> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/spatie/laravel-data/llms.txt
> Use this file to discover all available pages before exploring further.

# Injecting Property Values

> Automatically inject values from route parameters, authenticated users, and the service container into data object properties.

When creating a data object, it is possible to inject values into properties from all kinds of sources like route parameters, the current user or dependencies in the container.

## Filling Properties from a Route Parameter

When creating data objects from requests, it's possible to automatically fill data properties from request route parameters, such as route models.

The `FromRouteParameter` attribute allows filling properties with route parameter values.

### Using Scalar Route Parameters

```php theme={null}
Route::patch('/songs/{songId}', [SongController::class, 'update']);

class SongData extends Data {
    #[FromRouteParameter('songId')]
    public int $id;
    public string $name;
}
```

Here, the `$id` property will be filled with the `songId` route parameter value (which most likely is a string or integer).

### Using Models, Objects or Arrays as Route Parameters

Given that we have a route to create songs for a specific author, and that the `{author}` route parameter uses route model binding to automatically bind to an `Author` model:

```php theme={null}
Route::post('/songs/{artist}', [SongController::class, 'store']);

class SongData extends Data {
    public int $id;
    #[FromRouteParameter('artist')]
    public ArtistData $author;
}
```

Here, the `$artist` property will be filled with the `artist` route parameter value, which will be an instance of the `Artist` model. Note that the package will automatically cast the model to `ArtistData`.

## Filling Properties from Route Parameter Properties

The `FromRouteParameterProperty` attribute allows filling properties with values from route parameter properties. The main difference from `FromRouteParameter` is that the former uses the full route parameter value, while `FromRouteParameterProperty` uses a single property from the route parameter.

In the example below, we're using route model binding. `{song}` represents an instance of the `Song` model. `FromRouteParameterProperty` automatically attempts to fill the `SongData` `$id` property from `$song->id`:

```php theme={null}
Route::patch('/songs/{song}', [SongController::class, 'update']);

class SongData extends Data {
    #[FromRouteParameterProperty('song')]
    public int $id;
    public string $name;
}
```

### Using Custom Property Mapping

In the example below, `$name` property will be filled with `$song->title` (instead of `$song->name`):

```php theme={null}
Route::patch('/songs/{song}', [SongController::class, 'update']);

class SongData extends Data {
    #[FromRouteParameterProperty('song')]
    public int $id;
    #[FromRouteParameterProperty('song', 'title')]
    public string $name;
}
```

### Nested Property Mapping

Nested properties are supported as well. Here, we fill `$singerName` from `$artist->leadSinger->name`:

```php theme={null}
Route::patch('/artists/{artist}/songs/{song}', [SongController::class, 'update']);

class SongData extends Data {
    #[FromRouteParameterProperty('song')]
    public int $id;
    #[FromRouteParameterProperty('artist', 'leadSinger.name')]
    public string $singerName;
}
```

## Route Parameters Take Priority Over Request Body

By default, route parameters take priority over values in the request body. For example, when the song ID is present in the route model as well as request body, the ID from route model is used:

```php theme={null}
Route::patch('/songs/{song}', [SongController::class, 'update']);

// PATCH /songs/123
// { "id": 321, "name": "Never gonna give you up" }

class SongData extends Data {
    #[FromRouteParameterProperty('song')]
    public int $id;
    public string $name;
}
```

Here, `$id` will be `123` even though the request body has `321` as the ID value.

### Allowing Request Body to Override Route Parameters

The above behavior can be turned off by switching the `replaceWhenPresentInPayload` flag off. This can be useful when you *intend* to allow updating a property that is present in a route parameter, such as a slug:

```php theme={null}
Route::patch('/songs/{slug}', [SongController::class, 'update']);

// PATCH /songs/never
// { "slug": "never-gonna-give-you-up", "name": "Never gonna give you up" }

class SongData extends Data {
    #[FromRouteParameter('slug', replaceWhenPresentInPayload: false )]
    public string $slug;
}
```

Here, `$slug` will be `never-gonna-give-you-up` even though the route parameter value is `never`.

## Filling Properties from the Authenticated User

The `FromAuthenticatedUser` attribute allows filling properties with values from the authenticated user:

```php theme={null}
class SongData extends Data {
    #[FromAuthenticatedUser]
    public UserData $user;
}
```

It is possible to specify the guard to use when fetching the user:

```php theme={null}
class SongData extends Data {
    #[FromAuthenticatedUser('api')]
    public UserData $user;
}
```

Just like with route parameters, it is possible to fill properties with specific user properties using `FromAuthenticatedUserProperty`:

```php theme={null}
class SongData extends Data {
    #[FromAuthenticatedUserProperty('api','name')]
    public string $username;
}
```

All the other features like custom property mapping and not replacing values when present in the payload are supported as well.

## Filling Properties from the Container

The `FromContainer` attribute allows filling properties with dependencies from the container:

```php theme={null}
class SongData extends Data {
    #[FromContainer(SongService::class)]
    public SongService $song_service;
}
```

When a dependency requires additional parameters these can be provided as such:

```php theme={null}
class SongData extends Data {
    #[FromContainer(SongService::class, parameters: ['year' => 1984])]
    public SongService $song_service;
}
```

It is even possible to completely inject the container itself:

```php theme={null}
class SongData extends Data {
    #[FromContainer]
    public Container $container;
}
```

Selecting a property from a dependency can be done using `FromContainerProperty`:

```php theme={null}
class SongData extends Data {
    #[FromContainerProperty(SongService::class, 'name')]
    public string $service_name;
}
```

Again, all the other features like custom property mapping and not replacing values when present in the payload are supported as well.

## Creating Your Own Injectable Attributes

All the attributes we saw earlier implement the `InjectsPropertyValue` interface:

```php theme={null}
interface InjectsPropertyValue
{
    public function resolve(
        DataProperty $dataProperty,
        mixed $payload,
        array $properties,
        CreationContext $creationContext
    ): mixed;

    public function shouldBeReplacedWhenPresentInPayload() : bool;
}
```

It is possible to create your own attribute by implementing this interface. The `resolve` method is responsible for returning the value that should be injected into the property. The `shouldBeReplacedWhenPresentInPayload` method should return `true` if the value should be replaced when present in the payload.