Check if Ids exist in database before attach-CodePudding

I select an array with categories via json_decode and attach them to the article.

public static function setArticleCategory(Request $request) {
    
        $article = Article::where('id', $request->article_id)->first();

        if(!$article){
            return response()->json([
                'message' => 'Article not found'
                ], 404);
        }

        $categories_ids = json_decode($request->categories_ids);

        $article->categories()->attach($categories_ids);
    
        return response()->json([
            'message' => $categories_ids
        ], 200);
    }

The question is, how can I check in categories_ids, for example, if one of the selected categories does not exist in the array?

CodePudding user response：

The fastest way would be to use count()

$categories_ids = json_decode($request->categories_ids);
if (count($categories_ids) != Category::whereKey($categories_ids)->count()) {
    //return error.
}

It would not tell you wich one is the non existing category, but it will trigger an error if at least one of them doesnt exist.

Edit (comment)*

if you want to ignore the non existing IDs, use this

$categories_ids = json_decode($request->categories_ids);

$categoryPK = (new Category())->getKeyName();
$categories_ids = Category::whereKey($categories_ids)->pluck($categoryPK)->toArray();

It will return an array of ids that exists in the database based on the input (you need to check for empty array after that).