忽略不存在的类别

Question

为一篇文章添加多个类别:

public static function setCategory(Request $request) {

$article = Article::where('id', $request->article_id)->first();
$categories_ids = json_decode($request->categories_ids);
$article->categories()->attach($categories_ids);
}

假设输入数组[1,2,3,4]，其中4是一个不存在的类别。如何确保添加了所有现有的类别，而忽略了4个类别?

Answer 1

如果你想用一种优雅的方式来做，我会这样做:

$article = Article::findOrFail($request->article_id);
$requestedCategoriesIds = json_decode($request->categories_ids);
$keyName = (new Category())->getKeyName();
$existingCategoriesIds = Category
::whereKey($requestedCategoriesIds)
->pluck($keyName);
$article->categories()->attach($existingCategoriesIds);