱.

它在线路170上以WC_Emails send_transactional_email() method触发:

do_action_ref_array( current_filter() . '_notification', $args );

其中current_filter()指的是woocommerce_email_actions filter hook arguments:

array(
    'woocommerce_low_stock',
    'woocommerce_no_stock',
    'woocommerce_product_on_backorder',
    'woocommerce_order_status_pending_to_processing',
    'woocommerce_order_status_pending_to_completed',
    'woocommerce_order_status_processing_to_cancelled',
    'woocommerce_order_status_pending_to_failed',
    'woocommerce_order_status_pending_to_on-hold',
    'woocommerce_order_status_failed_to_processing',
    'woocommerce_order_status_failed_to_completed',
    'woocommerce_order_status_failed_to_on-hold',
    'woocommerce_order_status_cancelled_to_processing',
    'woocommerce_order_status_cancelled_to_completed',
    'woocommerce_order_status_cancelled_to_on-hold',
    'woocommerce_order_status_on-hold_to_processing',
    'woocommerce_order_status_on-hold_to_cancelled',
    'woocommerce_order_status_on-hold_to_failed',
    'woocommerce_order_status_completed', // <=== <=== <=== HERE
    'woocommerce_order_fully_refunded',
    'woocommerce_order_partially_refunded',
    'woocommerce_new_customer_note',
    'woocommerce_created_customer',
)

对于WC_Email_Customer_Completed_Order方法trigger()，钩被钩在WC_Email_Customer_Completed_Order in the constructor function线42中:

// Triggers for this email.
add_action( 'woocommerce_order_status_completed_notification', array( $this, 'trigger' ), 10, 2 );

因此，you can only use this hook with 101 as showed in this code snippet，删除当订单状态为"已完成"时发送给客户的邮箱通知.

请注意，WC()->mailer()只是WC_Emails类的一个实例对象，它加载Mailer类，类似于new WC_Emails().