From a model

It is possible to create a data object from a model, let's say we have the following model:

class Artist extends Model
{
    
}

It has the following columns in the database:

• id
• first_name
• last_name
• created_at
• updated_at

We can create a data object from this model like this:

class ArtistData extends Data
{
    public int $id;
    public string $first_name;
    public string $last_name;
    public CarbonImmutable $created_at;
    public CarbonImmutable $updated_at;
}

We now can create a data object from the model like this:

$artist = ArtistData::from(Artist::find(1));

##Casts

A model can have casts, these casts will be called before a data object is created. Let's extend the model:

class Artist extends Model
{
    public function casts(): array
    {
       return [
            'properties' => 'array'
       ];
    }
}

Within the database the new column will be stored as a JSON string, but in the data object we can just use the array type:

class ArtistData extends Data
{
    public int $id;
    public string $first_name;
    public string $last_name;
    public array $properties;
    public CarbonImmutable $created_at;
    public CarbonImmutable $updated_at;
}

##Attributes & Accessors

Laravel allows you to define attributes on a model, these will be called before a data object is created. Let's extend the model:

class Artist extends Model
{
    public function getFullNameAttribute(): string
    {
        return $this->first_name . ' ' . $this->last_name;
    }
}

We now can use the attribute in the data object:

class ArtistData extends Data
{
    public int $id;
    public string $full_name;
    public CarbonImmutable $created_at;
    public CarbonImmutable $updated_at;
}

Remember: we need to use the snake_case version of the attribute in the data object since that's how it is stored in the model. Read on for a more elegant solution when you want to use camelCase property names in your data object.

It is also possible to define accessors on a model which are the successor of the attributes:

class Artist extends Model
{
    public function getFullName(): Attribute
    {
        return Attribute::get(fn () => "{$this->first_name} {$this->last_name}");
    }
}

With the same data object we created earlier we can now use the accessor.

##Mapping property names

Sometimes you want to use camelCase property names in your data object, but the model uses snake_case. You can use an MapInputName to map the property names:

use Spatie\LaravelData\Attributes\MapInputName;
use Spatie\LaravelData\Mappers\SnakeCaseMapper;

class ArtistData extends Data
{
    public int $id;
    #[MapInputName(SnakeCaseMapper::class)]
    public string $fullName;
    public CarbonImmutable $created_at;
    public CarbonImmutable $updated_at;
}

An even more elegant solution would be to map every property within the data object:

#[MapInputName(SnakeCaseMapper::class)]
class ArtistData extends Data
{
    public int $id;
    public string $fullName;
    public CarbonImmutable $createAt;
    public CarbonImmutable $updatedAt;
}

##Relations

Let's create a new model:

class Song extends Model
{
    public function artist(): BelongsTo
    {
        return $this->belongsTo(Artist::class);
    }
}

Which has the following columns in the database:

• id
• artist_id
• title

We update our previous model as such:

class Artist extends Model
{
    public function songs(): HasMany
    {
        return $this->hasMany(Song::class);
    }
}

We can now create a data object like this:

class SongData extends Data
{
    public int $id;
    public string $title;
}

And update our previous data object like this:

class ArtistData extends Data
{
    public int $id;
    /** @var array<SongData>  */
    public array $songs;
    public CarbonImmutable $created_at;
    public CarbonImmutable $updated_at;
}

We can now create a data object with the relations like this:

$artist = ArtistData::from(Artist::with('songs')->find(1));

When you're not loading the relations in advance, null will be returned for the relation.

It is however possible to load the relation on the fly by adding the LoadRelation attribute to the property:

class ArtistData extends Data
{
    public int $id;
    /** @var array<SongData>  */
    #[LoadRelation]
    public array $songs;
    public CarbonImmutable $created_at;
    public CarbonImmutable $updated_at;
}

Now the data object with relations can be created like this:

$artist = ArtistData::from(Artist::find(1));

We even eager-load the relation for performance, neat!

##Be careful with automatic loading of relations

Let's update the SongData class like this:

class SongData extends Data
{
    public int $id;
    public string $title;
    #[LoadRelation]
    public ArtistData $artist;
}

When we now create a data object like this:

$song = SongData::from(Song::find(1));

We'll end up in an infinite loop, since the SongData class will try to load the ArtistData class, which will try to load the SongData class, and so on.