php - 缓存 Eloquent 关系查询

Question

如何缓存此 Eloquent 查询:

dd($user->roles);

因为上面会以某种方式触发我假设的 $user->roles() 查询。

我已经尝试过这个:

    public function roles() {
        return \Cache::remember('user_' . $this->id . '_roles', 10, function() {
            return $this->hasMany('App\Role');
        });
    }

但是它不起作用，因为它必须返回一个数组，而不是 Eloquent 查询。

有什么建议吗？

Answer 1

这是针对现代 Laravel 更新的方法:

// Define your relation
public function bookmarks(): HasMany
{
    return $this->hasMany(Bookmark::class);
}

// Define the cache key (as its used in multiple places)
protected function getBookmarksCacheKey(): string
{
    return sprintf('user-%d-bookmarks', $this->id);
}

// Provide a cache clearing mechanism
public function clearBookmarksCache(): bool
{
    return Cache::forget($this->getBookmarksCacheKey());
}

// Override the relation property getter
// It will return the cached collection when it exists, otherwise getting a fresh one from the database
// It then populates the relation with that collection for use elsewhere
public function getBookmarksAttribute(): Collection
{
    // If the relation is already loaded and set to the current instance of model, return it
    if ($this->relationLoaded('bookmarks')) {
        return $this->getRelationValue('bookmarks');
    }

    // Get the relation from the cache, or load it from the datasource and set to the cache
    $bookmarks = Cache::rememberForever($this->getBookmarksCacheKey(), function () {
        return $this->getRelationValue('bookmarks');
    });

    // Set the relation to the current instance of model
    $this->setRelation('bookmarks', $bookmarks);

    return $bookmarks;
}