在 Laravel 6 中，基于事件订阅者的重构

1、现阶段实现如下，在 EventServiceProvider 的 listen 属性中注册事件和监听器。/app/Providers/EventServiceProvider.php

use Illuminate\Cache\Events\CacheHit;
use Illuminate\Cache\Events\CacheMissed;
use Illuminate\Cache\Events\KeyForgotten;
use Illuminate\Cache\Events\KeyWritten;
use App\Listeners\Cache\LogCacheHitListener;
use App\Listeners\Cache\LogCacheMissedListener;
use App\Listeners\Cache\LogKeyForgottenListener;
use App\Listeners\Cache\LogKeyWrittenListener;

class EventServiceProvider extends ServiceProvider
{
    /**
     * The event listener mappings for the application.
     *
     * @var array
     */
    protected $listen = [
        CacheHit::class => [
            LogCacheHitListener::class
        ],

        CacheMissed::class => [
            LogCacheMissedListener::class
        ],

        KeyForgotten::class => [
            LogKeyForgottenListener::class,
        ],

        KeyWritten::class => [
            LogKeyWrittenListener::class,
        ],
    ];

2、其中一个监听器：LogKeyWrittenListener 实现如下，/app/Listeners/Cache/LogKeyWrittenListener.php

<?php

namespace App\Listeners\Cache;

use Illuminate\Cache\Events\KeyWritten;
use Illuminate\Support\Facades\Log;
use Modules\OnlineStoreThemeGraphQL\Preview\ThemePreviewInterface;

class LogKeyWrittenListener
{
    /**
     * 处理事件
     *
     * @param  KeyWritten  $event
     * @return void
     */
    public function handle(KeyWritten $event)
    {
        if (config('app.debug') === true && strpos($event->key, ThemePreviewInterface::THEME_EDITOR_SESSION_PREFIX) !== false) {
            Log::debug('theme_editor_session_key_written', [
                'key' => $event->key,
                'tags' => $event->tags,
                'value' => $event->value,
                'seconds' => $event->seconds
            ]);
        }
    }
}

3、其中一个监听器：LogCacheHitListener 实现如下，/app/Listeners/Cache/LogCacheHitListener.php

<?php

namespace App\Listeners\Cache;

use Illuminate\Cache\Events\CacheHit;
use Illuminate\Support\Facades\Log;
use Modules\OnlineStoreThemeGraphQL\Preview\ThemePreviewInterface;

class LogCacheHitListener
{
    /**
     * 处理事件
     *
     * @param  CacheHit  $event
     * @return void
     */
    public function handle(CacheHit $event)
    {
        if (config('app.debug') === true && strpos($event->key, ThemePreviewInterface::THEME_EDITOR_SESSION_PREFIX) !== false) {
            Log::debug('theme_editor_session_cache_hit', [
                'key' => $event->key,
                'tags' => $event->tags,
                'value' => $event->value
            ]);
        }
    }
}

4、决定基于事件订阅者重构。编写事件订阅者 CacheEventSubscriber，将 4 个监听器文件合并为 1 个。

<?php

namespace App\Listeners;

use Illuminate\Events\Dispatcher;
use Illuminate\Cache\Events\CacheHit;
use Illuminate\Cache\Events\CacheMissed;
use Illuminate\Cache\Events\KeyForgotten;
use Illuminate\Cache\Events\KeyWritten;
use Illuminate\Support\Facades\Log;
use Modules\OnlineStoreThemeGraphQL\Preview\ThemePreviewInterface;

class CacheEventSubscriber
{
    /**
     * 处理缓存命中事件
     * @param $event
     */
    public function handleLogCacheHit($event)
    {
        if ($this->isThemeEditorSessionLogDebug($event)) {
            Log::debug('theme_editor_session_cache_hit', [
                'key' => $event->key,
                'tags' => $event->tags,
                'value' => $event->value
            ]);
        }
    }

    /**
     * 处理缓存未命中事件
     */
    public function handleLogCacheMissed($event)
    {
        if ($this->isThemeEditorSessionLogDebug($event)) {
            Log::debug('theme_editor_session_cache_missed', [
                'key' => $event->key,
                'tags' => $event->tags
            ]);
        }
    }

    /**
     * 处理缓存删除事件
     */
    public function handleLogKeyForgotten($event)
    {
        if ($this->isThemeEditorSessionLogDebug($event)) {
            Log::debug('theme_editor_session_key_forgotten', [
                'key' => $event->key,
                'tags' => $event->tags
            ]);
        }
    }

    /**
     * 处理缓存写入事件
     */
    public function handleLogKeyWritten($event)
    {
        if ($this->isThemeEditorSessionLogDebug($event)) {
            Log::debug('theme_editor_session_key_written', [
                'key' => $event->key,
                'tags' => $event->tags,
                'value' => $event->value,
                'seconds' => $event->seconds
            ]);
        }
    }

    /**
     * 是否记录主题编辑器 Session 日志
     * @return bool
     */
    private function isThemeEditorSessionLogDebug($event)
    {
        return config('app.debug') === true && strpos($event->key, ThemePreviewInterface::THEME_EDITOR_SESSION_PREFIX) !== false;
    }

    /**
     * 为订阅者注册监听器
     *
     * @param  Dispatcher  $events
     */
    public function subscribe($events)
    {
        $events->listen(
            CacheHit::class,
            'App\Listeners\CacheEventSubscriber@handleLogCacheHit'
        );

        $events->listen(
            CacheMissed::class,
            'App\Listeners\CacheEventSubscriber@handleLogCacheMissed'
        );

        $events->listen(
            KeyForgotten::class,
            'App\Listeners\CacheEventSubscriber@handleLogKeyForgotten'
        );

        $events->listen(
            KeyWritten::class,
            'App\Listeners\CacheEventSubscriber@handleLogKeyWritten'
        );
    }
}

5、在 EventServiceProvider 的 listen 属性中删除事件和监听器，然后在 subscribe 属性中添加订阅者

class EventServiceProvider extends ServiceProvider
{
    /**
     * The event listener mappings for the application.
     *
     * @var array
     */
    protected $listen = [
    ];

    protected $subscribe = [
        \App\Listeners\CacheEventSubscriber::class
    ];

6、经过测试，4个事件，其中使用 flush 方法删除缓存数据时，KeyForgotten 未被触发。使用 forget 方法从缓存中删除缓存数据时，KeyForgotten 会被触发。

Cache::put(ThemePreviewInterface::THEME_EDITOR_SESSION_PREFIX . '20220921', '20220921.value', ThemePreviewInterface::TTL);
Cache::forget(ThemePreviewInterface::THEME_EDITOR_SESSION_PREFIX . '20220921');

[2022-09-21 10:11:12] local.DEBUG: theme_editor_session_key_written {
    "key": "theme_editor_session:20220921",
    "tags": [],
    "value": "20220921.value",
    "seconds": 86400
} 
[2022-09-21 10:14:19] local.DEBUG: theme_editor_session_key_forgotten {
    "key": "theme_editor_session:20220921",
    "tags": []
}