Magento 2.4通过Observer观察者设置Cookie不生效问题排查

以下是问题相关的代码：

1. events.xml 配置 #

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
    <event name="catalog_controller_product_view">
        <observer name="pdp_view_observer" instance="Ts\Catalog\Observer\View" />
    </event>
</config>

2. 观察者类 Ts\Catalog\Observer\View.php #

<?php
namespace Ts\Catalog\Observer;

use Magento\Framework\Event\ObserverInterface;
use Magento\Framework\Event\Observer;

class View implements ObserverInterface
{
    /**
     * @param \Ts\Catalog\Helper\ViewAllData $pdpHelper
     */
    public function __construct(
        \Ts\Catalog\Helper\ViewAllData $pdpHelper
    ) {
        $this->pdpHelper = $pdpHelper;
    }

    /**
     * @param Observer $observer
     */
    public function execute(Observer $observer)
    {
        /**
         * Set redirect cookie for google bot
         */
        $this->pdpHelper->setMyCookie();
    }
}

3. 助手类 Ts\Catalog\Helper\ViewAllData.php #

<?php
namespace Ts\Catalog\Helper;

/**
 * Class ViewAllData
 * @package Ts\Catalog\Helper
 */
class ViewAllData extends \Magento\Framework\App\Helper\AbstractHelper
{
    /**
     * @var \Magento\Framework\App\Config\ScopeConfigInterface
     */
    protected $scopeConfig;

    const VIEW_ALL_ENABLED = 'catalog/frontend/enable_view_all';
    const PRODUCT_VIDEO_AUTOPLAY_ENABLED = 'product_video/general/enable';
    const REDIRECT_COOKIE_LIFETIME = 'catalog/frontend/redirect_cookie_life_time';

    /**
     * @param \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig
     * @param \Magento\Store\Model\StoreManagerInterface $storeManager
     * @param \Magento\Framework\Stdlib\CookieManagerInterface $cookieManager
     * @param \Magento\Framework\Stdlib\Cookie\CookieMetadataFactory $cookieMetadataFactory
     * @param \Magento\Framework\App\Request\Http $request
     */
    public function __construct(
        \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig,
        \Magento\Store\Model\StoreManagerInterface $storeManager,
        \Magento\Framework\Stdlib\CookieManagerInterface $cookieManager,
        \Magento\Framework\Stdlib\Cookie\CookieMetadataFactory $cookieMetadataFactory,
        \Magento\Framework\App\Request\Http $request,
        \Magento\Framework\Session\SessionManagerInterface $sessionManager
    )
    {
        $this->scopeConfig = $scopeConfig;
        $this->storeManager = $storeManager;
        $this->cookieManager = $cookieManager;
        $this->cookieMetadataFactory = $cookieMetadataFactory;
        $this->request = $request;
        $this->sessionManager = $sessionManager;
    }  

 
    /**
     * @param string $cookieName
     * @param string $cookieValue
     * @throws \Magento\Framework\Exception\InputException
     * @throws \Magento\Framework\Stdlib\Cookie\CookieSizeLimitReachedException
     * @throws \Magento\Framework\Stdlib\Cookie\FailureToSendException
     */
    public function setCustomCookie($cookieName = '', $cookieValue = '') {
        $metaData = $this->cookieMetadataFactory->createPublicCookieMetadata();
        $metaData->setDuration(86400)
                 ->setPath($this->sessionManager->getCookiePath())
                 ->setDomain($this->sessionManager->getCookieDomain());
        $this->cookieManager->setPublicCookie(
            $cookieName,
            $cookieValue,
            $metaData
        );
        return $this;
    }


    /**
     * @throws \Magento\Framework\Exception\InputException
     * @throws \Magento\Framework\Exception\NoSuchEntityException
     * @throws \Magento\Framework\Stdlib\Cookie\CookieSizeLimitReachedException
     * @throws \Magento\Framework\Stdlib\Cookie\FailureToSendException
     */
    public function setMyCookie() {
        $this->setCustomCookie('my_cookie',1);
    }
}

• 响应头已提前发送：catalog_controller_product_view属于页面渲染阶段触发的事件，此时HTTP响应头很可能已经发送到客户端，后续调用Cookie设置接口不会生效。可以更换更早触发的事件，比如controller_action_predispatch_catalog_product_view，避免响应头已发送的问题。
• 全页缓存命中导致事件未触发：如果商品详情页开启了Magento全页缓存，缓存命中的请求不会执行观察者逻辑，自然不会设置Cookie。可以将设置Cookie的逻辑改为前端AJAX请求后端接口实现，或者使用控制器前后置插件处理。
• Cookie属性不匹配：检查当前站点配置的Cookie域名、路径是否和实际访问的地址一致，域名/路径不匹配会导致浏览器直接拒收Cookie。可以临时修改setPath为/，省略setDomain配置测试是否生效。
• 代码执行报错：检查站点日志var/log/exception.log、var/log/system.log是否存在对应报错，确认依赖注入正常，没有代码语法或编译问题。
• 浏览器Cookie限制：测试时使用无痕模式，排除本地浏览器Cookie禁用、第三方Cookie拦截、旧Cookie冲突的影响。

内容的提问来源于stack exchange，提问作者VIPIN A ROY