Laravel | Validate generated value - laravel

Question

I have an endpoint for data create.
The request is "name". I need to generate "slug" and validate that slug is unique.
So, let's say
book_genres table.
id | name | slug
Request is ["name" => "My first genre"].
I have a custom request with a rule:
"name" => "string|unique:book_genres,name".
I need the same check for the slug.
$slug = str_slug($name);
How can I add this validation to my custom request?
Custom request class:
class BookGenreCreate extends FormRequest
{
public function authorize()
{
return true;
}
public function rules()
{
return [
"name" => 'required|string|unique:book_genres,name',
];
}
}

Answer 1

So basically what you want to do is try to manipulate the request data before validation occurs. You can do this in your FormRequest class by overriding one of the methods that is called before validation occurs. I've found that this works best by overriding getValidatorInstance. You can then grab the existing data, add your slug to it and then replace the data within the request, all before validation occurs:
protected function getValidatorInstance()
{
$data = $this->all();
$data['slug'] = str_slug($data['name']);
$this->getInputSource()->replace($data);
return parent::getValidatorInstance();
}
You can also add the rules for your slug to your rules method as well:
public function rules()
{
return [
"name" => 'required|string|unique:book_genres,name',
"slug" => 'required|string|unique:book_genres,slug',
];
}
So your class will look something like this:
class BookGenreCreate extends FormRequest
{
public function authorize()
{
return true;
}
public function rules()
{
return [
'name' => 'required|string|unique:book_genres,name',
'slug' => 'required|string|unique:book_genres,slug',
];
}
protected function getValidatorInstance()
{
$data = $this->all();
$data['slug'] = str_slug($data['name']);
$this->getInputSource()->replace($data);
return parent::getValidatorInstance();
}
}
Now when the request comes through to your controller, it will have been validated and you can access the slug from the request object:
class YourController extends Controller
{
public function store(BookGenreCreate $request)
{
$slug = $request->input('slug');
// ...
}
}

Answer 2

You can add the 'slug' to the request, then use validations as usual.
rules() {
// set new property 'slug' to the request object.
$this->request->set('slug', str_slug($request->name));
// rules
return [
'name' => 'string|unique:book_genres,name',
'slug' => 'string|unique:book_genres,slug'
]
}