WordPress自定义支付方式感谢页及邮件内容重复问题解决

我基于WordPress为团队开发了一款自定义支付方式，除感谢页功能外其余均正常运行。用户完成订单后，感谢页和订单邮件里的支付指令内容会重复显示，一开始找不到问题根源。

自定义支付方式核心实现代码 #

public function __construct()
{
    $this->id = 'coupon'; 
    $this->icon = ''; 
    $this->has_fields = true;
    $this->title = __('Payment Coupon', 'text-domain'); 

    $this->method_description = __('Custom coupon payment gateway', 'woocommerce'); // payment method description

    // load the settings.
    $this->init_form_fields();
    $this->init_settings();
    
    // Define user set variables.
    $this->title = $this->get_option('title');
    $this->description = $this->get_option('description');
    $this->instructions = $this->get_option( 'instructions');
    $this->enabled = $this->get_option('enabled');
    

    add_action( 'woocommerce_thankyou_coupon', array( $this, 'thankyou_page' ) );
    add_action( 'woocommerce_email_before_order_table', array( $this, 'email_instructions' ), 10, 3 );

    // Action hook to save the settings
    if (is_admin()) {
        add_action('woocommerce_update_options_payment_gateways_' . $this->id, array($this, 'process_admin_options'));
    }
}

public function init_form_fields()
{
    $this->form_fields = array(
        'enabled' => array(
            'title'       => __('Enable/Disable', 'woocommerce'),
            'label'       => __('Enable Payment Coupon', 'text-domain'),
            'type'        => 'checkbox',
            'description' => __('This enable the Payment Coupon which allow to accept payment through transcash coupon.', 'woocommerce'),
            'default'     => 'no',
            'desc_tip'    => true
        ),
        'title' => array(
            'title'       => __('Title', 'woocommerce'),
            'type'        => 'safe_text',
            'description' => __('This controls the title which the user sees during checkout.', 'woocommerce'),
            'default'     => __('Coupon transcash', 'woocommerce'),
            'desc_tip'    => true,
        ),
        'description' => array(
            'title'       => __('Description', 'woocommerce'),
            'type'        => 'textarea',
            'description' => __('Payment method description that the customer will see on your checkout.', 'woocommerce'),
            'default'     => __("Payer à l'aide d'un coupon transcash.", 'woocommerce'),
            'desc_tip'    => true,
        ),
        'instructions' => array(
            'title'       => __('Instructions', 'woocommerce'),
            'type'        => 'textarea',
            'description' => __('Instructions qui seront ajoutés à la page de remerciement et dans les e-mails.', 'woocommerce'),
            'default'     => '',
            'desc_tip'    => true,
        )
    );
}

/**
 * Output for the order received page.
 *
 * @param int $order_id Order ID.
 */
public function thankyou_page( $order_id ) {
    if ( $this->instructions ) {
        echo wp_kses_post( wpautop( wptexturize( wp_kses_post( $this->instructions ) ) ) );
    }
}

问题排查过程 #

1. 首先替换add_action( 'woocommerce_thankyou_coupon', array( $this, 'thankyou_page' ) );为调试代码，查看动作触发次数：

add_action('woocommerce_thankyou_coupon', function() {
    error_log('Action woocommerce_thankyou_coupon déclenchée depuis : ' . debug_backtrace()[0]['file'] . ' à la ligne ' . debug_backtrace()[0]['line']);
});

日志显示该动作被触发两次，但无法直接定位原因。

2. 接着在thankyou_page方法中添加回溯代码，查看调用栈：

public function thankyou_page( $order_id ) {
    if ( $this->instructions ) {
            echo wp_debug_backtrace_summary();
            echo wp_kses_post( wpautop( wptexturize( wp_kses_post( $this->instructions ) ) ) );
    }
}

得到重复的调用栈信息后，逐步排查代码，最终发现删除类末尾的add_filter('woocommerce_payment_gateways', 'add_custom_gateway_class');代码后，重复显示的问题完全解决。

内容的提问来源于stack exchange，提问作者Zhalfir