Laravel 5雄辩，如何动态设置演员表属性 [英] Laravel 5 Eloquent, How to set cast attribute dynamically

问题描述

在laravel 5.1中，有一个称为Attribute Casting的新功能，在此处有详细记录: http://laravel.com/docs/5.1/eloquent-mutators#attribute-casting

In laravel 5.1 there is new feature called Attribute Casting, well documented at here : http://laravel.com/docs/5.1/eloquent-mutators#attribute-casting

我的问题是，可以动态地进行属性转换吗?

My question is, it is possible to make attribute casting dynamically ?

例如，我有一个带有列的表:

for example, I have a table with columns :

id | name          | value       | type    |
1  | Test_Array    | [somearray] | array   |
2  | Test_Boolean  | someboolean | boolean |

可以设置value属性强制转换，具体取决于type字段，该属性在write(create/update)和fetch吗?

it is possible to set value attribute cast, depends on type field, that work both in write(create/update) and fetch ?

推荐答案

您需要在模型类中覆盖Eloquent模型的 getCastType()方法:

You'll need to overwrite Eloquent model's getCastType() method in your model class:

protected function getCastType($key) {
  if ($key == 'value' && !empty($this->type)) {
    return $this->type;
  } else {
    return parent::getCastType($key);
  }
}

您还需要向 $ this-> casts 添加值，以便Eloquent将该字段识别为 castable .您可以在此处放置默认的演员表，如果您未设置 type 的话，将使用默认的演员表.

You'll also need to add value to $this->casts so that Eloquent recognizes that field as castable. You can put the default cast there that will be used if you didn't set type.

更新:

当从数据库中读取数据时，上面的方法非常有效.写入数据时，必须确保在值之前设置了类型.有2个选项:

The above works perfectly when reading data from the database. When writing data, you have to make sure that type is set before value. There are 2 options:

1. 始终传递属性数组，其中 type 键在 value 键之前-在模型的 fill()方法方面处理数据时键的顺序，但这不是面向未来的.

1. Always pass an array of attributes where type key comes before value key - at the moment model's fill() method respects the order of keys when processing data, but it's not future-proof.

明确设置 type 属性，然后再设置其他属性.可以使用以下代码轻松完成此操作:

Explicitely set type attribute before setting other attributes. It can be easily done with the following code:

$model == (new Model(['type' => $data['type']))->fill($data)->save();

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