为什么要在eloquent中使用appends

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讲真话的最大好处就是：不必记得自己讲过什么。

Eloquent has a convenient feature called Accessors – you can define your own custom fields on top of existing in the database table. But then there’s an Eloquent property $appends – should we use it or not? And what’s the difference?

First – how Accessors work

For those who don’t know or have forgotten: for example, if you have User model and fields first_name and last_name in the DB table, then you can create a function in app\User.php:

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function getFullNameAttribute() {
  return $this->first_name . ' ' . $this->last_name;
}

Then you have access to property full_name (in the function name it’s CamelCase, and the property name is with underscoresd, for example like this:

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ho User::find(1)->full_name;

But here’s the thing – if you just return User object, it won’t contain full_name:

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dd(User::find(1)->toJSON());

The result would look something like this:

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{
  "id":1,
  "first_name":"Povilas",
  "last_name":"Korop",
  "email":"povilas@webcoderpro.com",
  "created_at":"2015-06-19 08:16:58",
  "updated_at":"2015-06-19 19:48:09"
}

Here’s where $appends comes in

Now this is the trick – in your User model you can add $appends attribute and list the fields that would automatically be appended:

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class User extends Model
{
  // ...
  protected $appends = ['full_name'];

Now that attribute will be automatically added to the previous JSON:

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{
  "id":1,
  "first_name":"Povilas",
  "last_name":"Korop",
  "email":"povilas@webcoderpro.com",
  "created_at":"2015-06-19 08:16:58",
  "updated_at":"2015-06-19 19:48:09",
  "full_name":"Povilas Korop"
}

https://laraveldaily.com/why-use-appends-with-accessors-in-eloquent/