php - 从数据库返回时，Laravel 将模型转换为另一个模型

Question

背景信息

我有一个名为Product 的模型。产品可以有 3 种不同的进货方式:Serialize、Bulk 和 None。

• Serialize 当每个物理项目都有条形码时选择。
• Bulk 当我们关注数量变化时选择
• 无 当我们想要在库存中包含产品但我们不关心数量时选择。

---

我想做什么

我想创建这 3 个模型(序列化、批量、无)并将它们扩展到产品。然后能够调用类似 Product::all() 的东西并获得这样的集合:

Products [
   0   => Serialize[...]
   1   => Serialize[...]
   2   => Bulk[...]
   3   => None[...]
   ...
   500 => Bulk[...]
]

---

我的问题

如何让 Laravel 自动将每个对象转换为各自的类？

---

数据库架构

---

我的模型结构

产品型号

class Product extends Model
{
    use HasFactory;

    /**
     * The attributes that aren't mass assignable.
     *
     * @var array
     */
    protected $guarded = ['id'];

    /**
     * The attributes that should be cast to native types.
     *
     * @var array
     */
    protected $casts = [
        'purchase_price' => MoneyCast::class,
        'rental_price'   => MoneyCast::class,
        'is_active'      => 'boolean',
    ];

    /**
     * Get active products only
     *
     * @param Builder $builder
     *
     * @return Builder
     */
    public function scopeActive(Builder $builder): Builder
    {
        return $builder->where('is_active', '=', true);
    }

    /**
     * Get inactive products only
     *
     * @param Builder $builder
     *
     * @return Builder
     */
    public function scopeInactive(Builder $builder): Builder
    {
        return $builder->where('is_active', '=', false);
    }

    /**
     * Set the name and slug when saving to database
     *
     * @param $value
     */
    public function setNameAttribute($value): void
    {
        $this->attributes['name'] = $value;
        $this->attributes['slug'] = Str::slug($value);
    }

    /**
     * Get the products full name
     *
     * @return string
     */
    public function getFullNameAttribute(): string
    {
        return $this->details
            ? "{$this->name} {$this->details}"
            : $this->name;
    }

    /**
     * Calculate total stocks
     *
     * @return int
     */
    abstract public function getTotalAttribute(): int;

    /**
     * Calculate total stocks in quarantine
     *
     * @return int
     */
    abstract public function getQuarantinedAttribute(): int;

    /**
     * Calculate available stocks
     *
     * @return int
     */
    public function getAvailableAttribute(): int
    {
        return $this->getTotalAttribute() - $this->getQuarantinedAttribute();
    }

    /**
     * Get brand
     *
     * @return BelongsTo
     */
    public function brand(): BelongsTo
    {
        return $this->belongsTo(Brand::class);
    }

    /**
     * Get category
     *
     * @return BelongsTo
     */
    public function category(): BelongsTo
    {
        return $this->belongsTo(Category::class);
    }

序列化模型

class Serialize extends Product
{
/**
     * Calculate total stocks
     *
     * @return int
     */
    public function getTotalAttribute(): int
    {
        return $this->stocks()->count();
    }

    /**
     * Calculate total stocks in quarantine
     *
     * @return int
     */
    public function getQuarantinedAttribute(): int
    {
        return $this->stocks->sum(function ($stock) {
            return $stock->repairs()
                         ->where('status', '!=', last(Repair::STATUSES))
                         ->where('is_working', '=', false)
                         ->count();
        });
    }

    /**
     * Get associated stocks
     *
     * @return HasMany
     */
    public function stocks(): HasMany
    {
        return $this->hasMany(Stock::class)->orderBy('barcode');
    }
}

批量模型

class Bulk extends Product
{
    /**
     * Calculate total stocks
     *
     * @return int
     */
    public function getTotalAttribute(): int
    {
        return $this->transactions()->sum('quantity');
    }

    /**
     * Calculate total stocks in quarantine
     *
     * @return int
     */
    public function getQuarantinedAttribute(): int
    {
        return $this->stocks->sum(function ($stock) {
            return $stock->repairs()
                         ->where('status', '!=', last(Repair::STATUSES))
                         ->where('is_working', '=', false)
                         ->sum('quantity');
        });
    }

    /**
     * Get bulk stock transactions.
     *
     * @return HasMany
     */
    public function transactions(): HasMany
    {
        return $this->hasMany(Transaction::class)->latest();
    }
}

Answer 1

您可以基于 stock 方法返回这些子类型的新实例:

Product::all()
  ->map(function($product) {
       switch( $product->stock_method ) {
           case 'Serialize':
               return new Serialize((array) $product);
           case 'Bulk':
               return new Bulk((array) $product);
           // and so on..
       }
       return $product;
  });

你也可以覆盖 get 方法，这样就不必在每个 all 上都写这段代码了

class Product extends Model {
    // static method 'all' calls 'get' defined in Illuminate\Database\EloquentBuilder
    public function get($columns = ['*']) {
        return parent::get($columns)
            ->map(function($product) {
               switch( $product->stock_method ) {
                 case 'Serialize':
                   return new Serialize((array) $product);
                 case 'Bulk':
                   return new Bulk((array) $product);
                 // and so on..
              }
             return $product;
            });
    }