你怎么会忘记 Laravel 中缓存的 Eloquent 模型？

How would you forget cached Eloquent models in Laravel?

提问by Peter Fox

Theoretical question on Laravel here.

关于 Laravel 的理论问题在这里。

So Example of the caching I'd do is:

所以我要做的缓存示例是：

Article::with('comments')->remember(5)->get();

Ideally I'd like to have an event for Article updates that when the ID of a instance of that model (that's already cached) is updated I want to forget that key (even if it's the whole result of the query that's forgotten instead of just that one model instance), it is possible to do so?

理想情况下，我希望有一个用于文章更新的事件，当该模型的实例（已经缓存）更新时，我想忘记该键（即使它是查询的整个结果被遗忘而不是仅仅那个模型实例），有可能这样做吗？

If not is there some way to implement this reasonably cleanly?

如果没有，是否有某种方法可以合理干净地实现这一点？

回答by Syed I.R.

So i was looking for an answer to the same question as OP but was not really satisfied with the solutions. So i started playing around with this recently and going through the source code of the framework, I found out that the remember()method accepts second param called keyand for some reason it has not been documented on their site(Or did i miss that?).

所以我正在寻找与 OP 相同的问题的答案，但对解决方案并不满意。所以我最近开始玩这个并浏览框架的源代码，我发现该remember()方法接受调用的第二个参数，key并且由于某种原因它没有在他们的网站上记录（或者我错过了那个？）。

Now good thing about this is that, The database builder uses the same cache driver which is configured under app/config/cache.phpOr should i say the same cache system that has been documented here - Cache. So if you pass min and key to remember(), you can use the same key to clear the cache using Cache::forget()method and in fact, you can pretty much use all the Cachemethods listed on the official site, like Cache::get(), Cache::add(), Cache::put(), etc. But i don't recommend you to use those other methods unless you know what you're doing.

现在关于这一点的好处是，数据库构建器使用在 Cache 下配置的相同缓存驱动程序app/config/cache.php或者我应该说这里记录的相同缓存系统 - Cache。所以，如果你通过分和关键remember()，你可以使用相同的密钥使用清除缓存Cache::forget()方法，事实上，你几乎可以使用所有Cache的列出的方法官方网站，像Cache::get()，Cache::add()，Cache::put()等等。但我不建议您使用其他方法，除非您知道自己在做什么。

Here's an example for you and others to understand what i mean.

这是一个示例，您和其他人可以理解我的意思。

Article::with('comments')->remember(5, 'article_comments')->get();

Article::with('comments')->remember(5, 'article_comments')->get();

Now the above query result will be cached and will be associated with the article_commentskey which can then be used to clear it anytime (In my case, I do it when i update).

现在上面的查询结果将被缓存并与article_comments密钥相关联，然后可以随时使用它来清除它（在我的情况下，我在更新时这样做）。

So now if i want to clear that cache regardless of how much time it remembers for. I can just do it by calling Cache::forget('article_comments');and it should work just as expected.

所以现在如果我想清除缓存，不管它记得多少时间。我可以通过调用来完成它Cache::forget('article_comments');，它应该按预期工作。

Hope this helps everyone :)

希望这对大家有帮助:)

回答by Glad To Help

I think a good way to do is like this:

我认为一个好的办法做到像这样：

$value = Cache::remember('users', $minutes, function()
{
    return DB::table('users')->get();
});

and then use Model Observersto detect the event of updating the model

然后使用Model Observers检测更新模型的事件

class UserObserver {

    public function saving($model)
    {
        //
    }

    public function saved($model)
    {
        // forget from cache
        Cache::forget('users');
    }

}

User::observe(new UserObserver);

回答by tharumax

Currently there are no easy way. However I found this workaround, which so far worked for me.

目前没有简单的方法。但是我找到了这个解决方法，到目前为止它对我有用。

First you have to extend Illuminate\Database\Query\Builder.

首先，您必须扩展Illuminate\Database\Query\Builder.

<?php 

class ModifiedBuilder extends Illuminate\Database\Query\Builder {
    protected $forgetRequested = false;

    public function forget() 
    {
        $this->forgetRequested = true;
    }

    public function getCached($columns = array('*'))
    {
        if (is_null($this->columns)) $this->columns = $columns;

        list($key, $minutes) = $this->getCacheInfo();

        // If the query is requested ot be cached, we will cache it using a unique key
        // for this database connection and query statement, including the bindings
        // that are used on this query, providing great convenience when caching.
        $cache = $this->connection->getCacheManager();

        $callback = $this->getCacheCallback($columns);

        if($this->forgetRequested) {
            $cache->forget($key);
            $this->forgetRequested = false;
        }

        return $cache->remember($key, $minutes, $callback);
    }
}

Then you have to create new class which extends Eloquent Model.

然后你必须创建一个扩展 Eloquent 模型的新类。

<?php

class BaseModel extends Eloquent {
    protected function newBaseQueryBuilder() {
        $conn = $this->getConnection();

        $grammar = $conn->getQueryGrammar();

        return new ModifiedBuilder($conn, $grammar, $conn->getPostProcessor());
    }
}

Now when creating Eloquent Models, instead of extending EloquentModels extend newly created BaseModel.

现在在创建 Eloquent 模型时，不是扩展Eloquent模型而是扩展新创建的BaseModel.

Now you can rememberquery result as usual.

现在您可以remember照常查询结果了。

YourModel::remember(10)->get();

When you want to discard the cached result all you have to do is

当你想丢弃缓存的结果时，你所要做的就是

YourModel::forget()->get();

If you remember the result previously, after clearing the cached result, model will continue to remember the result for that amount of time.

如果您之前记得结果，清除缓存的结果后，模型将继续记住该时间段的结果。

Hope this helps.

希望这可以帮助。

回答by Lionel Morrison

I was testing for debug mode. So I found that if you put a test for app.debug in a constructor you are able to clear the cache associated with a key. Saves you having to duplicate the code for every function.

我正在测试调试模式。所以我发现如果你在构造函数中对 app.debug 进行测试，你就可以清除与键关联的缓存。让您不必为每个函数复制代码。

class Events {
    public function __construct() {
        if (\Config::get('app.debug')) {
            Cache::forget('events');
        }
    }

    public static function all() {
        $events = \DB::table('events as e')
            ->select('e.*')
            ->where('enabled', 1)
            ->remember(30, 'events')
            ->get();

        return $events;
    }
}