I've seen the following route:

Route::prefix('/users/{user}')->group(function () {
   Route::get('groups/{group}', 'UserGroupController@show');
}

And in UserGroupController:

use App\Group;

    public function show(Request $request, User $user, Group $group)
    {
        dd($group);
    }

My question is how does the $group model object gets constructed here from a raw route parameter string?

My guess is laravel's service container does the following magic (maybe sth like

1. Injecting the Group model,
2. then do sth like Group::where('id', $group)->first()

but unsure about this.

CodePudding user response：

You guess right. There is a binding in the core service provider which retrieves model. The bound model is the same if you would call:

$temp = new Group
$model = Group::where($temp->getRouteKeyName(), request()->route('group'))->firstOrFail();

UPD. Actualy just found where it happens:

    /**
     * Retrieve the model for a bound value.
     *
     * @param  \Illuminate\Database\Eloquent\Model|\Illuminate\Database\Eloquent\Relations\Relation  $query
     * @param  mixed  $value
     * @param  string|null  $field
     * @return \Illuminate\Database\Eloquent\Relations\Relation
     */
    public function resolveRouteBindingQuery($query, $value, $field = null)
    {
        return $query->where($field ?? $this->getRouteKeyName(), $value);
    }