Laravel 5.3 $附加不起作用

Question

Below is the code for model

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Product extends Model
{
    protected $appends = [
        "desc"
    ];

    protected $fillable = ['id'];

    public function getDescAttribute()
    {
        return strip_tags( $this->attributes['description'] );
    }
}

So now when i do

$product = Product::first();

It doesn't return desc field in the $product, though when i do $product->desc it returns the result, but i want that result to be appended in the model itself.

The following code gives me error

$product = Product::first()->get(['desc']);

It runs

Select desc from products...

But as the desc is not there i am getting error.

Is anything I'm doing wrong?

Answer 1

Fields that you add to $appends array are only appended when object is serialized to array/JSON. Otherwise it doesn't make sense to define this attribute until it's really needed - that's why you're getting the value when you access $product->desc. It's done to save unnecessary operations - calculating the value of a custom attribute could involve some heavy operations and is delayed till it's really needed.