在laravel 5.3中使用带有访问器的演员表 [英] Using casts with accessor in laravel 5.3

问题描述

我想使用laravel(5.3)雄辩的$casts属性，例如protected $casts = ["example" => "object"]和getExampleAttribute访问器，但是看来访问器会丢弃$casts行为.这对我来说至关重要，因为我想将JSON对象存储在数据库中并为其设置默认值，例如:

I want to use laravel (5.3) eloquent's $casts attribute like protected $casts = ["example" => "object"] with getExampleAttribute accessor, but as it seems accessor discards the $casts behaviour. It's crucial for me since I want to store JSON object in database and have a default value for it, e.g:

public function getExampleAttribute($value) {
    if($value === NULL) 
        return new \stdclass();
    return $value
}

所以我永远不会在我的视图中得到NULL值.除了在访问器和mutator中显式实现强制转换逻辑之外，还有什么方法比之更容易?

so I would never get NULL values in my views. Is there a way to do it easier than just implementing casts logic within accessor and mutator explicitly?

推荐答案

如果您希望该字段显式遵循$casts定义，则可以使用以下解决方案.您只需要从访问器mutator内部手动调用cast函数:

If you want the field to explicitly follow the $casts definition, the following solution works. You just need to manually call the cast function from inside an accessor mutator:

public function getExampleAttribute($value)
{
    // force the cast defined by $this->casts because
    // this accessor will cause it to be ignored
    $example = $this->castAttribute('example', $value);

    /** set defaults for $example **/

    return $example;
}

这种方法假设您将来可能会更改演员表，但是如果您知道它始终是一个array/json字段，则可以这样替换castAttribute()调用:

This method sort of assumes that you might change the cast in the future, but if you know it's always going to be an array/json field then you can substitute the castAttribute() call like this:

public function getExampleAttribute($value)
{
    // translate object from Json storage
    $example = $this->fromJson($value, true)

    /** set defaults for $example **/

    return $example;
}

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