在Laravel / Eloquent模型上加载一个自定义属性？ [英] Add a custom attribute to a Laravel / Eloquent model on load?

问题描述

我希望能够在Laravel / Eloquent模型加载时添加自定义属性/属性，类似于 RedBean的 $ model-> open（）方法。

I'd like to be able to add a custom attribute/property to an Laravel/Eloquent model when it is loaded, similar to how that might be achieved with RedBean's $model->open() method.

目前在我的控制器我有：

For instance, at the moment, in my controller I have:

public function index()
{
    $sessions = EventSession::all();
    foreach ($sessions as $i => $session) {
        $sessions[$i]->available = $session->getAvailability();
    }
    return $sessions;
}

可以省略循环并拥有'可用'属性已设置和填充。

It would be nice to be able to omit the loop and have the 'available' attribute already set and populated.

我已经尝试使用文档中描述的一些模型事件来附加该属性，当对象加载，但没有成功到目前为止

I've tried using some of the model events described in the documentation to attach this property when the object loads, but without success so far.

注意：

• 'available'不是基础表格中的一个字段。


• $ sessions 作为JSON对象作为API的一部分返回，因此在模板中调用类似 $ session-> available（）不是一个选项

• 'available' is not a field in the underlying table.
• $sessions is being returned as a JSON object as part of an API, and therefore calling something like $session->available() in a template isn't an option

推荐答案

问题是由于 Model 的 toArray（）方法忽略与基础表中的列直接相关的任何访问器。

The problem is caused by the fact that the Model's toArray() method ignores any accessors which do not directly relate to a column in the underlying table.

正如泰勒·奥特维尔所说这里，这是故意的，出于表现的原因。但是有一个简单的方法可以实现这一点：

As Taylor Otwell mentioned here, "This is intentional and for performance reasons." However there is an easy way to achieve this:

class EventSession extends Eloquent {

    protected $table = 'sessions';
    protected $appends = array('availability');

    public function getAvailabilityAttribute()
    {
        return $this->calculateAvailability();  
    }
}

$ appends属性中列出的任何属性将自动为包含在模型的数组或JSON格式中，前提是您已经添加了相应的访问器。

Any attributes listed in the $appends property will automatically be included in the array or JSON form of the model, provided that you've added the appropriate accessor.

旧答案（对于Laravel版本< 4.08）：

我发现最好的解决方案是覆盖 toArray（）方法，显性设置属性：

The best solution that I've found is to override the toArray() method and either explicity set the attribute:

class Book extends Eloquent {

    protected $table = 'books';

    public function toArray()
    {
        $array = parent::toArray();
        $array['upper'] = $this->upper;
        return $array;
    }

    public function getUpperAttribute()
    {
        return strtoupper($this->title);    
    }

}

或者，如果你有很多定制访问器，循环遍历它们并应用它们：

or, if you have lots of custom accessors, loop through them all and apply them:

class Book extends Eloquent {

    protected $table = 'books';

    public function toArray()
    {
        $array = parent::toArray();
        foreach ($this->getMutatedAttributes() as $key)
        {
            if ( ! array_key_exists($key, $array)) {
                $array[$key] = $this->{$key};   
            }
        }
        return $array;
    }

    public function getUpperAttribute()
    {
        return strtoupper($this->title);    
    }

}

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