Laravel 4，来自一个模型的多个多态关系 [英] Laravel 4, Multiple Polymorphic Relations from one Model

问题描述

我试图在Laravel 4中建立多态关系，以便我可以拥有一个Image类来处理与上载，取消链接等有关的所有事情，然后将其用于多个不同的Model.很好，直到我尝试从同一模型创建多个链接.

I'm trying to set up polymorphic relationships in Laravel 4 so that I can have one Image class which handles everything related to uploads, unlinks and so on, then have it used by multiple different Models. That's fine, until I get to trying to create multiple links from the same Model.

例如，我目前有这样的东西:

For example, I currently have something like this:

Models/Image.php

Models/Image.php

class Image extends Eloquent {
    public function of() { return $this->morphTo(); }
}

Models/Person.php

Models/Person.php

class Person extends Eloquent {
    public function mugshot() { return $this->morphOne('Image', 'of'); }
    public function photos() { return $this->morphMany('Image', 'of'); }
}

Models/Place.php

Models/Place.php

class Place extends Eloquent {
    public function photos() { return $this->morphMany('Image', 'of'); }
}

此处，一个人可以上传一个mugshot和许多photos，而一个地方可以具有许多photos.问题是，当我在Person上创建mugshot时，它会将其保存到数据库的images表中:

Here, a Person can upload one mugshot and many photos, while a Place can have many photos. The problem is that when I create a mugshot on a Person, it saves this into the images table in the database:

id: 1
of_id: 1
of_type: Person

它没有存储它是mugshot而不是photo的事实，因此当我去检索它时，$person->mugshot有时可能返回$person->photos之一，反之亦然.

It doesn't store the fact that it's a mugshot and not a photo, so when I go to retrieve it, $person->mugshot may sometimes return one of $person->photos and vice versa.

有没有(a)比在同一模型上创建2个链接更好的方法，或者(b)实际上使这种方法起作用的方法?

Is there either (a) a better way to do this than creating 2 links on the same Model, or (b) a way to actually make this way work?

推荐答案

目前没有内置方法.也许在Laravel 4.1中应该完全重写多态关系.

No built-in way right now. Maybe in Laravel 4.1 that's supposed to bring a complete rewrite of polymorphic relations.

向Image添加type属性，然后在关系上定义where条件:

Add a type property to Image, then define where conditions on the relations:

public function mugshot() { 
    return $this->morphOne('Image', 'of')->where('type', 'mugshot'); 
}

public function photos() { 
    return $this->morphMany('Image', 'of')->where('type', 'photo'); 
}

不要忘记在创建的Image上设置type. 或者，就像我下面一样，将这种逻辑隐藏在模型中.

Don't forget to set type on Images you create. Or, like I did bellow, hide that logic inside the model.

这是我的代码(我正在使用带有短数组表示法的PHP 5.4):

Here's my code (I'm using PHP 5.4 with short array notation):

图片:

namespace SP\Models;

class Image extends BaseModel {

    const MUGSHOT = 'mugshot';
    const PHOTO = 'photo';

    protected $hidden = ['type'];

    public function of()
    {
        return $this->morphTo();
    }
}

人员:

namespace SP\Models;

use SP\Models\Image;

class Person extends BaseModel {

    public function mugshot() { 
        return $this->morphOne('SP\Models\Image', 'of')
                            ->where('type', Image::MUGSHOT); 
    }

    public function photos() { 
        return $this->morphMany('SP\Models\Image', 'of')
                            ->where('type', Image::PHOTO); 
    }

    public function saveMugshot($image)
    {
        $image->type = Image::MUGSHOT;
        $image->save();
        $this->mugshot()->save($image);
    }

    public function savePhotos($images)
    {
        if(!is_array($images))
        {
            $images = [$images];
        }

        foreach($images as $image)
        {
            $image->type = Image::PHOTO;
            $image->save();
            $this->photos()->save($image);
        }
    }
}

控制器/服务中的某处:

Somewhere in a controller/service:

$person->savePhotos([$image1, $image2]);

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