Including relationships

The include query parameter will load any Eloquent relation or relation count on the resulting models. All includes must be explicitly allowed using allowedIncludes(). This method takes an array of relationship names or AllowedInclude instances.

##Basic usage

// GET /users?include=posts

$users = QueryBuilder::for(User::class)
    ->allowedIncludes(['posts'])
    ->get();

// $users will have all their their `posts()` related models loaded

You can load multiple relationships by separating them with a comma:

// GET /users?include=posts,permissions
$users = QueryBuilder::for(User::class)
    ->allowedIncludes(['posts', 'permissions'])
    ->get();

// $users will contain all users with their posts and permissions loaded

##Default includes

There is no way to include relationships by default in this package. Default relationships are built-in to Laravel itself using the with() method on a query:

$users = QueryBuilder::for(User::class)
    ->allowedIncludes(['friends'])
    ->with('posts') // posts will always by included, friends can be requested
    ->withCount('posts')
    ->get();

##Disallowed includes

When trying to include relationships that have not been allowed using allowedIncludes() an InvalidIncludeQuery exception will be thrown. Its exception message contains the allowed includes for reference.

##Nested relationships

You can load nested relationships using the dot . notation:

// GET /users?include=posts.comments,permissions

$users = QueryBuilder::for(User::class)
    ->allowedIncludes(['posts.comments', 'permissions'])
    ->get();

// $users will contain all users with their posts, comments on their posts and permissions loaded

##Including related model count

Every allowed include will automatically allow requesting its related model count using a Count suffix. On top of that it's also possible to specifically allow requesting and querying the related model count (and not include the entire relationship).

Under the hood this uses Laravel's withCount method. Read more about the withCount method here.

// GET /users?include=postsCount,friendsCount

$users = QueryBuilder::for(User::class)
    ->allowedIncludes([
        'posts', // allows including `posts` or `postsCount`
        AllowedInclude::count('friendsCount'), // only allows include the number of `friends()` related models
    ]); 
// every user in $users will contain a `posts_count` and `friends_count` property

##Custom includes

You can specify custom includes using the AllowedInclude::custom() method. Custom includes are instances of invokable classes that implement the \Spatie\QueryBuilder\Includes\IncludeInterface interface. The __invoke method will receive the current query builder instance and the include name. This way you can build any query your heart desires.

For example:

use Spatie\QueryBuilder\Includes\IncludeInterface;
use Illuminate\Database\Eloquent\Builder;
use App\Models\Post;

class AggregateInclude implements IncludeInterface
{
    protected string $column;

    protected string $function;

    public function __construct(string $column, string $function)
    {
        $this->column = $column;

        $this->function = $function;
    }

    public function __invoke(Builder $query, string $relations)
    {
        $query->withAggregate($relations, $this->column, $this->function);
    }
}

// In your controller for the following request:
// GET /posts?include=comments_sum_votes

$posts = QueryBuilder::for(Post::class)
    ->allowedIncludes([
        AllowedInclude::custom('comments_sum_votes', new AggregateInclude('votes', 'sum'), 'comments'),
    ])
    ->get();

// every post in $posts will contain a `comments_sum_votes` property

##Selecting included fields

You can select only some fields to be included using the allowedFields method on the query builder.

⚠️ allowedFields must be called before allowedIncludes. Otherwise the query builder wont know what fields to include for the requested includes and an exception will be thrown.

##Include casing

Relation/include names will be converted to camelCase when looking for the corresponding relationship on the model. This means /users?include=blog-posts and /users?include=blogPosts will both try to load the blogPosts() relationship.

##Eloquent API resources

Once the relationships are included, we'd recommend including them in your response by using Eloquent API resources and conditional relationships.